Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

64 files changed, 50472 insertions, 0 deletions

diff --git a/src/fmt/test/CMakeLists.txt b/src/fmt/test/CMakeLists.txt
new file mode 100644
index 000000000..971637859
--- /dev/null
+++ b/src/fmt/test/CMakeLists.txt
@@ -0,0 +1,245 @@
+add_subdirectory(gtest)
+
+set(TEST_MAIN_SRC test-main.cc gtest-extra.cc gtest-extra.h util.cc)
+add_library(test-main STATIC ${TEST_MAIN_SRC})
+target_include_directories(test-main PUBLIC
+  $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>)
+target_link_libraries(test-main gtest fmt)
+
+function(add_fmt_executable name)
+  add_executable(${name} ${ARGN})
+  # (Wstringop-overflow) - [meta-bug] bogus/missing -Wstringop-overflow warnings
+  #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88443
+  # Bogus -Wstringop-overflow warning
+  #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100395
+  # [10 Regression] spurious -Wstringop-overflow writing to a trailing array plus offset
+  #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95353
+  if (CMAKE_CXX_COMPILER_ID MATCHES "GNU" AND
+      NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 7.0)
+    target_compile_options(${name} PRIVATE -Wno-stringop-overflow)
+    # The linker flag is needed for LTO.
+    target_link_libraries(${name} -Wno-stringop-overflow)
+  endif ()
+endfunction()
+
+# Adds a test.
+# Usage: add_fmt_test(name srcs...)
+function(add_fmt_test name)
+  cmake_parse_arguments(ADD_FMT_TEST "HEADER_ONLY;MODULE" "" "" ${ARGN})
+
+  set(sources ${name}.cc ${ADD_FMT_TEST_UNPARSED_ARGUMENTS})
+  if (ADD_FMT_TEST_HEADER_ONLY)
+    set(sources ${sources} ${TEST_MAIN_SRC} ../src/os.cc)
+    set(libs gtest fmt-header-only)
+    if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+      set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wno-weak-vtables)
+    endif ()
+  elseif (ADD_FMT_TEST_MODULE)
+    set(libs gtest test-module)
+    set_source_files_properties(${name}.cc PROPERTIES OBJECT_DEPENDS test-module)
+  else ()
+    set(libs test-main fmt)
+  endif ()
+  add_fmt_executable(${name} ${sources})
+  target_link_libraries(${name} ${libs})
+
+  # Define if certain C++ features can be used.
+  if (FMT_PEDANTIC)
+    target_compile_options(${name} PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+  endif ()
+  if (FMT_WERROR)
+    target_compile_options(${name} PRIVATE ${WERROR_FLAG})
+  endif ()
+  add_test(NAME ${name} COMMAND ${name})
+endfunction()
+
+add_fmt_test(args-test)
+add_fmt_test(assert-test)
+add_fmt_test(chrono-test)
+add_fmt_test(color-test)
+add_fmt_test(core-test)
+add_fmt_test(gtest-extra-test)
+add_fmt_test(format-test mock-allocator.h)
+if (MSVC)
+  target_compile_options(format-test PRIVATE /bigobj)
+endif ()
+if (NOT (MSVC AND BUILD_SHARED_LIBS))
+  add_fmt_test(format-impl-test HEADER_ONLY header-only-test.cc)
+endif ()
+add_fmt_test(ostream-test)
+add_fmt_test(compile-test)
+add_fmt_test(compile-fp-test HEADER_ONLY)
+if (MSVC)
+  # Without this option, MSVC returns 199711L for the __cplusplus macro.
+  target_compile_options(compile-fp-test PRIVATE /Zc:__cplusplus)
+endif()
+add_fmt_test(printf-test)
+add_fmt_test(ranges-test ranges-odr-test.cc)
+add_fmt_test(scan-test)
+add_fmt_test(std-test)
+try_compile(compile_result_unused
+            ${CMAKE_CURRENT_BINARY_DIR}
+            SOURCES ${CMAKE_CURRENT_LIST_DIR}/detect-stdfs.cc
+            OUTPUT_VARIABLE RAWOUTPUT)
+string(REGEX REPLACE ".*libfound \"([^\"]*)\".*" "\\1" STDLIBFS "${RAWOUTPUT}")
+if (STDLIBFS)
+  target_link_libraries(std-test ${STDLIBFS})
+endif ()
+add_fmt_test(unicode-test HEADER_ONLY)
+if (MSVC)
+  target_compile_options(unicode-test PRIVATE /utf-8)
+endif ()
+add_fmt_test(xchar-test)
+add_fmt_test(enforce-checks-test)
+target_compile_definitions(enforce-checks-test PRIVATE
+                           -DFMT_ENFORCE_COMPILE_STRING)
+
+if (FMT_CAN_MODULE)
+  # The tests need {fmt} to be compiled as traditional library
+  # because of visibility of implementation details.
+  # If module support is present the module tests require a
+  # test-only module to be built from {fmt}
+  add_library(test-module OBJECT ${CMAKE_SOURCE_DIR}/src/fmt.cc)
+  target_compile_features(test-module PUBLIC ${FMT_REQUIRED_FEATURES})
+  target_include_directories(test-module PUBLIC
+    $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>)
+  enable_module(test-module)
+
+  add_fmt_test(module-test MODULE test-main.cc)
+  if (MSVC)
+    target_compile_options(test-module PRIVATE /utf-8 /Zc:__cplusplus
+                           /Zc:externConstexpr /Zc:inline)
+    target_compile_options(module-test PRIVATE /utf-8 /Zc:__cplusplus
+                           /Zc:externConstexpr /Zc:inline)
+  endif ()
+endif ()
+
+if (NOT DEFINED MSVC_STATIC_RUNTIME AND MSVC)
+  foreach (flag_var
+			 CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
+			 CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
+	if (${flag_var} MATCHES "^(/|-)(MT|MTd)")
+	  set(MSVC_STATIC_RUNTIME ON)
+	  break()
+	endif()
+  endforeach()
+endif()
+
+if (NOT MSVC_STATIC_RUNTIME)
+  add_fmt_executable(posix-mock-test
+    posix-mock-test.cc ../src/format.cc ${TEST_MAIN_SRC})
+  target_include_directories(
+    posix-mock-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
+  target_link_libraries(posix-mock-test gtest)
+  if (FMT_PEDANTIC)
+    target_compile_options(posix-mock-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+  endif ()
+  add_test(NAME posix-mock-test COMMAND posix-mock-test)
+  add_fmt_test(os-test)
+endif ()
+
+message(STATUS "FMT_PEDANTIC: ${FMT_PEDANTIC}")
+
+if (FMT_PEDANTIC)
+  # Test that the library can be compiled with exceptions disabled.
+  # -fno-exception is broken in icc: https://github.com/fmtlib/fmt/issues/822.
+  if (NOT CMAKE_CXX_COMPILER_ID STREQUAL "Intel")
+    check_cxx_compiler_flag(-fno-exceptions HAVE_FNO_EXCEPTIONS_FLAG)
+  endif ()
+  if (HAVE_FNO_EXCEPTIONS_FLAG)
+    add_library(noexception-test ../src/format.cc noexception-test.cc)
+    target_include_directories(
+      noexception-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
+    target_compile_options(noexception-test PRIVATE -fno-exceptions)
+    target_compile_options(noexception-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+  endif ()
+
+  # Test that the library compiles without locale.
+  add_library(nolocale-test ../src/format.cc)
+  target_include_directories(
+    nolocale-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
+  target_compile_definitions(
+    nolocale-test PRIVATE FMT_STATIC_THOUSANDS_SEPARATOR=1)
+endif ()
+
+# These tests are disabled on Windows because they take too long.
+if (FMT_PEDANTIC AND NOT WIN32)
+  # Test if incorrect API usages produce compilation error.
+  add_test(compile-error-test ${CMAKE_CTEST_COMMAND}
+    --build-and-test
+    "${CMAKE_CURRENT_SOURCE_DIR}/compile-error-test"
+    "${CMAKE_CURRENT_BINARY_DIR}/compile-error-test"
+    --build-generator ${CMAKE_GENERATOR}
+    --build-makeprogram ${CMAKE_MAKE_PROGRAM}
+    --build-options
+    "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+    "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
+    "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+    "-DCXX_STANDARD_FLAG=${CXX_STANDARD_FLAG}"
+    "-DFMT_DIR=${CMAKE_SOURCE_DIR}")
+
+  # Test if the targets are found from the build directory.
+  add_test(find-package-test ${CMAKE_CTEST_COMMAND}
+    -C ${CMAKE_BUILD_TYPE}
+    --build-and-test
+    "${CMAKE_CURRENT_SOURCE_DIR}/find-package-test"
+    "${CMAKE_CURRENT_BINARY_DIR}/find-package-test"
+    --build-generator ${CMAKE_GENERATOR}
+    --build-makeprogram ${CMAKE_MAKE_PROGRAM}
+    --build-options
+    "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+    "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
+    "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+    "-DFMT_DIR=${PROJECT_BINARY_DIR}"
+    "-DPEDANTIC_COMPILE_FLAGS=${PEDANTIC_COMPILE_FLAGS}"
+    "-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}")
+
+  # Test if the targets are found when add_subdirectory is used.
+  add_test(add-subdirectory-test ${CMAKE_CTEST_COMMAND}
+    -C ${CMAKE_BUILD_TYPE}
+    --build-and-test
+    "${CMAKE_CURRENT_SOURCE_DIR}/add-subdirectory-test"
+    "${CMAKE_CURRENT_BINARY_DIR}/add-subdirectory-test"
+    --build-generator ${CMAKE_GENERATOR}
+    --build-makeprogram ${CMAKE_MAKE_PROGRAM}
+    --build-options
+    "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+    "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+    "-DPEDANTIC_COMPILE_FLAGS=${PEDANTIC_COMPILE_FLAGS}"
+    "-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}")
+endif ()
+
+# This test are disabled on Windows because it is only *NIX issue.
+if (FMT_PEDANTIC AND NOT WIN32)
+  add_test(static-export-test ${CMAKE_CTEST_COMMAND}
+    -C ${CMAKE_BUILD_TYPE}
+    --build-and-test
+    "${CMAKE_CURRENT_SOURCE_DIR}/static-export-test"
+    "${CMAKE_CURRENT_BINARY_DIR}/static-export-test"
+    --build-generator ${CMAKE_GENERATOR}
+    --build-makeprogram ${CMAKE_MAKE_PROGRAM}
+    --build-options
+    "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+    "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+    "-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}")
+endif ()
+
+# Activate optional CUDA tests if CUDA is found. For version selection see
+# https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#cpp14-language-features
+if (FMT_CUDA_TEST)
+  if (${CMAKE_VERSION} VERSION_LESS 3.15)
+    find_package(CUDA 9.0)
+  else ()
+    include(CheckLanguage)
+    check_language(CUDA)
+    if (CMAKE_CUDA_COMPILER)
+      enable_language(CUDA OPTIONAL)
+      set(CUDA_FOUND TRUE)
+    endif ()
+  endif ()
+
+  if (CUDA_FOUND)
+    add_subdirectory(cuda-test)
+    add_test(NAME cuda-test COMMAND fmt-in-cuda-test)
+  endif ()
+endif ()
diff --git a/src/fmt/test/add-subdirectory-test/CMakeLists.txt b/src/fmt/test/add-subdirectory-test/CMakeLists.txt
new file mode 100644
index 000000000..e08d0cf70
--- /dev/null
+++ b/src/fmt/test/add-subdirectory-test/CMakeLists.txt
@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.1...3.18)
+
+project(fmt-test CXX)
+
+add_subdirectory(../.. fmt)
+
+add_executable(library-test main.cc)
+target_include_directories(library-test PUBLIC SYSTEM .)
+target_compile_options(library-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+target_link_libraries(library-test fmt::fmt)
+
+if (TARGET fmt::fmt-header-only)
+  add_executable(header-only-test main.cc)
+  target_include_directories(header-only-test PUBLIC SYSTEM .)
+  target_compile_options(header-only-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+  target_link_libraries(header-only-test fmt::fmt-header-only)
+endif ()
diff --git a/src/fmt/test/add-subdirectory-test/main.cc b/src/fmt/test/add-subdirectory-test/main.cc
new file mode 100644
index 000000000..fcdf232e0
--- /dev/null
+++ b/src/fmt/test/add-subdirectory-test/main.cc
@@ -0,0 +1,5 @@
+#include "fmt/core.h"
+
+int main(int argc, char** argv) {
+  for (int i = 0; i < argc; ++i) fmt::print("{}: {}\n", i, argv[i]);
+}
diff --git a/src/fmt/test/args-test.cc b/src/fmt/test/args-test.cc
new file mode 100644
index 000000000..aa01fa4e0
--- /dev/null
+++ b/src/fmt/test/args-test.cc
@@ -0,0 +1,186 @@
+// Formatting library for C++ - dynamic argument store tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/args.h"
+
+#include <memory>
+
+#include "gtest/gtest.h"
+
+TEST(args_test, basic) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(42);
+  store.push_back("abc1");
+  store.push_back(1.5f);
+  EXPECT_EQ("42 and abc1 and 1.5", fmt::vformat("{} and {} and {}", store));
+}
+
+TEST(args_test, strings_and_refs) {
+  // Unfortunately the tests are compiled with old ABI so strings use COW.
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  char str[] = "1234567890";
+  store.push_back(str);
+  store.push_back(std::cref(str));
+  store.push_back(fmt::string_view{str});
+  str[0] = 'X';
+
+  auto result = fmt::vformat("{} and {} and {}", store);
+  EXPECT_EQ("1234567890 and X234567890 and X234567890", result);
+}
+
+struct custom_type {
+  int i = 0;
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<custom_type> {
+  auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const custom_type& p, FormatContext& ctx) -> decltype(ctx.out()) {
+    return format_to(ctx.out(), "cust={}", p.i);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(args_test, custom_format) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  auto c = custom_type();
+  store.push_back(c);
+  ++c.i;
+  store.push_back(c);
+  ++c.i;
+  store.push_back(std::cref(c));
+  ++c.i;
+  auto result = fmt::vformat("{} and {} and {}", store);
+  EXPECT_EQ("cust=0 and cust=1 and cust=3", result);
+}
+
+struct to_stringable {
+  friend fmt::string_view to_string_view(to_stringable) { return {}; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<to_stringable> {
+  auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  auto format(to_stringable, format_context& ctx) -> decltype(ctx.out()) {
+    return ctx.out();
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(args_test, to_string_and_formatter) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  auto s = to_stringable();
+  store.push_back(s);
+  store.push_back(std::cref(s));
+  fmt::vformat("", store);
+}
+
+TEST(args_test, named_int) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(fmt::arg("a1", 42));
+  EXPECT_EQ("42", fmt::vformat("{a1}", store));
+}
+
+TEST(args_test, named_strings) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  char str[] = "1234567890";
+  store.push_back(fmt::arg("a1", str));
+  store.push_back(fmt::arg("a2", std::cref(str)));
+  str[0] = 'X';
+  EXPECT_EQ("1234567890 and X234567890", fmt::vformat("{a1} and {a2}", store));
+}
+
+TEST(args_test, named_arg_by_ref) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  char band[] = "Rolling Stones";
+  store.push_back(fmt::arg("band", std::cref(band)));
+  band[9] = 'c';  // Changing band affects the output.
+  EXPECT_EQ(fmt::vformat("{band}", store), "Rolling Scones");
+}
+
+TEST(args_test, named_custom_format) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  auto c = custom_type();
+  store.push_back(fmt::arg("c1", c));
+  ++c.i;
+  store.push_back(fmt::arg("c2", c));
+  ++c.i;
+  store.push_back(fmt::arg("c_ref", std::cref(c)));
+  ++c.i;
+  auto result = fmt::vformat("{c1} and {c2} and {c_ref}", store);
+  EXPECT_EQ("cust=0 and cust=1 and cust=3", result);
+}
+
+TEST(args_test, clear) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(42);
+
+  auto result = fmt::vformat("{}", store);
+  EXPECT_EQ("42", result);
+
+  store.push_back(43);
+  result = fmt::vformat("{} and {}", store);
+  EXPECT_EQ("42 and 43", result);
+
+  store.clear();
+  store.push_back(44);
+  result = fmt::vformat("{}", store);
+  EXPECT_EQ("44", result);
+}
+
+TEST(args_test, reserve) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.reserve(2, 1);
+  store.push_back(1.5f);
+  store.push_back(fmt::arg("a1", 42));
+  auto result = fmt::vformat("{a1} and {}", store);
+  EXPECT_EQ("42 and 1.5", result);
+}
+
+struct copy_throwable {
+  copy_throwable() {}
+  copy_throwable(const copy_throwable&) { throw "deal with it"; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<copy_throwable> {
+  auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+  auto format(copy_throwable, format_context& ctx) -> decltype(ctx.out()) {
+    return ctx.out();
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(args_test, throw_on_copy) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(std::string("foo"));
+  try {
+    store.push_back(copy_throwable());
+  } catch (...) {
+  }
+  EXPECT_EQ(fmt::vformat("{}", store), "foo");
+}
+
+TEST(args_test, move_constructor) {
+  using store_type = fmt::dynamic_format_arg_store<fmt::format_context>;
+  auto store = std::unique_ptr<store_type>(new store_type());
+  store->push_back(42);
+  store->push_back(std::string("foo"));
+  store->push_back(fmt::arg("a1", "foo"));
+  auto moved_store = std::move(*store);
+  store.reset();
+  EXPECT_EQ(fmt::vformat("{} {} {a1}", moved_store), "42 foo foo");
+}
diff --git a/src/fmt/test/assert-test.cc b/src/fmt/test/assert-test.cc
new file mode 100644
index 000000000..c74e617e6
--- /dev/null
+++ b/src/fmt/test/assert-test.cc
@@ -0,0 +1,31 @@
+// Formatting library for C++ - FMT_ASSERT test
+//
+// It is a separate test to minimize the number of EXPECT_DEBUG_DEATH checks
+// which are slow on some platforms. In other tests FMT_ASSERT is made to throw
+// an exception which is much faster and easier to check.
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/core.h"
+#include "gtest/gtest.h"
+
+TEST(assert_test, fail) {
+#if GTEST_HAS_DEATH_TEST
+  EXPECT_DEBUG_DEATH(FMT_ASSERT(false, "don't panic!"), "don't panic!");
+#else
+  fmt::print("warning: death tests are not supported\n");
+#endif
+}
+
+TEST(assert_test, dangling_else) {
+  bool test_condition = false;
+  bool executed_else = false;
+  if (test_condition)
+    FMT_ASSERT(true, "");
+  else
+    executed_else = true;
+  EXPECT_TRUE(executed_else);
+}
diff --git a/src/fmt/test/chrono-test.cc b/src/fmt/test/chrono-test.cc
new file mode 100644
index 000000000..0f2a2498e
--- /dev/null
+++ b/src/fmt/test/chrono-test.cc
@@ -0,0 +1,643 @@
+// Formatting library for C++ - time formatting tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/chrono.h"
+
+#include <ctime>
+#include <vector>
+
+#include "gtest-extra.h"  // EXPECT_THROW_MSG
+#include "util.h"         // get_locale
+
+using fmt::runtime;
+
+using testing::Contains;
+
+auto make_tm() -> std::tm {
+  auto time = std::tm();
+  time.tm_mday = 1;
+  return time;
+}
+
+auto make_hour(int h) -> std::tm {
+  auto time = make_tm();
+  time.tm_hour = h;
+  return time;
+}
+
+auto make_minute(int m) -> std::tm {
+  auto time = make_tm();
+  time.tm_min = m;
+  return time;
+}
+
+auto make_second(int s) -> std::tm {
+  auto time = make_tm();
+  time.tm_sec = s;
+  return time;
+}
+
+std::string system_strftime(const std::string& format, const std::tm* timeptr,
+                            std::locale* locptr = nullptr) {
+  auto loc = locptr ? *locptr : std::locale::classic();
+  auto& facet = std::use_facet<std::time_put<char>>(loc);
+  std::ostringstream os;
+  os.imbue(loc);
+  facet.put(os, os, ' ', timeptr, format.c_str(),
+            format.c_str() + format.size());
+#ifdef _WIN32
+  // Workaround a bug in older versions of Universal CRT.
+  auto str = os.str();
+  if (str == "-0000") str = "+0000";
+  return str;
+#else
+  return os.str();
+#endif
+}
+
+FMT_CONSTEXPR std::tm make_tm(int year, int mon, int mday, int hour, int min,
+                              int sec) {
+  auto tm = std::tm();
+  tm.tm_sec = sec;
+  tm.tm_min = min;
+  tm.tm_hour = hour;
+  tm.tm_mday = mday;
+  tm.tm_mon = mon - 1;
+  tm.tm_year = year - 1900;
+  return tm;
+}
+
+TEST(chrono_test, format_tm) {
+  auto tm = std::tm();
+  tm.tm_year = 116;
+  tm.tm_mon = 3;
+  tm.tm_mday = 25;
+  tm.tm_hour = 11;
+  tm.tm_min = 22;
+  tm.tm_sec = 33;
+  EXPECT_EQ(fmt::format("The date is {:%Y-%m-%d %H:%M:%S}.", tm),
+            "The date is 2016-04-25 11:22:33.");
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "2016");
+  EXPECT_EQ(fmt::format("{:%C}", tm), "20");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+  EXPECT_EQ(fmt::format("{:%e}", tm), "25");
+  EXPECT_EQ(fmt::format("{:%D}", tm), "04/25/16");
+  EXPECT_EQ(fmt::format("{:%F}", tm), "2016-04-25");
+  EXPECT_EQ(fmt::format("{:%T}", tm), "11:22:33");
+
+  // Short year
+  tm.tm_year = 999 - 1900;
+  tm.tm_mon = 0;   // for %G
+  tm.tm_mday = 2;  // for %G
+  tm.tm_wday = 3;  // for %G
+  tm.tm_yday = 1;  // for %G
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "0999");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), "0999");
+  EXPECT_EQ(fmt::format("{:%G}", tm), "0999");
+
+  tm.tm_year = 27 - 1900;
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "0027");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), "0027");
+
+  // Overflow year
+  tm.tm_year = 2147483647;
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "2147485547");
+
+  tm.tm_year = -2147483648;
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "-2147481748");
+
+  // for week on the year
+  // https://www.cl.cam.ac.uk/~mgk25/iso-time.html
+  std::vector<std::tm> tm_list = {
+      make_tm(1975, 12, 29, 12, 14, 16),  // W01
+      make_tm(1977, 1, 2, 12, 14, 16),    // W53
+      make_tm(1999, 12, 27, 12, 14, 16),  // W52
+      make_tm(1999, 12, 31, 12, 14, 16),  // W52
+      make_tm(2000, 1, 1, 12, 14, 16),    // W52
+      make_tm(2000, 1, 2, 12, 14, 16),    // W52
+      make_tm(2000, 1, 3, 12, 14, 16)     // W1
+  };
+
+#if defined(__MINGW32__) && !defined(_UCRT)
+  GTEST_SKIP() << "Skip the rest of this test because it relies on strftime() "
+                  "conforming to C99, but on this platform, MINGW + MSVCRT, "
+                  "the function conforms only to C89.";
+#endif
+
+  const std::string iso_week_spec = "%Y-%m-%d: %G %g %V";
+  for (auto ctm : tm_list) {
+    // Calculate tm_yday, tm_wday, etc.
+    std::time_t t = std::mktime(&ctm);
+    tm = *std::localtime(&t);
+
+    auto fmt_spec = fmt::format("{{:{}}}", iso_week_spec);
+    EXPECT_EQ(system_strftime(iso_week_spec, &tm),
+              fmt::format(fmt::runtime(fmt_spec), tm));
+  }
+
+  // Every day from 1970-01-01
+  std::time_t time_now = std::time(nullptr);
+  for (std::time_t t = 6 * 3600; t < time_now; t += 86400) {
+    tm = *std::localtime(&t);
+
+    auto fmt_spec = fmt::format("{{:{}}}", iso_week_spec);
+    EXPECT_EQ(system_strftime(iso_week_spec, &tm),
+              fmt::format(fmt::runtime(fmt_spec), tm));
+  }
+}
+
+// MSVC:
+//  minkernel\crts\ucrt\src\appcrt\time\wcsftime.cpp(971) : Assertion failed:
+//  timeptr->tm_year >= -1900 && timeptr->tm_year <= 8099
+#ifndef _WIN32
+TEST(chrono_test, format_tm_future) {
+  auto tm = std::tm();
+  tm.tm_year = 10445;  // 10000+ years
+  tm.tm_mon = 3;
+  tm.tm_mday = 25;
+  tm.tm_hour = 11;
+  tm.tm_min = 22;
+  tm.tm_sec = 33;
+  EXPECT_EQ(fmt::format("The date is {:%Y-%m-%d %H:%M:%S}.", tm),
+            "The date is 12345-04-25 11:22:33.");
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "12345");
+  EXPECT_EQ(fmt::format("{:%C}", tm), "123");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+  EXPECT_EQ(fmt::format("{:%D}", tm), "04/25/45");
+  EXPECT_EQ(fmt::format("{:%F}", tm), "12345-04-25");
+  EXPECT_EQ(fmt::format("{:%T}", tm), "11:22:33");
+}
+
+TEST(chrono_test, format_tm_past) {
+  auto tm = std::tm();
+  tm.tm_year = -2001;
+  tm.tm_mon = 3;
+  tm.tm_mday = 25;
+  tm.tm_hour = 11;
+  tm.tm_min = 22;
+  tm.tm_sec = 33;
+  EXPECT_EQ(fmt::format("The date is {:%Y-%m-%d %H:%M:%S}.", tm),
+            "The date is -101-04-25 11:22:33.");
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "-101");
+
+  // macOS  %C - "-1"
+  // Linux  %C - "-2"
+  // fmt    %C - "-1"
+  EXPECT_EQ(fmt::format("{:%C}", tm), "-1");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+
+  // macOS  %D - "04/25/01" (%y)
+  // Linux  %D - "04/25/99" (%y)
+  // fmt    %D - "04/25/01" (%y)
+  EXPECT_EQ(fmt::format("{:%D}", tm), "04/25/01");
+
+  EXPECT_EQ(fmt::format("{:%F}", tm), "-101-04-25");
+  EXPECT_EQ(fmt::format("{:%T}", tm), "11:22:33");
+
+  tm.tm_year = -1901;  // -1
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "-001");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+
+  tm.tm_year = -1911;  // -11
+  EXPECT_EQ(fmt::format("{:%Y}", tm), "-011");
+  EXPECT_EQ(fmt::format("{:%C%y}", tm), fmt::format("{:%Y}", tm));
+}
+#endif
+
+TEST(chrono_test, grow_buffer) {
+  auto s = std::string("{:");
+  for (int i = 0; i < 30; ++i) s += "%c";
+  s += "}\n";
+  auto t = std::time(nullptr);
+  (void)fmt::format(fmt::runtime(s), *std::localtime(&t));
+}
+
+TEST(chrono_test, format_to_empty_container) {
+  auto time = std::tm();
+  time.tm_sec = 42;
+  auto s = std::string();
+  fmt::format_to(std::back_inserter(s), "{:%S}", time);
+  EXPECT_EQ(s, "42");
+}
+
+TEST(chrono_test, empty_result) { EXPECT_EQ(fmt::format("{}", std::tm()), ""); }
+
+auto equal(const std::tm& lhs, const std::tm& rhs) -> bool {
+  return lhs.tm_sec == rhs.tm_sec && lhs.tm_min == rhs.tm_min &&
+         lhs.tm_hour == rhs.tm_hour && lhs.tm_mday == rhs.tm_mday &&
+         lhs.tm_mon == rhs.tm_mon && lhs.tm_year == rhs.tm_year &&
+         lhs.tm_wday == rhs.tm_wday && lhs.tm_yday == rhs.tm_yday &&
+         lhs.tm_isdst == rhs.tm_isdst;
+}
+
+TEST(chrono_test, localtime) {
+  auto t = std::time(nullptr);
+  auto tm = *std::localtime(&t);
+  EXPECT_TRUE(equal(tm, fmt::localtime(t)));
+}
+
+TEST(chrono_test, gmtime) {
+  auto t = std::time(nullptr);
+  auto tm = *std::gmtime(&t);
+  EXPECT_TRUE(equal(tm, fmt::gmtime(t)));
+}
+
+template <typename TimePoint> auto strftime_full(TimePoint tp) -> std::string {
+  auto t = std::chrono::system_clock::to_time_t(tp);
+  auto tm = *std::localtime(&t);
+  return system_strftime("%Y-%m-%d %H:%M:%S", &tm);
+}
+
+TEST(chrono_test, time_point) {
+  auto t1 = std::chrono::system_clock::now();
+  EXPECT_EQ(strftime_full(t1), fmt::format("{:%Y-%m-%d %H:%M:%S}", t1));
+  EXPECT_EQ(strftime_full(t1), fmt::format("{}", t1));
+  using time_point =
+      std::chrono::time_point<std::chrono::system_clock, std::chrono::seconds>;
+  auto t2 = time_point(std::chrono::seconds(42));
+  EXPECT_EQ(strftime_full(t2), fmt::format("{:%Y-%m-%d %H:%M:%S}", t2));
+
+  std::vector<std::string> spec_list = {
+      "%%",  "%n",  "%t",  "%Y",  "%EY", "%y",  "%Oy", "%Ey", "%C",
+      "%EC", "%G",  "%g",  "%b",  "%h",  "%B",  "%m",  "%Om", "%U",
+      "%OU", "%W",  "%OW", "%V",  "%OV", "%j",  "%d",  "%Od", "%e",
+      "%Oe", "%a",  "%A",  "%w",  "%Ow", "%u",  "%Ou", "%H",  "%OH",
+      "%I",  "%OI", "%M",  "%OM", "%S",  "%OS", "%x",  "%Ex", "%X",
+      "%EX", "%D",  "%F",  "%R",  "%T",  "%p",  "%z",  "%Z"};
+#ifndef _WIN32
+  // Disabled on Windows because these formats are not consistent among
+  // platforms.
+  spec_list.insert(spec_list.end(), {"%c", "%Ec", "%r"});
+#elif defined(__MINGW32__) && !defined(_UCRT)
+  // Only C89 conversion specifiers when using MSVCRT instead of UCRT
+  spec_list = {"%%", "%Y", "%y", "%b", "%B", "%m", "%U", "%W", "%j", "%d", "%a",
+               "%A", "%w", "%H", "%I", "%M", "%S", "%x", "%X", "%p", "%Z"};
+#endif
+  spec_list.push_back("%Y-%m-%d %H:%M:%S");
+
+  for (const auto& spec : spec_list) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::localtime(&t);
+
+    auto sys_output = system_strftime(spec, &tm);
+
+    auto fmt_spec = fmt::format("{{:{}}}", spec);
+    EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), t1));
+    EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), tm));
+  }
+}
+
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+
+TEST(chrono_test, format_default) {
+  EXPECT_EQ("42s", fmt::format("{}", std::chrono::seconds(42)));
+  EXPECT_EQ("42as",
+            fmt::format("{}", std::chrono::duration<int, std::atto>(42)));
+  EXPECT_EQ("42fs",
+            fmt::format("{}", std::chrono::duration<int, std::femto>(42)));
+  EXPECT_EQ("42ps",
+            fmt::format("{}", std::chrono::duration<int, std::pico>(42)));
+  EXPECT_EQ("42ns", fmt::format("{}", std::chrono::nanoseconds(42)));
+  EXPECT_EQ("42µs", fmt::format("{}", std::chrono::microseconds(42)));
+  EXPECT_EQ("42ms", fmt::format("{}", std::chrono::milliseconds(42)));
+  EXPECT_EQ("42cs",
+            fmt::format("{}", std::chrono::duration<int, std::centi>(42)));
+  EXPECT_EQ("42ds",
+            fmt::format("{}", std::chrono::duration<int, std::deci>(42)));
+  EXPECT_EQ("42s", fmt::format("{}", std::chrono::seconds(42)));
+  EXPECT_EQ("42das",
+            fmt::format("{}", std::chrono::duration<int, std::deca>(42)));
+  EXPECT_EQ("42hs",
+            fmt::format("{}", std::chrono::duration<int, std::hecto>(42)));
+  EXPECT_EQ("42ks",
+            fmt::format("{}", std::chrono::duration<int, std::kilo>(42)));
+  EXPECT_EQ("42Ms",
+            fmt::format("{}", std::chrono::duration<int, std::mega>(42)));
+  EXPECT_EQ("42Gs",
+            fmt::format("{}", std::chrono::duration<int, std::giga>(42)));
+  EXPECT_EQ("42Ts",
+            fmt::format("{}", std::chrono::duration<int, std::tera>(42)));
+  EXPECT_EQ("42Ps",
+            fmt::format("{}", std::chrono::duration<int, std::peta>(42)));
+  EXPECT_EQ("42Es",
+            fmt::format("{}", std::chrono::duration<int, std::exa>(42)));
+  EXPECT_EQ("42m", fmt::format("{}", std::chrono::minutes(42)));
+  EXPECT_EQ("42h", fmt::format("{}", std::chrono::hours(42)));
+  EXPECT_EQ(
+      "42[15]s",
+      fmt::format("{}", std::chrono::duration<int, std::ratio<15, 1>>(42)));
+  EXPECT_EQ(
+      "42[15/4]s",
+      fmt::format("{}", std::chrono::duration<int, std::ratio<15, 4>>(42)));
+}
+
+TEST(chrono_test, align) {
+  auto s = std::chrono::seconds(42);
+  EXPECT_EQ("42s  ", fmt::format("{:5}", s));
+  EXPECT_EQ("42s  ", fmt::format("{:{}}", s, 5));
+  EXPECT_EQ("  42s", fmt::format("{:>5}", s));
+  EXPECT_EQ("**42s**", fmt::format("{:*^7}", s));
+  EXPECT_EQ("03:25:45    ",
+            fmt::format("{:12%H:%M:%S}", std::chrono::seconds(12345)));
+  EXPECT_EQ("    03:25:45",
+            fmt::format("{:>12%H:%M:%S}", std::chrono::seconds(12345)));
+  EXPECT_EQ("~~03:25:45~~",
+            fmt::format("{:~^12%H:%M:%S}", std::chrono::seconds(12345)));
+  EXPECT_EQ("03:25:45    ",
+            fmt::format("{:{}%H:%M:%S}", std::chrono::seconds(12345), 12));
+}
+
+TEST(chrono_test, format_specs) {
+  EXPECT_EQ("%", fmt::format("{:%%}", std::chrono::seconds(0)));
+  EXPECT_EQ("\n", fmt::format("{:%n}", std::chrono::seconds(0)));
+  EXPECT_EQ("\t", fmt::format("{:%t}", std::chrono::seconds(0)));
+  EXPECT_EQ("00", fmt::format("{:%S}", std::chrono::seconds(0)));
+  EXPECT_EQ("00", fmt::format("{:%S}", std::chrono::seconds(60)));
+  EXPECT_EQ("42", fmt::format("{:%S}", std::chrono::seconds(42)));
+  EXPECT_EQ("01.234", fmt::format("{:%S}", std::chrono::milliseconds(1234)));
+  EXPECT_EQ("00", fmt::format("{:%M}", std::chrono::minutes(0)));
+  EXPECT_EQ("00", fmt::format("{:%M}", std::chrono::minutes(60)));
+  EXPECT_EQ("42", fmt::format("{:%M}", std::chrono::minutes(42)));
+  EXPECT_EQ("01", fmt::format("{:%M}", std::chrono::seconds(61)));
+  EXPECT_EQ("00", fmt::format("{:%H}", std::chrono::hours(0)));
+  EXPECT_EQ("00", fmt::format("{:%H}", std::chrono::hours(24)));
+  EXPECT_EQ("14", fmt::format("{:%H}", std::chrono::hours(14)));
+  EXPECT_EQ("01", fmt::format("{:%H}", std::chrono::minutes(61)));
+  EXPECT_EQ("12", fmt::format("{:%I}", std::chrono::hours(0)));
+  EXPECT_EQ("12", fmt::format("{:%I}", std::chrono::hours(12)));
+  EXPECT_EQ("12", fmt::format("{:%I}", std::chrono::hours(24)));
+  EXPECT_EQ("04", fmt::format("{:%I}", std::chrono::hours(4)));
+  EXPECT_EQ("02", fmt::format("{:%I}", std::chrono::hours(14)));
+  EXPECT_EQ("03:25:45",
+            fmt::format("{:%H:%M:%S}", std::chrono::seconds(12345)));
+  EXPECT_EQ("03:25", fmt::format("{:%R}", std::chrono::seconds(12345)));
+  EXPECT_EQ("03:25:45", fmt::format("{:%T}", std::chrono::seconds(12345)));
+  EXPECT_EQ("12345", fmt::format("{:%Q}", std::chrono::seconds(12345)));
+  EXPECT_EQ("s", fmt::format("{:%q}", std::chrono::seconds(12345)));
+}
+
+TEST(chrono_test, invalid_specs) {
+  auto sec = std::chrono::seconds(0);
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%a}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%A}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%c}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%x}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Ex}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%X}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%EX}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%D}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%F}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Ec}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%w}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%u}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%b}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%B}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%z}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Z}"), sec), fmt::format_error,
+                   "no date");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Eq}"), sec), fmt::format_error,
+                   "invalid format");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:%Oq}"), sec), fmt::format_error,
+                   "invalid format");
+}
+
+auto format_tm(const std::tm& time, fmt::string_view spec,
+               const std::locale& loc) -> std::string {
+  auto& facet = std::use_facet<std::time_put<char>>(loc);
+  std::ostringstream os;
+  os.imbue(loc);
+  facet.put(os, os, ' ', &time, spec.begin(), spec.end());
+  return os.str();
+}
+
+TEST(chrono_test, locale) {
+  auto loc = get_locale("ja_JP.utf8");
+  if (loc == std::locale::classic()) return;
+#  define EXPECT_TIME(spec, time, duration)                     \
+    {                                                           \
+      auto jp_loc = std::locale("ja_JP.utf8");                  \
+      EXPECT_EQ(format_tm(time, spec, jp_loc),                  \
+                fmt::format(jp_loc, "{:L" spec "}", duration)); \
+    }
+  EXPECT_TIME("%OH", make_hour(14), std::chrono::hours(14));
+  EXPECT_TIME("%OI", make_hour(14), std::chrono::hours(14));
+  EXPECT_TIME("%OM", make_minute(42), std::chrono::minutes(42));
+  EXPECT_TIME("%OS", make_second(42), std::chrono::seconds(42));
+  auto time = make_tm();
+  time.tm_hour = 3;
+  time.tm_min = 25;
+  time.tm_sec = 45;
+  auto sec = std::chrono::seconds(12345);
+  EXPECT_TIME("%r", time, sec);
+  EXPECT_TIME("%p", time, sec);
+}
+
+using dms = std::chrono::duration<double, std::milli>;
+
+TEST(chrono_test, format_default_fp) {
+  typedef std::chrono::duration<float> fs;
+  EXPECT_EQ("1.234s", fmt::format("{}", fs(1.234)));
+  typedef std::chrono::duration<float, std::milli> fms;
+  EXPECT_EQ("1.234ms", fmt::format("{}", fms(1.234)));
+  typedef std::chrono::duration<double> ds;
+  EXPECT_EQ("1.234s", fmt::format("{}", ds(1.234)));
+  EXPECT_EQ("1.234ms", fmt::format("{}", dms(1.234)));
+}
+
+TEST(chrono_test, format_precision) {
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{:.2}"), std::chrono::seconds(42)),
+      fmt::format_error, "precision not allowed for this argument type");
+  EXPECT_EQ("1ms", fmt::format("{:.0}", dms(1.234)));
+  EXPECT_EQ("1.2ms", fmt::format("{:.1}", dms(1.234)));
+  EXPECT_EQ("1.23ms", fmt::format("{:.{}}", dms(1.234), 2));
+
+  EXPECT_EQ("13ms", fmt::format("{:.0}", dms(12.56)));
+  EXPECT_EQ("12.6ms", fmt::format("{:.1}", dms(12.56)));
+  EXPECT_EQ("12.56ms", fmt::format("{:.2}", dms(12.56)));
+}
+
+TEST(chrono_test, format_full_specs) {
+  EXPECT_EQ("1ms   ", fmt::format("{:6.0}", dms(1.234)));
+  EXPECT_EQ("1.2ms ", fmt::format("{:6.1}", dms(1.234)));
+  EXPECT_EQ("  1.23ms", fmt::format("{:>8.{}}", dms(1.234), 2));
+  EXPECT_EQ(" 1.2ms ", fmt::format("{:^{}.{}}", dms(1.234), 7, 1));
+  EXPECT_EQ(" 1.23ms ", fmt::format("{0:^{2}.{1}}", dms(1.234), 2, 8));
+  EXPECT_EQ("=1.234ms=", fmt::format("{:=^{}.{}}", dms(1.234), 9, 3));
+  EXPECT_EQ("*1.2340ms*", fmt::format("{:*^10.4}", dms(1.234)));
+
+  EXPECT_EQ("13ms  ", fmt::format("{:6.0}", dms(12.56)));
+  EXPECT_EQ("    13ms", fmt::format("{:>8.{}}", dms(12.56), 0));
+  EXPECT_EQ(" 13ms ", fmt::format("{:^{}.{}}", dms(12.56), 6, 0));
+  EXPECT_EQ("  13ms  ", fmt::format("{0:^{2}.{1}}", dms(12.56), 0, 8));
+  EXPECT_EQ("==13ms===", fmt::format("{:=^{}.{}}", dms(12.56), 9, 0));
+  EXPECT_EQ("***13ms***", fmt::format("{:*^10.0}", dms(12.56)));
+}
+
+TEST(chrono_test, format_simple_q) {
+  typedef std::chrono::duration<float> fs;
+  EXPECT_EQ("1.234 s", fmt::format("{:%Q %q}", fs(1.234)));
+  typedef std::chrono::duration<float, std::milli> fms;
+  EXPECT_EQ("1.234 ms", fmt::format("{:%Q %q}", fms(1.234)));
+  typedef std::chrono::duration<double> ds;
+  EXPECT_EQ("1.234 s", fmt::format("{:%Q %q}", ds(1.234)));
+  EXPECT_EQ("1.234 ms", fmt::format("{:%Q %q}", dms(1.234)));
+}
+
+TEST(chrono_test, format_precision_q) {
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{:.2%Q %q}"), std::chrono::seconds(42)),
+      fmt::format_error, "precision not allowed for this argument type");
+  EXPECT_EQ("1.2 ms", fmt::format("{:.1%Q %q}", dms(1.234)));
+  EXPECT_EQ("1.23 ms", fmt::format("{:.{}%Q %q}", dms(1.234), 2));
+}
+
+TEST(chrono_test, format_full_specs_q) {
+  EXPECT_EQ("1 ms   ", fmt::format("{:7.0%Q %q}", dms(1.234)));
+  EXPECT_EQ("1.2 ms ", fmt::format("{:7.1%Q %q}", dms(1.234)));
+  EXPECT_EQ(" 1.23 ms", fmt::format("{:>8.{}%Q %q}", dms(1.234), 2));
+  EXPECT_EQ(" 1.2 ms ", fmt::format("{:^{}.{}%Q %q}", dms(1.234), 8, 1));
+  EXPECT_EQ(" 1.23 ms ", fmt::format("{0:^{2}.{1}%Q %q}", dms(1.234), 2, 9));
+  EXPECT_EQ("=1.234 ms=", fmt::format("{:=^{}.{}%Q %q}", dms(1.234), 10, 3));
+  EXPECT_EQ("*1.2340 ms*", fmt::format("{:*^11.4%Q %q}", dms(1.234)));
+
+  EXPECT_EQ("13 ms  ", fmt::format("{:7.0%Q %q}", dms(12.56)));
+  EXPECT_EQ("   13 ms", fmt::format("{:>8.{}%Q %q}", dms(12.56), 0));
+  EXPECT_EQ(" 13 ms  ", fmt::format("{:^{}.{}%Q %q}", dms(12.56), 8, 0));
+  EXPECT_EQ("  13 ms  ", fmt::format("{0:^{2}.{1}%Q %q}", dms(12.56), 0, 9));
+  EXPECT_EQ("==13 ms==", fmt::format("{:=^{}.{}%Q %q}", dms(12.56), 9, 0));
+  EXPECT_EQ("***13 ms***", fmt::format("{:*^11.0%Q %q}", dms(12.56)));
+}
+
+TEST(chrono_test, invalid_width_id) {
+  EXPECT_THROW((void)fmt::format(runtime("{:{o}"), std::chrono::seconds(0)),
+               fmt::format_error);
+}
+
+TEST(chrono_test, invalid_colons) {
+  EXPECT_THROW((void)fmt::format(runtime("{0}=:{0::"), std::chrono::seconds(0)),
+               fmt::format_error);
+}
+
+TEST(chrono_test, negative_durations) {
+  EXPECT_EQ("-12345", fmt::format("{:%Q}", std::chrono::seconds(-12345)));
+  EXPECT_EQ("-03:25:45",
+            fmt::format("{:%H:%M:%S}", std::chrono::seconds(-12345)));
+  EXPECT_EQ("-00:01",
+            fmt::format("{:%M:%S}", std::chrono::duration<double>(-1)));
+  EXPECT_EQ("s", fmt::format("{:%q}", std::chrono::seconds(-12345)));
+  EXPECT_EQ("-00.127",
+            fmt::format("{:%S}",
+                        std::chrono::duration<signed char, std::milli>{-127}));
+  auto min = std::numeric_limits<int>::min();
+  EXPECT_EQ(fmt::format("{}", min),
+            fmt::format("{:%Q}", std::chrono::duration<int>(min)));
+}
+
+TEST(chrono_test, special_durations) {
+  auto value = fmt::format("{:%S}", std::chrono::duration<double>(1e20));
+  EXPECT_EQ(value, "40");
+  auto nan = std::numeric_limits<double>::quiet_NaN();
+  EXPECT_EQ(
+      "nan nan nan nan nan:nan nan",
+      fmt::format("{:%I %H %M %S %R %r}", std::chrono::duration<double>(nan)));
+  EXPECT_EQ(fmt::format("{}", std::chrono::duration<float, std::exa>(1)),
+            "1Es");
+  EXPECT_EQ(fmt::format("{}", std::chrono::duration<float, std::atto>(1)),
+            "1as");
+  EXPECT_EQ(fmt::format("{:%R}", std::chrono::duration<char, std::mega>{2}),
+            "03:33");
+  EXPECT_EQ(fmt::format("{:%T}", std::chrono::duration<char, std::mega>{2}),
+            "03:33:20");
+  EXPECT_EQ("44.000000000000",
+            fmt::format("{:%S}", std::chrono::duration<float, std::pico>(
+                                     1.54213895E+26)));
+}
+
+TEST(chrono_test, unsigned_duration) {
+  EXPECT_EQ("42s", fmt::format("{}", std::chrono::duration<unsigned>(42)));
+}
+
+TEST(chrono_test, weekday) {
+  auto loc = get_locale("ru_RU.UTF-8");
+  std::locale::global(loc);
+  auto mon = fmt::weekday(1);
+
+  auto tm = std::tm();
+  tm.tm_wday = static_cast<int>(mon.c_encoding());
+
+  EXPECT_EQ(fmt::format("{}", mon), "Mon");
+  EXPECT_EQ(fmt::format("{:%a}", tm), "Mon");
+
+  if (loc != std::locale::classic()) {
+    EXPECT_THAT((std::vector<std::string>{"пн", "Пн", "пнд", "Пнд"}),
+                Contains(fmt::format(loc, "{:L}", mon)));
+    EXPECT_THAT((std::vector<std::string>{"пн", "Пн", "пнд", "Пнд"}),
+                Contains(fmt::format(loc, "{:%a}", tm)));
+  }
+}
+
+TEST(chrono_test, cpp20_duration_subsecond_support) {
+  using attoseconds = std::chrono::duration<long long, std::atto>;
+  // Check that 18 digits of subsecond precision are supported.
+  EXPECT_EQ(fmt::format("{:%S}", attoseconds{999999999999999999}),
+            "00.999999999999999999");
+  EXPECT_EQ(fmt::format("{:%S}", attoseconds{673231113420148734}),
+            "00.673231113420148734");
+  EXPECT_EQ(fmt::format("{:%S}", attoseconds{-673231113420148734}),
+            "-00.673231113420148734");
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::nanoseconds{13420148734}),
+            "13.420148734");
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::nanoseconds{-13420148734}),
+            "-13.420148734");
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::milliseconds{1234}), "01.234");
+  {
+    // Check that {:%H:%M:%S} is equivalent to {:%T}.
+    auto dur = std::chrono::milliseconds{3601234};
+    auto formatted_dur = fmt::format("{:%T}", dur);
+    EXPECT_EQ(formatted_dur, "01:00:01.234");
+    EXPECT_EQ(fmt::format("{:%H:%M:%S}", dur), formatted_dur);
+  }
+  using nanoseconds_dbl = std::chrono::duration<double, std::nano>;
+  EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{-123456789}), "-00.123456789");
+  EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{9123456789}), "09.123456789");
+  // Verify that only the seconds part is extracted and printed.
+  EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{99123456789}), "39.123456789");
+  EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{99123000000}), "39.123000000");
+  {
+    // Now the hour is printed, and we also test if negative doubles work.
+    auto dur = nanoseconds_dbl{-99123456789};
+    auto formatted_dur = fmt::format("{:%T}", dur);
+    EXPECT_EQ(formatted_dur, "-00:01:39.123456789");
+    EXPECT_EQ(fmt::format("{:%H:%M:%S}", dur), formatted_dur);
+  }
+  // Check that durations with precision greater than std::chrono::seconds have
+  // fixed precision, and print zeros even if there is no fractional part.
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::microseconds{7000000}),
+            "07.000000");
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::duration<long long, std::ratio<1, 3>>(1)),
+            "00.333333");
+  EXPECT_EQ(fmt::format("{:%S}", std::chrono::duration<long long, std::ratio<1, 7>>(1)),
+            "00.142857");
+}
+
+#endif  // FMT_STATIC_THOUSANDS_SEPARATOR
diff --git a/src/fmt/test/color-test.cc b/src/fmt/test/color-test.cc
new file mode 100644
index 000000000..c2ba13a97
--- /dev/null
+++ b/src/fmt/test/color-test.cc
@@ -0,0 +1,72 @@
+// Formatting library for C++ - color tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/color.h"
+
+#include <iterator>  // std::back_inserter
+
+#include "gtest-extra.h"  // EXPECT_WRITE
+
+TEST(color_test, format) {
+  EXPECT_EQ(fmt::format(fg(fmt::rgb(255, 20, 30)), "rgb(255,20,30)"),
+            "\x1b[38;2;255;020;030mrgb(255,20,30)\x1b[0m");
+  EXPECT_EQ(fmt::format(fg(fmt::color::blue), "blue"),
+            "\x1b[38;2;000;000;255mblue\x1b[0m");
+  EXPECT_EQ(
+      fmt::format(fg(fmt::color::blue) | bg(fmt::color::red), "two color"),
+      "\x1b[38;2;000;000;255m\x1b[48;2;255;000;000mtwo color\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::bold, "bold"), "\x1b[1mbold\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::faint, "faint"), "\x1b[2mfaint\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::italic, "italic"),
+            "\x1b[3mitalic\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::underline, "underline"),
+            "\x1b[4munderline\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::blink, "blink"), "\x1b[5mblink\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::reverse, "reverse"),
+            "\x1b[7mreverse\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::conceal, "conceal"),
+            "\x1b[8mconceal\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::strikethrough, "strikethrough"),
+            "\x1b[9mstrikethrough\x1b[0m");
+  EXPECT_EQ(
+      fmt::format(fg(fmt::color::blue) | fmt::emphasis::bold, "blue/bold"),
+      "\x1b[1m\x1b[38;2;000;000;255mblue/bold\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::bold, "bold error"),
+            "\x1b[1mbold error\x1b[0m");
+  EXPECT_EQ(fmt::format(fg(fmt::color::blue), "blue log"),
+            "\x1b[38;2;000;000;255mblue log\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::text_style(), "hi"), "hi");
+  EXPECT_EQ(fmt::format(fg(fmt::terminal_color::red), "tred"),
+            "\x1b[31mtred\x1b[0m");
+  EXPECT_EQ(fmt::format(bg(fmt::terminal_color::cyan), "tcyan"),
+            "\x1b[46mtcyan\x1b[0m");
+  EXPECT_EQ(fmt::format(fg(fmt::terminal_color::bright_green), "tbgreen"),
+            "\x1b[92mtbgreen\x1b[0m");
+  EXPECT_EQ(fmt::format(bg(fmt::terminal_color::bright_magenta), "tbmagenta"),
+            "\x1b[105mtbmagenta\x1b[0m");
+  EXPECT_EQ(fmt::format(fg(fmt::terminal_color::red), "{}", "foo"),
+            "\x1b[31mfoo\x1b[0m");
+  EXPECT_EQ(fmt::format("{}{}", fmt::styled("red", fg(fmt::color::red)),
+                        fmt::styled("bold", fmt::emphasis::bold)),
+            "\x1b[38;2;255;000;000mred\x1b[0m\x1b[1mbold\x1b[0m");
+  EXPECT_EQ(fmt::format("{}", fmt::styled("bar", fg(fmt::color::blue) |
+                                                     fmt::emphasis::underline)),
+            "\x1b[4m\x1b[38;2;000;000;255mbar\x1b[0m");
+}
+
+TEST(color_test, format_to) {
+  auto out = std::string();
+  fmt::format_to(std::back_inserter(out), fg(fmt::rgb(255, 20, 30)),
+                 "rgb(255,20,30){}{}{}", 1, 2, 3);
+  EXPECT_EQ(fmt::to_string(out),
+            "\x1b[38;2;255;020;030mrgb(255,20,30)123\x1b[0m");
+}
+
+TEST(color_test, print) {
+  EXPECT_WRITE(stdout, fmt::print(fg(fmt::rgb(255, 20, 30)), "rgb(255,20,30)"),
+               "\x1b[38;2;255;020;030mrgb(255,20,30)\x1b[0m");
+}
diff --git a/src/fmt/test/compile-error-test/CMakeLists.txt b/src/fmt/test/compile-error-test/CMakeLists.txt
new file mode 100644
index 000000000..9c65dfdce
--- /dev/null
+++ b/src/fmt/test/compile-error-test/CMakeLists.txt
@@ -0,0 +1,241 @@
+# Test if compile errors are produced where necessary.
+
+cmake_minimum_required(VERSION 3.1...3.18)
+project(compile-error-test CXX)
+
+set(fmt_headers "
+  #include <fmt/format.h>
+  #include <fmt/xchar.h>
+  #include <fmt/ostream.h>
+  #include <iostream>
+")
+
+set(error_test_names "")
+set(non_error_test_content "")
+
+# For error tests (we expect them to produce compilation error):
+#  * adds a name of test into `error_test_names` list
+#  * generates a single source file (with the same name) for each test
+# For non-error tests (we expect them to compile successfully):
+#  * adds a code segment as separate function to `non_error_test_content`
+function (expect_compile name code_fragment)
+  cmake_parse_arguments(EXPECT_COMPILE "ERROR" "" "" ${ARGN})
+  string(MAKE_C_IDENTIFIER "${name}" test_name)
+
+  if (EXPECT_COMPILE_ERROR)
+    file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/${test_name}.cc" "
+      ${fmt_headers}
+      void ${test_name}() {
+        ${code_fragment}
+      }
+    ")
+    set(error_test_names_copy "${error_test_names}")
+    list(APPEND error_test_names_copy "${test_name}")
+    set(error_test_names "${error_test_names_copy}" PARENT_SCOPE)
+  else()
+    set(non_error_test_content "
+      ${non_error_test_content}
+      void ${test_name}() {
+        ${code_fragment}
+      }" PARENT_SCOPE)
+  endif()
+endfunction ()
+
+# Generates a source file for non-error test with `non_error_test_content` and
+# CMake project file with all error and single non-error test targets.
+function (run_tests)
+  set(cmake_targets "")
+  foreach(test_name IN LISTS error_test_names)
+    set(cmake_targets "
+      ${cmake_targets}
+      add_library(test-${test_name} ${test_name}.cc)
+      target_link_libraries(test-${test_name} PRIVATE fmt::fmt)
+    ")
+  endforeach()
+
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/non_error_test.cc" "
+    ${fmt_headers}
+    ${non_error_test_content}
+  ")
+  set(cmake_targets "
+    ${cmake_targets}
+    add_library(non-error-test non_error_test.cc)
+    target_link_libraries(non-error-test PRIVATE fmt::fmt)
+  ")
+
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/CMakeLists.txt" "
+    cmake_minimum_required(VERSION 3.1...3.18)
+    project(tests CXX)
+    add_subdirectory(${FMT_DIR} fmt)
+    ${cmake_targets}
+  ")
+
+  set(build_directory "${CMAKE_CURRENT_BINARY_DIR}/test/build")
+  file(MAKE_DIRECTORY "${build_directory}")
+  execute_process(
+    COMMAND
+      "${CMAKE_COMMAND}"
+      "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+      "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
+      "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+      "-DCMAKE_GENERATOR=${CMAKE_GENERATOR}"
+      "-DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}"
+      "-DFMT_DIR=${FMT_DIR}"
+      "${CMAKE_CURRENT_BINARY_DIR}/test"
+    WORKING_DIRECTORY "${build_directory}"
+    RESULT_VARIABLE result_var
+    OUTPUT_VARIABLE output_var
+    ERROR_VARIABLE output_var)
+  if (NOT result_var EQUAL 0)
+    message(FATAL_ERROR "Unable to configure:\n${output_var}")
+  endif()
+
+  foreach(test_name IN LISTS error_test_names)
+    execute_process(
+      COMMAND
+        "${CMAKE_COMMAND}" --build "${build_directory}" --target "test-${test_name}"
+      WORKING_DIRECTORY "${build_directory}"
+      RESULT_VARIABLE result_var
+      OUTPUT_VARIABLE output_var
+      ERROR_QUIET)
+    if (result_var EQUAL 0)
+      message(SEND_ERROR "No compile error for \"${test_name}\":\n${output_var}")
+    endif ()
+  endforeach()
+
+  execute_process(
+    COMMAND
+      "${CMAKE_COMMAND}" --build "${build_directory}" --target "non-error-test"
+    WORKING_DIRECTORY "${build_directory}"
+    RESULT_VARIABLE result_var
+    OUTPUT_VARIABLE output_var
+    ERROR_VARIABLE output_var)
+  if (NOT result_var EQUAL 0)
+    message(SEND_ERROR "Compile error for combined non-error test:\n${output_var}")
+  endif ()
+endfunction ()
+
+
+# check if the source file skeleton compiles
+expect_compile(check "")
+expect_compile(check-error "compilation_error" ERROR)
+
+# Formatting a wide character with a narrow format string is forbidden.
+expect_compile(wide-character-narrow-format-string "fmt::format(L\"{}\", L'a');")
+expect_compile(wide-character-narrow-format-string-error "fmt::format(\"{}\", L'a');" ERROR)
+
+# Formatting a wide string with a narrow format string is forbidden.
+expect_compile(wide-string-narrow-format-string "fmt::format(L\"{}\", L\"foo\");")
+expect_compile(wide-string-narrow-format-string-error "fmt::format(\"{}\", L\"foo\");" ERROR)
+
+# Formatting a narrow string with a wide format string is forbidden because
+# mixing UTF-8 with UTF-16/32 can result in an invalid output.
+expect_compile(narrow-string-wide-format-string "fmt::format(L\"{}\", L\"foo\");")
+expect_compile(narrow-string-wide-format-string-error "fmt::format(L\"{}\", \"foo\");" ERROR)
+
+expect_compile(cast-to-string "
+  struct S {
+    operator std::string() const { return std::string(); }
+  };
+  fmt::format(\"{}\", std::string(S()));
+")
+expect_compile(cast-to-string-error "
+  struct S {
+    operator std::string() const { return std::string(); }
+  };
+  fmt::format(\"{}\", S());
+" ERROR)
+
+# Formatting a function
+expect_compile(format-function "
+  void (*f)();
+  fmt::format(\"{}\", fmt::ptr(f));
+")
+expect_compile(format-function-error "
+  void (*f)();
+  fmt::format(\"{}\", f);
+" ERROR)
+
+# Formatting an unformattable argument should always be a compile time error
+expect_compile(format-lots-of-arguments-with-unformattable "
+  struct E {};
+  fmt::format(\"\", 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, E());
+" ERROR)
+expect_compile(format-lots-of-arguments-with-function "
+  void (*f)();
+  fmt::format(\"\", 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, f);
+" ERROR)
+
+# Check if user-defined literals are available
+include(CheckCXXSourceCompiles)
+set(CMAKE_REQUIRED_FLAGS ${CXX_STANDARD_FLAG})
+check_cxx_source_compiles("
+  void operator\"\" _udl(long double);
+  int main() {}"
+  SUPPORTS_USER_DEFINED_LITERALS)
+set(CMAKE_REQUIRED_FLAGS )
+if (NOT SUPPORTS_USER_DEFINED_LITERALS)
+  set (SUPPORTS_USER_DEFINED_LITERALS OFF)
+endif ()
+
+# Make sure that compiler features detected in the header
+# match the features detected in CMake.
+if (SUPPORTS_USER_DEFINED_LITERALS)
+  set(supports_udl 1)
+else ()
+  set(supports_udl 0)
+endif ()
+expect_compile(udl-check "
+  #if FMT_USE_USER_DEFINED_LITERALS != ${supports_udl}
+  # error
+  #endif
+")
+
+if (CMAKE_CXX_STANDARD GREATER_EQUAL 20)
+  # Compile-time argument type check
+  expect_compile(format-string-number-spec "
+    #ifdef FMT_HAS_CONSTEVAL
+      fmt::format(\"{:d}\", 42);
+    #endif
+  ")
+  expect_compile(format-string-number-spec-error "
+    #ifdef FMT_HAS_CONSTEVAL
+      fmt::format(\"{:d}\", \"I am not a number\");
+    #else
+      #error
+    #endif
+  " ERROR)
+  expect_compile(print-string-number-spec-error "
+    #ifdef FMT_HAS_CONSTEVAL
+      fmt::print(\"{:d}\", \"I am not a number\");
+    #else
+      #error
+    #endif
+  " ERROR)
+  expect_compile(print-stream-string-number-spec-error "
+  #ifdef FMT_HAS_CONSTEVAL
+    fmt::print(std::cout, \"{:d}\", \"I am not a number\");
+  #else
+    #error
+  #endif
+  " ERROR)
+
+  # Compile-time argument name check
+  expect_compile(format-string-name "
+    #if defined(FMT_HAS_CONSTEVAL) && FMT_USE_NONTYPE_TEMPLATE_ARGS
+      using namespace fmt::literals;
+      fmt::print(\"{foo}\", \"foo\"_a=42);
+    #endif
+  ")
+  expect_compile(format-string-name-error "
+    #if defined(FMT_HAS_CONSTEVAL) && FMT_USE_NONTYPE_TEMPLATE_ARGS
+      using namespace fmt::literals;
+      fmt::print(\"{foo}\", \"bar\"_a=42);
+    #else
+      #error
+    #endif
+  " ERROR)
+endif ()
+
+# Run all tests
+run_tests()
diff --git a/src/fmt/test/compile-fp-test.cc b/src/fmt/test/compile-fp-test.cc
new file mode 100644
index 000000000..db0cd906c
--- /dev/null
+++ b/src/fmt/test/compile-fp-test.cc
@@ -0,0 +1,62 @@
+// Formatting library for C++ - formatting library tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/compile.h"
+#include "gmock/gmock.h"
+
+#if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806 && \
+    defined(__cpp_constexpr) && __cpp_constexpr >= 201907 &&       \
+    defined(__cpp_constexpr_dynamic_alloc) &&                      \
+    __cpp_constexpr_dynamic_alloc >= 201907 && FMT_CPLUSPLUS >= 202002L
+template <size_t max_string_length, typename Char = char> struct test_string {
+  template <typename T> constexpr bool operator==(const T& rhs) const noexcept {
+    return fmt::basic_string_view<Char>(rhs).compare(buffer) == 0;
+  }
+  Char buffer[max_string_length]{};
+};
+
+template <size_t max_string_length, typename Char = char, typename... Args>
+consteval auto test_format(auto format, const Args&... args) {
+  test_string<max_string_length, Char> string{};
+  fmt::format_to(string.buffer, format, args...);
+  return string;
+}
+
+TEST(compile_time_formatting_test, floating_point) {
+  EXPECT_EQ("0", test_format<2>(FMT_COMPILE("{}"), 0.0f));
+  EXPECT_EQ("392.500000", test_format<11>(FMT_COMPILE("{0:f}"), 392.5f));
+
+  EXPECT_EQ("0", test_format<2>(FMT_COMPILE("{:}"), 0.0));
+  EXPECT_EQ("0.000000", test_format<9>(FMT_COMPILE("{:f}"), 0.0));
+  EXPECT_EQ("0", test_format<2>(FMT_COMPILE("{:g}"), 0.0));
+  EXPECT_EQ("392.65", test_format<7>(FMT_COMPILE("{:}"), 392.65));
+  EXPECT_EQ("392.65", test_format<7>(FMT_COMPILE("{:g}"), 392.65));
+  EXPECT_EQ("392.65", test_format<7>(FMT_COMPILE("{:G}"), 392.65));
+  EXPECT_EQ("4.9014e+06", test_format<11>(FMT_COMPILE("{:g}"), 4.9014e6));
+  EXPECT_EQ("-392.650000", test_format<12>(FMT_COMPILE("{:f}"), -392.65));
+  EXPECT_EQ("-392.650000", test_format<12>(FMT_COMPILE("{:F}"), -392.65));
+
+  EXPECT_EQ("3.926500e+02", test_format<13>(FMT_COMPILE("{0:e}"), 392.65));
+  EXPECT_EQ("3.926500E+02", test_format<13>(FMT_COMPILE("{0:E}"), 392.65));
+  EXPECT_EQ("+0000392.6", test_format<11>(FMT_COMPILE("{0:+010.4g}"), 392.65));
+  EXPECT_EQ("9223372036854775808.000000",
+            test_format<27>(FMT_COMPILE("{:f}"), 9223372036854775807.0));
+
+  constexpr double nan = std::numeric_limits<double>::quiet_NaN();
+  EXPECT_EQ("nan", test_format<4>(FMT_COMPILE("{}"), nan));
+  EXPECT_EQ("+nan", test_format<5>(FMT_COMPILE("{:+}"), nan));
+  if (std::signbit(-nan))
+    EXPECT_EQ("-nan", test_format<5>(FMT_COMPILE("{}"), -nan));
+  else
+    fmt::print("Warning: compiler doesn't handle negative NaN correctly");
+
+  constexpr double inf = std::numeric_limits<double>::infinity();
+  EXPECT_EQ("inf", test_format<4>(FMT_COMPILE("{}"), inf));
+  EXPECT_EQ("+inf", test_format<5>(FMT_COMPILE("{:+}"), inf));
+  EXPECT_EQ("-inf", test_format<5>(FMT_COMPILE("{}"), -inf));
+}
+#endif
diff --git a/src/fmt/test/compile-test.cc b/src/fmt/test/compile-test.cc
new file mode 100644
index 000000000..005c49930
--- /dev/null
+++ b/src/fmt/test/compile-test.cc
@@ -0,0 +1,392 @@
+// Formatting library for C++ - formatting library tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/compile.h"
+
+#include <type_traits>
+
+#include "fmt/chrono.h"
+#include "gmock/gmock.h"
+#include "gtest-extra.h"
+
+TEST(iterator_test, counting_iterator) {
+  auto it = fmt::detail::counting_iterator();
+  auto prev = it++;
+  EXPECT_EQ(prev.count(), 0);
+  EXPECT_EQ(it.count(), 1);
+  EXPECT_EQ((it + 41).count(), 42);
+}
+
+TEST(iterator_test, truncating_iterator) {
+  char* p = nullptr;
+  auto it = fmt::detail::truncating_iterator<char*>(p, 3);
+  auto prev = it++;
+  EXPECT_EQ(prev.base(), p);
+  EXPECT_EQ(it.base(), p + 1);
+}
+
+TEST(iterator_test, truncating_iterator_default_construct) {
+  auto it = fmt::detail::truncating_iterator<char*>();
+  EXPECT_EQ(nullptr, it.base());
+  EXPECT_EQ(std::size_t{0}, it.count());
+}
+
+#ifdef __cpp_lib_ranges
+TEST(iterator_test, truncating_iterator_is_output_iterator) {
+  static_assert(
+      std::output_iterator<fmt::detail::truncating_iterator<char*>, char>);
+}
+#endif
+
+TEST(iterator_test, truncating_back_inserter) {
+  auto buffer = std::string();
+  auto bi = std::back_inserter(buffer);
+  auto it = fmt::detail::truncating_iterator<decltype(bi)>(bi, 2);
+  *it++ = '4';
+  *it++ = '2';
+  *it++ = '1';
+  EXPECT_EQ(buffer.size(), 2);
+  EXPECT_EQ(buffer, "42");
+}
+
+TEST(compile_test, compile_fallback) {
+  // FMT_COMPILE should fallback on runtime formatting when `if constexpr` is
+  // not available.
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42));
+}
+
+struct type_with_get {
+  template <int> friend void get(type_with_get);
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<type_with_get> : formatter<int> {
+  template <typename FormatContext>
+  auto format(type_with_get, FormatContext& ctx) -> decltype(ctx.out()) {
+    return formatter<int>::format(42, ctx);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(compile_test, compile_type_with_get) {
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), type_with_get()));
+}
+
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
+struct test_formattable {};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<test_formattable> : formatter<const char*> {
+  char word_spec = 'f';
+  constexpr auto parse(format_parse_context& ctx) {
+    auto it = ctx.begin(), end = ctx.end();
+    if (it == end || *it == '}') return it;
+    if (it != end && (*it == 'f' || *it == 'b')) word_spec = *it++;
+    if (it != end && *it != '}') throw format_error("invalid format");
+    return it;
+  }
+  template <typename FormatContext>
+  constexpr auto format(test_formattable, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<const char*>::format(word_spec == 'f' ? "foo" : "bar",
+                                          ctx);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(compile_test, format_default) {
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42));
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42u));
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42ll));
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42ull));
+  EXPECT_EQ("true", fmt::format(FMT_COMPILE("{}"), true));
+  EXPECT_EQ("x", fmt::format(FMT_COMPILE("{}"), 'x'));
+  EXPECT_EQ("4.2", fmt::format(FMT_COMPILE("{}"), 4.2));
+  EXPECT_EQ("foo", fmt::format(FMT_COMPILE("{}"), "foo"));
+  EXPECT_EQ("foo", fmt::format(FMT_COMPILE("{}"), std::string("foo")));
+  EXPECT_EQ("foo", fmt::format(FMT_COMPILE("{}"), test_formattable()));
+  auto t = std::chrono::system_clock::now();
+  EXPECT_EQ(fmt::format("{}", t), fmt::format(FMT_COMPILE("{}"), t));
+#  ifdef __cpp_lib_byte
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), std::byte{42}));
+#  endif
+}
+
+TEST(compile_test, format_wide_string) {
+  EXPECT_EQ(L"42", fmt::format(FMT_COMPILE(L"{}"), 42));
+}
+
+TEST(compile_test, format_specs) {
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{:x}"), 0x42));
+  EXPECT_EQ("1.2 ms ",
+            fmt::format(FMT_COMPILE("{:7.1%Q %q}"),
+                        std::chrono::duration<double, std::milli>(1.234)));
+}
+
+TEST(compile_test, dynamic_format_specs) {
+  EXPECT_EQ("foo  ", fmt::format(FMT_COMPILE("{:{}}"), "foo", 5));
+  EXPECT_EQ("  3.14", fmt::format(FMT_COMPILE("{:{}.{}f}"), 3.141592, 6, 2));
+  EXPECT_EQ(
+      "=1.234ms=",
+      fmt::format(FMT_COMPILE("{:=^{}.{}}"),
+                  std::chrono::duration<double, std::milli>(1.234), 9, 3));
+}
+
+TEST(compile_test, manual_ordering) {
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{0}"), 42));
+  EXPECT_EQ(" -42", fmt::format(FMT_COMPILE("{0:4}"), -42));
+  EXPECT_EQ("41 43", fmt::format(FMT_COMPILE("{0} {1}"), 41, 43));
+  EXPECT_EQ("41 43", fmt::format(FMT_COMPILE("{1} {0}"), 43, 41));
+  EXPECT_EQ("41 43", fmt::format(FMT_COMPILE("{0} {2}"), 41, 42, 43));
+  EXPECT_EQ("  41   43", fmt::format(FMT_COMPILE("{1:{2}} {0:4}"), 43, 41, 4));
+  EXPECT_EQ("42 1.2 ms ",
+            fmt::format(FMT_COMPILE("{0} {1:7.1%Q %q}"), 42,
+                        std::chrono::duration<double, std::milli>(1.234)));
+  EXPECT_EQ(
+      "true 42 42 foo 0x1234 foo",
+      fmt::format(FMT_COMPILE("{0} {1} {2} {3} {4} {5}"), true, 42, 42.0f,
+                  "foo", reinterpret_cast<void*>(0x1234), test_formattable()));
+  EXPECT_EQ(L"42", fmt::format(FMT_COMPILE(L"{0}"), 42));
+}
+
+TEST(compile_test, named) {
+  auto runtime_named_field_compiled =
+      fmt::detail::compile<decltype(fmt::arg("arg", 42))>(FMT_COMPILE("{arg}"));
+  static_assert(std::is_same_v<decltype(runtime_named_field_compiled),
+                               fmt::detail::runtime_named_field<char>>);
+
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), fmt::arg("arg", 42)));
+  EXPECT_EQ("41 43", fmt::format(FMT_COMPILE("{} {}"), fmt::arg("arg", 41),
+                                 fmt::arg("arg", 43)));
+
+  EXPECT_EQ("foobar",
+            fmt::format(FMT_COMPILE("{a0}{a1}"), fmt::arg("a0", "foo"),
+                        fmt::arg("a1", "bar")));
+  EXPECT_EQ("foobar", fmt::format(FMT_COMPILE("{}{a1}"), fmt::arg("a0", "foo"),
+                                  fmt::arg("a1", "bar")));
+  EXPECT_EQ("foofoo", fmt::format(FMT_COMPILE("{a0}{}"), fmt::arg("a0", "foo"),
+                                  fmt::arg("a1", "bar")));
+  EXPECT_EQ("foobar", fmt::format(FMT_COMPILE("{0}{a1}"), fmt::arg("a0", "foo"),
+                                  fmt::arg("a1", "bar")));
+  EXPECT_EQ("foobar", fmt::format(FMT_COMPILE("{a0}{1}"), fmt::arg("a0", "foo"),
+                                  fmt::arg("a1", "bar")));
+
+  EXPECT_EQ("foobar",
+            fmt::format(FMT_COMPILE("{}{a1}"), "foo", fmt::arg("a1", "bar")));
+  EXPECT_EQ("foobar",
+            fmt::format(FMT_COMPILE("{a0}{a1}"), fmt::arg("a1", "bar"),
+                        fmt::arg("a2", "baz"), fmt::arg("a0", "foo")));
+  EXPECT_EQ(" bar foo ",
+            fmt::format(FMT_COMPILE(" {foo} {bar} "), fmt::arg("foo", "bar"),
+                        fmt::arg("bar", "foo")));
+
+  EXPECT_THROW(fmt::format(FMT_COMPILE("{invalid}"), fmt::arg("valid", 42)),
+               fmt::format_error);
+
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+  using namespace fmt::literals;
+  auto statically_named_field_compiled =
+      fmt::detail::compile<decltype("arg"_a = 42)>(FMT_COMPILE("{arg}"));
+  static_assert(std::is_same_v<decltype(statically_named_field_compiled),
+                               fmt::detail::field<char, int, 0>>);
+
+  EXPECT_EQ("41 43",
+            fmt::format(FMT_COMPILE("{a0} {a1}"), "a0"_a = 41, "a1"_a = 43));
+  EXPECT_EQ("41 43",
+            fmt::format(FMT_COMPILE("{a1} {a0}"), "a0"_a = 43, "a1"_a = 41));
+#  endif
+}
+
+TEST(compile_test, join) {
+  unsigned char data[] = {0x1, 0x2, 0xaf};
+  EXPECT_EQ("0102af", fmt::format(FMT_COMPILE("{:02x}"), fmt::join(data, "")));
+}
+
+TEST(compile_test, format_to) {
+  char buf[8];
+  auto end = fmt::format_to(buf, FMT_COMPILE("{}"), 42);
+  *end = '\0';
+  EXPECT_STREQ("42", buf);
+  end = fmt::format_to(buf, FMT_COMPILE("{:x}"), 42);
+  *end = '\0';
+  EXPECT_STREQ("2a", buf);
+}
+
+TEST(compile_test, format_to_n) {
+  constexpr auto buffer_size = 8;
+  char buffer[buffer_size];
+  auto res = fmt::format_to_n(buffer, buffer_size, FMT_COMPILE("{}"), 42);
+  *res.out = '\0';
+  EXPECT_STREQ("42", buffer);
+  res = fmt::format_to_n(buffer, buffer_size, FMT_COMPILE("{:x}"), 42);
+  *res.out = '\0';
+  EXPECT_STREQ("2a", buffer);
+}
+
+#ifdef __cpp_lib_bit_cast
+TEST(compile_test, constexpr_formatted_size) {
+  FMT_CONSTEXPR20 size_t s1 = fmt::formatted_size(FMT_COMPILE("{0}"), 42);
+  EXPECT_EQ(2, s1);
+  FMT_CONSTEXPR20 size_t s2 = fmt::formatted_size(FMT_COMPILE("{0:<4.2f}"), 42.0);
+  EXPECT_EQ(5, s2);
+}
+#endif
+
+TEST(compile_test, text_and_arg) {
+  EXPECT_EQ(">>>42<<<", fmt::format(FMT_COMPILE(">>>{}<<<"), 42));
+  EXPECT_EQ("42!", fmt::format(FMT_COMPILE("{}!"), 42));
+}
+
+TEST(compile_test, unknown_format_fallback) {
+  EXPECT_EQ(" 42 ",
+            fmt::format(FMT_COMPILE("{name:^4}"), fmt::arg("name", 42)));
+
+  std::vector<char> v;
+  fmt::format_to(std::back_inserter(v), FMT_COMPILE("{name:^4}"),
+                 fmt::arg("name", 42));
+  EXPECT_EQ(" 42 ", fmt::string_view(v.data(), v.size()));
+
+  char buffer[4];
+  auto result = fmt::format_to_n(buffer, 4, FMT_COMPILE("{name:^5}"),
+                                 fmt::arg("name", 42));
+  EXPECT_EQ(5u, result.size);
+  EXPECT_EQ(buffer + 4, result.out);
+  EXPECT_EQ(" 42 ", fmt::string_view(buffer, 4));
+}
+
+TEST(compile_test, empty) { EXPECT_EQ("", fmt::format(FMT_COMPILE(""))); }
+
+struct to_stringable {
+  friend fmt::string_view to_string_view(to_stringable) { return {}; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<to_stringable> {
+  auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const to_stringable&, FormatContext& ctx) -> decltype(ctx.out()) {
+    return ctx.out();
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(compile_test, to_string_and_formatter) {
+  fmt::format(FMT_COMPILE("{}"), to_stringable());
+}
+
+TEST(compile_test, print) {
+  EXPECT_WRITE(stdout, fmt::print(FMT_COMPILE("Don't {}!"), "panic"),
+               "Don't panic!");
+  EXPECT_WRITE(stderr, fmt::print(stderr, FMT_COMPILE("Don't {}!"), "panic"),
+               "Don't panic!");
+}
+#endif
+
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+TEST(compile_test, compile_format_string_literal) {
+  using namespace fmt::literals;
+  EXPECT_EQ("", fmt::format(""_cf));
+  EXPECT_EQ("42", fmt::format("{}"_cf, 42));
+  EXPECT_EQ(L"42", fmt::format(L"{}"_cf, 42));
+}
+#endif
+
+// MSVS 2019 19.29.30145.0 - Support C++20 and OK.
+// MSVS 2022 19.32.31332.0 - compile-test.cc(362,3): fatal error C1001: Internal
+// compiler error.
+//  (compiler file
+//  'D:\a\_work\1\s\src\vctools\Compiler\CxxFE\sl\p1\c\constexpr\constexpr.cpp',
+//  line 8635)
+#if ((FMT_CPLUSPLUS >= 202002L) &&                    \
+     (!FMT_MSC_VERSION || FMT_MSC_VERSION < 1930)) || \
+    (FMT_CPLUSPLUS >= 201709L && FMT_GCC_VERSION >= 1002)
+template <size_t max_string_length, typename Char = char> struct test_string {
+  template <typename T> constexpr bool operator==(const T& rhs) const noexcept {
+    return fmt::basic_string_view<Char>(rhs).compare(buffer) == 0;
+  }
+  Char buffer[max_string_length]{};
+};
+
+template <size_t max_string_length, typename Char = char, typename... Args>
+consteval auto test_format(auto format, const Args&... args) {
+  test_string<max_string_length, Char> string{};
+  fmt::format_to(string.buffer, format, args...);
+  return string;
+}
+
+TEST(compile_time_formatting_test, bool) {
+  EXPECT_EQ("true", test_format<5>(FMT_COMPILE("{}"), true));
+  EXPECT_EQ("false", test_format<6>(FMT_COMPILE("{}"), false));
+  EXPECT_EQ("true ", test_format<6>(FMT_COMPILE("{:5}"), true));
+  EXPECT_EQ("1", test_format<2>(FMT_COMPILE("{:d}"), true));
+}
+
+TEST(compile_time_formatting_test, integer) {
+  EXPECT_EQ("42", test_format<3>(FMT_COMPILE("{}"), 42));
+  EXPECT_EQ("420", test_format<4>(FMT_COMPILE("{}"), 420));
+  EXPECT_EQ("42 42", test_format<6>(FMT_COMPILE("{} {}"), 42, 42));
+  EXPECT_EQ("42 42",
+            test_format<6>(FMT_COMPILE("{} {}"), uint32_t{42}, uint64_t{42}));
+
+  EXPECT_EQ("+42", test_format<4>(FMT_COMPILE("{:+}"), 42));
+  EXPECT_EQ("42", test_format<3>(FMT_COMPILE("{:-}"), 42));
+  EXPECT_EQ(" 42", test_format<4>(FMT_COMPILE("{: }"), 42));
+
+  EXPECT_EQ("-0042", test_format<6>(FMT_COMPILE("{:05}"), -42));
+
+  EXPECT_EQ("101010", test_format<7>(FMT_COMPILE("{:b}"), 42));
+  EXPECT_EQ("0b101010", test_format<9>(FMT_COMPILE("{:#b}"), 42));
+  EXPECT_EQ("0B101010", test_format<9>(FMT_COMPILE("{:#B}"), 42));
+  EXPECT_EQ("042", test_format<4>(FMT_COMPILE("{:#o}"), 042));
+  EXPECT_EQ("0x4a", test_format<5>(FMT_COMPILE("{:#x}"), 0x4a));
+  EXPECT_EQ("0X4A", test_format<5>(FMT_COMPILE("{:#X}"), 0x4a));
+
+  EXPECT_EQ("   42", test_format<6>(FMT_COMPILE("{:5}"), 42));
+  EXPECT_EQ("   42", test_format<6>(FMT_COMPILE("{:5}"), 42ll));
+  EXPECT_EQ("   42", test_format<6>(FMT_COMPILE("{:5}"), 42ull));
+
+  EXPECT_EQ("42  ", test_format<5>(FMT_COMPILE("{:<4}"), 42));
+  EXPECT_EQ("  42", test_format<5>(FMT_COMPILE("{:>4}"), 42));
+  EXPECT_EQ(" 42 ", test_format<5>(FMT_COMPILE("{:^4}"), 42));
+  EXPECT_EQ("**-42", test_format<6>(FMT_COMPILE("{:*>5}"), -42));
+}
+
+TEST(compile_time_formatting_test, char) {
+  EXPECT_EQ("c", test_format<2>(FMT_COMPILE("{}"), 'c'));
+
+  EXPECT_EQ("c  ", test_format<4>(FMT_COMPILE("{:3}"), 'c'));
+  EXPECT_EQ("99", test_format<3>(FMT_COMPILE("{:d}"), 'c'));
+}
+
+TEST(compile_time_formatting_test, string) {
+  EXPECT_EQ("42", test_format<3>(FMT_COMPILE("{}"), "42"));
+  EXPECT_EQ("The answer is 42",
+            test_format<17>(FMT_COMPILE("{} is {}"), "The answer", "42"));
+
+  EXPECT_EQ("abc**", test_format<6>(FMT_COMPILE("{:*<5}"), "abc"));
+  EXPECT_EQ("**🤡**", test_format<9>(FMT_COMPILE("{:*^6}"), "🤡"));
+}
+
+TEST(compile_time_formatting_test, combination) {
+  EXPECT_EQ("420, true, answer",
+            test_format<18>(FMT_COMPILE("{}, {}, {}"), 420, true, "answer"));
+
+  EXPECT_EQ(" -42", test_format<5>(FMT_COMPILE("{:{}}"), -42, 4));
+}
+
+TEST(compile_time_formatting_test, custom_type) {
+  EXPECT_EQ("foo", test_format<4>(FMT_COMPILE("{}"), test_formattable()));
+  EXPECT_EQ("bar", test_format<4>(FMT_COMPILE("{:b}"), test_formattable()));
+}
+
+TEST(compile_time_formatting_test, multibyte_fill) {
+  EXPECT_EQ("жж42", test_format<8>(FMT_COMPILE("{:ж>4}"), 42));
+}
+#endif
diff --git a/src/fmt/test/core-test.cc b/src/fmt/test/core-test.cc
new file mode 100644
index 000000000..c76dc1617
--- /dev/null
+++ b/src/fmt/test/core-test.cc
@@ -0,0 +1,978 @@
+// Formatting library for C++ - core tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+// clang-format off
+#include "test-assert.h"
+// clang-format on
+
+#define I 42  // simulate https://en.cppreference.com/w/c/numeric/complex/I
+#include "fmt/core.h"
+#undef I
+
+#include <algorithm>    // std::copy_n
+#include <climits>      // INT_MAX
+#include <cstring>      // std::strlen
+#include <functional>   // std::equal_to
+#include <iterator>     // std::back_insert_iterator
+#include <limits>       // std::numeric_limits
+#include <string>       // std::string
+#include <type_traits>  // std::is_same
+
+#include "gmock/gmock.h"
+
+using fmt::string_view;
+using fmt::detail::buffer;
+
+using testing::_;
+using testing::Invoke;
+using testing::Return;
+
+#ifdef FMT_FORMAT_H_
+#  error core-test includes format.h
+#endif
+
+TEST(string_view_test, value_type) {
+  static_assert(std::is_same<string_view::value_type, char>::value, "");
+}
+
+TEST(string_view_test, ctor) {
+  EXPECT_STREQ("abc", fmt::string_view("abc").data());
+  EXPECT_EQ(3u, fmt::string_view("abc").size());
+
+  EXPECT_STREQ("defg", fmt::string_view(std::string("defg")).data());
+  EXPECT_EQ(4u, fmt::string_view(std::string("defg")).size());
+}
+
+TEST(string_view_test, length) {
+  // Test that string_view::size() returns string length, not buffer size.
+  char str[100] = "some string";
+  EXPECT_EQ(std::strlen(str), string_view(str).size());
+  EXPECT_LT(std::strlen(str), sizeof(str));
+}
+
+// Check string_view's comparison operator.
+template <template <typename> class Op> void check_op() {
+  const char* inputs[] = {"foo", "fop", "fo"};
+  size_t num_inputs = sizeof(inputs) / sizeof(*inputs);
+  for (size_t i = 0; i < num_inputs; ++i) {
+    for (size_t j = 0; j < num_inputs; ++j) {
+      string_view lhs(inputs[i]), rhs(inputs[j]);
+      EXPECT_EQ(Op<int>()(lhs.compare(rhs), 0), Op<string_view>()(lhs, rhs));
+    }
+  }
+}
+
+TEST(string_view_test, compare) {
+  EXPECT_EQ(string_view("foo").compare(string_view("foo")), 0);
+  EXPECT_GT(string_view("fop").compare(string_view("foo")), 0);
+  EXPECT_LT(string_view("foo").compare(string_view("fop")), 0);
+  EXPECT_GT(string_view("foo").compare(string_view("fo")), 0);
+  EXPECT_LT(string_view("fo").compare(string_view("foo")), 0);
+  check_op<std::equal_to>();
+  check_op<std::not_equal_to>();
+  check_op<std::less>();
+  check_op<std::less_equal>();
+  check_op<std::greater>();
+  check_op<std::greater_equal>();
+}
+
+namespace test_ns {
+template <typename Char> class test_string {
+ private:
+  std::basic_string<Char> s_;
+
+ public:
+  test_string(const Char* s) : s_(s) {}
+  const Char* data() const { return s_.data(); }
+  size_t length() const { return s_.size(); }
+  operator const Char*() const { return s_.c_str(); }
+};
+
+template <typename Char>
+fmt::basic_string_view<Char> to_string_view(const test_string<Char>& s) {
+  return {s.data(), s.length()};
+}
+}  // namespace test_ns
+
+TEST(core_test, is_output_iterator) {
+  EXPECT_TRUE((fmt::detail::is_output_iterator<char*, char>::value));
+  EXPECT_FALSE((fmt::detail::is_output_iterator<const char*, char>::value));
+  EXPECT_FALSE((fmt::detail::is_output_iterator<std::string, char>::value));
+  EXPECT_TRUE(
+      (fmt::detail::is_output_iterator<std::back_insert_iterator<std::string>,
+                                       char>::value));
+  EXPECT_TRUE(
+      (fmt::detail::is_output_iterator<std::string::iterator, char>::value));
+  EXPECT_FALSE((fmt::detail::is_output_iterator<std::string::const_iterator,
+                                                char>::value));
+}
+
+TEST(core_test, buffer_appender) {
+  // back_insert_iterator is not default-constructible before C++20, so
+  // buffer_appender can only be default-constructible when back_insert_iterator
+  // is.
+  static_assert(
+      std::is_default_constructible<
+          std::back_insert_iterator<fmt::detail::buffer<char>>>::value ==
+          std::is_default_constructible<
+              fmt::detail::buffer_appender<char>>::value,
+      "");
+
+#ifdef __cpp_lib_ranges
+  static_assert(std::output_iterator<fmt::detail::buffer_appender<char>, char>);
+#endif
+}
+
+#if !FMT_GCC_VERSION || FMT_GCC_VERSION >= 470
+TEST(buffer_test, noncopyable) {
+  EXPECT_FALSE(std::is_copy_constructible<buffer<char>>::value);
+#  if !FMT_MSC_VERSION
+  // std::is_copy_assignable is broken in MSVC2013.
+  EXPECT_FALSE(std::is_copy_assignable<buffer<char>>::value);
+#  endif
+}
+
+TEST(buffer_test, nonmoveable) {
+  EXPECT_FALSE(std::is_move_constructible<buffer<char>>::value);
+#  if !FMT_MSC_VERSION
+  // std::is_move_assignable is broken in MSVC2013.
+  EXPECT_FALSE(std::is_move_assignable<buffer<char>>::value);
+#  endif
+}
+#endif
+
+TEST(buffer_test, indestructible) {
+  static_assert(!std::is_destructible<fmt::detail::buffer<int>>(),
+                "buffer's destructor is protected");
+}
+
+template <typename T> struct mock_buffer final : buffer<T> {
+  MOCK_METHOD1(do_grow, size_t(size_t capacity));
+
+  void grow(size_t capacity) override {
+    this->set(this->data(), do_grow(capacity));
+  }
+
+  mock_buffer(T* data = nullptr, size_t buf_capacity = 0) {
+    this->set(data, buf_capacity);
+    ON_CALL(*this, do_grow(_)).WillByDefault(Invoke([](size_t capacity) {
+      return capacity;
+    }));
+  }
+};
+
+TEST(buffer_test, ctor) {
+  {
+    mock_buffer<int> buffer;
+    EXPECT_EQ(nullptr, buffer.data());
+    EXPECT_EQ(static_cast<size_t>(0), buffer.size());
+    EXPECT_EQ(static_cast<size_t>(0), buffer.capacity());
+  }
+  {
+    int dummy;
+    mock_buffer<int> buffer(&dummy);
+    EXPECT_EQ(&dummy, &buffer[0]);
+    EXPECT_EQ(static_cast<size_t>(0), buffer.size());
+    EXPECT_EQ(static_cast<size_t>(0), buffer.capacity());
+  }
+  {
+    int dummy;
+    size_t capacity = std::numeric_limits<size_t>::max();
+    mock_buffer<int> buffer(&dummy, capacity);
+    EXPECT_EQ(&dummy, &buffer[0]);
+    EXPECT_EQ(static_cast<size_t>(0), buffer.size());
+    EXPECT_EQ(capacity, buffer.capacity());
+  }
+}
+
+TEST(buffer_test, access) {
+  char data[10];
+  mock_buffer<char> buffer(data, sizeof(data));
+  buffer[0] = 11;
+  EXPECT_EQ(11, buffer[0]);
+  buffer[3] = 42;
+  EXPECT_EQ(42, *(&buffer[0] + 3));
+  const fmt::detail::buffer<char>& const_buffer = buffer;
+  EXPECT_EQ(42, const_buffer[3]);
+}
+
+TEST(buffer_test, try_resize) {
+  char data[123];
+  mock_buffer<char> buffer(data, sizeof(data));
+  buffer[10] = 42;
+  EXPECT_EQ(42, buffer[10]);
+  buffer.try_resize(20);
+  EXPECT_EQ(20u, buffer.size());
+  EXPECT_EQ(123u, buffer.capacity());
+  EXPECT_EQ(42, buffer[10]);
+  buffer.try_resize(5);
+  EXPECT_EQ(5u, buffer.size());
+  EXPECT_EQ(123u, buffer.capacity());
+  EXPECT_EQ(42, buffer[10]);
+  // Check if try_resize calls grow.
+  EXPECT_CALL(buffer, do_grow(124));
+  buffer.try_resize(124);
+  EXPECT_CALL(buffer, do_grow(200));
+  buffer.try_resize(200);
+}
+
+TEST(buffer_test, try_resize_partial) {
+  char data[10];
+  mock_buffer<char> buffer(data, sizeof(data));
+  EXPECT_CALL(buffer, do_grow(20)).WillOnce(Return(15));
+  buffer.try_resize(20);
+  EXPECT_EQ(buffer.capacity(), 15);
+  EXPECT_EQ(buffer.size(), 15);
+}
+
+TEST(buffer_test, clear) {
+  mock_buffer<char> buffer;
+  EXPECT_CALL(buffer, do_grow(20));
+  buffer.try_resize(20);
+  buffer.try_resize(0);
+  EXPECT_EQ(static_cast<size_t>(0), buffer.size());
+  EXPECT_EQ(20u, buffer.capacity());
+}
+
+TEST(buffer_test, append) {
+  char data[15];
+  mock_buffer<char> buffer(data, 10);
+  auto test = "test";
+  buffer.append(test, test + 5);
+  EXPECT_STREQ(test, &buffer[0]);
+  EXPECT_EQ(5u, buffer.size());
+  buffer.try_resize(10);
+  EXPECT_CALL(buffer, do_grow(12));
+  buffer.append(test, test + 2);
+  EXPECT_EQ('t', buffer[10]);
+  EXPECT_EQ('e', buffer[11]);
+  EXPECT_EQ(12u, buffer.size());
+}
+
+TEST(buffer_test, append_partial) {
+  char data[10];
+  mock_buffer<char> buffer(data, sizeof(data));
+  testing::InSequence seq;
+  EXPECT_CALL(buffer, do_grow(15)).WillOnce(Return(10));
+  EXPECT_CALL(buffer, do_grow(15)).WillOnce(Invoke([&buffer](size_t) {
+    EXPECT_EQ(fmt::string_view(buffer.data(), buffer.size()), "0123456789");
+    buffer.clear();
+    return 10;
+  }));
+  auto test = "0123456789abcde";
+  buffer.append(test, test + 15);
+}
+
+TEST(buffer_test, append_allocates_enough_storage) {
+  char data[19];
+  mock_buffer<char> buffer(data, 10);
+  auto test = "abcdefgh";
+  buffer.try_resize(10);
+  EXPECT_CALL(buffer, do_grow(19));
+  buffer.append(test, test + 9);
+}
+
+struct custom_context {
+  using char_type = char;
+  using parse_context_type = fmt::format_parse_context;
+
+  bool called = false;
+
+  template <typename T> struct formatter_type {
+    auto parse(fmt::format_parse_context& ctx) -> decltype(ctx.begin()) {
+      return ctx.begin();
+    }
+
+    const char* format(const T&, custom_context& ctx) {
+      ctx.called = true;
+      return nullptr;
+    }
+  };
+
+  void advance_to(const char*) {}
+};
+
+struct test_struct {};
+
+FMT_BEGIN_NAMESPACE
+template <typename Char> struct formatter<test_struct, Char> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  auto format(test_struct, format_context& ctx) -> decltype(ctx.out()) {
+    auto test = string_view("test");
+    return std::copy_n(test.data(), test.size(), ctx.out());
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(arg_test, format_args) {
+  auto args = fmt::format_args();
+  EXPECT_FALSE(args.get(1));
+}
+
+TEST(arg_test, make_value_with_custom_context) {
+  auto t = test_struct();
+  fmt::detail::value<custom_context> arg(
+      fmt::detail::arg_mapper<custom_context>().map(t));
+  auto ctx = custom_context();
+  auto parse_ctx = fmt::format_parse_context("");
+  arg.custom.format(&t, parse_ctx, ctx);
+  EXPECT_TRUE(ctx.called);
+}
+
+// Use a unique result type to make sure that there are no undesirable
+// conversions.
+struct test_result {};
+
+template <typename T> struct mock_visitor {
+  template <typename U> struct result { using type = test_result; };
+
+  mock_visitor() {
+    ON_CALL(*this, visit(_)).WillByDefault(Return(test_result()));
+  }
+
+  MOCK_METHOD1_T(visit, test_result(T value));
+  MOCK_METHOD0_T(unexpected, void());
+
+  test_result operator()(T value) { return visit(value); }
+
+  template <typename U> test_result operator()(U) {
+    unexpected();
+    return test_result();
+  }
+};
+
+template <typename T> struct visit_type { using type = T; };
+
+#define VISIT_TYPE(type_, visit_type_) \
+  template <> struct visit_type<type_> { using type = visit_type_; }
+
+VISIT_TYPE(signed char, int);
+VISIT_TYPE(unsigned char, unsigned);
+VISIT_TYPE(short, int);
+VISIT_TYPE(unsigned short, unsigned);
+
+#if LONG_MAX == INT_MAX
+VISIT_TYPE(long, int);
+VISIT_TYPE(unsigned long, unsigned);
+#else
+VISIT_TYPE(long, long long);
+VISIT_TYPE(unsigned long, unsigned long long);
+#endif
+
+#define CHECK_ARG(Char, expected, value)                                  \
+  {                                                                       \
+    testing::StrictMock<mock_visitor<decltype(expected)>> visitor;        \
+    EXPECT_CALL(visitor, visit(expected));                                \
+    using iterator = std::back_insert_iterator<buffer<Char>>;             \
+    fmt::visit_format_arg(                                                \
+        visitor,                                                          \
+        fmt::detail::make_arg<fmt::basic_format_context<iterator, Char>>( \
+            value));                                                      \
+  }
+
+#define CHECK_ARG_SIMPLE(value)                             \
+  {                                                         \
+    using value_type = decltype(value);                     \
+    typename visit_type<value_type>::type expected = value; \
+    CHECK_ARG(char, expected, value)                        \
+    CHECK_ARG(wchar_t, expected, value)                     \
+  }
+
+template <typename T> class numeric_arg_test : public testing::Test {};
+
+using test_types =
+    testing::Types<bool, signed char, unsigned char, short, unsigned short, int,
+                   unsigned, long, unsigned long, long long, unsigned long long,
+                   float, double, long double>;
+TYPED_TEST_SUITE(numeric_arg_test, test_types);
+
+template <typename T, fmt::enable_if_t<std::is_integral<T>::value, int> = 0>
+T test_value() {
+  return static_cast<T>(42);
+}
+
+template <typename T,
+          fmt::enable_if_t<std::is_floating_point<T>::value, int> = 0>
+T test_value() {
+  return static_cast<T>(4.2);
+}
+
+TYPED_TEST(numeric_arg_test, make_and_visit) {
+  CHECK_ARG_SIMPLE(test_value<TypeParam>());
+  CHECK_ARG_SIMPLE(std::numeric_limits<TypeParam>::min());
+  CHECK_ARG_SIMPLE(std::numeric_limits<TypeParam>::max());
+}
+
+TEST(arg_test, char_arg) { CHECK_ARG(char, 'a', 'a'); }
+
+TEST(arg_test, string_arg) {
+  char str_data[] = "test";
+  char* str = str_data;
+  const char* cstr = str;
+  CHECK_ARG(char, cstr, str);
+
+  auto sv = fmt::string_view(str);
+  CHECK_ARG(char, sv, std::string(str));
+}
+
+TEST(arg_test, wstring_arg) {
+  wchar_t str_data[] = L"test";
+  wchar_t* str = str_data;
+  const wchar_t* cstr = str;
+
+  auto sv = fmt::basic_string_view<wchar_t>(str);
+  CHECK_ARG(wchar_t, cstr, str);
+  CHECK_ARG(wchar_t, cstr, cstr);
+  CHECK_ARG(wchar_t, sv, std::wstring(str));
+  CHECK_ARG(wchar_t, sv, fmt::basic_string_view<wchar_t>(str));
+}
+
+TEST(arg_test, pointer_arg) {
+  void* p = nullptr;
+  const void* cp = nullptr;
+  CHECK_ARG(char, cp, p);
+  CHECK_ARG(wchar_t, cp, p);
+  CHECK_ARG_SIMPLE(cp);
+}
+
+struct check_custom {
+  test_result operator()(
+      fmt::basic_format_arg<fmt::format_context>::handle h) const {
+    struct test_buffer final : fmt::detail::buffer<char> {
+      char data[10];
+      test_buffer() : fmt::detail::buffer<char>(data, 0, 10) {}
+      void grow(size_t) override {}
+    } buffer;
+    auto parse_ctx = fmt::format_parse_context("");
+    auto ctx = fmt::format_context(fmt::detail::buffer_appender<char>(buffer),
+                                   fmt::format_args());
+    h.format(parse_ctx, ctx);
+    EXPECT_EQ("test", std::string(buffer.data, buffer.size()));
+    return test_result();
+  }
+};
+
+TEST(arg_test, custom_arg) {
+  auto test = test_struct();
+  using visitor =
+      mock_visitor<fmt::basic_format_arg<fmt::format_context>::handle>;
+  testing::StrictMock<visitor> v;
+  EXPECT_CALL(v, visit(_)).WillOnce(Invoke(check_custom()));
+  fmt::visit_format_arg(v, fmt::detail::make_arg<fmt::format_context>(test));
+}
+
+TEST(arg_test, visit_invalid_arg) {
+  testing::StrictMock<mock_visitor<fmt::monostate>> visitor;
+  EXPECT_CALL(visitor, visit(_));
+  auto arg = fmt::basic_format_arg<fmt::format_context>();
+  fmt::visit_format_arg(visitor, arg);
+}
+
+#if FMT_USE_CONSTEXPR
+
+enum class arg_id_result { none, empty, index, name, error };
+struct test_arg_id_handler {
+  arg_id_result res = arg_id_result::none;
+  int index = 0;
+  string_view name;
+
+  constexpr void operator()() { res = arg_id_result::empty; }
+
+  constexpr void operator()(int i) {
+    res = arg_id_result::index;
+    index = i;
+  }
+
+  constexpr void operator()(string_view n) {
+    res = arg_id_result::name;
+    name = n;
+  }
+
+  constexpr void on_error(const char*) { res = arg_id_result::error; }
+};
+
+template <size_t N>
+constexpr test_arg_id_handler parse_arg_id(const char (&s)[N]) {
+  test_arg_id_handler h;
+  fmt::detail::parse_arg_id(s, s + N, h);
+  return h;
+}
+
+TEST(format_test, constexpr_parse_arg_id) {
+  static_assert(parse_arg_id(":").res == arg_id_result::empty, "");
+  static_assert(parse_arg_id("}").res == arg_id_result::empty, "");
+  static_assert(parse_arg_id("42:").res == arg_id_result::index, "");
+  static_assert(parse_arg_id("42:").index == 42, "");
+  static_assert(parse_arg_id("foo:").res == arg_id_result::name, "");
+  static_assert(parse_arg_id("foo:").name.size() == 3, "");
+  static_assert(parse_arg_id("!").res == arg_id_result::error, "");
+}
+
+struct test_format_specs_handler {
+  enum result { none, hash, zero, loc, error };
+  result res = none;
+
+  fmt::align_t alignment = fmt::align::none;
+  fmt::sign_t sign = fmt::sign::none;
+  char fill = 0;
+  int width = 0;
+  fmt::detail::arg_ref<char> width_ref;
+  int precision = 0;
+  fmt::detail::arg_ref<char> precision_ref;
+  fmt::presentation_type type = fmt::presentation_type::none;
+
+  // Workaround for MSVC2017 bug that results in "expression did not evaluate
+  // to a constant" with compiler-generated copy ctor.
+  constexpr test_format_specs_handler() {}
+  constexpr test_format_specs_handler(const test_format_specs_handler& other) =
+      default;
+
+  constexpr void on_align(fmt::align_t a) { alignment = a; }
+  constexpr void on_fill(fmt::string_view f) { fill = f[0]; }
+  constexpr void on_sign(fmt::sign_t s) { sign = s; }
+  constexpr void on_hash() { res = hash; }
+  constexpr void on_zero() { res = zero; }
+  constexpr void on_localized() { res = loc; }
+
+  constexpr void on_width(int w) { width = w; }
+  constexpr void on_dynamic_width(fmt::detail::auto_id) {}
+  constexpr void on_dynamic_width(int index) { width_ref = index; }
+  constexpr void on_dynamic_width(string_view) {}
+
+  constexpr void on_precision(int p) { precision = p; }
+  constexpr void on_dynamic_precision(fmt::detail::auto_id) {}
+  constexpr void on_dynamic_precision(int index) { precision_ref = index; }
+  constexpr void on_dynamic_precision(string_view) {}
+
+  constexpr void end_precision() {}
+  constexpr void on_type(fmt::presentation_type t) { type = t; }
+  constexpr void on_error(const char*) { res = error; }
+};
+
+template <size_t N>
+constexpr test_format_specs_handler parse_test_specs(const char (&s)[N]) {
+  auto h = test_format_specs_handler();
+  fmt::detail::parse_format_specs(s, s + N - 1, h);
+  return h;
+}
+
+TEST(core_test, constexpr_parse_format_specs) {
+  using handler = test_format_specs_handler;
+  static_assert(parse_test_specs("<").alignment == fmt::align::left, "");
+  static_assert(parse_test_specs("*^").fill == '*', "");
+  static_assert(parse_test_specs("+").sign == fmt::sign::plus, "");
+  static_assert(parse_test_specs("-").sign == fmt::sign::minus, "");
+  static_assert(parse_test_specs(" ").sign == fmt::sign::space, "");
+  static_assert(parse_test_specs("#").res == handler::hash, "");
+  static_assert(parse_test_specs("0").res == handler::zero, "");
+  static_assert(parse_test_specs("L").res == handler::loc, "");
+  static_assert(parse_test_specs("42").width == 42, "");
+  static_assert(parse_test_specs("{42}").width_ref.val.index == 42, "");
+  static_assert(parse_test_specs(".42").precision == 42, "");
+  static_assert(parse_test_specs(".{42}").precision_ref.val.index == 42, "");
+  static_assert(parse_test_specs("d").type == fmt::presentation_type::dec, "");
+  static_assert(parse_test_specs("{<").res == handler::error, "");
+}
+
+struct test_parse_context {
+  using char_type = char;
+
+  constexpr int next_arg_id() { return 11; }
+  template <typename Id> FMT_CONSTEXPR void check_arg_id(Id) {}
+  FMT_CONSTEXPR void check_dynamic_spec(int) {}
+
+  constexpr const char* begin() { return nullptr; }
+  constexpr const char* end() { return nullptr; }
+
+  void on_error(const char*) {}
+};
+
+template <size_t N>
+constexpr fmt::detail::dynamic_format_specs<char> parse_dynamic_specs(
+    const char (&s)[N]) {
+  auto specs = fmt::detail::dynamic_format_specs<char>();
+  auto ctx = test_parse_context();
+  auto h = fmt::detail::dynamic_specs_handler<test_parse_context>(specs, ctx);
+  parse_format_specs(s, s + N - 1, h);
+  return specs;
+}
+
+TEST(format_test, constexpr_dynamic_specs_handler) {
+  static_assert(parse_dynamic_specs("<").align == fmt::align::left, "");
+  static_assert(parse_dynamic_specs("*^").fill[0] == '*', "");
+  static_assert(parse_dynamic_specs("+").sign == fmt::sign::plus, "");
+  static_assert(parse_dynamic_specs("-").sign == fmt::sign::minus, "");
+  static_assert(parse_dynamic_specs(" ").sign == fmt::sign::space, "");
+  static_assert(parse_dynamic_specs("#").alt, "");
+  static_assert(parse_dynamic_specs("0").align == fmt::align::numeric, "");
+  static_assert(parse_dynamic_specs("42").width == 42, "");
+  static_assert(parse_dynamic_specs("{}").width_ref.val.index == 11, "");
+  static_assert(parse_dynamic_specs("{42}").width_ref.val.index == 42, "");
+  static_assert(parse_dynamic_specs(".42").precision == 42, "");
+  static_assert(parse_dynamic_specs(".{}").precision_ref.val.index == 11, "");
+  static_assert(parse_dynamic_specs(".{42}").precision_ref.val.index == 42, "");
+  static_assert(parse_dynamic_specs("d").type == fmt::presentation_type::dec,
+                "");
+}
+
+template <size_t N>
+constexpr test_format_specs_handler check_specs(const char (&s)[N]) {
+  fmt::detail::specs_checker<test_format_specs_handler> checker(
+      test_format_specs_handler(), fmt::detail::type::double_type);
+  parse_format_specs(s, s + N - 1, checker);
+  return checker;
+}
+
+TEST(format_test, constexpr_specs_checker) {
+  using handler = test_format_specs_handler;
+  static_assert(check_specs("<").alignment == fmt::align::left, "");
+  static_assert(check_specs("*^").fill == '*', "");
+  static_assert(check_specs("+").sign == fmt::sign::plus, "");
+  static_assert(check_specs("-").sign == fmt::sign::minus, "");
+  static_assert(check_specs(" ").sign == fmt::sign::space, "");
+  static_assert(check_specs("#").res == handler::hash, "");
+  static_assert(check_specs("0").res == handler::zero, "");
+  static_assert(check_specs("42").width == 42, "");
+  static_assert(check_specs("{42}").width_ref.val.index == 42, "");
+  static_assert(check_specs(".42").precision == 42, "");
+  static_assert(check_specs(".{42}").precision_ref.val.index == 42, "");
+  static_assert(check_specs("d").type == fmt::presentation_type::dec, "");
+  static_assert(check_specs("{<").res == handler::error, "");
+}
+
+struct test_format_string_handler {
+  constexpr void on_text(const char*, const char*) {}
+
+  constexpr int on_arg_id() { return 0; }
+
+  template <typename T> constexpr int on_arg_id(T) { return 0; }
+
+  constexpr void on_replacement_field(int, const char*) {}
+
+  constexpr const char* on_format_specs(int, const char* begin, const char*) {
+    return begin;
+  }
+
+  constexpr void on_error(const char*) { error = true; }
+
+  bool error = false;
+};
+
+template <size_t N> constexpr bool parse_string(const char (&s)[N]) {
+  auto h = test_format_string_handler();
+  fmt::detail::parse_format_string<true>(fmt::string_view(s, N - 1), h);
+  return !h.error;
+}
+
+TEST(format_test, constexpr_parse_format_string) {
+  static_assert(parse_string("foo"), "");
+  static_assert(!parse_string("}"), "");
+  static_assert(parse_string("{}"), "");
+  static_assert(parse_string("{42}"), "");
+  static_assert(parse_string("{foo}"), "");
+  static_assert(parse_string("{:}"), "");
+}
+#endif  // FMT_USE_CONSTEXPR
+
+struct enabled_formatter {};
+struct enabled_ptr_formatter {};
+struct disabled_formatter {};
+struct disabled_formatter_convertible {
+  operator int() const { return 42; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<enabled_formatter> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+  auto format(enabled_formatter, format_context& ctx) -> decltype(ctx.out()) {
+    return ctx.out();
+  }
+};
+
+template <> struct formatter<enabled_ptr_formatter*> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+  auto format(enabled_ptr_formatter*, format_context& ctx)
+      -> decltype(ctx.out()) {
+    return ctx.out();
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(core_test, has_formatter) {
+  using fmt::has_formatter;
+  using context = fmt::format_context;
+  static_assert(has_formatter<enabled_formatter, context>::value, "");
+  static_assert(!has_formatter<disabled_formatter, context>::value, "");
+  static_assert(!has_formatter<disabled_formatter_convertible, context>::value,
+                "");
+}
+
+struct const_formattable {};
+struct nonconst_formattable {};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<const_formattable> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  auto format(const const_formattable&, format_context& ctx)
+      -> decltype(ctx.out()) {
+    auto test = string_view("test");
+    return std::copy_n(test.data(), test.size(), ctx.out());
+  }
+};
+
+template <> struct formatter<nonconst_formattable> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  auto format(nonconst_formattable&, format_context& ctx)
+      -> decltype(ctx.out()) {
+    auto test = string_view("test");
+    return std::copy_n(test.data(), test.size(), ctx.out());
+  }
+};
+FMT_END_NAMESPACE
+
+struct convertible_to_pointer {
+  operator const int*() const { return nullptr; }
+};
+
+struct convertible_to_pointer_formattable {
+  operator const int*() const { return nullptr; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<convertible_to_pointer_formattable> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  auto format(convertible_to_pointer_formattable, format_context& ctx) const
+      -> decltype(ctx.out()) {
+    auto test = string_view("test");
+    return std::copy_n(test.data(), test.size(), ctx.out());
+  }
+};
+FMT_END_NAMESPACE
+
+enum class unformattable_scoped_enum {};
+
+namespace test {
+enum class formattable_scoped_enum {};
+auto format_as(formattable_scoped_enum) -> int { return 42; }
+
+struct convertible_to_enum {
+  operator formattable_scoped_enum() const { return {}; }
+};
+}  // namespace test
+
+TEST(core_test, is_formattable) {
+#if 0
+  // This should be enabled once corresponding map overloads are gone.
+  static_assert(fmt::is_formattable<signed char*>::value, "");
+  static_assert(fmt::is_formattable<unsigned char*>::value, "");
+  static_assert(fmt::is_formattable<const signed char*>::value, "");
+  static_assert(fmt::is_formattable<const unsigned char*>::value, "");
+#endif
+  static_assert(!fmt::is_formattable<wchar_t>::value, "");
+#ifdef __cpp_char8_t
+  static_assert(!fmt::is_formattable<char8_t>::value, "");
+#endif
+  static_assert(!fmt::is_formattable<char16_t>::value, "");
+  static_assert(!fmt::is_formattable<char32_t>::value, "");
+  static_assert(!fmt::is_formattable<const wchar_t*>::value, "");
+  static_assert(!fmt::is_formattable<const wchar_t[3]>::value, "");
+  static_assert(!fmt::is_formattable<fmt::basic_string_view<wchar_t>>::value,
+                "");
+  static_assert(fmt::is_formattable<enabled_formatter>::value, "");
+  static_assert(!fmt::is_formattable<enabled_ptr_formatter*>::value, "");
+  static_assert(!fmt::is_formattable<disabled_formatter>::value, "");
+  static_assert(fmt::is_formattable<disabled_formatter_convertible>::value, "");
+
+  static_assert(fmt::is_formattable<const_formattable&>::value, "");
+  static_assert(fmt::is_formattable<const const_formattable&>::value, "");
+
+  static_assert(fmt::is_formattable<nonconst_formattable&>::value, "");
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
+  static_assert(!fmt::is_formattable<const nonconst_formattable&>::value, "");
+#endif
+
+  static_assert(!fmt::is_formattable<convertible_to_pointer>::value, "");
+  const auto f = convertible_to_pointer_formattable();
+  EXPECT_EQ(fmt::format("{}", f), "test");
+
+  static_assert(!fmt::is_formattable<void (*)()>::value, "");
+
+  struct s;
+  static_assert(!fmt::is_formattable<int(s::*)>::value, "");
+  static_assert(!fmt::is_formattable<int (s::*)()>::value, "");
+  static_assert(!fmt::is_formattable<unformattable_scoped_enum>::value, "");
+  static_assert(fmt::is_formattable<test::formattable_scoped_enum>::value, "");
+  static_assert(!fmt::is_formattable<test::convertible_to_enum>::value, "");
+}
+
+TEST(core_test, format) { EXPECT_EQ(fmt::format("{}", 42), "42"); }
+
+TEST(core_test, format_to) {
+  std::string s;
+  fmt::format_to(std::back_inserter(s), "{}", 42);
+  EXPECT_EQ(s, "42");
+}
+
+TEST(core_test, format_as) {
+  EXPECT_EQ(fmt::format("{}", test::formattable_scoped_enum()), "42");
+}
+
+struct convertible_to_int {
+  operator int() const { return 42; }
+};
+
+struct convertible_to_c_string {
+  operator const char*() const { return "foo"; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<convertible_to_int> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+  auto format(convertible_to_int, format_context& ctx) -> decltype(ctx.out()) {
+    return std::copy_n("foo", 3, ctx.out());
+  }
+};
+
+template <> struct formatter<convertible_to_c_string> {
+  FMT_CONSTEXPR auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+  auto format(convertible_to_c_string, format_context& ctx)
+      -> decltype(ctx.out()) {
+    return std::copy_n("bar", 3, ctx.out());
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(core_test, formatter_overrides_implicit_conversion) {
+  EXPECT_EQ(fmt::format("{}", convertible_to_int()), "foo");
+  EXPECT_EQ(fmt::format("{}", convertible_to_c_string()), "bar");
+}
+
+// Test that check is not found by ADL.
+template <typename T> void check(T);
+TEST(core_test, adl_check) {
+  EXPECT_EQ(fmt::format("{}", test_struct()), "test");
+}
+
+TEST(core_test, to_string_view_foreign_strings) {
+  using namespace test_ns;
+  EXPECT_EQ(to_string_view(test_string<char>("42")), "42");
+  fmt::detail::type type =
+      fmt::detail::mapped_type_constant<test_string<char>,
+                                        fmt::format_context>::value;
+  EXPECT_EQ(type, fmt::detail::type::string_type);
+}
+
+struct implicitly_convertible_to_string {
+  operator std::string() const { return "foo"; }
+};
+
+struct implicitly_convertible_to_string_view {
+  operator fmt::string_view() const { return "foo"; }
+};
+
+TEST(core_test, format_implicitly_convertible_to_string_view) {
+  EXPECT_EQ("foo", fmt::format("{}", implicitly_convertible_to_string_view()));
+}
+
+// std::is_constructible is broken in MSVC until version 2015.
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1900
+struct explicitly_convertible_to_string_view {
+  explicit operator fmt::string_view() const { return "foo"; }
+};
+
+TEST(core_test, format_explicitly_convertible_to_string_view) {
+  // Types explicitly convertible to string_view are not formattable by
+  // default because it may introduce ODR violations.
+  static_assert(
+      !fmt::is_formattable<explicitly_convertible_to_string_view>::value, "");
+}
+
+#  ifdef FMT_USE_STRING_VIEW
+struct explicitly_convertible_to_std_string_view {
+  explicit operator std::string_view() const { return "foo"; }
+};
+
+TEST(core_test, format_explicitly_convertible_to_std_string_view) {
+  // Types explicitly convertible to string_view are not formattable by
+  // default because it may introduce ODR violations.
+  static_assert(
+      !fmt::is_formattable<explicitly_convertible_to_std_string_view>::value,
+      "");
+}
+#  endif
+#endif
+
+struct convertible_to_long_long {
+  operator long long() const { return 1LL << 32; }
+};
+
+TEST(format_test, format_convertible_to_long_long) {
+  EXPECT_EQ("100000000", fmt::format("{:x}", convertible_to_long_long()));
+}
+
+struct disabled_rvalue_conversion {
+  operator const char*() const& { return "foo"; }
+  operator const char*() & { return "foo"; }
+  operator const char*() const&& = delete;
+  operator const char*() && = delete;
+};
+
+TEST(core_test, disabled_rvalue_conversion) {
+  EXPECT_EQ("foo", fmt::format("{}", disabled_rvalue_conversion()));
+}
+
+namespace adl_test {
+template <typename... T> void make_format_args(const T&...) = delete;
+
+struct string : std::string {};
+}  // namespace adl_test
+
+// Test that formatting functions compile when make_format_args is found by ADL.
+TEST(core_test, adl) {
+  // Only check compilation and don't run the code to avoid polluting the output
+  // and since the output is tested elsewhere.
+  if (fmt::detail::const_check(true)) return;
+  auto s = adl_test::string();
+  char buf[10];
+  (void)fmt::format("{}", s);
+  fmt::format_to(buf, "{}", s);
+  fmt::format_to_n(buf, 10, "{}", s);
+  (void)fmt::formatted_size("{}", s);
+  fmt::print("{}", s);
+  fmt::print(stdout, "{}", s);
+}
+
+TEST(core_test, has_const_formatter) {
+  EXPECT_TRUE((fmt::detail::has_const_formatter<const_formattable,
+                                                fmt::format_context>()));
+  EXPECT_FALSE((fmt::detail::has_const_formatter<nonconst_formattable,
+                                                 fmt::format_context>()));
+}
+
+TEST(core_test, format_nonconst) {
+  EXPECT_EQ(fmt::format("{}", nonconst_formattable()), "test");
+}
diff --git a/src/fmt/test/cuda-test/CMakeLists.txt b/src/fmt/test/cuda-test/CMakeLists.txt
new file mode 100644
index 000000000..be8685b89
--- /dev/null
+++ b/src/fmt/test/cuda-test/CMakeLists.txt
@@ -0,0 +1,73 @@
+# We can find some usecases which follow the guide of CMake which uses
+# `enable_language(CUDA)` instead of `find_package(CUDA)` and let the CMake
+# built-in functions use NVCC.
+
+# See: https://cmake.org/cmake/help/latest/module/FindCUDA.html#replacement
+#
+# However, this requires CMake version 3.10 or higher and we can't be sure most
+# of the CUDA projects are using those.
+#
+# This test relies on `find_package(CUDA)` in the parent CMake config.
+
+# These can be updated when NVCC becomes ready for C++ 17 features
+# https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#cpp14-language-features
+set(CMAKE_CUDA_STANDARD 14)
+set(CMAKE_CUDA_STANDARD_REQUIRED 14)
+
+# In this test, we assume that the user is going to compile CUDA source code
+# with some libraries (fmt in this case).
+#
+# In addition to that, this test invokes both the C++ host compiler and NVCC
+# by providing another (non-CUDA) C++ source code.
+if (${CMAKE_VERSION} VERSION_LESS 3.15)
+  # https://docs.nvidia.com/cuda/cuda-compiler-driver-nvcc/index.html
+  list(APPEND CUDA_NVCC_FLAGS "-std=c++14")
+  if (MSVC)
+    # This is the solution of pytorch:
+    # https://github.com/pytorch/pytorch/pull/7118
+    list(APPEND CUDA_NVCC_FLAGS "-Xcompiler" "/std:c++14")
+    list(APPEND CUDA_NVCC_FLAGS "-Xcompiler" "/Zc:__cplusplus")
+    # for the reason of this -Xcompiler options, see below.
+  endif ()
+  cuda_add_executable(fmt-in-cuda-test cuda-cpp14.cu cpp14.cc)
+  target_compile_features(fmt-in-cuda-test PRIVATE cxx_std_14)
+  if (MSVC)
+    # This part is for (non-CUDA) C++ code. MSVC can define incorrect
+    # `__cplusplus` macro. Fix for the issue is to use additional compiler flag. 
+    #
+    # See Also:
+    # https://devblogs.microsoft.com/cppblog/msvc-now-correctly-reports-__cplusplus/
+    # https://github.com/Microsoft/vscode-cpptools/issues/2595
+    target_compile_options(fmt-in-cuda-test PRIVATE /Zc:__cplusplus /permissive-)
+  endif ()
+else()
+  # now using a "new" way of handling CUDA
+  add_executable(fmt-in-cuda-test cuda-cpp14.cu cpp14.cc)
+  set_target_properties(fmt-in-cuda-test PROPERTIES CUDA_SEPARABLE_COMPILATION ON)
+  target_compile_features(fmt-in-cuda-test PRIVATE cxx_std_14)
+  if (MSVC)
+    # with MSVC, 'cxx_std_14' will only propagate to the host code (MSVC), but will
+    # not set __cplusplus correctly anyway, while nvcc will ignore it.
+    # If specified for nvcc on the command line as '-std=c++14' nvcc will emit this
+    # message instead:
+    # nvcc warning : The -std=c++14 flag is not supported with the configured host
+    #                compiler. Flag will be ignored.
+    set_property(SOURCE cuda-cpp14.cu APPEND PROPERTY
+      COMPILE_OPTIONS -Xcompiler /std:c++14 -Xcompiler /Zc:__cplusplus)
+    set_property(SOURCE cpp14.cc APPEND PROPERTY
+      COMPILE_OPTIONS /std:c++14 /Zc:__cplusplus)
+  endif()
+endif()
+
+get_target_property(IN_USE_CUDA_STANDARD fmt-in-cuda-test CUDA_STANDARD)
+message(STATUS "cuda_standard:          ${IN_USE_CUDA_STANDARD}")
+
+get_target_property(IN_USE_CUDA_STANDARD_REQUIRED
+    fmt-in-cuda-test CUDA_STANDARD_REQUIRED)
+message(STATUS "cuda_standard_required: ${IN_USE_CUDA_STANDARD_REQUIRED}")
+
+# We don't use PUBLIC or other keyword for reasons explained in the
+# CUDA_LINK_LIBRARIES_KEYWORD section in
+# https://cmake.org/cmake/help/latest/module/FindCUDA.html
+target_link_libraries(fmt-in-cuda-test fmt::fmt)
+
diff --git a/src/fmt/test/cuda-test/cpp14.cc b/src/fmt/test/cuda-test/cpp14.cc
new file mode 100644
index 000000000..ad8463962
--- /dev/null
+++ b/src/fmt/test/cuda-test/cpp14.cc
@@ -0,0 +1,11 @@
+#include <fmt/core.h>
+
+// The purpose of this part is to ensure NVCC's host compiler also supports
+// the standard version. See 'cuda-cpp14.cu'.
+//
+// https://en.cppreference.com/w/cpp/preprocessor/replace#Predefined_macros
+static_assert(__cplusplus >= 201402L, "expect C++ 2014 for host compiler");
+
+auto make_message_cpp() -> std::string {
+  return fmt::format("host compiler \t: __cplusplus == {}", __cplusplus);
+}
diff --git a/src/fmt/test/cuda-test/cuda-cpp14.cu b/src/fmt/test/cuda-test/cuda-cpp14.cu
new file mode 100644
index 000000000..76a9d0883
--- /dev/null
+++ b/src/fmt/test/cuda-test/cuda-cpp14.cu
@@ -0,0 +1,28 @@
+//  Direct NVCC command line example:
+//
+//  nvcc ./cuda-cpp14.cu -x cu -I"../include" -l"fmtd" -L"../build/Debug" \
+//       -std=c++14 -Xcompiler /std:c++14 -Xcompiler /Zc:__cplusplus
+
+// Ensure that we are using the latest C++ standard for NVCC
+// The version is C++14
+//
+// https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#c-cplusplus-language-support
+// https://en.cppreference.com/w/cpp/preprocessor/replace#Predefined_macros
+static_assert(__cplusplus >= 201402L, "expect C++ 2014 for nvcc");
+
+#include <fmt/core.h>
+
+#include <cuda.h>
+#include <iostream>
+
+extern auto make_message_cpp() -> std::string;
+extern auto make_message_cuda() -> std::string;
+
+int main() {
+  std::cout << make_message_cuda() << std::endl;
+  std::cout << make_message_cpp() << std::endl;
+}
+
+auto make_message_cuda() -> std::string {
+  return fmt::format("nvcc compiler \t: __cplusplus == {}", __cplusplus);
+}
diff --git a/src/fmt/test/detect-stdfs.cc b/src/fmt/test/detect-stdfs.cc
new file mode 100644
index 000000000..2dc665383
--- /dev/null
+++ b/src/fmt/test/detect-stdfs.cc
@@ -0,0 +1,18 @@
+// Formatting library for C++ - tests of formatters for standard library types
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <exception>  // _GLIBCXX_RELEASE & _LIBCPP_VERSION
+
+#if defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE == 8
+#  error libfound "stdc++fs"
+#elif !defined(__apple_build_version__) && defined(_LIBCPP_VERSION) && \
+    _LIBCPP_VERSION >= 7000 && _LIBCPP_VERSION < 9000
+#  error libfound "c++fs"
+#else
+// none if std::filesystem does not require additional libraries
+#  error libfound ""
+#endif
diff --git a/src/fmt/test/enforce-checks-test.cc b/src/fmt/test/enforce-checks-test.cc
new file mode 100644
index 000000000..c77cb142f
--- /dev/null
+++ b/src/fmt/test/enforce-checks-test.cc
@@ -0,0 +1,63 @@
+// Formatting library for C++ - formatting library tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <iterator>
+#include <vector>
+
+#include "fmt/chrono.h"
+#include "fmt/color.h"
+#include "fmt/format.h"
+#include "fmt/ostream.h"
+#include "fmt/ranges.h"
+#include "fmt/xchar.h"
+
+// Exercise the API to verify that everything we expect to can compile.
+void test_format_api() {
+  (void)fmt::format(FMT_STRING("{}"), 42);
+  (void)fmt::format(FMT_STRING(L"{}"), 42);
+  (void)fmt::format(FMT_STRING("noop"));
+
+  (void)fmt::to_string(42);
+  (void)fmt::to_wstring(42);
+
+  std::vector<char> out;
+  fmt::format_to(std::back_inserter(out), FMT_STRING("{}"), 42);
+
+  char buffer[4];
+  fmt::format_to_n(buffer, 3, FMT_STRING("{}"), 12345);
+
+  wchar_t wbuffer[4];
+  fmt::format_to_n(wbuffer, 3, FMT_STRING(L"{}"), 12345);
+}
+
+void test_chrono() {
+  (void)fmt::format(FMT_STRING("{}"), std::chrono::seconds(42));
+  (void)fmt::format(FMT_STRING(L"{}"), std::chrono::seconds(42));
+}
+
+void test_text_style() {
+  fmt::print(fg(fmt::rgb(255, 20, 30)), FMT_STRING("{}"), "rgb(255,20,30)");
+  (void)fmt::format(fg(fmt::rgb(255, 20, 30)), FMT_STRING("{}"),
+                    "rgb(255,20,30)");
+
+  fmt::text_style ts = fg(fmt::rgb(255, 20, 30));
+  std::string out;
+  fmt::format_to(std::back_inserter(out), ts,
+                 FMT_STRING("rgb(255,20,30){}{}{}"), 1, 2, 3);
+}
+
+void test_range() {
+  std::vector<char> hello = {'h', 'e', 'l', 'l', 'o'};
+  (void)fmt::format(FMT_STRING("{}"), hello);
+}
+
+int main() {
+  test_format_api();
+  test_chrono();
+  test_text_style();
+  test_range();
+}
diff --git a/src/fmt/test/find-package-test/CMakeLists.txt b/src/fmt/test/find-package-test/CMakeLists.txt
new file mode 100644
index 000000000..93d686e64
--- /dev/null
+++ b/src/fmt/test/find-package-test/CMakeLists.txt
@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.1...3.18)
+
+project(fmt-test)
+
+find_package(FMT REQUIRED)
+
+add_executable(library-test main.cc)
+target_link_libraries(library-test fmt::fmt)
+target_compile_options(library-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+target_include_directories(library-test PUBLIC SYSTEM .)
+
+if (TARGET fmt::fmt-header-only)
+  add_executable(header-only-test main.cc)
+  target_link_libraries(header-only-test fmt::fmt-header-only)
+  target_compile_options(header-only-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+  target_include_directories(header-only-test PUBLIC SYSTEM .)
+endif ()
diff --git a/src/fmt/test/find-package-test/main.cc b/src/fmt/test/find-package-test/main.cc
new file mode 100644
index 000000000..911e0e8d1
--- /dev/null
+++ b/src/fmt/test/find-package-test/main.cc
@@ -0,0 +1,5 @@
+#include "fmt/format.h"
+
+int main(int argc, char** argv) {
+  for (int i = 0; i < argc; ++i) fmt::print("{}: {}\n", i, argv[i]);
+}
diff --git a/src/fmt/test/format-impl-test.cc b/src/fmt/test/format-impl-test.cc
new file mode 100644
index 000000000..46486a6f4
--- /dev/null
+++ b/src/fmt/test/format-impl-test.cc
@@ -0,0 +1,547 @@
+// Formatting library for C++ - formatting library implementation tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <algorithm>
+#include <cstring>
+
+// clang-format off
+#include "test-assert.h"
+// clang-format on
+
+#include "fmt/format.h"
+#include "gmock/gmock.h"
+#include "util.h"
+
+using fmt::detail::bigint;
+using fmt::detail::fp;
+using fmt::detail::max_value;
+
+static_assert(!std::is_copy_constructible<bigint>::value, "");
+static_assert(!std::is_copy_assignable<bigint>::value, "");
+
+TEST(bigint_test, construct) {
+  EXPECT_EQ(fmt::to_string(bigint()), "");
+  EXPECT_EQ(fmt::to_string(bigint(0x42)), "42");
+  EXPECT_EQ(fmt::to_string(bigint(0x123456789abcedf0)), "123456789abcedf0");
+}
+
+TEST(bigint_test, compare) {
+  bigint n1(42);
+  bigint n2(42);
+  EXPECT_EQ(compare(n1, n2), 0);
+  n2 <<= 32;
+  EXPECT_LT(compare(n1, n2), 0);
+  bigint n3(43);
+  EXPECT_LT(compare(n1, n3), 0);
+  EXPECT_GT(compare(n3, n1), 0);
+  bigint n4(42 * 0x100000001);
+  EXPECT_LT(compare(n2, n4), 0);
+  EXPECT_GT(compare(n4, n2), 0);
+}
+
+TEST(bigint_test, add_compare) {
+  EXPECT_LT(
+      add_compare(bigint(0xffffffff), bigint(0xffffffff), bigint(1) <<= 64), 0);
+  EXPECT_LT(add_compare(bigint(1) <<= 32, bigint(1), bigint(1) <<= 96), 0);
+  EXPECT_GT(add_compare(bigint(1) <<= 32, bigint(0), bigint(0xffffffff)), 0);
+  EXPECT_GT(add_compare(bigint(0), bigint(1) <<= 32, bigint(0xffffffff)), 0);
+  EXPECT_GT(add_compare(bigint(42), bigint(1), bigint(42)), 0);
+  EXPECT_GT(add_compare(bigint(0xffffffff), bigint(1), bigint(0xffffffff)), 0);
+  EXPECT_LT(add_compare(bigint(10), bigint(10), bigint(22)), 0);
+  EXPECT_LT(add_compare(bigint(0x100000010), bigint(0x100000010),
+                        bigint(0x300000010)),
+            0);
+  EXPECT_GT(add_compare(bigint(0x1ffffffff), bigint(0x100000002),
+                        bigint(0x300000000)),
+            0);
+  EXPECT_EQ(add_compare(bigint(0x1ffffffff), bigint(0x100000002),
+                        bigint(0x300000001)),
+            0);
+  EXPECT_LT(add_compare(bigint(0x1ffffffff), bigint(0x100000002),
+                        bigint(0x300000002)),
+            0);
+  EXPECT_LT(add_compare(bigint(0x1ffffffff), bigint(0x100000002),
+                        bigint(0x300000003)),
+            0);
+}
+
+TEST(bigint_test, shift_left) {
+  bigint n(0x42);
+  n <<= 0;
+  EXPECT_EQ(fmt::to_string(n), "42");
+  n <<= 1;
+  EXPECT_EQ(fmt::to_string(n), "84");
+  n <<= 25;
+  EXPECT_EQ(fmt::to_string(n), "108000000");
+}
+
+TEST(bigint_test, multiply) {
+  bigint n(0x42);
+  EXPECT_THROW(n *= 0, assertion_failure);
+  n *= 1;
+  EXPECT_EQ(fmt::to_string(n), "42");
+
+  n *= 2;
+  EXPECT_EQ(fmt::to_string(n), "84");
+  n *= 0x12345678;
+  EXPECT_EQ(fmt::to_string(n), "962fc95e0");
+
+  bigint bigmax(max_value<uint32_t>());
+  bigmax *= max_value<uint32_t>();
+  EXPECT_EQ(fmt::to_string(bigmax), "fffffffe00000001");
+
+  const auto max64 = max_value<uint64_t>();
+  bigmax = max64;
+  bigmax *= max64;
+  EXPECT_EQ(fmt::to_string(bigmax), "fffffffffffffffe0000000000000001");
+
+  const auto max128 = (fmt::detail::uint128_t(max64) << 64) | max64;
+  bigmax = max128;
+  bigmax *= max128;
+  EXPECT_EQ(fmt::to_string(bigmax),
+            "fffffffffffffffffffffffffffffffe00000000000000000000000000000001");
+}
+
+TEST(bigint_test, square) {
+  bigint n0(0);
+  n0.square();
+  EXPECT_EQ(fmt::to_string(n0), "0");
+  bigint n1(0x100);
+  n1.square();
+  EXPECT_EQ(fmt::to_string(n1), "10000");
+  bigint n2(0xfffffffff);
+  n2.square();
+  EXPECT_EQ(fmt::to_string(n2), "ffffffffe000000001");
+  bigint n3(max_value<uint64_t>());
+  n3.square();
+  EXPECT_EQ(fmt::to_string(n3), "fffffffffffffffe0000000000000001");
+  bigint n4;
+  n4.assign_pow10(10);
+  EXPECT_EQ(fmt::to_string(n4), "2540be400");
+}
+
+TEST(bigint_test, divmod_assign_zero_divisor) {
+  bigint zero(0);
+  EXPECT_THROW(bigint(0).divmod_assign(zero), assertion_failure);
+  EXPECT_THROW(bigint(42).divmod_assign(zero), assertion_failure);
+}
+
+TEST(bigint_test, divmod_assign_self) {
+  bigint n(100);
+  EXPECT_THROW(n.divmod_assign(n), assertion_failure);
+}
+
+TEST(bigint_test, divmod_assign_unaligned) {
+  // (42 << 340) / pow(10, 100):
+  bigint n1(42);
+  n1 <<= 340;
+  bigint n2;
+  n2.assign_pow10(100);
+  int result = n1.divmod_assign(n2);
+  EXPECT_EQ(result, 9406);
+  EXPECT_EQ(fmt::to_string(n1),
+            "10f8353019583bfc29ffc8f564e1b9f9d819dbb4cf783e4507eca1539220p96");
+}
+
+TEST(bigint_test, divmod_assign) {
+  // 100 / 10:
+  bigint n1(100);
+  int result = n1.divmod_assign(bigint(10));
+  EXPECT_EQ(result, 10);
+  EXPECT_EQ(fmt::to_string(n1), "0");
+  // pow(10, 100) / (42 << 320):
+  n1.assign_pow10(100);
+  result = n1.divmod_assign(bigint(42) <<= 320);
+  EXPECT_EQ(result, 111);
+  EXPECT_EQ(fmt::to_string(n1),
+            "13ad2594c37ceb0b2784c4ce0bf38ace408e211a7caab24308a82e8f10p96");
+  // 42 / 100:
+  bigint n2(42);
+  n1.assign_pow10(2);
+  result = n2.divmod_assign(n1);
+  EXPECT_EQ(result, 0);
+  EXPECT_EQ(fmt::to_string(n2), "2a");
+}
+
+template <bool is_iec559> void run_double_tests() {
+  fmt::print("warning: double is not IEC559, skipping FP tests\n");
+}
+
+template <> void run_double_tests<true>() {
+  // Construct from double.
+  EXPECT_EQ(fp(1.23), fp(0x13ae147ae147aeu, -52));
+}
+
+TEST(fp_test, double_tests) {
+  run_double_tests<std::numeric_limits<double>::is_iec559>();
+}
+
+TEST(fp_test, normalize) {
+  const auto v = fp(0xbeef, 42);
+  auto normalized = normalize(v);
+  EXPECT_EQ(normalized.f, 0xbeef000000000000);
+  EXPECT_EQ(normalized.e, -6);
+}
+
+TEST(fp_test, multiply) {
+  auto v = fp(123ULL << 32, 4) * fp(56ULL << 32, 7);
+  EXPECT_EQ(v.f, 123u * 56u);
+  EXPECT_EQ(v.e, 4 + 7 + 64);
+  v = fp(123ULL << 32, 4) * fp(567ULL << 31, 8);
+  EXPECT_EQ(v.f, (123 * 567 + 1u) / 2);
+  EXPECT_EQ(v.e, 4 + 8 + 64);
+}
+
+TEST(fp_test, get_cached_power) {
+  using limits = std::numeric_limits<double>;
+  for (auto exp = limits::min_exponent; exp <= limits::max_exponent; ++exp) {
+    int dec_exp = 0;
+    auto power = fmt::detail::get_cached_power(exp, dec_exp);
+    bigint exact, cache(power.f);
+    if (dec_exp >= 0) {
+      exact.assign_pow10(dec_exp);
+      if (power.e <= 0)
+        exact <<= -power.e;
+      else
+        cache <<= power.e;
+      exact.align(cache);
+      cache.align(exact);
+      auto exact_str = fmt::to_string(exact);
+      auto cache_str = fmt::to_string(cache);
+      EXPECT_EQ(exact_str.size(), cache_str.size());
+      EXPECT_EQ(exact_str.substr(0, 15), cache_str.substr(0, 15));
+      int diff = cache_str[15] - exact_str[15];
+      if (diff == 1)
+        EXPECT_GT(exact_str[16], '8');
+      else
+        EXPECT_EQ(diff, 0);
+    } else {
+      cache.assign_pow10(-dec_exp);
+      cache *= power.f + 1;  // Inexact check.
+      exact = 1;
+      exact <<= -power.e;
+      exact.align(cache);
+      auto exact_str = fmt::to_string(exact);
+      auto cache_str = fmt::to_string(cache);
+      EXPECT_EQ(exact_str.size(), cache_str.size());
+      EXPECT_EQ(exact_str.substr(0, 16), cache_str.substr(0, 16));
+    }
+  }
+}
+
+TEST(fp_test, dragonbox_max_k) {
+  using fmt::detail::dragonbox::floor_log10_pow2;
+  using float_info = fmt::detail::dragonbox::float_info<float>;
+  EXPECT_EQ(
+      fmt::detail::const_check(float_info::max_k),
+      float_info::kappa -
+          floor_log10_pow2(std::numeric_limits<float>::min_exponent -
+                           fmt::detail::num_significand_bits<float>() - 1));
+  using double_info = fmt::detail::dragonbox::float_info<double>;
+  EXPECT_EQ(
+      fmt::detail::const_check(double_info::max_k),
+      double_info::kappa -
+          floor_log10_pow2(std::numeric_limits<double>::min_exponent -
+                           fmt::detail::num_significand_bits<double>() - 1));
+}
+
+TEST(fp_test, get_round_direction) {
+  using fmt::detail::get_round_direction;
+  using fmt::detail::round_direction;
+  EXPECT_EQ(get_round_direction(100, 50, 0), round_direction::down);
+  EXPECT_EQ(get_round_direction(100, 51, 0), round_direction::up);
+  EXPECT_EQ(get_round_direction(100, 40, 10), round_direction::down);
+  EXPECT_EQ(get_round_direction(100, 60, 10), round_direction::up);
+  for (size_t i = 41; i < 60; ++i)
+    EXPECT_EQ(get_round_direction(100, i, 10), round_direction::unknown);
+  uint64_t max = max_value<uint64_t>();
+  EXPECT_THROW(get_round_direction(100, 100, 0), assertion_failure);
+  EXPECT_THROW(get_round_direction(100, 0, 100), assertion_failure);
+  EXPECT_THROW(get_round_direction(100, 0, 50), assertion_failure);
+  // Check that remainder + error doesn't overflow.
+  EXPECT_EQ(get_round_direction(max, max - 1, 2), round_direction::up);
+  // Check that 2 * (remainder + error) doesn't overflow.
+  EXPECT_EQ(get_round_direction(max, max / 2 + 1, max / 2),
+            round_direction::unknown);
+  // Check that remainder - error doesn't overflow.
+  EXPECT_EQ(get_round_direction(100, 40, 41), round_direction::unknown);
+  // Check that 2 * (remainder - error) doesn't overflow.
+  EXPECT_EQ(get_round_direction(max, max - 1, 1), round_direction::up);
+}
+
+TEST(fp_test, fixed_handler) {
+  struct handler : fmt::detail::gen_digits_handler {
+    char buffer[10];
+    handler(int prec = 0) : fmt::detail::gen_digits_handler() {
+      buf = buffer;
+      precision = prec;
+    }
+  };
+  handler().on_digit('0', 100, 99, 0, false);
+  EXPECT_THROW(handler().on_digit('0', 100, 100, 0, false), assertion_failure);
+  namespace digits = fmt::detail::digits;
+  EXPECT_EQ(handler(1).on_digit('0', 100, 10, 10, false), digits::error);
+  // Check that divisor - error doesn't overflow.
+  EXPECT_EQ(handler(1).on_digit('0', 100, 10, 101, false), digits::error);
+  // Check that 2 * error doesn't overflow.
+  uint64_t max = max_value<uint64_t>();
+  EXPECT_EQ(handler(1).on_digit('0', max, 10, max - 1, false), digits::error);
+}
+
+TEST(fp_test, grisu_format_compiles_with_on_ieee_double) {
+  auto buf = fmt::memory_buffer();
+  format_float(0.42, -1, fmt::detail::float_specs(), buf);
+}
+
+TEST(format_impl_test, format_error_code) {
+  std::string msg = "error 42", sep = ": ";
+  {
+    auto buffer = fmt::memory_buffer();
+    format_to(fmt::appender(buffer), "garbage");
+    fmt::detail::format_error_code(buffer, 42, "test");
+    EXPECT_EQ(to_string(buffer), "test: " + msg);
+  }
+  {
+    auto buffer = fmt::memory_buffer();
+    auto prefix =
+        std::string(fmt::inline_buffer_size - msg.size() - sep.size() + 1, 'x');
+    fmt::detail::format_error_code(buffer, 42, prefix);
+    EXPECT_EQ(msg, to_string(buffer));
+  }
+  int codes[] = {42, -1};
+  for (size_t i = 0, n = sizeof(codes) / sizeof(*codes); i < n; ++i) {
+    // Test maximum buffer size.
+    msg = fmt::format("error {}", codes[i]);
+    fmt::memory_buffer buffer;
+    auto prefix =
+        std::string(fmt::inline_buffer_size - msg.size() - sep.size(), 'x');
+    fmt::detail::format_error_code(buffer, codes[i], prefix);
+    EXPECT_EQ(prefix + sep + msg, to_string(buffer));
+    size_t size = fmt::inline_buffer_size;
+    EXPECT_EQ(size, buffer.size());
+    buffer.resize(0);
+    // Test with a message that doesn't fit into the buffer.
+    prefix += 'x';
+    fmt::detail::format_error_code(buffer, codes[i], prefix);
+    EXPECT_EQ(to_string(buffer), msg);
+  }
+}
+
+TEST(format_impl_test, compute_width) {
+  EXPECT_EQ(4,
+            fmt::detail::compute_width(
+                fmt::basic_string_view<fmt::detail::char8_type>(
+                    reinterpret_cast<const fmt::detail::char8_type*>("ёжик"))));
+}
+
+// Tests fmt::detail::count_digits for integer type Int.
+template <typename Int> void test_count_digits() {
+  for (Int i = 0; i < 10; ++i) EXPECT_EQ(1u, fmt::detail::count_digits(i));
+  for (Int i = 1, n = 1, end = max_value<Int>() / 10; n <= end; ++i) {
+    n *= 10;
+    EXPECT_EQ(fmt::detail::count_digits(n - 1), i);
+    EXPECT_EQ(fmt::detail::count_digits(n), i + 1);
+  }
+}
+
+TEST(format_impl_test, count_digits) {
+  test_count_digits<uint32_t>();
+  test_count_digits<uint64_t>();
+}
+
+#if FMT_USE_FLOAT128
+TEST(format_impl_test, write_float128) {
+  auto s = std::string();
+  fmt::detail::write<char>(std::back_inserter(s), __float128(42));
+  EXPECT_EQ(s, "42");
+}
+#endif
+
+struct double_double {
+  double a;
+  double b;
+
+  explicit constexpr double_double(double a_val = 0, double b_val = 0)
+      : a(a_val), b(b_val) {}
+
+  operator double() const { return a + b; }
+  auto operator-() const -> double_double { return double_double(-a, -b); }
+};
+
+bool operator>=(const double_double& lhs, const double_double& rhs) {
+  return lhs.a + lhs.b >= rhs.a + rhs.b;
+}
+
+struct slow_float {
+  float value;
+
+  explicit constexpr slow_float(float val = 0) : value(val) {}
+  operator float() const { return value; }
+  auto operator-() const -> slow_float { return slow_float(-value); }
+};
+
+namespace std {
+template <> struct is_floating_point<double_double> : std::true_type {};
+template <> struct numeric_limits<double_double> {
+  // is_iec559 is true for double-double in libstdc++.
+  static constexpr bool is_iec559 = true;
+  static constexpr int digits = 106;
+};
+
+template <> struct is_floating_point<slow_float> : std::true_type {};
+template <> struct numeric_limits<slow_float> : numeric_limits<float> {};
+}  // namespace std
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+template <> struct is_fast_float<slow_float> : std::false_type {};
+namespace dragonbox {
+template <> struct float_info<slow_float> {
+  using carrier_uint = uint32_t;
+  static const int exponent_bits = 8;
+};
+}  // namespace dragonbox
+}  // namespace detail
+FMT_END_NAMESPACE
+
+TEST(format_impl_test, write_double_double) {
+  auto s = std::string();
+  fmt::detail::write<char>(std::back_inserter(s), double_double(42), {});
+  // Specializing is_floating_point is broken in MSVC.
+  if (!FMT_MSC_VERSION) EXPECT_EQ(s, "42");
+}
+
+TEST(format_impl_test, write_dragon_even) {
+  auto s = std::string();
+  fmt::detail::write<char>(std::back_inserter(s), slow_float(33554450.0f), {});
+  // Specializing is_floating_point is broken in MSVC.
+  if (!FMT_MSC_VERSION) EXPECT_EQ(s, "33554450");
+}
+
+#ifdef _WIN32
+#  include <windows.h>
+
+TEST(format_impl_test, write_console_signature) {
+  decltype(::WriteConsoleW)* p = fmt::detail::WriteConsoleW;
+  (void)p;
+}
+#endif
+
+// A public domain branchless UTF-8 decoder by Christopher Wellons:
+// https://github.com/skeeto/branchless-utf8
+constexpr bool unicode_is_surrogate(uint32_t c) {
+  return c >= 0xD800U && c <= 0xDFFFU;
+}
+
+FMT_CONSTEXPR char* utf8_encode(char* s, uint32_t c) {
+  if (c >= (1UL << 16)) {
+    s[0] = static_cast<char>(0xf0 | (c >> 18));
+    s[1] = static_cast<char>(0x80 | ((c >> 12) & 0x3f));
+    s[2] = static_cast<char>(0x80 | ((c >> 6) & 0x3f));
+    s[3] = static_cast<char>(0x80 | ((c >> 0) & 0x3f));
+    return s + 4;
+  } else if (c >= (1UL << 11)) {
+    s[0] = static_cast<char>(0xe0 | (c >> 12));
+    s[1] = static_cast<char>(0x80 | ((c >> 6) & 0x3f));
+    s[2] = static_cast<char>(0x80 | ((c >> 0) & 0x3f));
+    return s + 3;
+  } else if (c >= (1UL << 7)) {
+    s[0] = static_cast<char>(0xc0 | (c >> 6));
+    s[1] = static_cast<char>(0x80 | ((c >> 0) & 0x3f));
+    return s + 2;
+  } else {
+    s[0] = static_cast<char>(c);
+    return s + 1;
+  }
+}
+
+// Make sure it can decode every character
+TEST(format_impl_test, utf8_decode_decode_all) {
+  for (uint32_t i = 0; i < 0x10ffff; i++) {
+    if (!unicode_is_surrogate(i)) {
+      int e;
+      uint32_t c;
+      char buf[8] = {0};
+      char* end = utf8_encode(buf, i);
+      const char* res = fmt::detail::utf8_decode(buf, &c, &e);
+      EXPECT_EQ(end, res);
+      EXPECT_EQ(c, i);
+      EXPECT_EQ(e, 0);
+    }
+  }
+}
+
+// Reject everything outside of U+0000..U+10FFFF
+TEST(format_impl_test, utf8_decode_out_of_range) {
+  for (uint32_t i = 0x110000; i < 0x1fffff; i++) {
+    int e;
+    uint32_t c;
+    char buf[8] = {0};
+    utf8_encode(buf, i);
+    const char* end = fmt::detail::utf8_decode(buf, &c, &e);
+    EXPECT_NE(e, 0);
+    EXPECT_EQ(end - buf, 4);
+  }
+}
+
+// Does it reject all surrogate halves?
+TEST(format_impl_test, utf8_decode_surrogate_halves) {
+  for (uint32_t i = 0xd800; i <= 0xdfff; i++) {
+    int e;
+    uint32_t c;
+    char buf[8] = {0};
+    utf8_encode(buf, i);
+    fmt::detail::utf8_decode(buf, &c, &e);
+    EXPECT_NE(e, 0);
+  }
+}
+
+// How about non-canonical encodings?
+TEST(format_impl_test, utf8_decode_non_canonical_encodings) {
+  int e;
+  uint32_t c;
+  const char* end;
+
+  char buf2[8] = {char(0xc0), char(0xA4)};
+  end = fmt::detail::utf8_decode(buf2, &c, &e);
+  EXPECT_NE(e, 0);           // non-canonical len 2
+  EXPECT_EQ(end, buf2 + 2);  // non-canonical recover 2
+
+  char buf3[8] = {char(0xe0), char(0x80), char(0xA4)};
+  end = fmt::detail::utf8_decode(buf3, &c, &e);
+  EXPECT_NE(e, 0);           // non-canonical len 3
+  EXPECT_EQ(end, buf3 + 3);  // non-canonical recover 3
+
+  char buf4[8] = {char(0xf0), char(0x80), char(0x80), char(0xA4)};
+  end = fmt::detail::utf8_decode(buf4, &c, &e);
+  EXPECT_NE(e, 0);           // non-canonical encoding len 4
+  EXPECT_EQ(end, buf4 + 4);  // non-canonical recover 4
+}
+
+// Let's try some bogus byte sequences
+TEST(format_impl_test, utf8_decode_bogus_byte_sequences) {
+  int e;
+  uint32_t c;
+
+  // Invalid first byte
+  char buf0[4] = {char(0xff)};
+  auto len = fmt::detail::utf8_decode(buf0, &c, &e) - buf0;
+  EXPECT_NE(e, 0);    // "bogus [ff] 0x%02x U+%04lx", e, (unsigned long)c);
+  EXPECT_EQ(len, 1);  // "bogus [ff] recovery %d", len);
+
+  // Invalid first byte
+  char buf1[4] = {char(0x80)};
+  len = fmt::detail::utf8_decode(buf1, &c, &e) - buf1;
+  EXPECT_NE(e, 0);    // "bogus [80] 0x%02x U+%04lx", e, (unsigned long)c);
+  EXPECT_EQ(len, 1);  // "bogus [80] recovery %d", len);
+
+  // Looks like a two-byte sequence but second byte is wrong
+  char buf2[4] = {char(0xc0), char(0x0a)};
+  len = fmt::detail::utf8_decode(buf2, &c, &e) - buf2;
+  EXPECT_NE(e, 0);    // "bogus [c0 0a] 0x%02x U+%04lx", e, (unsigned long)c
+  EXPECT_EQ(len, 2);  // "bogus [c0 0a] recovery %d", len);
+}
diff --git a/src/fmt/test/format-test.cc b/src/fmt/test/format-test.cc
new file mode 100644
index 000000000..f3bdb4649
--- /dev/null
+++ b/src/fmt/test/format-test.cc
@@ -0,0 +1,2311 @@
+// Formatting library for C++ - formatting library tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+// Check if fmt/format.h compiles with windows.h included before it.
+#ifdef _WIN32
+#  include <windows.h>
+#endif
+// clang-format off
+#include "fmt/format.h"
+// clang-format on
+
+#include <stdint.h>  // uint32_t
+
+#include <climits>      // INT_MAX
+#include <cmath>        // std::signbit
+#include <cstring>      // std::strlen
+#include <iterator>     // std::back_inserter
+#include <list>         // std::list
+#include <memory>       // std::unique_ptr
+#include <type_traits>  // std::is_default_constructible
+
+#include "gtest-extra.h"
+#include "mock-allocator.h"
+#include "util.h"
+
+using fmt::basic_memory_buffer;
+using fmt::format_error;
+using fmt::memory_buffer;
+using fmt::runtime;
+using fmt::string_view;
+using fmt::detail::max_value;
+using fmt::detail::uint128_fallback;
+
+using testing::Return;
+using testing::StrictMock;
+
+enum { buffer_size = 256 };
+
+TEST(uint128_test, ctor) {
+  auto n = uint128_fallback();
+  EXPECT_EQ(n, 0);
+  n = uint128_fallback(42);
+  EXPECT_EQ(n, 42);
+  EXPECT_EQ(static_cast<uint64_t>(n), 42);
+}
+
+TEST(uint128_test, shift) {
+  auto n = uint128_fallback(42);
+  n = n << 64;
+  EXPECT_EQ(static_cast<uint64_t>(n), 0);
+  n = n >> 64;
+  EXPECT_EQ(static_cast<uint64_t>(n), 42);
+  n = n << 62;
+  EXPECT_EQ(static_cast<uint64_t>(n >> 64), 0xa);
+  EXPECT_EQ(static_cast<uint64_t>(n), 0x8000000000000000);
+  n = n >> 62;
+  EXPECT_EQ(static_cast<uint64_t>(n), 42);
+  EXPECT_EQ(uint128_fallback(1) << 112, uint128_fallback(0x1000000000000, 0));
+  EXPECT_EQ(uint128_fallback(0x1000000000000, 0) >> 112, uint128_fallback(1));
+}
+
+TEST(uint128_test, minus) {
+  auto n = uint128_fallback(42);
+  EXPECT_EQ(n - 2, 40);
+}
+
+TEST(uint128_test, plus_assign) {
+  auto n = uint128_fallback(32);
+  n += uint128_fallback(10);
+  EXPECT_EQ(n, 42);
+  n = uint128_fallback(max_value<uint64_t>());
+  n += uint128_fallback(1);
+  EXPECT_EQ(n, uint128_fallback(1) << 64);
+}
+
+TEST(uint128_test, multiply) {
+  auto n = uint128_fallback(2251799813685247);
+  n = n * 3611864890;
+  EXPECT_EQ(static_cast<uint64_t>(n >> 64), 440901);
+}
+
+template <typename Float> void check_isfinite() {
+  using fmt::detail::isfinite;
+  EXPECT_TRUE(isfinite(Float(0.0)));
+  EXPECT_TRUE(isfinite(Float(42.0)));
+  EXPECT_TRUE(isfinite(Float(-42.0)));
+  EXPECT_TRUE(isfinite(Float(fmt::detail::max_value<double>())));
+  // Use double because std::numeric_limits is broken for __float128.
+  using limits = std::numeric_limits<double>;
+  FMT_CONSTEXPR20 auto result = isfinite(Float(limits::infinity()));
+  EXPECT_FALSE(result);
+  EXPECT_FALSE(isfinite(Float(limits::infinity())));
+  EXPECT_FALSE(isfinite(Float(-limits::infinity())));
+  EXPECT_FALSE(isfinite(Float(limits::quiet_NaN())));
+  EXPECT_FALSE(isfinite(Float(-limits::quiet_NaN())));
+}
+
+TEST(float_test, isfinite) {
+  check_isfinite<double>();
+#if FMT_USE_FLOAT128
+  check_isfinite<fmt::detail::float128>();
+#endif
+}
+
+template <typename Float> void check_isnan() {
+  using fmt::detail::isnan;
+  EXPECT_FALSE(isnan(Float(0.0)));
+  EXPECT_FALSE(isnan(Float(42.0)));
+  EXPECT_FALSE(isnan(Float(-42.0)));
+  EXPECT_FALSE(isnan(Float(fmt::detail::max_value<double>())));
+  // Use double because std::numeric_limits is broken for __float128.
+  using limits = std::numeric_limits<double>;
+  EXPECT_FALSE(isnan(Float(limits::infinity())));
+  EXPECT_FALSE(isnan(Float(-limits::infinity())));
+  EXPECT_TRUE(isnan(Float(limits::quiet_NaN())));
+  EXPECT_TRUE(isnan(Float(-limits::quiet_NaN())));
+}
+
+TEST(float_test, isnan) {
+  check_isnan<double>();
+#if FMT_USE_FLOAT128
+  check_isnan<fmt::detail::float128>();
+#endif
+}
+
+struct uint32_pair {
+  uint32_t u[2];
+};
+
+TEST(util_test, bit_cast) {
+  auto s = fmt::detail::bit_cast<uint32_pair>(uint64_t{42});
+  EXPECT_EQ(fmt::detail::bit_cast<uint64_t>(s), 42ull);
+  s = fmt::detail::bit_cast<uint32_pair>(~uint64_t{0});
+  EXPECT_EQ(fmt::detail::bit_cast<uint64_t>(s), ~0ull);
+}
+
+// Increment a number in a string.
+void increment(char* s) {
+  for (int i = static_cast<int>(std::strlen(s)) - 1; i >= 0; --i) {
+    if (s[i] != '9') {
+      ++s[i];
+      break;
+    }
+    s[i] = '0';
+  }
+}
+
+TEST(util_test, increment) {
+  char s[10] = "123";
+  increment(s);
+  EXPECT_STREQ("124", s);
+  s[2] = '8';
+  increment(s);
+  EXPECT_STREQ("129", s);
+  increment(s);
+  EXPECT_STREQ("130", s);
+  s[1] = s[2] = '9';
+  increment(s);
+  EXPECT_STREQ("200", s);
+}
+
+TEST(util_test, parse_nonnegative_int) {
+  auto s = fmt::string_view("10000000000");
+  auto begin = s.begin(), end = s.end();
+  EXPECT_EQ(fmt::detail::parse_nonnegative_int(begin, end, -1), -1);
+  s = "2147483649";
+  begin = s.begin();
+  end = s.end();
+  EXPECT_EQ(fmt::detail::parse_nonnegative_int(begin, end, -1), -1);
+}
+
+TEST(util_test, utf8_to_utf16) {
+  auto u = fmt::detail::utf8_to_utf16("лошадка");
+  EXPECT_EQ(L"\x043B\x043E\x0448\x0430\x0434\x043A\x0430", u.str());
+  EXPECT_EQ(7, u.size());
+  // U+10437 { DESERET SMALL LETTER YEE }
+  EXPECT_EQ(L"\xD801\xDC37", fmt::detail::utf8_to_utf16("𐐷").str());
+  EXPECT_THROW_MSG(fmt::detail::utf8_to_utf16("\xc3\x28"), std::runtime_error,
+                   "invalid utf8");
+  EXPECT_THROW_MSG(fmt::detail::utf8_to_utf16(fmt::string_view("л", 1)),
+                   std::runtime_error, "invalid utf8");
+  EXPECT_EQ(L"123456", fmt::detail::utf8_to_utf16("123456").str());
+}
+
+TEST(util_test, utf8_to_utf16_empty_string) {
+  auto s = std::string();
+  auto u = fmt::detail::utf8_to_utf16(s.c_str());
+  EXPECT_EQ(L"", u.str());
+  EXPECT_EQ(s.size(), u.size());
+}
+
+TEST(util_test, allocator_ref) {
+  using test_allocator_ref = allocator_ref<mock_allocator<int>>;
+  auto check_forwarding = [](mock_allocator<int>& alloc,
+                             test_allocator_ref& ref) {
+    int mem;
+    // Check if value_type is properly defined.
+    allocator_ref<mock_allocator<int>>::value_type* ptr = &mem;
+    // Check forwarding.
+    EXPECT_CALL(alloc, allocate(42)).WillOnce(Return(ptr));
+    ref.allocate(42);
+    EXPECT_CALL(alloc, deallocate(ptr, 42));
+    ref.deallocate(ptr, 42);
+  };
+
+  StrictMock<mock_allocator<int>> alloc;
+  auto ref = test_allocator_ref(&alloc);
+  // Check if allocator_ref forwards to the underlying allocator.
+  check_forwarding(alloc, ref);
+  test_allocator_ref ref2(ref);
+  check_forwarding(alloc, ref2);
+  test_allocator_ref ref3;
+  EXPECT_EQ(nullptr, ref3.get());
+  ref3 = ref;
+  check_forwarding(alloc, ref3);
+}
+
+TEST(util_test, format_system_error) {
+  fmt::memory_buffer message;
+  fmt::format_system_error(message, EDOM, "test");
+  auto ec = std::error_code(EDOM, std::generic_category());
+  EXPECT_EQ(to_string(message), std::system_error(ec, "test").what());
+  message = fmt::memory_buffer();
+
+  // Check if std::allocator throws on allocating max size_t / 2 chars.
+  size_t max_size = max_value<size_t>() / 2;
+  bool throws_on_alloc = false;
+  try {
+    auto alloc = std::allocator<char>();
+    alloc.deallocate(alloc.allocate(max_size), max_size);
+  } catch (const std::bad_alloc&) {
+    throws_on_alloc = true;
+  }
+  if (!throws_on_alloc) {
+    fmt::print("warning: std::allocator allocates {} chars\n", max_size);
+    return;
+  }
+}
+
+TEST(util_test, system_error) {
+  auto test_error = fmt::system_error(EDOM, "test");
+  auto ec = std::error_code(EDOM, std::generic_category());
+  EXPECT_STREQ(test_error.what(), std::system_error(ec, "test").what());
+  EXPECT_EQ(test_error.code(), ec);
+
+  auto error = std::system_error(std::error_code());
+  try {
+    throw fmt::system_error(EDOM, "test {}", "error");
+  } catch (const std::system_error& e) {
+    error = e;
+  }
+  fmt::memory_buffer message;
+  fmt::format_system_error(message, EDOM, "test error");
+  EXPECT_EQ(error.what(), to_string(message));
+  EXPECT_EQ(error.code(), std::error_code(EDOM, std::generic_category()));
+}
+
+TEST(util_test, report_system_error) {
+  fmt::memory_buffer out;
+  fmt::format_system_error(out, EDOM, "test error");
+  out.push_back('\n');
+  EXPECT_WRITE(stderr, fmt::report_system_error(EDOM, "test error"),
+               to_string(out));
+}
+
+TEST(memory_buffer_test, ctor) {
+  basic_memory_buffer<char, 123> buffer;
+  EXPECT_EQ(static_cast<size_t>(0), buffer.size());
+  EXPECT_EQ(123u, buffer.capacity());
+}
+
+using std_allocator = allocator_ref<std::allocator<char>>;
+
+TEST(memory_buffer_test, move_ctor_inline_buffer) {
+  auto check_move_buffer =
+      [](const char* str, basic_memory_buffer<char, 5, std_allocator>& buffer) {
+        std::allocator<char>* alloc = buffer.get_allocator().get();
+        basic_memory_buffer<char, 5, std_allocator> buffer2(std::move(buffer));
+        // Move shouldn't destroy the inline content of the first buffer.
+        EXPECT_EQ(str, std::string(&buffer[0], buffer.size()));
+        EXPECT_EQ(str, std::string(&buffer2[0], buffer2.size()));
+        EXPECT_EQ(5u, buffer2.capacity());
+        // Move should transfer allocator.
+        EXPECT_EQ(nullptr, buffer.get_allocator().get());
+        EXPECT_EQ(alloc, buffer2.get_allocator().get());
+      };
+
+  auto alloc = std::allocator<char>();
+  basic_memory_buffer<char, 5, std_allocator> buffer((std_allocator(&alloc)));
+  const char test[] = "test";
+  buffer.append(string_view(test, 4));
+  check_move_buffer("test", buffer);
+  // Adding one more character fills the inline buffer, but doesn't cause
+  // dynamic allocation.
+  buffer.push_back('a');
+  check_move_buffer("testa", buffer);
+}
+
+TEST(memory_buffer_test, move_ctor_dynamic_buffer) {
+  auto alloc = std::allocator<char>();
+  basic_memory_buffer<char, 4, std_allocator> buffer((std_allocator(&alloc)));
+  const char test[] = "test";
+  buffer.append(test, test + 4);
+  const char* inline_buffer_ptr = &buffer[0];
+  // Adding one more character causes the content to move from the inline to
+  // a dynamically allocated buffer.
+  buffer.push_back('a');
+  basic_memory_buffer<char, 4, std_allocator> buffer2(std::move(buffer));
+  // Move should rip the guts of the first buffer.
+  EXPECT_EQ(&buffer[0], inline_buffer_ptr);
+  EXPECT_EQ(buffer.size(), 0);
+  EXPECT_EQ(std::string(&buffer2[0], buffer2.size()), "testa");
+  EXPECT_GT(buffer2.capacity(), 4u);
+}
+
+void check_move_assign_buffer(const char* str,
+                              basic_memory_buffer<char, 5>& buffer) {
+  basic_memory_buffer<char, 5> buffer2;
+  buffer2 = std::move(buffer);
+  // Move shouldn't destroy the inline content of the first buffer.
+  EXPECT_EQ(str, std::string(&buffer[0], buffer.size()));
+  EXPECT_EQ(str, std::string(&buffer2[0], buffer2.size()));
+  EXPECT_EQ(5u, buffer2.capacity());
+}
+
+TEST(memory_buffer_test, move_assignment) {
+  basic_memory_buffer<char, 5> buffer;
+  const char test[] = "test";
+  buffer.append(test, test + 4);
+  check_move_assign_buffer("test", buffer);
+  // Adding one more character fills the inline buffer, but doesn't cause
+  // dynamic allocation.
+  buffer.push_back('a');
+  check_move_assign_buffer("testa", buffer);
+  const char* inline_buffer_ptr = &buffer[0];
+  // Adding one more character causes the content to move from the inline to
+  // a dynamically allocated buffer.
+  buffer.push_back('b');
+  basic_memory_buffer<char, 5> buffer2;
+  buffer2 = std::move(buffer);
+  // Move should rip the guts of the first buffer.
+  EXPECT_EQ(inline_buffer_ptr, &buffer[0]);
+  EXPECT_EQ("testab", std::string(&buffer2[0], buffer2.size()));
+  EXPECT_GT(buffer2.capacity(), 5u);
+}
+
+TEST(memory_buffer_test, grow) {
+  typedef allocator_ref<mock_allocator<int>> Allocator;
+  mock_allocator<int> alloc;
+  basic_memory_buffer<int, 10, Allocator> buffer((Allocator(&alloc)));
+  buffer.resize(7);
+  using fmt::detail::to_unsigned;
+  for (int i = 0; i < 7; ++i) buffer[to_unsigned(i)] = i * i;
+  EXPECT_EQ(10u, buffer.capacity());
+  int mem[20];
+  mem[7] = 0xdead;
+  EXPECT_CALL(alloc, allocate(20)).WillOnce(Return(mem));
+  buffer.try_reserve(20);
+  EXPECT_EQ(20u, buffer.capacity());
+  // Check if size elements have been copied
+  for (int i = 0; i < 7; ++i) EXPECT_EQ(i * i, buffer[to_unsigned(i)]);
+  // and no more than that.
+  EXPECT_EQ(0xdead, buffer[7]);
+  EXPECT_CALL(alloc, deallocate(mem, 20));
+}
+
+TEST(memory_buffer_test, allocator) {
+  using test_allocator = allocator_ref<mock_allocator<char>>;
+  basic_memory_buffer<char, 10, test_allocator> buffer;
+  EXPECT_EQ(nullptr, buffer.get_allocator().get());
+  StrictMock<mock_allocator<char>> alloc;
+  char mem;
+  {
+    basic_memory_buffer<char, 10, test_allocator> buffer2(
+        (test_allocator(&alloc)));
+    EXPECT_EQ(&alloc, buffer2.get_allocator().get());
+    size_t size = 2 * fmt::inline_buffer_size;
+    EXPECT_CALL(alloc, allocate(size)).WillOnce(Return(&mem));
+    buffer2.reserve(size);
+    EXPECT_CALL(alloc, deallocate(&mem, size));
+  }
+}
+
+TEST(memory_buffer_test, exception_in_deallocate) {
+  using test_allocator = allocator_ref<mock_allocator<char>>;
+  StrictMock<mock_allocator<char>> alloc;
+  basic_memory_buffer<char, 10, test_allocator> buffer(
+      (test_allocator(&alloc)));
+  size_t size = 2 * fmt::inline_buffer_size;
+  auto mem = std::vector<char>(size);
+  {
+    EXPECT_CALL(alloc, allocate(size)).WillOnce(Return(&mem[0]));
+    buffer.resize(size);
+    std::fill(&buffer[0], &buffer[0] + size, 'x');
+  }
+  auto mem2 = std::vector<char>(2 * size);
+  {
+    EXPECT_CALL(alloc, allocate(2 * size)).WillOnce(Return(&mem2[0]));
+    auto e = std::exception();
+    EXPECT_CALL(alloc, deallocate(&mem[0], size)).WillOnce(testing::Throw(e));
+    EXPECT_THROW(buffer.reserve(2 * size), std::exception);
+    EXPECT_EQ(&mem2[0], &buffer[0]);
+    // Check that the data has been copied.
+    for (size_t i = 0; i < size; ++i) EXPECT_EQ('x', buffer[i]);
+  }
+  EXPECT_CALL(alloc, deallocate(&mem2[0], 2 * size));
+}
+
+template <typename Allocator, size_t MaxSize>
+class max_size_allocator : public Allocator {
+ public:
+  using typename Allocator::value_type;
+  size_t max_size() const noexcept { return MaxSize; }
+  value_type* allocate(size_t n) {
+    if (n > max_size()) {
+      throw std::length_error("size > max_size");
+    }
+    return std::allocator_traits<Allocator>::allocate(
+        *static_cast<Allocator*>(this), n);
+  }
+  void deallocate(value_type* p, size_t n) {
+    std::allocator_traits<Allocator>::deallocate(*static_cast<Allocator*>(this),
+                                                 p, n);
+  }
+};
+
+TEST(memory_buffer_test, max_size_allocator) {
+  // 160 = 128 + 32
+  using test_allocator = max_size_allocator<std::allocator<char>, 160>;
+  basic_memory_buffer<char, 10, test_allocator> buffer;
+  buffer.resize(128);
+  // new_capacity = 128 + 128/2 = 192 > 160
+  buffer.resize(160);  // Shouldn't throw.
+}
+
+TEST(memory_buffer_test, max_size_allocator_overflow) {
+  using test_allocator = max_size_allocator<std::allocator<char>, 160>;
+  basic_memory_buffer<char, 10, test_allocator> buffer;
+  EXPECT_THROW(buffer.resize(161), std::exception);
+}
+
+TEST(format_test, escape) {
+  EXPECT_EQ("{", fmt::format("{{"));
+  EXPECT_EQ("before {", fmt::format("before {{"));
+  EXPECT_EQ("{ after", fmt::format("{{ after"));
+  EXPECT_EQ("before { after", fmt::format("before {{ after"));
+
+  EXPECT_EQ("}", fmt::format("}}"));
+  EXPECT_EQ("before }", fmt::format("before }}"));
+  EXPECT_EQ("} after", fmt::format("}} after"));
+  EXPECT_EQ("before } after", fmt::format("before }} after"));
+
+  EXPECT_EQ("{}", fmt::format("{{}}"));
+  EXPECT_EQ("{42}", fmt::format("{{{0}}}", 42));
+}
+
+TEST(format_test, unmatched_braces) {
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{")), format_error,
+                   "invalid format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("}")), format_error,
+                   "unmatched '}' in format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0{}")), format_error,
+                   "invalid format string");
+}
+
+TEST(format_test, no_args) { EXPECT_EQ("test", fmt::format("test")); }
+
+TEST(format_test, args_in_different_positions) {
+  EXPECT_EQ("42", fmt::format("{0}", 42));
+  EXPECT_EQ("before 42", fmt::format("before {0}", 42));
+  EXPECT_EQ("42 after", fmt::format("{0} after", 42));
+  EXPECT_EQ("before 42 after", fmt::format("before {0} after", 42));
+  EXPECT_EQ("answer = 42", fmt::format("{0} = {1}", "answer", 42));
+  EXPECT_EQ("42 is the answer", fmt::format("{1} is the {0}", "answer", 42));
+  EXPECT_EQ("abracadabra", fmt::format("{0}{1}{0}", "abra", "cad"));
+}
+
+TEST(format_test, arg_errors) {
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{")), format_error,
+                   "invalid format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{?}")), format_error,
+                   "invalid format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0")), format_error,
+                   "invalid format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0}")), format_error,
+                   "argument not found");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{00}"), 42), format_error,
+                   "invalid format string");
+
+  char format_str[buffer_size];
+  safe_sprintf(format_str, "{%u", INT_MAX);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str)), format_error,
+                   "invalid format string");
+  safe_sprintf(format_str, "{%u}", INT_MAX);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str)), format_error,
+                   "argument not found");
+
+  safe_sprintf(format_str, "{%u", INT_MAX + 1u);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str)), format_error,
+                   "invalid format string");
+  safe_sprintf(format_str, "{%u}", INT_MAX + 1u);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str)), format_error,
+                   "argument not found");
+}
+
+template <int N> struct test_format {
+  template <typename... T>
+  static std::string format(fmt::string_view fmt, const T&... args) {
+    return test_format<N - 1>::format(fmt, N - 1, args...);
+  }
+};
+
+template <> struct test_format<0> {
+  template <typename... T>
+  static std::string format(fmt::string_view fmt, const T&... args) {
+    return fmt::format(runtime(fmt), args...);
+  }
+};
+
+TEST(format_test, many_args) {
+  EXPECT_EQ("19", test_format<20>::format("{19}"));
+  EXPECT_THROW_MSG(test_format<20>::format("{20}"), format_error,
+                   "argument not found");
+  EXPECT_THROW_MSG(test_format<21>::format("{21}"), format_error,
+                   "argument not found");
+  using fmt::detail::max_packed_args;
+  std::string format_str = fmt::format("{{{}}}", max_packed_args + 1);
+  EXPECT_THROW_MSG(test_format<max_packed_args>::format(format_str),
+                   format_error, "argument not found");
+}
+
+TEST(format_test, named_arg) {
+  EXPECT_EQ("1/a/A", fmt::format("{_1}/{a_}/{A_}", fmt::arg("a_", 'a'),
+                                 fmt::arg("A_", "A"), fmt::arg("_1", 1)));
+  EXPECT_EQ(" -42", fmt::format("{0:{width}}", -42, fmt::arg("width", 4)));
+  EXPECT_EQ("st",
+            fmt::format("{0:.{precision}}", "str", fmt::arg("precision", 2)));
+  EXPECT_EQ("1 2", fmt::format("{} {two}", 1, fmt::arg("two", 2)));
+  EXPECT_EQ("42",
+            fmt::format("{c}", fmt::arg("a", 0), fmt::arg("b", 0),
+                        fmt::arg("c", 42), fmt::arg("d", 0), fmt::arg("e", 0),
+                        fmt::arg("f", 0), fmt::arg("g", 0), fmt::arg("h", 0),
+                        fmt::arg("i", 0), fmt::arg("j", 0), fmt::arg("k", 0),
+                        fmt::arg("l", 0), fmt::arg("m", 0), fmt::arg("n", 0),
+                        fmt::arg("o", 0), fmt::arg("p", 0)));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{a}")), format_error,
+                   "argument not found");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{a}"), 42), format_error,
+                   "argument not found");
+}
+
+TEST(format_test, auto_arg_index) {
+  EXPECT_EQ("abc", fmt::format("{}{}{}", 'a', 'b', 'c'));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0}{}"), 'a', 'b'), format_error,
+                   "cannot switch from manual to automatic argument indexing");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{}{0}"), 'a', 'b'), format_error,
+                   "cannot switch from automatic to manual argument indexing");
+  EXPECT_EQ("1.2", fmt::format("{:.{}}", 1.2345, 2));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0}:.{}"), 1.2345, 2),
+                   format_error,
+                   "cannot switch from manual to automatic argument indexing");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:.{0}}"), 1.2345, 2),
+                   format_error,
+                   "cannot switch from automatic to manual argument indexing");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{}")), format_error,
+                   "argument not found");
+}
+
+TEST(format_test, empty_specs) { EXPECT_EQ("42", fmt::format("{0:}", 42)); }
+
+TEST(format_test, left_align) {
+  EXPECT_EQ("42  ", fmt::format("{0:<4}", 42));
+  EXPECT_EQ("42  ", fmt::format("{0:<4o}", 042));
+  EXPECT_EQ("42  ", fmt::format("{0:<4x}", 0x42));
+  EXPECT_EQ("-42  ", fmt::format("{0:<5}", -42));
+  EXPECT_EQ("42   ", fmt::format("{0:<5}", 42u));
+  EXPECT_EQ("-42  ", fmt::format("{0:<5}", -42l));
+  EXPECT_EQ("42   ", fmt::format("{0:<5}", 42ul));
+  EXPECT_EQ("-42  ", fmt::format("{0:<5}", -42ll));
+  EXPECT_EQ("42   ", fmt::format("{0:<5}", 42ull));
+  EXPECT_EQ("-42  ", fmt::format("{0:<5}", -42.0));
+  EXPECT_EQ("-42  ", fmt::format("{0:<5}", -42.0l));
+  EXPECT_EQ("c    ", fmt::format("{0:<5}", 'c'));
+  EXPECT_EQ("abc  ", fmt::format("{0:<5}", "abc"));
+  EXPECT_EQ("0xface  ", fmt::format("{0:<8}", reinterpret_cast<void*>(0xface)));
+}
+
+TEST(format_test, right_align) {
+  EXPECT_EQ("  42", fmt::format("{0:>4}", 42));
+  EXPECT_EQ("  42", fmt::format("{0:>4o}", 042));
+  EXPECT_EQ("  42", fmt::format("{0:>4x}", 0x42));
+  EXPECT_EQ("  -42", fmt::format("{0:>5}", -42));
+  EXPECT_EQ("   42", fmt::format("{0:>5}", 42u));
+  EXPECT_EQ("  -42", fmt::format("{0:>5}", -42l));
+  EXPECT_EQ("   42", fmt::format("{0:>5}", 42ul));
+  EXPECT_EQ("  -42", fmt::format("{0:>5}", -42ll));
+  EXPECT_EQ("   42", fmt::format("{0:>5}", 42ull));
+  EXPECT_EQ("  -42", fmt::format("{0:>5}", -42.0));
+  EXPECT_EQ("  -42", fmt::format("{0:>5}", -42.0l));
+  EXPECT_EQ("    c", fmt::format("{0:>5}", 'c'));
+  EXPECT_EQ("  abc", fmt::format("{0:>5}", "abc"));
+  EXPECT_EQ("  0xface", fmt::format("{0:>8}", reinterpret_cast<void*>(0xface)));
+}
+
+TEST(format_test, center_align) {
+  EXPECT_EQ(" 42  ", fmt::format("{0:^5}", 42));
+  EXPECT_EQ(" 42  ", fmt::format("{0:^5o}", 042));
+  EXPECT_EQ(" 42  ", fmt::format("{0:^5x}", 0x42));
+  EXPECT_EQ(" -42 ", fmt::format("{0:^5}", -42));
+  EXPECT_EQ(" 42  ", fmt::format("{0:^5}", 42u));
+  EXPECT_EQ(" -42 ", fmt::format("{0:^5}", -42l));
+  EXPECT_EQ(" 42  ", fmt::format("{0:^5}", 42ul));
+  EXPECT_EQ(" -42 ", fmt::format("{0:^5}", -42ll));
+  EXPECT_EQ(" 42  ", fmt::format("{0:^5}", 42ull));
+  EXPECT_EQ(" -42 ", fmt::format("{0:^5}", -42.0));
+  EXPECT_EQ(" -42 ", fmt::format("{0:^5}", -42.0l));
+  EXPECT_EQ("  c  ", fmt::format("{0:^5}", 'c'));
+  EXPECT_EQ(" abc  ", fmt::format("{0:^6}", "abc"));
+  EXPECT_EQ(" 0xface ", fmt::format("{0:^8}", reinterpret_cast<void*>(0xface)));
+}
+
+TEST(format_test, fill) {
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{<5}"), 'c'), format_error,
+                   "invalid fill character '{'");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{<5}}"), 'c'), format_error,
+                   "invalid fill character '{'");
+  EXPECT_EQ("**42", fmt::format("{0:*>4}", 42));
+  EXPECT_EQ("**-42", fmt::format("{0:*>5}", -42));
+  EXPECT_EQ("***42", fmt::format("{0:*>5}", 42u));
+  EXPECT_EQ("**-42", fmt::format("{0:*>5}", -42l));
+  EXPECT_EQ("***42", fmt::format("{0:*>5}", 42ul));
+  EXPECT_EQ("**-42", fmt::format("{0:*>5}", -42ll));
+  EXPECT_EQ("***42", fmt::format("{0:*>5}", 42ull));
+  EXPECT_EQ("**-42", fmt::format("{0:*>5}", -42.0));
+  EXPECT_EQ("**-42", fmt::format("{0:*>5}", -42.0l));
+  EXPECT_EQ("c****", fmt::format("{0:*<5}", 'c'));
+  EXPECT_EQ("abc**", fmt::format("{0:*<5}", "abc"));
+  EXPECT_EQ("**0xface",
+            fmt::format("{0:*>8}", reinterpret_cast<void*>(0xface)));
+  EXPECT_EQ("foo=", fmt::format("{:}=", "foo"));
+  EXPECT_EQ(std::string("\0\0\0*", 4),
+            fmt::format(string_view("{:\0>4}", 6), '*'));
+  EXPECT_EQ("жж42", fmt::format("{0:ж>4}", 42));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:\x80\x80\x80\x80\x80>}"), 0),
+                   format_error, "invalid type specifier");
+}
+
+TEST(format_test, plus_sign) {
+  EXPECT_EQ("+42", fmt::format("{0:+}", 42));
+  EXPECT_EQ("-42", fmt::format("{0:+}", -42));
+  EXPECT_EQ("+42", fmt::format("{0:+}", 42));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 42u), format_error,
+                   "format specifier requires signed argument");
+  EXPECT_EQ("+42", fmt::format("{0:+}", 42l));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 42ul), format_error,
+                   "format specifier requires signed argument");
+  EXPECT_EQ("+42", fmt::format("{0:+}", 42ll));
+#if FMT_USE_INT128
+  EXPECT_EQ("+42", fmt::format("{0:+}", __int128_t(42)));
+#endif
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 42ull), format_error,
+                   "format specifier requires signed argument");
+  EXPECT_EQ("+42", fmt::format("{0:+}", 42.0));
+  EXPECT_EQ("+42", fmt::format("{0:+}", 42.0l));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+"), 'c'), format_error,
+                   "missing '}' in format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), 'c'), format_error,
+                   "invalid format specifier for char");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), "abc"), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{0:+}"), reinterpret_cast<void*>(0x42)),
+      format_error, "format specifier requires numeric argument");
+}
+
+TEST(format_test, minus_sign) {
+  EXPECT_EQ("42", fmt::format("{0:-}", 42));
+  EXPECT_EQ("-42", fmt::format("{0:-}", -42));
+  EXPECT_EQ("42", fmt::format("{0:-}", 42));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 42u), format_error,
+                   "format specifier requires signed argument");
+  EXPECT_EQ("42", fmt::format("{0:-}", 42l));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 42ul), format_error,
+                   "format specifier requires signed argument");
+  EXPECT_EQ("42", fmt::format("{0:-}", 42ll));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 42ull), format_error,
+                   "format specifier requires signed argument");
+  EXPECT_EQ("42", fmt::format("{0:-}", 42.0));
+  EXPECT_EQ("42", fmt::format("{0:-}", 42.0l));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-"), 'c'), format_error,
+                   "missing '}' in format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), 'c'), format_error,
+                   "invalid format specifier for char");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), "abc"), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{0:-}"), reinterpret_cast<void*>(0x42)),
+      format_error, "format specifier requires numeric argument");
+}
+
+TEST(format_test, space_sign) {
+  EXPECT_EQ(" 42", fmt::format("{0: }", 42));
+  EXPECT_EQ("-42", fmt::format("{0: }", -42));
+  EXPECT_EQ(" 42", fmt::format("{0: }", 42));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 42u), format_error,
+                   "format specifier requires signed argument");
+  EXPECT_EQ(" 42", fmt::format("{0: }", 42l));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 42ul), format_error,
+                   "format specifier requires signed argument");
+  EXPECT_EQ(" 42", fmt::format("{0: }", 42ll));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 42ull), format_error,
+                   "format specifier requires signed argument");
+  EXPECT_EQ(" 42", fmt::format("{0: }", 42.0));
+  EXPECT_EQ(" 42", fmt::format("{0: }", 42.0l));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: "), 'c'), format_error,
+                   "missing '}' in format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), 'c'), format_error,
+                   "invalid format specifier for char");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), "abc"), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{0: }"), reinterpret_cast<void*>(0x42)),
+      format_error, "format specifier requires numeric argument");
+}
+
+TEST(format_test, hash_flag) {
+  EXPECT_EQ("42", fmt::format("{0:#}", 42));
+  EXPECT_EQ("-42", fmt::format("{0:#}", -42));
+  EXPECT_EQ("0b101010", fmt::format("{0:#b}", 42));
+  EXPECT_EQ("0B101010", fmt::format("{0:#B}", 42));
+  EXPECT_EQ("-0b101010", fmt::format("{0:#b}", -42));
+  EXPECT_EQ("0x42", fmt::format("{0:#x}", 0x42));
+  EXPECT_EQ("0X42", fmt::format("{0:#X}", 0x42));
+  EXPECT_EQ("-0x42", fmt::format("{0:#x}", -0x42));
+  EXPECT_EQ("0", fmt::format("{0:#o}", 0));
+  EXPECT_EQ("042", fmt::format("{0:#o}", 042));
+  EXPECT_EQ("-042", fmt::format("{0:#o}", -042));
+  EXPECT_EQ("42", fmt::format("{0:#}", 42u));
+  EXPECT_EQ("0x42", fmt::format("{0:#x}", 0x42u));
+  EXPECT_EQ("042", fmt::format("{0:#o}", 042u));
+
+  EXPECT_EQ("-42", fmt::format("{0:#}", -42l));
+  EXPECT_EQ("0x42", fmt::format("{0:#x}", 0x42l));
+  EXPECT_EQ("-0x42", fmt::format("{0:#x}", -0x42l));
+  EXPECT_EQ("042", fmt::format("{0:#o}", 042l));
+  EXPECT_EQ("-042", fmt::format("{0:#o}", -042l));
+  EXPECT_EQ("42", fmt::format("{0:#}", 42ul));
+  EXPECT_EQ("0x42", fmt::format("{0:#x}", 0x42ul));
+  EXPECT_EQ("042", fmt::format("{0:#o}", 042ul));
+
+  EXPECT_EQ("-42", fmt::format("{0:#}", -42ll));
+  EXPECT_EQ("0x42", fmt::format("{0:#x}", 0x42ll));
+  EXPECT_EQ("-0x42", fmt::format("{0:#x}", -0x42ll));
+  EXPECT_EQ("042", fmt::format("{0:#o}", 042ll));
+  EXPECT_EQ("-042", fmt::format("{0:#o}", -042ll));
+  EXPECT_EQ("42", fmt::format("{0:#}", 42ull));
+  EXPECT_EQ("0x42", fmt::format("{0:#x}", 0x42ull));
+  EXPECT_EQ("042", fmt::format("{0:#o}", 042ull));
+
+  EXPECT_EQ("-42.0", fmt::format("{0:#}", -42.0));
+  EXPECT_EQ("-42.0", fmt::format("{0:#}", -42.0l));
+  EXPECT_EQ("4.e+01", fmt::format("{:#.0e}", 42.0));
+  EXPECT_EQ("0.", fmt::format("{:#.0f}", 0.01));
+  EXPECT_EQ("0.50", fmt::format("{:#.2g}", 0.5));
+  EXPECT_EQ("0.", fmt::format("{:#.0f}", 0.5));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#"), 'c'), format_error,
+                   "missing '}' in format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#}"), 'c'), format_error,
+                   "invalid format specifier for char");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#}"), "abc"), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{0:#}"), reinterpret_cast<void*>(0x42)),
+      format_error, "format specifier requires numeric argument");
+}
+
+TEST(format_test, zero_flag) {
+  EXPECT_EQ("42", fmt::format("{0:0}", 42));
+  EXPECT_EQ("-0042", fmt::format("{0:05}", -42));
+  EXPECT_EQ("00042", fmt::format("{0:05}", 42u));
+  EXPECT_EQ("-0042", fmt::format("{0:05}", -42l));
+  EXPECT_EQ("00042", fmt::format("{0:05}", 42ul));
+  EXPECT_EQ("-0042", fmt::format("{0:05}", -42ll));
+  EXPECT_EQ("00042", fmt::format("{0:05}", 42ull));
+  EXPECT_EQ("-000042", fmt::format("{0:07}", -42.0));
+  EXPECT_EQ("-000042", fmt::format("{0:07}", -42.0l));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:0"), 'c'), format_error,
+                   "missing '}' in format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:05}"), 'c'), format_error,
+                   "invalid format specifier for char");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:05}"), "abc"), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{0:05}"), reinterpret_cast<void*>(0x42)),
+      format_error, "format specifier requires numeric argument");
+}
+
+TEST(format_test, width) {
+  char format_str[buffer_size];
+  safe_sprintf(format_str, "{0:%u", UINT_MAX);
+  increment(format_str + 3);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "number is too big");
+  size_t size = std::strlen(format_str);
+  format_str[size] = '}';
+  format_str[size + 1] = 0;
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "number is too big");
+
+  safe_sprintf(format_str, "{0:%u", INT_MAX + 1u);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "number is too big");
+  safe_sprintf(format_str, "{0:%u}", INT_MAX + 1u);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "number is too big");
+  EXPECT_EQ(" -42", fmt::format("{0:4}", -42));
+  EXPECT_EQ("   42", fmt::format("{0:5}", 42u));
+  EXPECT_EQ("   -42", fmt::format("{0:6}", -42l));
+  EXPECT_EQ("     42", fmt::format("{0:7}", 42ul));
+  EXPECT_EQ("   -42", fmt::format("{0:6}", -42ll));
+  EXPECT_EQ("     42", fmt::format("{0:7}", 42ull));
+  EXPECT_EQ("   -1.23", fmt::format("{0:8}", -1.23));
+  EXPECT_EQ("    -1.23", fmt::format("{0:9}", -1.23l));
+  EXPECT_EQ("    0xcafe",
+            fmt::format("{0:10}", reinterpret_cast<void*>(0xcafe)));
+  EXPECT_EQ("x          ", fmt::format("{0:11}", 'x'));
+  EXPECT_EQ("str         ", fmt::format("{0:12}", "str"));
+  EXPECT_EQ(fmt::format("{:*^6}", "🤡"), "**🤡**");
+  EXPECT_EQ(fmt::format("{:*^8}", "你好"), "**你好**");
+  EXPECT_EQ(fmt::format("{:#6}", 42.0), "  42.0");
+  EXPECT_EQ(fmt::format("{:6c}", static_cast<int>('x')), "x     ");
+  EXPECT_EQ(fmt::format("{:>06.0f}", 0.00884311), "000000");
+}
+
+TEST(format_test, runtime_width) {
+  char format_str[buffer_size];
+  safe_sprintf(format_str, "{0:{%u", UINT_MAX);
+  increment(format_str + 4);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "invalid format string");
+  size_t size = std::strlen(format_str);
+  format_str[size] = '}';
+  format_str[size + 1] = 0;
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "argument not found");
+  format_str[size + 1] = '}';
+  format_str[size + 2] = 0;
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "argument not found");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{"), 0), format_error,
+                   "invalid format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{}"), 0), format_error,
+                   "cannot switch from manual to automatic argument indexing");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{?}}"), 0), format_error,
+                   "invalid format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0), format_error,
+                   "argument not found");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{0:}}"), 0), format_error,
+                   "invalid format string");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, -1), format_error,
+                   "negative width");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, (INT_MAX + 1u)),
+                   format_error, "number is too big");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, -1l), format_error,
+                   "negative width");
+  if (fmt::detail::const_check(sizeof(long) > sizeof(int))) {
+    long value = INT_MAX;
+    EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, (value + 1)),
+                     format_error, "number is too big");
+  }
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, (INT_MAX + 1ul)),
+                   format_error, "number is too big");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, '0'), format_error,
+                   "width is not integer");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{1}}"), 0, 0.0), format_error,
+                   "width is not integer");
+
+  EXPECT_EQ(" -42", fmt::format("{0:{1}}", -42, 4));
+  EXPECT_EQ("   42", fmt::format("{0:{1}}", 42u, 5));
+  EXPECT_EQ("   -42", fmt::format("{0:{1}}", -42l, 6));
+  EXPECT_EQ("     42", fmt::format("{0:{1}}", 42ul, 7));
+  EXPECT_EQ("   -42", fmt::format("{0:{1}}", -42ll, 6));
+  EXPECT_EQ("     42", fmt::format("{0:{1}}", 42ull, 7));
+  EXPECT_EQ("   -1.23", fmt::format("{0:{1}}", -1.23, 8));
+  EXPECT_EQ("    -1.23", fmt::format("{0:{1}}", -1.23l, 9));
+  EXPECT_EQ("    0xcafe",
+            fmt::format("{0:{1}}", reinterpret_cast<void*>(0xcafe), 10));
+  EXPECT_EQ("x          ", fmt::format("{0:{1}}", 'x', 11));
+  EXPECT_EQ("str         ", fmt::format("{0:{1}}", "str", 12));
+  EXPECT_EQ(fmt::format("{:{}}", 42, short(4)), "  42");
+}
+
+TEST(format_test, precision) {
+  char format_str[buffer_size];
+  safe_sprintf(format_str, "{0:.%u", UINT_MAX);
+  increment(format_str + 4);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "number is too big");
+  size_t size = std::strlen(format_str);
+  format_str[size] = '}';
+  format_str[size + 1] = 0;
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "number is too big");
+
+  safe_sprintf(format_str, "{0:.%u", INT_MAX + 1u);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "number is too big");
+  safe_sprintf(format_str, "{0:.%u}", INT_MAX + 1u);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "number is too big");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:."), 0), format_error,
+                   "missing precision specifier");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.}"), 0), format_error,
+                   "missing precision specifier");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2"), 0), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42u), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42u), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42l), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42l), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42ul), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42ul), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42ll), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42ll), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2}"), 42ull), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.2f}"), 42ull), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:3.0}"), 'x'), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_EQ("1.2", fmt::format("{0:.2}", 1.2345));
+  EXPECT_EQ("1.2", fmt::format("{0:.2}", 1.2345l));
+  EXPECT_EQ("1.2e+56", fmt::format("{:.2}", 1.234e56));
+  EXPECT_EQ("1.1", fmt::format("{0:.3}", 1.1));
+  EXPECT_EQ("1e+00", fmt::format("{:.0e}", 1.0L));
+  EXPECT_EQ("  0.0e+00", fmt::format("{:9.1e}", 0.0));
+  EXPECT_EQ(
+      fmt::format("{:.494}", 4.9406564584124654E-324),
+      "4.9406564584124654417656879286822137236505980261432476442558568250067550"
+      "727020875186529983636163599237979656469544571773092665671035593979639877"
+      "479601078187812630071319031140452784581716784898210368871863605699873072"
+      "305000638740915356498438731247339727316961514003171538539807412623856559"
+      "117102665855668676818703956031062493194527159149245532930545654440112748"
+      "012970999954193198940908041656332452475714786901472678015935523861155013"
+      "480352649347201937902681071074917033322268447533357208324319361e-324");
+  EXPECT_EQ(
+      fmt::format("{:.1074f}", 1.1125369292536e-308),
+      "0.0000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000111253692925360019747947051741965785554081512200979"
+      "355021686109411883779182127659725163430929750364498219730822952552570601"
+      "152163505899912777129583674906301179059298598412303893909188340988729019"
+      "014361467448914817838555156840459458527907308695109202499990850735085304"
+      "478476991912072201449236975063640913461919914396877093174125167509869762"
+      "482369631100360266123742648159508919592746619553246586039571522788247697"
+      "156360766271842991667238355464496455107749716934387136380536472531224398"
+      "559833794807213172371254492216255558078524900147957309382830827524104234"
+      "530961756787819847850302379672357738807808384667004752163416921762619527"
+      "462847642037420991432005657440259928195996762610375541867198059294212446"
+      "81962777939941034720757232455434770912461317493580281734466552734375");
+
+  std::string outputs[] = {
+      "-0X1.41FE3FFE71C9E000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000P+127",
+      "-0XA.0FF1FFF38E4F0000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000000000000000000000000"
+      "000000000000000000000000000000000000000000000000000P+124"};
+  EXPECT_THAT(outputs,
+              testing::Contains(fmt::format("{:.838A}", -2.14001164E+38)));
+
+  if (std::numeric_limits<long double>::digits == 64) {
+    auto ld = (std::numeric_limits<long double>::min)();
+    EXPECT_EQ(fmt::format("{:.0}", ld), "3e-4932");
+    EXPECT_EQ(
+        fmt::format("{:0g}", std::numeric_limits<long double>::denorm_min()),
+        "3.6452e-4951");
+  }
+
+  EXPECT_EQ("123.", fmt::format("{:#.0f}", 123.0));
+  EXPECT_EQ("1.23", fmt::format("{:.02f}", 1.234));
+  EXPECT_EQ("0.001", fmt::format("{:.1g}", 0.001));
+  EXPECT_EQ("1019666400", fmt::format("{}", 1019666432.0f));
+  EXPECT_EQ("1e+01", fmt::format("{:.0e}", 9.5));
+  EXPECT_EQ("1.0e-34", fmt::format("{:.1e}", 1e-34));
+
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{0:.2}"), reinterpret_cast<void*>(0xcafe)),
+      format_error, "precision not allowed for this argument type");
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{0:.2f}"), reinterpret_cast<void*>(0xcafe)),
+      format_error, "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:.{}e}"), 42.0,
+                                     fmt::detail::max_value<int>()),
+                   format_error, "number is too big");
+  EXPECT_THROW_MSG(
+      (void)fmt::format("{:.2147483646f}", -2.2121295195081227E+304),
+      format_error, "number is too big");
+
+  EXPECT_EQ("st", fmt::format("{0:.2}", "str"));
+  EXPECT_EQ("вожык", fmt::format("{0:.5}", "вожыкі"));
+}
+
+TEST(format_test, runtime_precision) {
+  char format_str[buffer_size];
+  safe_sprintf(format_str, "{0:.{%u", UINT_MAX);
+  increment(format_str + 5);
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "invalid format string");
+  size_t size = std::strlen(format_str);
+  format_str[size] = '}';
+  format_str[size + 1] = 0;
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "argument not found");
+  format_str[size + 1] = '}';
+  format_str[size + 2] = 0;
+  EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), 0), format_error,
+                   "argument not found");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{"), 0), format_error,
+                   "invalid format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{}"), 0), format_error,
+                   "cannot switch from manual to automatic argument indexing");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{?}}"), 0), format_error,
+                   "invalid format string");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}"), 0, 0), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0), format_error,
+                   "argument not found");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{0:}}"), 0), format_error,
+                   "invalid format string");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, -1), format_error,
+                   "negative precision");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, (INT_MAX + 1u)),
+                   format_error, "number is too big");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, -1l), format_error,
+                   "negative precision");
+  if (fmt::detail::const_check(sizeof(long) > sizeof(int))) {
+    long value = INT_MAX;
+    EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, (value + 1)),
+                     format_error, "number is too big");
+  }
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, (INT_MAX + 1ul)),
+                   format_error, "number is too big");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, '0'), format_error,
+                   "precision is not integer");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 0, 0.0), format_error,
+                   "precision is not integer");
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42, 2), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42, 2), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42u, 2), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42u, 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42l, 2), format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42l, 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42ul, 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42ul, 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42ll, 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42ll, 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"), 42ull, 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"), 42ull, 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:3.{1}}"), 'x', 0),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_EQ("1.2", fmt::format("{0:.{1}}", 1.2345, 2));
+  EXPECT_EQ("1.2", fmt::format("{1:.{0}}", 2, 1.2345l));
+
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}}"),
+                                     reinterpret_cast<void*>(0xcafe), 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:.{1}f}"),
+                                     reinterpret_cast<void*>(0xcafe), 2),
+                   format_error,
+                   "precision not allowed for this argument type");
+
+  EXPECT_EQ("st", fmt::format("{0:.{1}}", "str", 2));
+}
+
+TEST(format_test, format_bool) {
+  EXPECT_EQ("true", fmt::format("{}", true));
+  EXPECT_EQ("false", fmt::format("{}", false));
+  EXPECT_EQ("1", fmt::format("{:d}", true));
+  EXPECT_EQ("true ", fmt::format("{:5}", true));
+  EXPECT_EQ("true", fmt::format("{:s}", true));
+  EXPECT_EQ("false", fmt::format("{:s}", false));
+  EXPECT_EQ("false ", fmt::format("{:6s}", false));
+}
+
+TEST(format_test, format_short) {
+  short s = 42;
+  EXPECT_EQ("42", fmt::format("{0:d}", s));
+  unsigned short us = 42;
+  EXPECT_EQ("42", fmt::format("{0:d}", us));
+}
+
+template <typename T>
+void check_unknown_types(const T& value, const char* types, const char*) {
+  char format_str[buffer_size];
+  const char* special = ".0123456789L?}";
+  for (int i = CHAR_MIN; i <= CHAR_MAX; ++i) {
+    char c = static_cast<char>(i);
+    if (std::strchr(types, c) || std::strchr(special, c) || !c) continue;
+    safe_sprintf(format_str, "{0:10%c}", c);
+    const char* message = "invalid type specifier";
+    EXPECT_THROW_MSG((void)fmt::format(runtime(format_str), value),
+                     format_error, message)
+        << format_str << " " << message;
+  }
+}
+
+TEST(format_test, format_int) {
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:v"), 42), format_error,
+                   "invalid type specifier");
+  check_unknown_types(42, "bBdoxXnLc", "integer");
+  EXPECT_EQ("x", fmt::format("{:c}", static_cast<int>('x')));
+}
+
+TEST(format_test, format_bin) {
+  EXPECT_EQ("0", fmt::format("{0:b}", 0));
+  EXPECT_EQ("101010", fmt::format("{0:b}", 42));
+  EXPECT_EQ("101010", fmt::format("{0:b}", 42u));
+  EXPECT_EQ("-101010", fmt::format("{0:b}", -42));
+  EXPECT_EQ("11000000111001", fmt::format("{0:b}", 12345));
+  EXPECT_EQ("10010001101000101011001111000", fmt::format("{0:b}", 0x12345678));
+  EXPECT_EQ("10010000101010111100110111101111",
+            fmt::format("{0:b}", 0x90ABCDEF));
+  EXPECT_EQ("11111111111111111111111111111111",
+            fmt::format("{0:b}", max_value<uint32_t>()));
+}
+
+#if FMT_USE_INT128
+constexpr auto int128_max = static_cast<__int128_t>(
+    (static_cast<__uint128_t>(1) << ((__SIZEOF_INT128__ * CHAR_BIT) - 1)) - 1);
+constexpr auto int128_min = -int128_max - 1;
+
+constexpr auto uint128_max = ~static_cast<__uint128_t>(0);
+#endif
+
+TEST(format_test, format_dec) {
+  EXPECT_EQ("0", fmt::format("{0}", 0));
+  EXPECT_EQ("42", fmt::format("{0}", 42));
+  EXPECT_EQ("42", fmt::format("{0:d}", 42));
+  EXPECT_EQ("42", fmt::format("{0}", 42u));
+  EXPECT_EQ("-42", fmt::format("{0}", -42));
+  EXPECT_EQ("12345", fmt::format("{0}", 12345));
+  EXPECT_EQ("67890", fmt::format("{0}", 67890));
+#if FMT_USE_INT128
+  EXPECT_EQ("0", fmt::format("{0}", static_cast<__int128_t>(0)));
+  EXPECT_EQ("0", fmt::format("{0}", static_cast<__uint128_t>(0)));
+  EXPECT_EQ("9223372036854775808",
+            fmt::format("{0}", static_cast<__int128_t>(INT64_MAX) + 1));
+  EXPECT_EQ("-9223372036854775809",
+            fmt::format("{0}", static_cast<__int128_t>(INT64_MIN) - 1));
+  EXPECT_EQ("18446744073709551616",
+            fmt::format("{0}", static_cast<__int128_t>(UINT64_MAX) + 1));
+  EXPECT_EQ("170141183460469231731687303715884105727",
+            fmt::format("{0}", int128_max));
+  EXPECT_EQ("-170141183460469231731687303715884105728",
+            fmt::format("{0}", int128_min));
+  EXPECT_EQ("340282366920938463463374607431768211455",
+            fmt::format("{0}", uint128_max));
+#endif
+
+  char buffer[buffer_size];
+  safe_sprintf(buffer, "%d", INT_MIN);
+  EXPECT_EQ(buffer, fmt::format("{0}", INT_MIN));
+  safe_sprintf(buffer, "%d", INT_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0}", INT_MAX));
+  safe_sprintf(buffer, "%u", UINT_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0}", UINT_MAX));
+  safe_sprintf(buffer, "%ld", 0 - static_cast<unsigned long>(LONG_MIN));
+  EXPECT_EQ(buffer, fmt::format("{0}", LONG_MIN));
+  safe_sprintf(buffer, "%ld", LONG_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0}", LONG_MAX));
+  safe_sprintf(buffer, "%lu", ULONG_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0}", ULONG_MAX));
+}
+
+TEST(format_test, format_hex) {
+  EXPECT_EQ("0", fmt::format("{0:x}", 0));
+  EXPECT_EQ("42", fmt::format("{0:x}", 0x42));
+  EXPECT_EQ("42", fmt::format("{0:x}", 0x42u));
+  EXPECT_EQ("-42", fmt::format("{0:x}", -0x42));
+  EXPECT_EQ("12345678", fmt::format("{0:x}", 0x12345678));
+  EXPECT_EQ("90abcdef", fmt::format("{0:x}", 0x90abcdef));
+  EXPECT_EQ("12345678", fmt::format("{0:X}", 0x12345678));
+  EXPECT_EQ("90ABCDEF", fmt::format("{0:X}", 0x90ABCDEF));
+#if FMT_USE_INT128
+  EXPECT_EQ("0", fmt::format("{0:x}", static_cast<__int128_t>(0)));
+  EXPECT_EQ("0", fmt::format("{0:x}", static_cast<__uint128_t>(0)));
+  EXPECT_EQ("8000000000000000",
+            fmt::format("{0:x}", static_cast<__int128_t>(INT64_MAX) + 1));
+  EXPECT_EQ("-8000000000000001",
+            fmt::format("{0:x}", static_cast<__int128_t>(INT64_MIN) - 1));
+  EXPECT_EQ("10000000000000000",
+            fmt::format("{0:x}", static_cast<__int128_t>(UINT64_MAX) + 1));
+  EXPECT_EQ("7fffffffffffffffffffffffffffffff",
+            fmt::format("{0:x}", int128_max));
+  EXPECT_EQ("-80000000000000000000000000000000",
+            fmt::format("{0:x}", int128_min));
+  EXPECT_EQ("ffffffffffffffffffffffffffffffff",
+            fmt::format("{0:x}", uint128_max));
+#endif
+
+  char buffer[buffer_size];
+  safe_sprintf(buffer, "-%x", 0 - static_cast<unsigned>(INT_MIN));
+  EXPECT_EQ(buffer, fmt::format("{0:x}", INT_MIN));
+  safe_sprintf(buffer, "%x", INT_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0:x}", INT_MAX));
+  safe_sprintf(buffer, "%x", UINT_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0:x}", UINT_MAX));
+  safe_sprintf(buffer, "-%lx", 0 - static_cast<unsigned long>(LONG_MIN));
+  EXPECT_EQ(buffer, fmt::format("{0:x}", LONG_MIN));
+  safe_sprintf(buffer, "%lx", LONG_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0:x}", LONG_MAX));
+  safe_sprintf(buffer, "%lx", ULONG_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0:x}", ULONG_MAX));
+}
+
+TEST(format_test, format_oct) {
+  EXPECT_EQ("0", fmt::format("{0:o}", 0));
+  EXPECT_EQ("42", fmt::format("{0:o}", 042));
+  EXPECT_EQ("42", fmt::format("{0:o}", 042u));
+  EXPECT_EQ("-42", fmt::format("{0:o}", -042));
+  EXPECT_EQ("12345670", fmt::format("{0:o}", 012345670));
+#if FMT_USE_INT128
+  EXPECT_EQ("0", fmt::format("{0:o}", static_cast<__int128_t>(0)));
+  EXPECT_EQ("0", fmt::format("{0:o}", static_cast<__uint128_t>(0)));
+  EXPECT_EQ("1000000000000000000000",
+            fmt::format("{0:o}", static_cast<__int128_t>(INT64_MAX) + 1));
+  EXPECT_EQ("-1000000000000000000001",
+            fmt::format("{0:o}", static_cast<__int128_t>(INT64_MIN) - 1));
+  EXPECT_EQ("2000000000000000000000",
+            fmt::format("{0:o}", static_cast<__int128_t>(UINT64_MAX) + 1));
+  EXPECT_EQ("1777777777777777777777777777777777777777777",
+            fmt::format("{0:o}", int128_max));
+  EXPECT_EQ("-2000000000000000000000000000000000000000000",
+            fmt::format("{0:o}", int128_min));
+  EXPECT_EQ("3777777777777777777777777777777777777777777",
+            fmt::format("{0:o}", uint128_max));
+#endif
+
+  char buffer[buffer_size];
+  safe_sprintf(buffer, "-%o", 0 - static_cast<unsigned>(INT_MIN));
+  EXPECT_EQ(buffer, fmt::format("{0:o}", INT_MIN));
+  safe_sprintf(buffer, "%o", INT_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0:o}", INT_MAX));
+  safe_sprintf(buffer, "%o", UINT_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0:o}", UINT_MAX));
+  safe_sprintf(buffer, "-%lo", 0 - static_cast<unsigned long>(LONG_MIN));
+  EXPECT_EQ(buffer, fmt::format("{0:o}", LONG_MIN));
+  safe_sprintf(buffer, "%lo", LONG_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0:o}", LONG_MAX));
+  safe_sprintf(buffer, "%lo", ULONG_MAX);
+  EXPECT_EQ(buffer, fmt::format("{0:o}", ULONG_MAX));
+}
+
+TEST(format_test, format_int_locale) {
+  EXPECT_EQ("1234", fmt::format("{:L}", 1234));
+}
+
+TEST(format_test, format_float) {
+  EXPECT_EQ("0", fmt::format("{}", 0.0f));
+  EXPECT_EQ("392.500000", fmt::format("{0:f}", 392.5f));
+}
+
+TEST(format_test, format_double) {
+  EXPECT_EQ(fmt::format("{}", 0.0), "0");
+  check_unknown_types(1.2, "eEfFgGaAnL%", "double");
+  EXPECT_EQ(fmt::format("{:}", 0.0), "0");
+  EXPECT_EQ(fmt::format("{:f}", 0.0), "0.000000");
+  EXPECT_EQ(fmt::format("{:g}", 0.0), "0");
+  EXPECT_EQ(fmt::format("{:}", 392.65), "392.65");
+  EXPECT_EQ(fmt::format("{:g}", 392.65), "392.65");
+  EXPECT_EQ(fmt::format("{:G}", 392.65), "392.65");
+  EXPECT_EQ(fmt::format("{:g}", 4.9014e6), "4.9014e+06");
+  EXPECT_EQ(fmt::format("{:f}", 392.65), "392.650000");
+  EXPECT_EQ(fmt::format("{:F}", 392.65), "392.650000");
+  EXPECT_EQ(fmt::format("{:L}", 42.0), "42");
+  EXPECT_EQ(fmt::format("{:24a}", 4.2), "    0x1.0cccccccccccdp+2");
+  EXPECT_EQ(fmt::format("{:<24a}", 4.2), "0x1.0cccccccccccdp+2    ");
+  EXPECT_EQ(fmt::format("{0:e}", 392.65), "3.926500e+02");
+  EXPECT_EQ(fmt::format("{0:E}", 392.65), "3.926500E+02");
+  EXPECT_EQ(fmt::format("{0:+010.4g}", 392.65), "+0000392.6");
+  char buffer[buffer_size];
+  safe_sprintf(buffer, "%a", -42.0);
+  EXPECT_EQ(fmt::format("{:a}", -42.0), buffer);
+  safe_sprintf(buffer, "%A", -42.0);
+  EXPECT_EQ(fmt::format("{:A}", -42.0), buffer);
+  EXPECT_EQ(fmt::format("{:f}", 9223372036854775807.0),
+            "9223372036854775808.000000");
+}
+
+TEST(format_test, precision_rounding) {
+  EXPECT_EQ("0", fmt::format("{:.0f}", 0.0));
+  EXPECT_EQ("0", fmt::format("{:.0f}", 0.01));
+  EXPECT_EQ("0", fmt::format("{:.0f}", 0.1));
+  EXPECT_EQ("0.000", fmt::format("{:.3f}", 0.00049));
+  EXPECT_EQ("0.001", fmt::format("{:.3f}", 0.0005));
+  EXPECT_EQ("0.001", fmt::format("{:.3f}", 0.00149));
+  EXPECT_EQ("0.002", fmt::format("{:.3f}", 0.0015));
+  EXPECT_EQ("1.000", fmt::format("{:.3f}", 0.9999));
+  EXPECT_EQ("0.00123", fmt::format("{:.3}", 0.00123));
+  EXPECT_EQ("0.1", fmt::format("{:.16g}", 0.1));
+  EXPECT_EQ("1", fmt::format("{:.0}", 1.0));
+  EXPECT_EQ("225.51575035152063720",
+            fmt::format("{:.17f}", 225.51575035152064));
+  EXPECT_EQ("-761519619559038.2", fmt::format("{:.1f}", -761519619559038.2));
+  EXPECT_EQ("1.9156918820264798e-56",
+            fmt::format("{}", 1.9156918820264798e-56));
+  EXPECT_EQ("0.0000", fmt::format("{:.4f}", 7.2809479766055470e-15));
+
+  // Trigger a rounding error in Grisu by a specially chosen number.
+  EXPECT_EQ("3788512123356.985352", fmt::format("{:f}", 3788512123356.985352));
+}
+
+TEST(format_test, prettify_float) {
+  EXPECT_EQ("0.0001", fmt::format("{}", 1e-4));
+  EXPECT_EQ("1e-05", fmt::format("{}", 1e-5));
+  EXPECT_EQ("1000000000000000", fmt::format("{}", 1e15));
+  EXPECT_EQ("1e+16", fmt::format("{}", 1e16));
+  EXPECT_EQ("9.999e-05", fmt::format("{}", 9.999e-5));
+  EXPECT_EQ("10000000000", fmt::format("{}", 1e10));
+  EXPECT_EQ("100000000000", fmt::format("{}", 1e11));
+  EXPECT_EQ("12340000000", fmt::format("{}", 1234e7));
+  EXPECT_EQ("12.34", fmt::format("{}", 1234e-2));
+  EXPECT_EQ("0.001234", fmt::format("{}", 1234e-6));
+  EXPECT_EQ("0.1", fmt::format("{}", 0.1f));
+  EXPECT_EQ("0.10000000149011612", fmt::format("{}", double(0.1f)));
+  EXPECT_EQ("1.3563156e-19", fmt::format("{}", 1.35631564e-19f));
+}
+
+TEST(format_test, format_nan) {
+  double nan = std::numeric_limits<double>::quiet_NaN();
+  EXPECT_EQ("nan", fmt::format("{}", nan));
+  EXPECT_EQ("+nan", fmt::format("{:+}", nan));
+  EXPECT_EQ("  +nan", fmt::format("{:+06}", nan));
+  EXPECT_EQ("+nan  ", fmt::format("{:<+06}", nan));
+  EXPECT_EQ(" +nan ", fmt::format("{:^+06}", nan));
+  EXPECT_EQ("  +nan", fmt::format("{:>+06}", nan));
+  if (std::signbit(-nan)) {
+    EXPECT_EQ("-nan", fmt::format("{}", -nan));
+    EXPECT_EQ("  -nan", fmt::format("{:+06}", -nan));
+  } else {
+    fmt::print("Warning: compiler doesn't handle negative NaN correctly");
+  }
+  EXPECT_EQ(" nan", fmt::format("{: }", nan));
+  EXPECT_EQ("NAN", fmt::format("{:F}", nan));
+  EXPECT_EQ("nan    ", fmt::format("{:<7}", nan));
+  EXPECT_EQ("  nan  ", fmt::format("{:^7}", nan));
+  EXPECT_EQ("    nan", fmt::format("{:>7}", nan));
+}
+
+TEST(format_test, format_infinity) {
+  double inf = std::numeric_limits<double>::infinity();
+  EXPECT_EQ("inf", fmt::format("{}", inf));
+  EXPECT_EQ("+inf", fmt::format("{:+}", inf));
+  EXPECT_EQ("-inf", fmt::format("{}", -inf));
+  EXPECT_EQ("  +inf", fmt::format("{:+06}", inf));
+  EXPECT_EQ("  -inf", fmt::format("{:+06}", -inf));
+  EXPECT_EQ("+inf  ", fmt::format("{:<+06}", inf));
+  EXPECT_EQ(" +inf ", fmt::format("{:^+06}", inf));
+  EXPECT_EQ("  +inf", fmt::format("{:>+06}", inf));
+  EXPECT_EQ(" inf", fmt::format("{: }", inf));
+  EXPECT_EQ("INF", fmt::format("{:F}", inf));
+  EXPECT_EQ("inf    ", fmt::format("{:<7}", inf));
+  EXPECT_EQ("  inf  ", fmt::format("{:^7}", inf));
+  EXPECT_EQ("    inf", fmt::format("{:>7}", inf));
+}
+
+TEST(format_test, format_long_double) {
+  EXPECT_EQ("0", fmt::format("{0:}", 0.0l));
+  EXPECT_EQ("0.000000", fmt::format("{0:f}", 0.0l));
+  EXPECT_EQ("392.65", fmt::format("{0:}", 392.65l));
+  EXPECT_EQ("392.65", fmt::format("{0:g}", 392.65l));
+  EXPECT_EQ("392.65", fmt::format("{0:G}", 392.65l));
+  EXPECT_EQ("392.650000", fmt::format("{0:f}", 392.65l));
+  EXPECT_EQ("392.650000", fmt::format("{0:F}", 392.65l));
+  char buffer[buffer_size];
+  safe_sprintf(buffer, "%Le", 392.65l);
+  EXPECT_EQ(buffer, fmt::format("{0:e}", 392.65l));
+  EXPECT_EQ("+0000392.6", fmt::format("{0:+010.4g}", 392.64l));
+  safe_sprintf(buffer, "%La", 3.31l);
+  EXPECT_EQ(buffer, fmt::format("{:a}", 3.31l));
+}
+
+TEST(format_test, format_char) {
+  const char types[] = "cbBdoxX";
+  check_unknown_types('a', types, "char");
+  EXPECT_EQ("a", fmt::format("{0}", 'a'));
+  EXPECT_EQ("z", fmt::format("{0:c}", 'z'));
+  int n = 'x';
+  for (const char* type = types + 1; *type; ++type) {
+    std::string format_str = fmt::format("{{:{}}}", *type);
+    EXPECT_EQ(fmt::format(runtime(format_str), n),
+              fmt::format(runtime(format_str), 'x'))
+        << format_str;
+  }
+  EXPECT_EQ(fmt::format("{:02X}", n), fmt::format("{:02X}", 'x'));
+
+  EXPECT_EQ("\n", fmt::format("{}", '\n'));
+  EXPECT_EQ("'\\n'", fmt::format("{:?}", '\n'));
+}
+
+TEST(format_test, format_volatile_char) {
+  volatile char c = 'x';
+  EXPECT_EQ("x", fmt::format("{}", c));
+}
+
+TEST(format_test, format_unsigned_char) {
+  EXPECT_EQ("42", fmt::format("{}", static_cast<unsigned char>(42)));
+  EXPECT_EQ("42", fmt::format("{}", static_cast<uint8_t>(42)));
+}
+
+TEST(format_test, format_cstring) {
+  check_unknown_types("test", "sp", "string");
+  EXPECT_EQ("test", fmt::format("{0}", "test"));
+  EXPECT_EQ("test", fmt::format("{0:s}", "test"));
+  char nonconst[] = "nonconst";
+  EXPECT_EQ("nonconst", fmt::format("{0}", nonconst));
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("{0}"), static_cast<const char*>(nullptr)),
+      format_error, "string pointer is null");
+}
+
+void function_pointer_test(int, double, std::string) {}
+
+TEST(format_test, format_pointer) {
+  check_unknown_types(reinterpret_cast<void*>(0x1234), "p", "pointer");
+  EXPECT_EQ("0x0", fmt::format("{0}", static_cast<void*>(nullptr)));
+  EXPECT_EQ("0x1234", fmt::format("{0}", reinterpret_cast<void*>(0x1234)));
+  EXPECT_EQ("0x1234", fmt::format("{0:p}", reinterpret_cast<void*>(0x1234)));
+  // On CHERI (or other fat-pointer) systems, the size of a pointer is greater
+  // than the size an integer that can hold a virtual address.  There is no
+  // portable address-as-an-integer type (yet) in C++, so we use `size_t` as
+  // the closest equivalent for now.
+  EXPECT_EQ("0x" + std::string(sizeof(size_t) * CHAR_BIT / 4, 'f'),
+            fmt::format("{0}", reinterpret_cast<void*>(~uintptr_t())));
+  EXPECT_EQ("0x1234",
+            fmt::format("{}", fmt::ptr(reinterpret_cast<int*>(0x1234))));
+  std::unique_ptr<int> up(new int(1));
+  EXPECT_EQ(fmt::format("{}", fmt::ptr(up.get())),
+            fmt::format("{}", fmt::ptr(up)));
+  std::shared_ptr<int> sp(new int(1));
+  EXPECT_EQ(fmt::format("{}", fmt::ptr(sp.get())),
+            fmt::format("{}", fmt::ptr(sp)));
+  EXPECT_EQ(fmt::format("{}", fmt::detail::bit_cast<const void*>(
+                                  &function_pointer_test)),
+            fmt::format("{}", fmt::ptr(function_pointer_test)));
+  EXPECT_EQ("0x0", fmt::format("{}", nullptr));
+}
+
+TEST(format_test, write_uintptr_fallback) {
+  // Test that formatting a pointer by converting it to uint128_fallback works.
+  // This is needed to support systems without uintptr_t.
+  auto s = std::string();
+  fmt::detail::write_ptr<char>(
+      std::back_inserter(s),
+      fmt::detail::bit_cast<fmt::detail::uint128_fallback>(
+          reinterpret_cast<void*>(0xface)),
+      nullptr);
+  EXPECT_EQ(s, "0xface");
+}
+
+enum class color { red, green, blue };
+
+namespace test_ns {
+enum class color { red, green, blue };
+using fmt::enums::format_as;
+}  // namespace test_ns
+
+TEST(format_test, format_enum_class) {
+  EXPECT_EQ(fmt::format("{}", fmt::underlying(color::red)), "0");
+  EXPECT_EQ(fmt::format("{}", test_ns::color::red), "0");
+}
+
+TEST(format_test, format_string) {
+  EXPECT_EQ(fmt::format("{0}", std::string("test")), "test");
+  EXPECT_EQ(fmt::format("{0}", std::string("test")), "test");
+  EXPECT_EQ(fmt::format("{:?}", std::string("test")), "\"test\"");
+  EXPECT_EQ(fmt::format("{:*^10?}", std::string("test")), "**\"test\"**");
+  EXPECT_EQ(fmt::format("{:?}", std::string("\test")), "\"\\test\"");
+  EXPECT_THROW((void)fmt::format(fmt::runtime("{:x}"), std::string("test")),
+               fmt::format_error);
+}
+
+TEST(format_test, format_string_view) {
+  EXPECT_EQ("test", fmt::format("{}", string_view("test")));
+  EXPECT_EQ("\"t\\nst\"", fmt::format("{:?}", string_view("t\nst")));
+  EXPECT_EQ("", fmt::format("{}", string_view()));
+}
+
+#ifdef FMT_USE_STRING_VIEW
+struct string_viewable {};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<string_viewable> : formatter<std::string_view> {
+  auto format(string_viewable, format_context& ctx) -> decltype(ctx.out()) {
+    return formatter<std::string_view>::format("foo", ctx);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(format_test, format_std_string_view) {
+  EXPECT_EQ("test", fmt::format("{}", std::string_view("test")));
+  EXPECT_EQ("foo", fmt::format("{}", string_viewable()));
+}
+
+struct explicitly_convertible_to_std_string_view {
+  explicit operator std::string_view() const { return "foo"; }
+};
+
+template <>
+struct fmt::formatter<explicitly_convertible_to_std_string_view>
+    : formatter<std::string_view> {
+  auto format(explicitly_convertible_to_std_string_view v, format_context& ctx)
+      -> decltype(ctx.out()) {
+    return format_to(ctx.out(), "'{}'", std::string_view(v));
+  }
+};
+
+TEST(format_test, format_explicitly_convertible_to_std_string_view) {
+  EXPECT_EQ("'foo'",
+            fmt::format("{}", explicitly_convertible_to_std_string_view()));
+}
+#endif
+
+struct converible_to_anything {
+  template <typename T> operator T() const { return T(); }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<converible_to_anything> {
+  FMT_CONSTEXPR auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  auto format(converible_to_anything, format_context& ctx)
+      -> decltype(ctx.out()) {
+    return format_to(ctx.out(), "foo");
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(format_test, format_convertible_to_anything) {
+  EXPECT_EQ("foo", fmt::format("{}", converible_to_anything()));
+}
+
+class Answer {};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<date> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    auto it = ctx.begin();
+    if (it != ctx.end() && *it == 'd') ++it;
+    return it;
+  }
+
+  auto format(const date& d, format_context& ctx) -> decltype(ctx.out()) {
+    format_to(ctx.out(), "{}-{}-{}", d.year(), d.month(), d.day());
+    return ctx.out();
+  }
+};
+
+template <> struct formatter<Answer> : formatter<int> {
+  template <typename FormatContext>
+  auto format(Answer, FormatContext& ctx) -> decltype(ctx.out()) {
+    return formatter<int>::format(42, ctx);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(format_test, format_custom) {
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:s}"), date(2012, 12, 9)),
+                   format_error, "unknown format specifier");
+  EXPECT_EQ("42", fmt::format("{0}", Answer()));
+  EXPECT_EQ("0042", fmt::format("{:04}", Answer()));
+}
+
+TEST(format_test, format_to_custom) {
+  char buf[10] = {};
+  auto end =
+      &*fmt::format_to(fmt::detail::make_checked(buf, 10), "{}", Answer());
+  EXPECT_EQ(end, buf + 2);
+  EXPECT_STREQ(buf, "42");
+}
+
+TEST(format_test, format_string_from_speed_test) {
+  EXPECT_EQ("1.2340000000:0042:+3.13:str:0x3e8:X:%",
+            fmt::format("{0:0.10f}:{1:04}:{2:+g}:{3}:{4}:{5}:%", 1.234, 42,
+                        3.13, "str", reinterpret_cast<void*>(1000), 'X'));
+}
+
+TEST(format_test, format_examples) {
+  std::string message = fmt::format("The answer is {}", 42);
+  EXPECT_EQ("The answer is 42", message);
+
+  EXPECT_EQ("42", fmt::format("{}", 42));
+
+  memory_buffer out;
+  format_to(std::back_inserter(out), "The answer is {}.", 42);
+  EXPECT_EQ("The answer is 42.", to_string(out));
+
+  const char* filename = "nonexistent";
+  FILE* ftest = safe_fopen(filename, "r");
+  if (ftest) fclose(ftest);
+  int error_code = errno;
+  EXPECT_TRUE(ftest == nullptr);
+  EXPECT_SYSTEM_ERROR(
+      {
+        FILE* f = safe_fopen(filename, "r");
+        if (!f)
+          throw fmt::system_error(errno, "Cannot open file '{}'", filename);
+        fclose(f);
+      },
+      error_code, "Cannot open file 'nonexistent'");
+
+  EXPECT_EQ("First, thou shalt count to three",
+            fmt::format("First, thou shalt count to {0}", "three"));
+  EXPECT_EQ("Bring me a shrubbery", fmt::format("Bring me a {}", "shrubbery"));
+  EXPECT_EQ("From 1 to 3", fmt::format("From {} to {}", 1, 3));
+
+  char buffer[buffer_size];
+  safe_sprintf(buffer, "%03.2f", -1.2);
+  EXPECT_EQ(buffer, fmt::format("{:03.2f}", -1.2));
+
+  EXPECT_EQ("a, b, c", fmt::format("{0}, {1}, {2}", 'a', 'b', 'c'));
+  EXPECT_EQ("a, b, c", fmt::format("{}, {}, {}", 'a', 'b', 'c'));
+  EXPECT_EQ("c, b, a", fmt::format("{2}, {1}, {0}", 'a', 'b', 'c'));
+  EXPECT_EQ("abracadabra", fmt::format("{0}{1}{0}", "abra", "cad"));
+
+  EXPECT_EQ("left aligned                  ",
+            fmt::format("{:<30}", "left aligned"));
+  EXPECT_EQ("                 right aligned",
+            fmt::format("{:>30}", "right aligned"));
+  EXPECT_EQ("           centered           ",
+            fmt::format("{:^30}", "centered"));
+  EXPECT_EQ("***********centered***********",
+            fmt::format("{:*^30}", "centered"));
+
+  EXPECT_EQ("+3.140000; -3.140000", fmt::format("{:+f}; {:+f}", 3.14, -3.14));
+  EXPECT_EQ(" 3.140000; -3.140000", fmt::format("{: f}; {: f}", 3.14, -3.14));
+  EXPECT_EQ("3.140000; -3.140000", fmt::format("{:-f}; {:-f}", 3.14, -3.14));
+
+  EXPECT_EQ("int: 42;  hex: 2a;  oct: 52",
+            fmt::format("int: {0:d};  hex: {0:x};  oct: {0:o}", 42));
+  EXPECT_EQ("int: 42;  hex: 0x2a;  oct: 052",
+            fmt::format("int: {0:d};  hex: {0:#x};  oct: {0:#o}", 42));
+
+  EXPECT_EQ("The answer is 42", fmt::format("The answer is {}", 42));
+  EXPECT_THROW_MSG(
+      (void)fmt::format(runtime("The answer is {:d}"), "forty-two"),
+      format_error, "invalid type specifier");
+
+  EXPECT_WRITE(
+      stdout, fmt::print("{}", std::numeric_limits<double>::infinity()), "inf");
+}
+
+TEST(format_test, print) {
+  EXPECT_WRITE(stdout, fmt::print("Don't {}!", "panic"), "Don't panic!");
+  EXPECT_WRITE(stderr, fmt::print(stderr, "Don't {}!", "panic"),
+               "Don't panic!");
+}
+
+TEST(format_test, variadic) {
+  EXPECT_EQ("abc1", fmt::format("{}c{}", "ab", 1));
+}
+
+TEST(format_test, dynamic) {
+  using ctx = fmt::format_context;
+  auto args = std::vector<fmt::basic_format_arg<ctx>>();
+  args.emplace_back(fmt::detail::make_arg<ctx>(42));
+  args.emplace_back(fmt::detail::make_arg<ctx>("abc1"));
+  args.emplace_back(fmt::detail::make_arg<ctx>(1.5f));
+
+  std::string result = fmt::vformat(
+      "{} and {} and {}",
+      fmt::format_args(args.data(), static_cast<int>(args.size())));
+
+  EXPECT_EQ("42 and abc1 and 1.5", result);
+}
+
+TEST(format_test, bytes) {
+  auto s = fmt::format("{:10}", fmt::bytes("ёжик"));
+  EXPECT_EQ("ёжик  ", s);
+  EXPECT_EQ(10, s.size());
+}
+
+TEST(format_test, group_digits_view) {
+  EXPECT_EQ(fmt::format("{}", fmt::group_digits(10000000)), "10,000,000");
+  EXPECT_EQ(fmt::format("{:8}", fmt::group_digits(1000)), "   1,000");
+}
+
+enum test_enum { foo, bar };
+auto format_as(test_enum e) -> int { return e; }
+
+TEST(format_test, join) {
+  using fmt::join;
+  int v1[3] = {1, 2, 3};
+  auto v2 = std::vector<float>();
+  v2.push_back(1.2f);
+  v2.push_back(3.4f);
+  void* v3[2] = {&v1[0], &v1[1]};
+
+  EXPECT_EQ("(1, 2, 3)", fmt::format("({})", join(v1, v1 + 3, ", ")));
+  EXPECT_EQ("(1)", fmt::format("({})", join(v1, v1 + 1, ", ")));
+  EXPECT_EQ("()", fmt::format("({})", join(v1, v1, ", ")));
+  EXPECT_EQ("(001, 002, 003)", fmt::format("({:03})", join(v1, v1 + 3, ", ")));
+  EXPECT_EQ("(+01.20, +03.40)",
+            fmt::format("({:+06.2f})", join(v2.begin(), v2.end(), ", ")));
+
+  EXPECT_EQ("1, 2, 3", fmt::format("{0:{1}}", join(v1, v1 + 3, ", "), 1));
+
+  EXPECT_EQ(fmt::format("{}, {}", v3[0], v3[1]),
+            fmt::format("{}", join(v3, v3 + 2, ", ")));
+
+  EXPECT_EQ("(1, 2, 3)", fmt::format("({})", join(v1, ", ")));
+  EXPECT_EQ("(+01.20, +03.40)", fmt::format("({:+06.2f})", join(v2, ", ")));
+
+  auto v4 = std::vector<test_enum>{foo, bar, foo};
+  EXPECT_EQ("0 1 0", fmt::format("{}", join(v4, " ")));
+}
+
+#ifdef __cpp_lib_byte
+TEST(format_test, format_byte) {
+  using arg_mapper = fmt::detail::arg_mapper<fmt::format_context>;
+  EXPECT_EQ(arg_mapper().map(std::byte(42)), 42);
+  EXPECT_EQ(fmt::format("{}", std::byte(42)), "42");
+}
+
+TEST(format_test, join_bytes) {
+  auto v = std::vector<std::byte>{std::byte(1), std::byte(2), std::byte(3)};
+  EXPECT_EQ(fmt::format("{}", fmt::join(v, ", ")), "1, 2, 3");
+}
+#endif
+
+std::string vformat_message(int id, const char* format, fmt::format_args args) {
+  auto buffer = fmt::memory_buffer();
+  format_to(fmt::appender(buffer), "[{}] ", id);
+  vformat_to(fmt::appender(buffer), format, args);
+  return to_string(buffer);
+}
+
+template <typename... Args>
+std::string format_message(int id, const char* format, const Args&... args) {
+  auto va = fmt::make_format_args(args...);
+  return vformat_message(id, format, va);
+}
+
+TEST(format_test, format_message_example) {
+  EXPECT_EQ("[42] something happened",
+            format_message(42, "{} happened", "something"));
+}
+
+template <typename... Args>
+void print_error(const char* file, int line, const char* format,
+                 const Args&... args) {
+  fmt::print("{}: {}: ", file, line);
+  fmt::print(format, args...);
+}
+
+TEST(format_test, unpacked_args) {
+  EXPECT_EQ("0123456789abcdefg",
+            fmt::format("{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}", 0, 1, 2, 3, 4, 5,
+                        6, 7, 8, 9, 'a', 'b', 'c', 'd', 'e', 'f', 'g'));
+}
+
+struct string_like {};
+fmt::string_view to_string_view(string_like) { return "foo"; }
+
+constexpr char with_null[3] = {'{', '}', '\0'};
+constexpr char no_null[2] = {'{', '}'};
+static constexpr const char static_with_null[3] = {'{', '}', '\0'};
+static constexpr const char static_no_null[2] = {'{', '}'};
+
+TEST(format_test, compile_time_string) {
+  EXPECT_EQ("foo", fmt::format(FMT_STRING("foo")));
+  EXPECT_EQ("42", fmt::format(FMT_STRING("{}"), 42));
+  EXPECT_EQ("foo", fmt::format(FMT_STRING("{}"), string_like()));
+
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+  using namespace fmt::literals;
+  EXPECT_EQ("foobar", fmt::format(FMT_STRING("{foo}{bar}"), "bar"_a = "bar",
+                                  "foo"_a = "foo"));
+  EXPECT_EQ("", fmt::format(FMT_STRING("")));
+  EXPECT_EQ("", fmt::format(FMT_STRING(""), "arg"_a = 42));
+  EXPECT_EQ("42", fmt::format(FMT_STRING("{answer}"), "answer"_a = Answer()));
+#endif
+
+  (void)static_with_null;
+  (void)static_no_null;
+#ifndef _MSC_VER
+  EXPECT_EQ("42", fmt::format(FMT_STRING(static_with_null), 42));
+  EXPECT_EQ("42", fmt::format(FMT_STRING(static_no_null), 42));
+#endif
+
+  (void)with_null;
+  (void)no_null;
+#if FMT_CPLUSPLUS >= 201703L
+  EXPECT_EQ("42", fmt::format(FMT_STRING(with_null), 42));
+  EXPECT_EQ("42", fmt::format(FMT_STRING(no_null), 42));
+#endif
+#if defined(FMT_USE_STRING_VIEW) && FMT_CPLUSPLUS >= 201703L
+  EXPECT_EQ("42", fmt::format(FMT_STRING(std::string_view("{}")), 42));
+#endif
+}
+
+TEST(format_test, custom_format_compile_time_string) {
+  EXPECT_EQ("42", fmt::format(FMT_STRING("{}"), Answer()));
+  auto answer = Answer();
+  EXPECT_EQ("42", fmt::format(FMT_STRING("{}"), answer));
+  char buf[10] = {};
+  fmt::format_to(buf, FMT_STRING("{}"), answer);
+  const Answer const_answer = Answer();
+  EXPECT_EQ("42", fmt::format(FMT_STRING("{}"), const_answer));
+}
+
+#if FMT_USE_USER_DEFINED_LITERALS
+TEST(format_test, named_arg_udl) {
+  using namespace fmt::literals;
+  auto udl_a = fmt::format("{first}{second}{first}{third}", "first"_a = "abra",
+                           "second"_a = "cad", "third"_a = 99);
+  EXPECT_EQ(
+      fmt::format("{first}{second}{first}{third}", fmt::arg("first", "abra"),
+                  fmt::arg("second", "cad"), fmt::arg("third", 99)),
+      udl_a);
+
+  EXPECT_EQ("42", fmt::format("{answer}", "answer"_a = Answer()));
+}
+#endif  // FMT_USE_USER_DEFINED_LITERALS
+
+TEST(format_test, enum) { EXPECT_EQ("0", fmt::format("{}", foo)); }
+
+TEST(format_test, formatter_not_specialized) {
+  static_assert(!fmt::has_formatter<fmt::formatter<test_enum>,
+                                    fmt::format_context>::value,
+                "");
+}
+
+#if FMT_HAS_FEATURE(cxx_strong_enums)
+enum big_enum : unsigned long long { big_enum_value = 5000000000ULL };
+auto format_as(big_enum e) -> unsigned long long { return e; }
+
+TEST(format_test, strong_enum) {
+  EXPECT_EQ("5000000000", fmt::format("{}", big_enum_value));
+}
+#endif
+
+TEST(format_test, non_null_terminated_format_string) {
+  EXPECT_EQ("42", fmt::format(string_view("{}foo", 2), 42));
+}
+
+struct variant {
+  enum { int_type, string_type } type;
+  explicit variant(int) : type(int_type) {}
+  explicit variant(const char*) : type(string_type) {}
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<variant> : dynamic_formatter<> {
+  auto format(variant value, format_context& ctx) -> decltype(ctx.out()) {
+    if (value.type == variant::int_type)
+      return dynamic_formatter<>::format(42, ctx);
+    return dynamic_formatter<>::format("foo", ctx);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(format_test, dynamic_formatter) {
+  auto num = variant(42);
+  auto str = variant("foo");
+  EXPECT_EQ("42", fmt::format("{:d}", num));
+  EXPECT_EQ("foo", fmt::format("{:s}", str));
+  EXPECT_EQ(" 42 foo ", fmt::format("{:{}} {:{}}", num, 3, str, 4));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:{}}"), num), format_error,
+                   "cannot switch from manual to automatic argument indexing");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:{0}}"), num), format_error,
+                   "cannot switch from automatic to manual argument indexing");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:+}"), str), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:-}"), str), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{: }"), str), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:#}"), str), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:0}"), str), format_error,
+                   "format specifier requires numeric argument");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{:.2}"), num), format_error,
+                   "precision not allowed for this argument type");
+}
+
+namespace adl_test {
+namespace fmt {
+namespace detail {
+struct foo {};
+template <typename, typename OutputIt> void write(OutputIt, foo) = delete;
+}  // namespace detail
+}  // namespace fmt
+}  // namespace adl_test
+
+FMT_BEGIN_NAMESPACE
+template <>
+struct formatter<adl_test::fmt::detail::foo> : formatter<std::string> {
+  template <typename FormatContext>
+  auto format(adl_test::fmt::detail::foo, FormatContext& ctx)
+      -> decltype(ctx.out()) {
+    return formatter<std::string>::format("foo", ctx);
+  }
+};
+FMT_END_NAMESPACE
+
+struct convertible_to_int {
+  operator int() const { return value; }
+
+  int value = 42;
+};
+
+TEST(format_test, to_string) {
+  EXPECT_EQ(fmt::to_string(42), "42");
+  EXPECT_EQ(fmt::to_string(reinterpret_cast<void*>(0x1234)), "0x1234");
+  EXPECT_EQ(fmt::to_string(adl_test::fmt::detail::foo()), "foo");
+  EXPECT_EQ(fmt::to_string(convertible_to_int()), "42");
+  EXPECT_EQ(fmt::to_string(foo), "0");
+
+#if FMT_USE_FLOAT128
+  EXPECT_EQ(fmt::to_string(__float128(0.5)), "0.5");
+#endif
+}
+
+TEST(format_test, output_iterators) {
+  std::list<char> out;
+  fmt::format_to(std::back_inserter(out), "{}", 42);
+  EXPECT_EQ("42", std::string(out.begin(), out.end()));
+  std::stringstream s;
+  fmt::format_to(std::ostream_iterator<char>(s), "{}", 42);
+  EXPECT_EQ("42", s.str());
+}
+
+TEST(format_test, formatted_size) {
+  EXPECT_EQ(2u, fmt::formatted_size("{}", 42));
+}
+
+TEST(format_test, format_to_no_args) {
+  std::string s;
+  fmt::format_to(std::back_inserter(s), "test");
+  EXPECT_EQ("test", s);
+}
+
+TEST(format_test, format_to) {
+  std::string s;
+  fmt::format_to(std::back_inserter(s), "part{0}", 1);
+  EXPECT_EQ("part1", s);
+  fmt::format_to(std::back_inserter(s), "part{0}", 2);
+  EXPECT_EQ("part1part2", s);
+}
+
+TEST(format_test, format_to_memory_buffer) {
+  auto buf = fmt::basic_memory_buffer<char, 100>();
+  fmt::format_to(fmt::appender(buf), "{}", "foo");
+  EXPECT_EQ("foo", to_string(buf));
+}
+
+TEST(format_test, format_to_vector) {
+  std::vector<char> v;
+  fmt::format_to(std::back_inserter(v), "{}", "foo");
+  EXPECT_EQ(string_view(v.data(), v.size()), "foo");
+}
+
+struct nongrowing_container {
+  using value_type = char;
+  void push_back(char) { throw std::runtime_error("can't take it any more"); }
+};
+
+TEST(format_test, format_to_propagates_exceptions) {
+  auto c = nongrowing_container();
+  EXPECT_THROW(fmt::format_to(std::back_inserter(c), "{}", 42),
+               std::runtime_error);
+}
+
+TEST(format_test, format_to_n) {
+  char buffer[4];
+  buffer[3] = 'x';
+  auto result = fmt::format_to_n(buffer, 3, "{}", 12345);
+  EXPECT_EQ(5u, result.size);
+  EXPECT_EQ(buffer + 3, result.out);
+  EXPECT_EQ("123x", fmt::string_view(buffer, 4));
+
+  result = fmt::format_to_n(buffer, 3, "{:s}", "foobar");
+  EXPECT_EQ(6u, result.size);
+  EXPECT_EQ(buffer + 3, result.out);
+  EXPECT_EQ("foox", fmt::string_view(buffer, 4));
+
+  buffer[0] = 'x';
+  buffer[1] = 'x';
+  buffer[2] = 'x';
+  result = fmt::format_to_n(buffer, 3, "{}", 'A');
+  EXPECT_EQ(1u, result.size);
+  EXPECT_EQ(buffer + 1, result.out);
+  EXPECT_EQ("Axxx", fmt::string_view(buffer, 4));
+
+  result = fmt::format_to_n(buffer, 3, "{}{} ", 'B', 'C');
+  EXPECT_EQ(3u, result.size);
+  EXPECT_EQ(buffer + 3, result.out);
+  EXPECT_EQ("BC x", fmt::string_view(buffer, 4));
+
+  result = fmt::format_to_n(buffer, 4, "{}", "ABCDE");
+  EXPECT_EQ(5u, result.size);
+  EXPECT_EQ("ABCD", fmt::string_view(buffer, 4));
+
+  buffer[3] = 'x';
+  result = fmt::format_to_n(buffer, 3, "{}", std::string(1000, '*'));
+  EXPECT_EQ(1000u, result.size);
+  EXPECT_EQ("***x", fmt::string_view(buffer, 4));
+}
+
+struct test_output_iterator {
+  char* data;
+
+  using iterator_category = std::output_iterator_tag;
+  using value_type = void;
+  using difference_type = void;
+  using pointer = void;
+  using reference = void;
+
+  test_output_iterator& operator++() {
+    ++data;
+    return *this;
+  }
+  test_output_iterator operator++(int) {
+    auto tmp = *this;
+    ++data;
+    return tmp;
+  }
+  char& operator*() { return *data; }
+};
+
+TEST(format_test, format_to_n_output_iterator) {
+  char buf[10] = {};
+  fmt::format_to_n(test_output_iterator{buf}, 10, "{}", 42);
+  EXPECT_STREQ(buf, "42");
+}
+
+#if FMT_USE_CONSTEXPR
+struct test_error_handler {
+  const char*& error;
+
+  FMT_CONSTEXPR test_error_handler(const char*& err) : error(err) {}
+
+  FMT_CONSTEXPR test_error_handler(const test_error_handler& other)
+      : error(other.error) {}
+
+  FMT_CONSTEXPR void on_error(const char* message) {
+    if (!error) error = message;
+  }
+};
+
+FMT_CONSTEXPR size_t len(const char* s) {
+  size_t len = 0;
+  while (*s++) ++len;
+  return len;
+}
+
+FMT_CONSTEXPR bool equal(const char* s1, const char* s2) {
+  if (!s1 || !s2) return s1 == s2;
+  while (*s1 && *s1 == *s2) {
+    ++s1;
+    ++s2;
+  }
+  return *s1 == *s2;
+}
+
+template <typename... Args>
+FMT_CONSTEXPR bool test_error(const char* fmt, const char* expected_error) {
+  const char* actual_error = nullptr;
+  auto s = string_view(fmt, len(fmt));
+  auto checker =
+      fmt::detail::format_string_checker<char, test_error_handler, Args...>(
+          s, test_error_handler(actual_error));
+  fmt::detail::parse_format_string<true>(s, checker);
+  return equal(actual_error, expected_error);
+}
+
+#  define EXPECT_ERROR_NOARGS(fmt, error) \
+    static_assert(test_error(fmt, error), "")
+#  define EXPECT_ERROR(fmt, error, ...) \
+    static_assert(test_error<__VA_ARGS__>(fmt, error), "")
+
+TEST(format_test, format_string_errors) {
+  EXPECT_ERROR_NOARGS("foo", nullptr);
+  EXPECT_ERROR_NOARGS("}", "unmatched '}' in format string");
+  EXPECT_ERROR("{0:s", "unknown format specifier", date);
+#  if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1916
+  // This causes an detail compiler error in MSVC2017.
+  EXPECT_ERROR("{:{<}", "invalid fill character '{'", int);
+  EXPECT_ERROR("{:10000000000}", "number is too big", int);
+  EXPECT_ERROR("{:.10000000000}", "number is too big", int);
+  EXPECT_ERROR_NOARGS("{:x}", "argument not found");
+  EXPECT_ERROR("{:+}", "format specifier requires numeric argument",
+               const char*);
+  EXPECT_ERROR("{:-}", "format specifier requires numeric argument",
+               const char*);
+  EXPECT_ERROR("{:#}", "format specifier requires numeric argument",
+               const char*);
+  EXPECT_ERROR("{: }", "format specifier requires numeric argument",
+               const char*);
+  EXPECT_ERROR("{:0}", "format specifier requires numeric argument",
+               const char*);
+  EXPECT_ERROR("{:+}", "format specifier requires signed argument", unsigned);
+  EXPECT_ERROR("{:-}", "format specifier requires signed argument", unsigned);
+  EXPECT_ERROR("{: }", "format specifier requires signed argument", unsigned);
+  EXPECT_ERROR("{:{}}", "argument not found", int);
+  EXPECT_ERROR("{:.{}}", "argument not found", double);
+  EXPECT_ERROR("{:{}}", "width/precision is not integer", int, double);
+  EXPECT_ERROR("{:.2}", "precision not allowed for this argument type", int);
+  EXPECT_ERROR("{:s}", "invalid type specifier", int);
+  EXPECT_ERROR("{:s}", "invalid type specifier", char);
+  EXPECT_ERROR("{:+}", "invalid format specifier for char", char);
+  EXPECT_ERROR("{:s}", "invalid type specifier", double);
+  EXPECT_ERROR("{:d}", "invalid type specifier", const char*);
+  EXPECT_ERROR("{:d}", "invalid type specifier", std::string);
+  EXPECT_ERROR("{:s}", "invalid type specifier", void*);
+#  else
+  fmt::print("warning: constexpr is broken in this version of MSVC\n");
+#  endif
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+  using namespace fmt::literals;
+  EXPECT_ERROR("{foo}", "named argument is not found", decltype("bar"_a = 42));
+  EXPECT_ERROR("{foo}", "named argument is not found",
+               decltype(fmt::arg("foo", 42)));
+#  else
+  EXPECT_ERROR("{foo}",
+               "compile-time checks for named arguments require C++20 support",
+               int);
+#  endif
+  EXPECT_ERROR_NOARGS("{10000000000}", "argument not found");
+  EXPECT_ERROR_NOARGS("{0x}", "invalid format string");
+  EXPECT_ERROR_NOARGS("{-}", "invalid format string");
+  EXPECT_ERROR("{:{0x}}", "invalid format string", int);
+  EXPECT_ERROR("{:{-}}", "invalid format string", int);
+  EXPECT_ERROR("{:.{0x}}", "invalid format string", int);
+  EXPECT_ERROR("{:.{-}}", "invalid format string", int);
+  EXPECT_ERROR("{:.x}", "missing precision specifier", int);
+  EXPECT_ERROR_NOARGS("{}", "argument not found");
+  EXPECT_ERROR("{1}", "argument not found", int);
+  EXPECT_ERROR("{1}{}",
+               "cannot switch from manual to automatic argument indexing", int,
+               int);
+  EXPECT_ERROR("{}{1}",
+               "cannot switch from automatic to manual argument indexing", int,
+               int);
+}
+
+TEST(format_test, vformat_to) {
+  using context = fmt::format_context;
+  fmt::basic_format_arg<context> arg = fmt::detail::make_arg<context>(42);
+  auto args = fmt::basic_format_args<context>(&arg, 1);
+  auto s = std::string();
+  fmt::vformat_to(std::back_inserter(s), "{}", args);
+  EXPECT_EQ("42", s);
+  s.clear();
+  fmt::vformat_to(std::back_inserter(s), FMT_STRING("{}"), args);
+  EXPECT_EQ("42", s);
+}
+
+#endif  // FMT_USE_CONSTEXPR
+
+TEST(format_test, char_traits_is_not_ambiguous) {
+  // Test that we don't inject detail names into the std namespace.
+  using namespace std;
+  auto c = char_traits<char>::char_type();
+  (void)c;
+#if FMT_CPLUSPLUS >= 201103L
+  auto s = std::string();
+  auto lval = begin(s);
+  (void)lval;
+#endif
+}
+
+struct check_back_appender {};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<check_back_appender> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename Context>
+  auto format(check_back_appender, Context& ctx) -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    static_assert(std::is_same<decltype(++out), decltype(out)&>::value,
+                  "needs to satisfy weakly_incrementable");
+    *out = 'y';
+    return ++out;
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(format_test, back_insert_slicing) {
+  EXPECT_EQ(fmt::format("{}", check_back_appender{}), "y");
+}
+
+template <typename Char, typename T> bool check_enabled_formatter() {
+  static_assert(std::is_default_constructible<fmt::formatter<T, Char>>::value,
+                "");
+  return true;
+}
+
+template <typename Char, typename... T> void check_enabled_formatters() {
+  auto dummy = {check_enabled_formatter<Char, T>()...};
+  (void)dummy;
+}
+
+TEST(format_test, test_formatters_enabled) {
+  check_enabled_formatters<char, bool, char, signed char, unsigned char, short,
+                           unsigned short, int, unsigned, long, unsigned long,
+                           long long, unsigned long long, float, double,
+                           long double, void*, const void*, char*, const char*,
+                           std::string, std::nullptr_t>();
+  check_enabled_formatters<wchar_t, bool, wchar_t, signed char, unsigned char,
+                           short, unsigned short, int, unsigned, long,
+                           unsigned long, long long, unsigned long long, float,
+                           double, long double, void*, const void*, wchar_t*,
+                           const wchar_t*, std::wstring, std::nullptr_t>();
+}
+
+TEST(format_int_test, data) {
+  fmt::format_int format_int(42);
+  EXPECT_EQ("42", std::string(format_int.data(), format_int.size()));
+}
+
+TEST(format_int_test, format_int) {
+  EXPECT_EQ("42", fmt::format_int(42).str());
+  EXPECT_EQ(2u, fmt::format_int(42).size());
+  EXPECT_EQ("-42", fmt::format_int(-42).str());
+  EXPECT_EQ(3u, fmt::format_int(-42).size());
+  EXPECT_EQ("42", fmt::format_int(42ul).str());
+  EXPECT_EQ("-42", fmt::format_int(-42l).str());
+  EXPECT_EQ("42", fmt::format_int(42ull).str());
+  EXPECT_EQ("-42", fmt::format_int(-42ll).str());
+  std::ostringstream os;
+  os << max_value<int64_t>();
+  EXPECT_EQ(os.str(), fmt::format_int(max_value<int64_t>()).str());
+}
diff --git a/src/fmt/test/fuzzing/.gitignore b/src/fmt/test/fuzzing/.gitignore
new file mode 100644
index 000000000..ea4104026
--- /dev/null
+++ b/src/fmt/test/fuzzing/.gitignore
@@ -0,0 +1,3 @@
+# ignore artifacts from the build.sh script
+build-*/
+
diff --git a/src/fmt/test/fuzzing/CMakeLists.txt b/src/fmt/test/fuzzing/CMakeLists.txt
new file mode 100644
index 000000000..0280c5cdf
--- /dev/null
+++ b/src/fmt/test/fuzzing/CMakeLists.txt
@@ -0,0 +1,30 @@
+# Copyright (c) 2019, Paul Dreik
+# License: see LICENSE.rst in the fmt root directory
+
+# Link in the main function. Useful for reproducing, kcov, gdb, afl, valgrind.
+# (Note that libFuzzer can also reproduce, just pass it the files.)
+option(FMT_FUZZ_LINKMAIN "Enables the reproduce mode, instead of libFuzzer" On)
+
+# For oss-fuzz - insert $LIB_FUZZING_ENGINE into the link flags, but only for
+# the fuzz targets, otherwise the CMake configuration step fails.
+set(FMT_FUZZ_LDFLAGS "" CACHE STRING "LDFLAGS for the fuzz targets")
+
+# Adds a binary for reproducing, i.e. no fuzzing, just enables replaying data
+# through the fuzzers.
+function(add_fuzzer source)
+  get_filename_component(basename ${source} NAME_WE)
+  set(name ${basename}-fuzzer)
+  add_executable(${name} ${source} fuzzer-common.h)
+  if (FMT_FUZZ_LINKMAIN)
+    target_sources(${name} PRIVATE main.cc)
+  endif ()
+  target_link_libraries(${name} PRIVATE fmt)
+  if (FMT_FUZZ_LDFLAGS)
+    target_link_libraries(${name} PRIVATE ${FMT_FUZZ_LDFLAGS})
+  endif ()
+  target_compile_features(${name} PRIVATE cxx_generic_lambdas)
+endfunction()
+
+foreach (source chrono-duration.cc chrono-timepoint.cc float.cc named-arg.cc one-arg.cc two-args.cc)
+  add_fuzzer(${source})
+endforeach ()
diff --git a/src/fmt/test/fuzzing/README.md b/src/fmt/test/fuzzing/README.md
new file mode 100644
index 000000000..bb3d0e04f
--- /dev/null
+++ b/src/fmt/test/fuzzing/README.md
@@ -0,0 +1,25 @@
+# Running the fuzzers locally
+
+There is a [helper script](build.sh) to build the fuzzers, which has only been
+tested on Debian and Ubuntu linux so far. There should be no problems fuzzing on
+Windows (using clang>=8) or on Mac, but the script will probably not work out of
+the box.
+
+Something along
+```sh
+mkdir build
+cd build
+export CXX=clang++
+export CXXFLAGS="-fsanitize=fuzzer-no-link -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION= -g"
+cmake .. -DFMT_SAFE_DURATION_CAST=On -DFMT_FUZZ=On -DFMT_FUZZ_LINKMAIN=Off -DFMT_FUZZ_LDFLAGS="-fsanitize=fuzzer"
+cmake --build .
+```
+should work to build the fuzzers for all platforms which clang supports.
+
+Execute a fuzzer with for instance
+```sh
+cd build
+export UBSAN_OPTIONS=halt_on_error=1
+mkdir out_chrono
+bin/fuzzer_chrono_duration out_chrono
+```
diff --git a/src/fmt/test/fuzzing/build.sh b/src/fmt/test/fuzzing/build.sh
new file mode 100755
index 000000000..4497b62c1
--- /dev/null
+++ b/src/fmt/test/fuzzing/build.sh
@@ -0,0 +1,90 @@
+#!/bin/sh
+#
+# Creates fuzzer builds of various kinds
+# - oss-fuzz emulated mode (makes sure a simulated invocation by oss-fuzz works)
+# - libFuzzer build (you will need clang)
+# - afl build (you will need afl)
+#
+#
+# Copyright (c) 2019 Paul Dreik
+#
+# For the license information refer to format.h.
+
+set -e
+me=$(basename $0)
+root=$(readlink -f "$(dirname "$0")/../..")
+
+
+echo $me: root=$root
+
+here=$(pwd)
+
+CXXFLAGSALL="-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION= -g"
+CMAKEFLAGSALL="$root -GNinja -DCMAKE_BUILD_TYPE=Debug -DFMT_DOC=Off -DFMT_TEST=Off -DFMT_FUZZ=On -DCMAKE_CXX_STANDARD=17"
+
+CLANG=clang++-11
+
+# For performance analysis of the fuzzers.
+builddir=$here/build-fuzzers-perfanalysis
+mkdir -p $builddir
+cd $builddir
+CXX="ccache g++" CXXFLAGS="$CXXFLAGSALL -g" cmake \
+$CMAKEFLAGSALL \
+-DFMT_FUZZ_LINKMAIN=On \
+-DCMAKE_BUILD_TYPE=Release
+
+cmake --build $builddir
+
+# Builds the fuzzers as oss-fuzz does.
+builddir=$here/build-fuzzers-ossfuzz
+mkdir -p $builddir
+cd $builddir
+CXX=$CLANG \
+CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link" cmake \
+cmake $CMAKEFLAGSALL \
+-DFMT_FUZZ_LINKMAIN=Off \
+-DFMT_FUZZ_LDFLAGS="-fsanitize=fuzzer"
+
+cmake --build $builddir
+
+
+# Builds fuzzers for local fuzzing with libfuzzer with asan+usan.
+builddir=$here/build-fuzzers-libfuzzer
+mkdir -p $builddir
+cd $builddir
+CXX=$CLANG \
+CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link,address,undefined" cmake \
+cmake $CMAKEFLAGSALL \
+-DFMT_FUZZ_LINKMAIN=Off \
+-DFMT_FUZZ_LDFLAGS="-fsanitize=fuzzer"
+
+cmake --build $builddir
+
+# Builds a fast fuzzer for making coverage fast.
+builddir=$here/build-fuzzers-fast
+mkdir -p $builddir
+cd $builddir
+CXX=$CLANG \
+CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link -O3" cmake \
+cmake $CMAKEFLAGSALL \
+-DFMT_FUZZ_LINKMAIN=Off \
+-DFMT_FUZZ_LDFLAGS="-fsanitize=fuzzer" \
+ -DCMAKE_BUILD_TYPE=Release
+
+cmake --build $builddir
+
+
+# Builds fuzzers for local fuzzing with afl.
+builddir=$here/build-fuzzers-afl
+mkdir -p $builddir
+cd $builddir
+CXX="afl-g++" \
+CXXFLAGS="$CXXFLAGSALL -fsanitize=address,undefined" \
+cmake $CMAKEFLAGSALL \
+-DFMT_FUZZ_LINKMAIN=On
+
+cmake --build $builddir
+
+
+echo $me: all good
+
diff --git a/src/fmt/test/fuzzing/chrono-duration.cc b/src/fmt/test/fuzzing/chrono-duration.cc
new file mode 100644
index 000000000..d66068d9c
--- /dev/null
+++ b/src/fmt/test/fuzzing/chrono-duration.cc
@@ -0,0 +1,136 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#include <fmt/chrono.h>
+
+#include <cstdint>
+
+#include "fuzzer-common.h"
+
+template <typename Period, typename Rep>
+void invoke_inner(fmt::string_view format_str, Rep rep) {
+  auto value = std::chrono::duration<Rep, Period>(rep);
+  try {
+#if FMT_FUZZ_FORMAT_TO_STRING
+    std::string message = fmt::format(format_str, value);
+#else
+    auto buf = fmt::memory_buffer();
+    fmt::format_to(std::back_inserter(buf), format_str, value);
+#endif
+  } catch (std::exception&) {
+  }
+}
+
+// Rep is a duration's representation type.
+template <typename Rep>
+void invoke_outer(const uint8_t* data, size_t size, int period) {
+  // Always use a fixed location of the data.
+  static_assert(sizeof(Rep) <= fixed_size, "fixed size is too small");
+  if (size <= fixed_size + 1) return;
+
+  const Rep rep = assign_from_buf<Rep>(data);
+  data += fixed_size;
+  size -= fixed_size;
+
+  // data is already allocated separately in libFuzzer so reading past the end
+  // will most likely be detected anyway.
+  const auto format_str = fmt::string_view(as_chars(data), size);
+
+  // yocto, zepto, zetta and yotta are not handled.
+  switch (period) {
+  case 1:
+    invoke_inner<std::atto>(format_str, rep);
+    break;
+  case 2:
+    invoke_inner<std::femto>(format_str, rep);
+    break;
+  case 3:
+    invoke_inner<std::pico>(format_str, rep);
+    break;
+  case 4:
+    invoke_inner<std::nano>(format_str, rep);
+    break;
+  case 5:
+    invoke_inner<std::micro>(format_str, rep);
+    break;
+  case 6:
+    invoke_inner<std::milli>(format_str, rep);
+    break;
+  case 7:
+    invoke_inner<std::centi>(format_str, rep);
+    break;
+  case 8:
+    invoke_inner<std::deci>(format_str, rep);
+    break;
+  case 9:
+    invoke_inner<std::deca>(format_str, rep);
+    break;
+  case 10:
+    invoke_inner<std::kilo>(format_str, rep);
+    break;
+  case 11:
+    invoke_inner<std::mega>(format_str, rep);
+    break;
+  case 12:
+    invoke_inner<std::giga>(format_str, rep);
+    break;
+  case 13:
+    invoke_inner<std::tera>(format_str, rep);
+    break;
+  case 14:
+    invoke_inner<std::peta>(format_str, rep);
+    break;
+  case 15:
+    invoke_inner<std::exa>(format_str, rep);
+    break;
+  }
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= 4) return 0;
+
+  const auto representation = data[0];
+  const auto period = data[1];
+  data += 2;
+  size -= 2;
+
+  switch (representation) {
+  case 1:
+    invoke_outer<char>(data, size, period);
+    break;
+  case 2:
+    invoke_outer<signed char>(data, size, period);
+    break;
+  case 3:
+    invoke_outer<unsigned char>(data, size, period);
+    break;
+  case 4:
+    invoke_outer<short>(data, size, period);
+    break;
+  case 5:
+    invoke_outer<unsigned short>(data, size, period);
+    break;
+  case 6:
+    invoke_outer<int>(data, size, period);
+    break;
+  case 7:
+    invoke_outer<unsigned int>(data, size, period);
+    break;
+  case 8:
+    invoke_outer<long>(data, size, period);
+    break;
+  case 9:
+    invoke_outer<unsigned long>(data, size, period);
+    break;
+  case 10:
+    invoke_outer<float>(data, size, period);
+    break;
+  case 11:
+    invoke_outer<double>(data, size, period);
+    break;
+  case 12:
+    invoke_outer<long double>(data, size, period);
+    break;
+  }
+  return 0;
+}
diff --git a/src/fmt/test/fuzzing/chrono-timepoint.cc b/src/fmt/test/fuzzing/chrono-timepoint.cc
new file mode 100644
index 000000000..8a1b24d29
--- /dev/null
+++ b/src/fmt/test/fuzzing/chrono-timepoint.cc
@@ -0,0 +1,32 @@
+// Copyright (c) 2021, Paul Dreik
+// For license information refer to format.h.
+#include <fmt/chrono.h>
+
+#include "fuzzer-common.h"
+
+/*
+ * a fuzzer for the chrono timepoints formatters
+ * C is a clock (std::chrono::system_clock etc)
+ */
+template <typename C> void doit(const uint8_t* data, size_t size) {
+  using Rep = typename C::time_point::rep;
+  constexpr auto N = sizeof(Rep);
+  if (size < N) return;
+
+  const auto x = assign_from_buf<Rep>(data);
+  typename C::duration dur{x};
+  typename C::time_point timepoint{dur};
+  data += N;
+  size -= N;
+  data_to_string format_str(data, size);
+
+  std::string message = fmt::format(format_str.get(), timepoint);
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  try {
+    doit<std::chrono::system_clock>(data, size);
+  } catch (...) {
+  }
+  return 0;
+}
diff --git a/src/fmt/test/fuzzing/float.cc b/src/fmt/test/fuzzing/float.cc
new file mode 100644
index 000000000..d4c9e4f57
--- /dev/null
+++ b/src/fmt/test/fuzzing/float.cc
@@ -0,0 +1,39 @@
+// A fuzzer for floating-point formatter.
+// For the license information refer to format.h.
+
+#include <fmt/format.h>
+
+#include <cstdint>
+#include <cstdlib>
+#include <limits>
+#include <stdexcept>
+
+#include "fuzzer-common.h"
+
+void check_round_trip(fmt::string_view format_str, double value) {
+  auto buffer = fmt::memory_buffer();
+  fmt::format_to(std::back_inserter(buffer), format_str, value);
+
+  if (std::isnan(value)) {
+    auto nan = std::signbit(value) ? "-nan" : "nan";
+    if (fmt::string_view(buffer.data(), buffer.size()) != nan)
+      throw std::runtime_error("round trip failure");
+    return;
+  }
+
+  buffer.push_back('\0');
+  char* ptr = nullptr;
+  if (std::strtod(buffer.data(), &ptr) != value)
+    throw std::runtime_error("round trip failure");
+  if (ptr + 1 != buffer.end()) throw std::runtime_error("unparsed output");
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= sizeof(double) || !std::numeric_limits<double>::is_iec559)
+    return 0;
+  check_round_trip("{}", assign_from_buf<double>(data));
+  // A larger than necessary precision is used to trigger the fallback
+  // formatter.
+  check_round_trip("{:.50g}", assign_from_buf<double>(data));
+  return 0;
+}
diff --git a/src/fmt/test/fuzzing/fuzzer-common.h b/src/fmt/test/fuzzing/fuzzer-common.h
new file mode 100644
index 000000000..c0a246722
--- /dev/null
+++ b/src/fmt/test/fuzzing/fuzzer-common.h
@@ -0,0 +1,77 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#ifndef FUZZER_COMMON_H
+#define FUZZER_COMMON_H
+
+#include <fmt/core.h>
+
+#include <cstdint>  // std::uint8_t
+#include <cstring>  // memcpy
+#include <vector>
+
+// One can format to either a string, or a buffer. The latter is faster, but
+// one may be interested in formatting to a string instead to verify it works
+// as intended. To avoid a combinatoric explosion, select this at compile time
+// instead of dynamically from the fuzz data.
+#define FMT_FUZZ_FORMAT_TO_STRING 0
+
+// If {fmt} is given a buffer that is separately allocated, chances that address
+// sanitizer detects out of bound reads is much higher. However, it slows down
+// the fuzzing.
+#define FMT_FUZZ_SEPARATE_ALLOCATION 1
+
+// The size of the largest possible type in use.
+// To let the the fuzzer mutation be efficient at cross pollinating between
+// different types, use a fixed size format. The same bit pattern, interpreted
+// as another type, is likely interesting.
+constexpr auto fixed_size = 16;
+
+// Casts data to a char pointer.
+template <typename T> inline const char* as_chars(const T* data) {
+  return reinterpret_cast<const char*>(data);
+}
+
+// Casts data to a byte pointer.
+template <typename T> inline const std::uint8_t* as_bytes(const T* data) {
+  return reinterpret_cast<const std::uint8_t*>(data);
+}
+
+// Blits bytes from data to form an (assumed trivially constructible) object
+// of type Item.
+template <class Item> inline Item assign_from_buf(const std::uint8_t* data) {
+  auto item = Item();
+  std::memcpy(&item, data, sizeof(Item));
+  return item;
+}
+
+// Reads a boolean value by looking at the first byte from data.
+template <> inline bool assign_from_buf<bool>(const std::uint8_t* data) {
+  return *data != 0;
+}
+
+struct data_to_string {
+#if FMT_FUZZ_SEPARATE_ALLOCATION
+  std::vector<char> buffer;
+
+  data_to_string(const uint8_t* data, size_t size, bool add_terminator = false)
+      : buffer(size + (add_terminator ? 1 : 0)) {
+    if (size) {
+      std::memcpy(buffer.data(), data, size);
+    }
+  }
+
+  fmt::string_view get() const { return {buffer.data(), buffer.size()}; }
+#else
+  fmt::string_view sv;
+
+  data_to_string(const uint8_t* data, size_t size, bool = false)
+      : str(as_chars(data), size) {}
+
+  fmt::string_view get() const { return sv; }
+#endif
+
+  const char* data() const { return get().data(); }
+};
+
+#endif  // FUZZER_COMMON_H
diff --git a/src/fmt/test/fuzzing/main.cc b/src/fmt/test/fuzzing/main.cc
new file mode 100644
index 000000000..8f8c719b7
--- /dev/null
+++ b/src/fmt/test/fuzzing/main.cc
@@ -0,0 +1,22 @@
+#include <cassert>
+#include <fstream>
+#include <vector>
+
+#include "fuzzer-common.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size);
+
+int main(int argc, char** argv) {
+  for (int i = 1; i < argc; ++i) {
+    std::ifstream in(argv[i]);
+    assert(in);
+    in.seekg(0, std::ios_base::end);
+    const auto size = in.tellg();
+    assert(size >= 0);
+    in.seekg(0, std::ios_base::beg);
+    std::vector<char> buf(static_cast<size_t>(size));
+    in.read(buf.data(), size);
+    assert(in.gcount() == size);
+    LLVMFuzzerTestOneInput(as_bytes(buf.data()), buf.size());
+  }
+}
diff --git a/src/fmt/test/fuzzing/named-arg.cc b/src/fmt/test/fuzzing/named-arg.cc
new file mode 100644
index 000000000..3bee1ae3b
--- /dev/null
+++ b/src/fmt/test/fuzzing/named-arg.cc
@@ -0,0 +1,102 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#include <fmt/chrono.h>
+
+#include <cstdint>
+#include <type_traits>
+#include <vector>
+
+#include "fuzzer-common.h"
+
+template <typename T>
+void invoke_fmt(const uint8_t* data, size_t size, unsigned arg_name_size) {
+  static_assert(sizeof(T) <= fixed_size, "fixed_size too small");
+  if (size <= fixed_size) return;
+  const T value = assign_from_buf<T>(data);
+  data += fixed_size;
+  size -= fixed_size;
+
+  if (arg_name_size <= 0 || arg_name_size >= size) return;
+  data_to_string arg_name(data, arg_name_size, true);
+  data += arg_name_size;
+  size -= arg_name_size;
+
+  data_to_string format_str(data, size);
+  try {
+#if FMT_FUZZ_FORMAT_TO_STRING
+    std::string message =
+        fmt::format(format_str.get(), fmt::arg(arg_name.data(), value));
+#else
+    fmt::memory_buffer out;
+    fmt::format_to(std::back_inserter(out), format_str.get(),
+                   fmt::arg(arg_name.data(), value));
+#endif
+  } catch (std::exception&) {
+  }
+}
+
+// For dynamic dispatching to an explicit instantiation.
+template <typename Callback> void invoke(int type, Callback callback) {
+  switch (type) {
+  case 0:
+    callback(bool());
+    break;
+  case 1:
+    callback(char());
+    break;
+  case 2:
+    using sc = signed char;
+    callback(sc());
+    break;
+  case 3:
+    using uc = unsigned char;
+    callback(uc());
+    break;
+  case 4:
+    callback(short());
+    break;
+  case 5:
+    using us = unsigned short;
+    callback(us());
+    break;
+  case 6:
+    callback(int());
+    break;
+  case 7:
+    callback(unsigned());
+    break;
+  case 8:
+    callback(long());
+    break;
+  case 9:
+    using ul = unsigned long;
+    callback(ul());
+    break;
+  case 10:
+    callback(float());
+    break;
+  case 11:
+    callback(double());
+    break;
+  case 12:
+    using LD = long double;
+    callback(LD());
+    break;
+  }
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= 3) return 0;
+
+  // Switch types depending on the first byte of the input.
+  const auto type = data[0] & 0x0F;
+  const unsigned arg_name_size = (data[0] & 0xF0) >> 4;
+  data++;
+  size--;
+
+  invoke(type, [=](auto arg) {
+    invoke_fmt<decltype(arg)>(data, size, arg_name_size);
+  });
+  return 0;
+}
diff --git a/src/fmt/test/fuzzing/one-arg.cc b/src/fmt/test/fuzzing/one-arg.cc
new file mode 100644
index 000000000..af9787f81
--- /dev/null
+++ b/src/fmt/test/fuzzing/one-arg.cc
@@ -0,0 +1,92 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#include <fmt/chrono.h>
+
+#include <cstdint>
+#include <exception>
+
+#include "fuzzer-common.h"
+
+template <typename T, typename Repr> const T* from_repr(const Repr& r) {
+  return &r;
+}
+
+template <> const std::tm* from_repr<std::tm>(const std::time_t& t) {
+  return std::localtime(&t);
+}
+
+template <typename T, typename Repr = T>
+void invoke_fmt(const uint8_t* data, size_t size) {
+  static_assert(sizeof(Repr) <= fixed_size, "Nfixed is too small");
+  if (size <= fixed_size) return;
+  auto repr = assign_from_buf<Repr>(data);
+  const T* value = from_repr<T>(repr);
+  if (!value) return;
+  data += fixed_size;
+  size -= fixed_size;
+  data_to_string format_str(data, size);
+  try {
+#if FMT_FUZZ_FORMAT_TO_STRING
+    std::string message = fmt::format(format_str.get(), *value);
+#else
+    auto buf = fmt::memory_buffer();
+    fmt::format_to(std::back_inserter(buf), format_str.get(), *value);
+#endif
+  } catch (std::exception&) {
+  }
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= 3) return 0;
+
+  const auto first = data[0];
+  data++;
+  size--;
+
+  switch (first) {
+  case 0:
+    invoke_fmt<bool>(data, size);
+    break;
+  case 1:
+    invoke_fmt<char>(data, size);
+    break;
+  case 2:
+    invoke_fmt<unsigned char>(data, size);
+    break;
+  case 3:
+    invoke_fmt<signed char>(data, size);
+    break;
+  case 4:
+    invoke_fmt<short>(data, size);
+    break;
+  case 5:
+    invoke_fmt<unsigned short>(data, size);
+    break;
+  case 6:
+    invoke_fmt<int>(data, size);
+    break;
+  case 7:
+    invoke_fmt<unsigned int>(data, size);
+    break;
+  case 8:
+    invoke_fmt<long>(data, size);
+    break;
+  case 9:
+    invoke_fmt<unsigned long>(data, size);
+    break;
+  case 10:
+    invoke_fmt<float>(data, size);
+    break;
+  case 11:
+    invoke_fmt<double>(data, size);
+    break;
+  case 12:
+    invoke_fmt<long double>(data, size);
+    break;
+  case 13:
+    invoke_fmt<std::tm, std::time_t>(data, size);
+    break;
+  }
+  return 0;
+}
diff --git a/src/fmt/test/fuzzing/two-args.cc b/src/fmt/test/fuzzing/two-args.cc
new file mode 100644
index 000000000..931c64656
--- /dev/null
+++ b/src/fmt/test/fuzzing/two-args.cc
@@ -0,0 +1,106 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#include <fmt/format.h>
+
+#include <cstdint>
+#include <exception>
+#include <string>
+
+#include "fuzzer-common.h"
+
+template <typename Item1, typename Item2>
+void invoke_fmt(const uint8_t* data, size_t size) {
+  static_assert(sizeof(Item1) <= fixed_size, "size1 exceeded");
+  static_assert(sizeof(Item2) <= fixed_size, "size2 exceeded");
+  if (size <= fixed_size + fixed_size) return;
+
+  const Item1 item1 = assign_from_buf<Item1>(data);
+  data += fixed_size;
+  size -= fixed_size;
+
+  const Item2 item2 = assign_from_buf<Item2>(data);
+  data += fixed_size;
+  size -= fixed_size;
+
+  auto format_str = fmt::string_view(as_chars(data), size);
+#if FMT_FUZZ_FORMAT_TO_STRING
+  std::string message = fmt::format(format_str, item1, item2);
+#else
+  auto buf = fmt::memory_buffer();
+  fmt::format_to(std::back_inserter(buf), format_str, item1, item2);
+#endif
+}
+
+// For dynamic dispatching to an explicit instantiation.
+template <typename Callback> void invoke(int index, Callback callback) {
+  switch (index) {
+  case 0:
+    callback(bool());
+    break;
+  case 1:
+    callback(char());
+    break;
+  case 2:
+    using sc = signed char;
+    callback(sc());
+    break;
+  case 3:
+    using uc = unsigned char;
+    callback(uc());
+    break;
+  case 4:
+    callback(short());
+    break;
+  case 5:
+    using us = unsigned short;
+    callback(us());
+    break;
+  case 6:
+    callback(int());
+    break;
+  case 7:
+    callback(unsigned());
+    break;
+  case 8:
+    callback(long());
+    break;
+  case 9:
+    using ul = unsigned long;
+    callback(ul());
+    break;
+  case 10:
+    callback(float());
+    break;
+  case 11:
+    callback(double());
+    break;
+  case 12:
+    using LD = long double;
+    callback(LD());
+    break;
+  case 13:
+    using ptr = void*;
+    callback(ptr());
+    break;
+  }
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= 3) return 0;
+
+  // Switch types depending on the first byte of the input.
+  const auto type1 = data[0] & 0x0F;
+  const auto type2 = (data[0] & 0xF0) >> 4;
+  data++;
+  size--;
+  try {
+    invoke(type1, [=](auto param1) {
+      invoke(type2, [=](auto param2) {
+        invoke_fmt<decltype(param1), decltype(param2)>(data, size);
+      });
+    });
+  } catch (std::exception&) {
+  }
+  return 0;
+}
diff --git a/src/fmt/test/gtest-extra-test.cc b/src/fmt/test/gtest-extra-test.cc
new file mode 100644
index 000000000..69e42bc68
--- /dev/null
+++ b/src/fmt/test/gtest-extra-test.cc
@@ -0,0 +1,413 @@
+// Formatting library for C++ - tests of custom Google Test assertions
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "gtest-extra.h"
+
+#include <gtest/gtest-spi.h>
+
+#include <cstring>
+#include <memory>
+#include <stdexcept>
+
+#include "fmt/os.h"
+#include "util.h"
+
+// Tests that assertion macros evaluate their arguments exactly once.
+namespace {
+class single_evaluation_test : public ::testing::Test {
+ protected:
+  single_evaluation_test() {
+    p_ = s_;
+    a_ = 0;
+    b_ = 0;
+  }
+
+  static const char* const s_;
+  static const char* p_;
+
+  static int a_;
+  static int b_;
+};
+}  // namespace
+
+const char* const single_evaluation_test::s_ = "01234";
+const char* single_evaluation_test::p_;
+int single_evaluation_test::a_;
+int single_evaluation_test::b_;
+
+void do_nothing() {}
+
+FMT_NORETURN void throw_exception() { throw std::runtime_error("test"); }
+
+FMT_NORETURN void throw_system_error() {
+  throw fmt::system_error(EDOM, "test");
+}
+
+// Tests that when EXPECT_THROW_MSG fails, it evaluates its message argument
+// exactly once.
+TEST_F(single_evaluation_test, failed_expect_throw_msg) {
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_THROW_MSG(throw_exception(), std::exception, p_++), "01234");
+  EXPECT_EQ(s_ + 1, p_);
+}
+
+// Tests that when EXPECT_SYSTEM_ERROR fails, it evaluates its message argument
+// exactly once.
+TEST_F(single_evaluation_test, failed_expect_system_error) {
+  EXPECT_NONFATAL_FAILURE(EXPECT_SYSTEM_ERROR(throw_system_error(), EDOM, p_++),
+                          "01234");
+  EXPECT_EQ(s_ + 1, p_);
+}
+
+// Tests that assertion arguments are evaluated exactly once.
+TEST_F(single_evaluation_test, exception_tests) {
+  // successful EXPECT_THROW_MSG
+  EXPECT_THROW_MSG(
+      {  // NOLINT
+        a_++;
+        throw_exception();
+      },
+      std::exception, (b_++, "test"));
+  EXPECT_EQ(1, a_);
+  EXPECT_EQ(1, b_);
+
+  // failed EXPECT_THROW_MSG, throws different type
+  EXPECT_NONFATAL_FAILURE(EXPECT_THROW_MSG(
+                              {  // NOLINT
+                                a_++;
+                                throw_exception();
+                              },
+                              std::logic_error, (b_++, "test")),
+                          "throws a different type");
+  EXPECT_EQ(2, a_);
+  EXPECT_EQ(2, b_);
+
+  // failed EXPECT_THROW_MSG, throws an exception with different message
+  EXPECT_NONFATAL_FAILURE(EXPECT_THROW_MSG(
+                              {  // NOLINT
+                                a_++;
+                                throw_exception();
+                              },
+                              std::exception, (b_++, "other")),
+                          "throws an exception with a different message");
+  EXPECT_EQ(3, a_);
+  EXPECT_EQ(3, b_);
+
+  // failed EXPECT_THROW_MSG, throws nothing
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_THROW_MSG(a_++, std::exception, (b_++, "test")), "throws nothing");
+  EXPECT_EQ(4, a_);
+  EXPECT_EQ(4, b_);
+}
+
+TEST_F(single_evaluation_test, system_error_tests) {
+  // successful EXPECT_SYSTEM_ERROR
+  EXPECT_SYSTEM_ERROR(
+      {  // NOLINT
+        a_++;
+        throw_system_error();
+      },
+      EDOM, (b_++, "test"));
+  EXPECT_EQ(1, a_);
+  EXPECT_EQ(1, b_);
+
+  // failed EXPECT_SYSTEM_ERROR, throws different type
+  EXPECT_NONFATAL_FAILURE(EXPECT_SYSTEM_ERROR(
+                              {  // NOLINT
+                                a_++;
+                                throw_exception();
+                              },
+                              EDOM, (b_++, "test")),
+                          "throws a different type");
+  EXPECT_EQ(2, a_);
+  EXPECT_EQ(2, b_);
+
+  // failed EXPECT_SYSTEM_ERROR, throws an exception with different message
+  EXPECT_NONFATAL_FAILURE(EXPECT_SYSTEM_ERROR(
+                              {  // NOLINT
+                                a_++;
+                                throw_system_error();
+                              },
+                              EDOM, (b_++, "other")),
+                          "throws an exception with a different message");
+  EXPECT_EQ(3, a_);
+  EXPECT_EQ(3, b_);
+
+  // failed EXPECT_SYSTEM_ERROR, throws nothing
+  EXPECT_NONFATAL_FAILURE(EXPECT_SYSTEM_ERROR(a_++, EDOM, (b_++, "test")),
+                          "throws nothing");
+  EXPECT_EQ(4, a_);
+  EXPECT_EQ(4, b_);
+}
+
+#if FMT_USE_FCNTL
+// Tests that when EXPECT_WRITE fails, it evaluates its message argument
+// exactly once.
+TEST_F(single_evaluation_test, failed_expect_write) {
+  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout, std::printf("test"), p_++),
+                          "01234");
+  EXPECT_EQ(s_ + 1, p_);
+}
+
+// Tests that assertion arguments are evaluated exactly once.
+TEST_F(single_evaluation_test, write_tests) {
+  // successful EXPECT_WRITE
+  EXPECT_WRITE(
+      stdout,
+      {  // NOLINT
+        a_++;
+        std::printf("test");
+      },
+      (b_++, "test"));
+  EXPECT_EQ(1, a_);
+  EXPECT_EQ(1, b_);
+
+  // failed EXPECT_WRITE
+  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(
+                              stdout,
+                              {  // NOLINT
+                                a_++;
+                                std::printf("test");
+                              },
+                              (b_++, "other")),
+                          "Actual: test");
+  EXPECT_EQ(2, a_);
+  EXPECT_EQ(2, b_);
+}
+
+// Tests EXPECT_WRITE.
+TEST(gtest_extra_test, expect_write) {
+  EXPECT_WRITE(stdout, do_nothing(), "");
+  EXPECT_WRITE(stdout, std::printf("test"), "test");
+  EXPECT_WRITE(stderr, std::fprintf(stderr, "test"), "test");
+  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout, std::printf("that"), "this"),
+                          "Expected: this\n"
+                          "  Actual: that");
+}
+
+TEST(gtest_extra_test, expect_write_streaming) {
+  EXPECT_WRITE(stdout, std::printf("test"), "test") << "unexpected failure";
+  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout, std::printf("test"), "other")
+                              << "expected failure",
+                          "expected failure");
+}
+#endif  // FMT_USE_FCNTL
+
+// Tests that the compiler will not complain about unreachable code in the
+// EXPECT_THROW_MSG macro.
+TEST(gtest_extra_test, expect_throw_no_unreachable_code_warning) {
+  int n = 0;
+  using std::runtime_error;
+  EXPECT_THROW_MSG(throw runtime_error(""), runtime_error, "");
+  EXPECT_NONFATAL_FAILURE(EXPECT_THROW_MSG(n++, runtime_error, ""), "");
+  EXPECT_NONFATAL_FAILURE(EXPECT_THROW_MSG(throw 1, runtime_error, ""), "");
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_THROW_MSG(throw runtime_error("a"), runtime_error, "b"), "");
+}
+
+// Tests that the compiler will not complain about unreachable code in the
+// EXPECT_SYSTEM_ERROR macro.
+TEST(gtest_extra_test, expect_system_error_no_unreachable_code_warning) {
+  int n = 0;
+  EXPECT_SYSTEM_ERROR(throw fmt::system_error(EDOM, "test"), EDOM, "test");
+  EXPECT_NONFATAL_FAILURE(EXPECT_SYSTEM_ERROR(n++, EDOM, ""), "");
+  EXPECT_NONFATAL_FAILURE(EXPECT_SYSTEM_ERROR(throw 1, EDOM, ""), "");
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_SYSTEM_ERROR(throw fmt::system_error(EDOM, "aaa"), EDOM, "bbb"),
+      "");
+}
+
+TEST(gtest_extra_test, expect_throw_behaves_like_single_statement) {
+  if (::testing::internal::AlwaysFalse())
+    EXPECT_THROW_MSG(do_nothing(), std::exception, "");
+
+  if (::testing::internal::AlwaysTrue())
+    EXPECT_THROW_MSG(throw_exception(), std::exception, "test");
+  else
+    do_nothing();
+}
+
+TEST(gtest_extra_test, expect_system_error_behaves_like_single_statement) {
+  if (::testing::internal::AlwaysFalse())
+    EXPECT_SYSTEM_ERROR(do_nothing(), EDOM, "");
+
+  if (::testing::internal::AlwaysTrue())
+    EXPECT_SYSTEM_ERROR(throw_system_error(), EDOM, "test");
+  else
+    do_nothing();
+}
+
+TEST(gtest_extra_test, expect_write_behaves_like_single_statement) {
+  if (::testing::internal::AlwaysFalse())
+    EXPECT_WRITE(stdout, std::printf("x"), "x");
+
+  if (::testing::internal::AlwaysTrue())
+    EXPECT_WRITE(stdout, std::printf("x"), "x");
+  else
+    do_nothing();
+}
+
+// Tests EXPECT_THROW_MSG.
+TEST(gtest_extra_test, expect_throw_msg) {
+  EXPECT_THROW_MSG(throw_exception(), std::exception, "test");
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_THROW_MSG(throw_exception(), std::logic_error, "test"),
+      "Expected: throw_exception() throws an exception of "
+      "type std::logic_error.\n  Actual: it throws a different type.");
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_THROW_MSG(do_nothing(), std::exception, "test"),
+      "Expected: do_nothing() throws an exception of type std::exception.\n"
+      "  Actual: it throws nothing.");
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_THROW_MSG(throw_exception(), std::exception, "other"),
+      "throw_exception() throws an exception with a different message.\n"
+      "Expected: other\n"
+      "  Actual: test");
+}
+
+// Tests EXPECT_SYSTEM_ERROR.
+TEST(gtest_extra_test, expect_system_error) {
+  EXPECT_SYSTEM_ERROR(throw_system_error(), EDOM, "test");
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_SYSTEM_ERROR(throw_exception(), EDOM, "test"),
+      "Expected: throw_exception() throws an exception of "
+      "type std::system_error.\n  Actual: it throws a different type.");
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_SYSTEM_ERROR(do_nothing(), EDOM, "test"),
+      "Expected: do_nothing() throws an exception of type std::system_error.\n"
+      "  Actual: it throws nothing.");
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_SYSTEM_ERROR(throw_system_error(), EDOM, "other"),
+      fmt::format(
+          "throw_system_error() throws an exception with a different message.\n"
+          "Expected: {}\n"
+          "  Actual: {}",
+          system_error_message(EDOM, "other"),
+          system_error_message(EDOM, "test")));
+}
+
+TEST(gtest_extra_test, expect_throw_msg_streaming) {
+  EXPECT_THROW_MSG(throw_exception(), std::exception, "test")
+      << "unexpected failure";
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_THROW_MSG(throw_exception(), std::exception, "other")
+          << "expected failure",
+      "expected failure");
+}
+
+TEST(gtest_extra_test, expect_system_error_streaming) {
+  EXPECT_SYSTEM_ERROR(throw_system_error(), EDOM, "test")
+      << "unexpected failure";
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_SYSTEM_ERROR(throw_system_error(), EDOM, "other")
+          << "expected failure",
+      "expected failure");
+}
+
+#if FMT_USE_FCNTL
+
+using fmt::buffered_file;
+using fmt::file;
+
+TEST(output_redirect_test, scoped_redirect) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  {
+    buffered_file file(write_end.fdopen("w"));
+    std::fprintf(file.get(), "[[[");
+    {
+      output_redirect redir(file.get());
+      std::fprintf(file.get(), "censored");
+    }
+    std::fprintf(file.get(), "]]]");
+  }
+  EXPECT_READ(read_end, "[[[]]]");
+}
+
+// Test that output_redirect handles errors in flush correctly.
+TEST(output_redirect_test, flush_error_in_ctor) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  int write_fd = write_end.descriptor();
+  file write_copy = write_end.dup(write_fd);
+  buffered_file f = write_end.fdopen("w");
+  // Put a character in a file buffer.
+  EXPECT_EQ('x', fputc('x', f.get()));
+  FMT_POSIX(close(write_fd));
+  std::unique_ptr<output_redirect> redir{nullptr};
+  EXPECT_SYSTEM_ERROR_NOASSERT(redir.reset(new output_redirect(f.get())), EBADF,
+                               "cannot flush stream");
+  redir.reset(nullptr);
+  write_copy.dup2(write_fd);  // "undo" close or dtor will fail
+}
+
+TEST(output_redirect_test, dup_error_in_ctor) {
+  buffered_file f = open_buffered_file();
+  int fd = (f.descriptor)();
+  file copy = file::dup(fd);
+  FMT_POSIX(close(fd));
+  std::unique_ptr<output_redirect> redir{nullptr};
+  EXPECT_SYSTEM_ERROR_NOASSERT(
+      redir.reset(new output_redirect(f.get())), EBADF,
+      fmt::format("cannot duplicate file descriptor {}", fd));
+  copy.dup2(fd);  // "undo" close or dtor will fail
+}
+
+TEST(output_redirect_test, restore_and_read) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  buffered_file file(write_end.fdopen("w"));
+  std::fprintf(file.get(), "[[[");
+  output_redirect redir(file.get());
+  std::fprintf(file.get(), "censored");
+  EXPECT_EQ("censored", redir.restore_and_read());
+  EXPECT_EQ("", redir.restore_and_read());
+  std::fprintf(file.get(), "]]]");
+  file = buffered_file();
+  EXPECT_READ(read_end, "[[[]]]");
+}
+
+// Test that OutputRedirect handles errors in flush correctly.
+TEST(output_redirect_test, flush_error_in_restore_and_read) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  int write_fd = write_end.descriptor();
+  file write_copy = write_end.dup(write_fd);
+  buffered_file f = write_end.fdopen("w");
+  output_redirect redir(f.get());
+  // Put a character in a file buffer.
+  EXPECT_EQ('x', fputc('x', f.get()));
+  FMT_POSIX(close(write_fd));
+  EXPECT_SYSTEM_ERROR_NOASSERT(redir.restore_and_read(), EBADF,
+                               "cannot flush stream");
+  write_copy.dup2(write_fd);  // "undo" close or dtor will fail
+}
+
+TEST(output_redirect_test, error_in_dtor) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  int write_fd = write_end.descriptor();
+  file write_copy = write_end.dup(write_fd);
+  buffered_file f = write_end.fdopen("w");
+  std::unique_ptr<output_redirect> redir(new output_redirect(f.get()));
+  // Put a character in a file buffer.
+  EXPECT_EQ('x', fputc('x', f.get()));
+  EXPECT_WRITE(
+      stderr,
+      {
+        // The close function must be called inside EXPECT_WRITE,
+        // otherwise the system may recycle closed file descriptor when
+        // redirecting the output in EXPECT_STDERR and the second close
+        // will break output redirection.
+        FMT_POSIX(close(write_fd));
+        SUPPRESS_ASSERT(redir.reset(nullptr));
+      },
+      system_error_message(EBADF, "cannot flush stream"));
+  write_copy.dup2(write_fd);  // "undo" close or dtor of buffered_file will fail
+}
+
+#endif  // FMT_USE_FCNTL
diff --git a/src/fmt/test/gtest-extra.cc b/src/fmt/test/gtest-extra.cc
new file mode 100644
index 000000000..542e4b5e6
--- /dev/null
+++ b/src/fmt/test/gtest-extra.cc
@@ -0,0 +1,80 @@
+// Formatting library for C++ - custom Google Test assertions
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "gtest-extra.h"
+
+#if FMT_USE_FCNTL
+
+using fmt::file;
+
+output_redirect::output_redirect(FILE* f) : file_(f) {
+  flush();
+  int fd = FMT_POSIX(fileno(f));
+  // Create a file object referring to the original file.
+  original_ = file::dup(fd);
+  // Create a pipe.
+  file write_end;
+  file::pipe(read_end_, write_end);
+  // Connect the passed FILE object to the write end of the pipe.
+  write_end.dup2(fd);
+}
+
+output_redirect::~output_redirect() noexcept {
+  try {
+    restore();
+  } catch (const std::exception& e) {
+    std::fputs(e.what(), stderr);
+  }
+}
+
+void output_redirect::flush() {
+  int result = 0;
+  do {
+    result = fflush(file_);
+  } while (result == EOF && errno == EINTR);
+  if (result != 0) throw fmt::system_error(errno, "cannot flush stream");
+}
+
+void output_redirect::restore() {
+  if (original_.descriptor() == -1) return;  // Already restored.
+  flush();
+  // Restore the original file.
+  original_.dup2(FMT_POSIX(fileno(file_)));
+  original_.close();
+}
+
+std::string output_redirect::restore_and_read() {
+  // Restore output.
+  restore();
+
+  // Read everything from the pipe.
+  std::string content;
+  if (read_end_.descriptor() == -1) return content;  // Already read.
+  enum { BUFFER_SIZE = 4096 };
+  char buffer[BUFFER_SIZE];
+  size_t count = 0;
+  do {
+    count = read_end_.read(buffer, BUFFER_SIZE);
+    content.append(buffer, count);
+  } while (count != 0);
+  read_end_.close();
+  return content;
+}
+
+std::string read(file& f, size_t count) {
+  std::string buffer(count, '\0');
+  size_t n = 0, offset = 0;
+  do {
+    n = f.read(&buffer[offset], count - offset);
+    // We can't read more than size_t bytes since count has type size_t.
+    offset += n;
+  } while (offset < count && n != 0);
+  buffer.resize(offset);
+  return buffer;
+}
+
+#endif  // FMT_USE_FCNTL
diff --git a/src/fmt/test/gtest-extra.h b/src/fmt/test/gtest-extra.h
new file mode 100644
index 000000000..ef2a04e7c
--- /dev/null
+++ b/src/fmt/test/gtest-extra.h
@@ -0,0 +1,170 @@
+// Formatting library for C++ - custom Google Test assertions
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_GTEST_EXTRA_H_
+#define FMT_GTEST_EXTRA_H_
+
+#include <stdlib.h>  // _invalid_parameter_handler
+
+#include <string>
+
+#ifdef FMT_MODULE_TEST
+import fmt;
+#else
+#  include "fmt/os.h"
+#endif  // FMG_MODULE_TEST
+
+#include "gmock/gmock.h"
+
+#define FMT_TEST_THROW_(statement, expected_exception, expected_message, fail) \
+  GTEST_AMBIGUOUS_ELSE_BLOCKER_                                                \
+  if (::testing::AssertionResult gtest_ar = ::testing::AssertionSuccess()) {   \
+    std::string gtest_expected_message = expected_message;                     \
+    bool gtest_caught_expected = false;                                        \
+    try {                                                                      \
+      GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement);               \
+    } catch (expected_exception const& e) {                                    \
+      if (gtest_expected_message != e.what()) {                                \
+        gtest_ar << #statement                                                 \
+            " throws an exception with a different message.\n"                 \
+                 << "Expected: " << gtest_expected_message << "\n"             \
+                 << "  Actual: " << e.what();                                  \
+        goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__);            \
+      }                                                                        \
+      gtest_caught_expected = true;                                            \
+    } catch (...) {                                                            \
+      gtest_ar << "Expected: " #statement                                      \
+                  " throws an exception of type " #expected_exception          \
+                  ".\n  Actual: it throws a different type.";                  \
+      goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__);              \
+    }                                                                          \
+    if (!gtest_caught_expected) {                                              \
+      gtest_ar << "Expected: " #statement                                      \
+                  " throws an exception of type " #expected_exception          \
+                  ".\n  Actual: it throws nothing.";                           \
+      goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__);              \
+    }                                                                          \
+  } else                                                                       \
+    GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__)                      \
+        : fail(gtest_ar.failure_message())
+
+// Tests that the statement throws the expected exception and the exception's
+// what() method returns expected message.
+#define EXPECT_THROW_MSG(statement, expected_exception, expected_message) \
+  FMT_TEST_THROW_(statement, expected_exception, expected_message,        \
+                  GTEST_NONFATAL_FAILURE_)
+
+inline std::string system_error_message(int error_code,
+                                        const std::string& message) {
+  auto ec = std::error_code(error_code, std::generic_category());
+  return std::system_error(ec, message).what();
+}
+
+#define EXPECT_SYSTEM_ERROR(statement, error_code, message) \
+  EXPECT_THROW_MSG(statement, std::system_error,            \
+                   system_error_message(error_code, message))
+
+#if FMT_USE_FCNTL
+
+// Captures file output by redirecting it to a pipe.
+// The output it can handle is limited by the pipe capacity.
+class output_redirect {
+ private:
+  FILE* file_;
+  fmt::file original_;  // Original file passed to redirector.
+  fmt::file read_end_;  // Read end of the pipe where the output is redirected.
+
+  void flush();
+  void restore();
+
+ public:
+  explicit output_redirect(FILE* file);
+  ~output_redirect() noexcept;
+
+  output_redirect(const output_redirect&) = delete;
+  void operator=(const output_redirect&) = delete;
+
+  // Restores the original file, reads output from the pipe into a string
+  // and returns it.
+  std::string restore_and_read();
+};
+
+#  define FMT_TEST_WRITE_(statement, expected_output, file, fail)              \
+    GTEST_AMBIGUOUS_ELSE_BLOCKER_                                              \
+    if (::testing::AssertionResult gtest_ar = ::testing::AssertionSuccess()) { \
+      std::string gtest_expected_output = expected_output;                     \
+      output_redirect gtest_redir(file);                                       \
+      GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement);               \
+      std::string gtest_output = gtest_redir.restore_and_read();               \
+      if (gtest_output != gtest_expected_output) {                             \
+        gtest_ar << #statement " produces different output.\n"                 \
+                 << "Expected: " << gtest_expected_output << "\n"              \
+                 << "  Actual: " << gtest_output;                              \
+        goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__);            \
+      }                                                                        \
+    } else                                                                     \
+      GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__)                    \
+          : fail(gtest_ar.failure_message())
+
+// Tests that the statement writes the expected output to file.
+#  define EXPECT_WRITE(file, statement, expected_output) \
+    FMT_TEST_WRITE_(statement, expected_output, file, GTEST_NONFATAL_FAILURE_)
+
+#  ifdef _MSC_VER
+
+// Suppresses Windows assertions on invalid file descriptors, making
+// POSIX functions return proper error codes instead of crashing on Windows.
+class suppress_assert {
+ private:
+  _invalid_parameter_handler original_handler_;
+  int original_report_mode_;
+
+  static void handle_invalid_parameter(const wchar_t*, const wchar_t*,
+                                       const wchar_t*, unsigned, uintptr_t) {}
+
+ public:
+  suppress_assert()
+      : original_handler_(
+            _set_invalid_parameter_handler(handle_invalid_parameter)),
+        original_report_mode_(_CrtSetReportMode(_CRT_ASSERT, 0)) {}
+  ~suppress_assert() {
+    _set_invalid_parameter_handler(original_handler_);
+    _CrtSetReportMode(_CRT_ASSERT, original_report_mode_);
+    (void)original_report_mode_;
+  }
+};
+
+#    define SUPPRESS_ASSERT(statement) \
+      {                                \
+        suppress_assert sa;            \
+        statement;                     \
+      }
+#  else
+#    define SUPPRESS_ASSERT(statement) statement
+#  endif  // _MSC_VER
+
+#  define EXPECT_SYSTEM_ERROR_NOASSERT(statement, error_code, message) \
+    EXPECT_SYSTEM_ERROR(SUPPRESS_ASSERT(statement), error_code, message)
+
+// Attempts to read count characters from a file.
+std::string read(fmt::file& f, size_t count);
+
+#  define EXPECT_READ(file, expected_content) \
+    EXPECT_EQ(expected_content,               \
+              read(file, fmt::string_view(expected_content).size()))
+
+#else
+#  define EXPECT_WRITE(file, statement, expected_output) \
+    do {                                                 \
+      (void)(file);                                      \
+      (void)(statement);                                 \
+      (void)(expected_output);                           \
+      SUCCEED();                                         \
+    } while (false)
+#endif  // FMT_USE_FCNTL
+
+#endif  // FMT_GTEST_EXTRA_H_
diff --git a/src/fmt/test/gtest/.clang-format b/src/fmt/test/gtest/.clang-format
new file mode 100644
index 000000000..ec09b9b6b
--- /dev/null
+++ b/src/fmt/test/gtest/.clang-format
@@ -0,0 +1,3 @@
+# Disable clang-format here
+DisableFormat: true
+SortIncludes: Never
diff --git a/src/fmt/test/gtest/CMakeLists.txt b/src/fmt/test/gtest/CMakeLists.txt
new file mode 100644
index 000000000..ed0e59d5f
--- /dev/null
+++ b/src/fmt/test/gtest/CMakeLists.txt
@@ -0,0 +1,38 @@
+#------------------------------------------------------------------------------
+# Build the google test library
+
+# We compile Google Test ourselves instead of using pre-compiled libraries.
+# See the Google Test FAQ "Why is it not recommended to install a
+# pre-compiled copy of Google Test (for example, into /usr/local)?"
+# at http://code.google.com/p/googletest/wiki/FAQ for more details.
+add_library(gtest STATIC
+  gmock-gtest-all.cc gmock/gmock.h gtest/gtest.h gtest/gtest-spi.h)
+target_compile_definitions(gtest PUBLIC GTEST_HAS_STD_WSTRING=1)
+target_include_directories(gtest SYSTEM PUBLIC .)
+
+find_package(Threads)
+if (Threads_FOUND)
+  target_link_libraries(gtest ${CMAKE_THREAD_LIBS_INIT})
+else ()
+  target_compile_definitions(gtest PUBLIC GTEST_HAS_PTHREAD=0)
+endif ()
+
+# Workaround GTest bug https://github.com/google/googletest/issues/705.
+fmt_check_cxx_compiler_flag(
+  -fno-delete-null-pointer-checks HAVE_FNO_DELETE_NULL_POINTER_CHECKS)
+if (HAVE_FNO_DELETE_NULL_POINTER_CHECKS)
+  target_compile_options(gtest PUBLIC -fno-delete-null-pointer-checks)
+endif ()
+
+if (MSVC)
+  # Disable MSVC warnings of _CRT_INSECURE_DEPRECATE functions.
+  target_compile_definitions(gtest PRIVATE _CRT_SECURE_NO_WARNINGS)
+  if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    # Disable MSVC warnings of POSIX functions.
+    target_compile_options(gtest PUBLIC -Wno-deprecated-declarations)
+  endif ()
+endif ()
+
+# Silence MSVC tr1 deprecation warning in gmock.
+target_compile_definitions(gtest
+  PUBLIC _SILENCE_TR1_NAMESPACE_DEPRECATION_WARNING=1)
diff --git a/src/fmt/test/gtest/gmock-gtest-all.cc b/src/fmt/test/gtest/gmock-gtest-all.cc
new file mode 100644
index 000000000..439ebc621
--- /dev/null
+++ b/src/fmt/test/gtest/gmock-gtest-all.cc
@@ -0,0 +1,14434 @@
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// Google C++ Testing and Mocking Framework (Google Test)
+//
+// Sometimes it's desirable to build Google Test by compiling a single file.
+// This file serves this purpose.
+
+// This line ensures that gtest.h can be compiled on its own, even
+// when it's fused.
+#include "gtest/gtest.h"
+
+// The following lines pull in the real gtest *.cc files.
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// The Google C++ Testing and Mocking Framework (Google Test)
+
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// Utilities for testing Google Test itself and code that uses Google Test
+// (e.g. frameworks built on top of Google Test).
+
+// GOOGLETEST_CM0004 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_SPI_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_SPI_H_
+
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+namespace testing {
+
+// This helper class can be used to mock out Google Test failure reporting
+// so that we can test Google Test or code that builds on Google Test.
+//
+// An object of this class appends a TestPartResult object to the
+// TestPartResultArray object given in the constructor whenever a Google Test
+// failure is reported. It can either intercept only failures that are
+// generated in the same thread that created this object or it can intercept
+// all generated failures. The scope of this mock object can be controlled with
+// the second argument to the two arguments constructor.
+class GTEST_API_ ScopedFakeTestPartResultReporter
+    : public TestPartResultReporterInterface {
+ public:
+  // The two possible mocking modes of this object.
+  enum InterceptMode {
+    INTERCEPT_ONLY_CURRENT_THREAD,  // Intercepts only thread local failures.
+    INTERCEPT_ALL_THREADS           // Intercepts all failures.
+  };
+
+  // The c'tor sets this object as the test part result reporter used
+  // by Google Test.  The 'result' parameter specifies where to report the
+  // results. This reporter will only catch failures generated in the current
+  // thread. DEPRECATED
+  explicit ScopedFakeTestPartResultReporter(TestPartResultArray* result);
+
+  // Same as above, but you can choose the interception scope of this object.
+  ScopedFakeTestPartResultReporter(InterceptMode intercept_mode,
+                                   TestPartResultArray* result);
+
+  // The d'tor restores the previous test part result reporter.
+  ~ScopedFakeTestPartResultReporter() override;
+
+  // Appends the TestPartResult object to the TestPartResultArray
+  // received in the constructor.
+  //
+  // This method is from the TestPartResultReporterInterface
+  // interface.
+  void ReportTestPartResult(const TestPartResult& result) override;
+
+ private:
+  void Init();
+
+  const InterceptMode intercept_mode_;
+  TestPartResultReporterInterface* old_reporter_;
+  TestPartResultArray* const result_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ScopedFakeTestPartResultReporter);
+};
+
+namespace internal {
+
+// A helper class for implementing EXPECT_FATAL_FAILURE() and
+// EXPECT_NONFATAL_FAILURE().  Its destructor verifies that the given
+// TestPartResultArray contains exactly one failure that has the given
+// type and contains the given substring.  If that's not the case, a
+// non-fatal failure will be generated.
+class GTEST_API_ SingleFailureChecker {
+ public:
+  // The constructor remembers the arguments.
+  SingleFailureChecker(const TestPartResultArray* results,
+                       TestPartResult::Type type, const std::string& substr);
+  ~SingleFailureChecker();
+ private:
+  const TestPartResultArray* const results_;
+  const TestPartResult::Type type_;
+  const std::string substr_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(SingleFailureChecker);
+};
+
+}  // namespace internal
+
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+// A set of macros for testing Google Test assertions or code that's expected
+// to generate Google Test fatal failures.  It verifies that the given
+// statement will cause exactly one fatal Google Test failure with 'substr'
+// being part of the failure message.
+//
+// There are two different versions of this macro. EXPECT_FATAL_FAILURE only
+// affects and considers failures generated in the current thread and
+// EXPECT_FATAL_FAILURE_ON_ALL_THREADS does the same but for all threads.
+//
+// The verification of the assertion is done correctly even when the statement
+// throws an exception or aborts the current function.
+//
+// Known restrictions:
+//   - 'statement' cannot reference local non-static variables or
+//     non-static members of the current object.
+//   - 'statement' cannot return a value.
+//   - You cannot stream a failure message to this macro.
+//
+// Note that even though the implementations of the following two
+// macros are much alike, we cannot refactor them to use a common
+// helper macro, due to some peculiarity in how the preprocessor
+// works.  The AcceptsMacroThatExpandsToUnprotectedComma test in
+// gtest_unittest.cc will fail to compile if we do that.
+#define EXPECT_FATAL_FAILURE(statement, substr) \
+  do { \
+    class GTestExpectFatalFailureHelper {\
+     public:\
+      static void Execute() { statement; }\
+    };\
+    ::testing::TestPartResultArray gtest_failures;\
+    ::testing::internal::SingleFailureChecker gtest_checker(\
+        &gtest_failures, ::testing::TestPartResult::kFatalFailure, (substr));\
+    {\
+      ::testing::ScopedFakeTestPartResultReporter gtest_reporter(\
+          ::testing::ScopedFakeTestPartResultReporter:: \
+          INTERCEPT_ONLY_CURRENT_THREAD, &gtest_failures);\
+      GTestExpectFatalFailureHelper::Execute();\
+    }\
+  } while (::testing::internal::AlwaysFalse())
+
+#define EXPECT_FATAL_FAILURE_ON_ALL_THREADS(statement, substr) \
+  do { \
+    class GTestExpectFatalFailureHelper {\
+     public:\
+      static void Execute() { statement; }\
+    };\
+    ::testing::TestPartResultArray gtest_failures;\
+    ::testing::internal::SingleFailureChecker gtest_checker(\
+        &gtest_failures, ::testing::TestPartResult::kFatalFailure, (substr));\
+    {\
+      ::testing::ScopedFakeTestPartResultReporter gtest_reporter(\
+          ::testing::ScopedFakeTestPartResultReporter:: \
+          INTERCEPT_ALL_THREADS, &gtest_failures);\
+      GTestExpectFatalFailureHelper::Execute();\
+    }\
+  } while (::testing::internal::AlwaysFalse())
+
+// A macro for testing Google Test assertions or code that's expected to
+// generate Google Test non-fatal failures.  It asserts that the given
+// statement will cause exactly one non-fatal Google Test failure with 'substr'
+// being part of the failure message.
+//
+// There are two different versions of this macro. EXPECT_NONFATAL_FAILURE only
+// affects and considers failures generated in the current thread and
+// EXPECT_NONFATAL_FAILURE_ON_ALL_THREADS does the same but for all threads.
+//
+// 'statement' is allowed to reference local variables and members of
+// the current object.
+//
+// The verification of the assertion is done correctly even when the statement
+// throws an exception or aborts the current function.
+//
+// Known restrictions:
+//   - You cannot stream a failure message to this macro.
+//
+// Note that even though the implementations of the following two
+// macros are much alike, we cannot refactor them to use a common
+// helper macro, due to some peculiarity in how the preprocessor
+// works.  If we do that, the code won't compile when the user gives
+// EXPECT_NONFATAL_FAILURE() a statement that contains a macro that
+// expands to code containing an unprotected comma.  The
+// AcceptsMacroThatExpandsToUnprotectedComma test in gtest_unittest.cc
+// catches that.
+//
+// For the same reason, we have to write
+//   if (::testing::internal::AlwaysTrue()) { statement; }
+// instead of
+//   GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement)
+// to avoid an MSVC warning on unreachable code.
+#define EXPECT_NONFATAL_FAILURE(statement, substr) \
+  do {\
+    ::testing::TestPartResultArray gtest_failures;\
+    ::testing::internal::SingleFailureChecker gtest_checker(\
+        &gtest_failures, ::testing::TestPartResult::kNonFatalFailure, \
+        (substr));\
+    {\
+      ::testing::ScopedFakeTestPartResultReporter gtest_reporter(\
+          ::testing::ScopedFakeTestPartResultReporter:: \
+          INTERCEPT_ONLY_CURRENT_THREAD, &gtest_failures);\
+      if (::testing::internal::AlwaysTrue()) { statement; }\
+    }\
+  } while (::testing::internal::AlwaysFalse())
+
+#define EXPECT_NONFATAL_FAILURE_ON_ALL_THREADS(statement, substr) \
+  do {\
+    ::testing::TestPartResultArray gtest_failures;\
+    ::testing::internal::SingleFailureChecker gtest_checker(\
+        &gtest_failures, ::testing::TestPartResult::kNonFatalFailure, \
+        (substr));\
+    {\
+      ::testing::ScopedFakeTestPartResultReporter gtest_reporter(\
+          ::testing::ScopedFakeTestPartResultReporter::INTERCEPT_ALL_THREADS, \
+          &gtest_failures);\
+      if (::testing::internal::AlwaysTrue()) { statement; }\
+    }\
+  } while (::testing::internal::AlwaysFalse())
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_SPI_H_
+
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include <algorithm>
+#include <chrono>  // NOLINT
+#include <cmath>
+#include <cstdint>
+#include <iomanip>
+#include <limits>
+#include <list>
+#include <map>
+#include <ostream>  // NOLINT
+#include <sstream>
+#include <vector>
+
+#if GTEST_OS_LINUX
+
+# include <fcntl.h>  // NOLINT
+# include <limits.h>  // NOLINT
+# include <sched.h>  // NOLINT
+// Declares vsnprintf().  This header is not available on Windows.
+# include <strings.h>  // NOLINT
+# include <sys/mman.h>  // NOLINT
+# include <sys/time.h>  // NOLINT
+# include <unistd.h>  // NOLINT
+# include <string>
+
+#elif GTEST_OS_ZOS
+# include <sys/time.h>  // NOLINT
+
+// On z/OS we additionally need strings.h for strcasecmp.
+# include <strings.h>  // NOLINT
+
+#elif GTEST_OS_WINDOWS_MOBILE  // We are on Windows CE.
+
+# include <windows.h>  // NOLINT
+# undef min
+
+#elif GTEST_OS_WINDOWS  // We are on Windows proper.
+
+# include <windows.h>  // NOLINT
+# undef min
+
+#ifdef _MSC_VER
+# include <crtdbg.h>  // NOLINT
+#endif
+
+# include <io.h>  // NOLINT
+# include <sys/timeb.h>  // NOLINT
+# include <sys/types.h>  // NOLINT
+# include <sys/stat.h>  // NOLINT
+
+# if GTEST_OS_WINDOWS_MINGW
+#  include <sys/time.h>  // NOLINT
+# endif  // GTEST_OS_WINDOWS_MINGW
+
+#else
+
+// cpplint thinks that the header is already included, so we want to
+// silence it.
+# include <sys/time.h>  // NOLINT
+# include <unistd.h>  // NOLINT
+
+#endif  // GTEST_OS_LINUX
+
+#if GTEST_HAS_EXCEPTIONS
+# include <stdexcept>
+#endif
+
+#if GTEST_CAN_STREAM_RESULTS_
+# include <arpa/inet.h>  // NOLINT
+# include <netdb.h>  // NOLINT
+# include <sys/socket.h>  // NOLINT
+# include <sys/types.h>  // NOLINT
+#endif
+
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Utility functions and classes used by the Google C++ testing framework.//
+// This file contains purely Google Test's internal implementation.  Please
+// DO NOT #INCLUDE IT IN A USER PROGRAM.
+
+#ifndef GOOGLETEST_SRC_GTEST_INTERNAL_INL_H_
+#define GOOGLETEST_SRC_GTEST_INTERNAL_INL_H_
+
+#ifndef _WIN32_WCE
+# include <errno.h>
+#endif  // !_WIN32_WCE
+#include <stddef.h>
+#include <stdlib.h>  // For strtoll/_strtoul64/malloc/free.
+#include <string.h>  // For memmove.
+
+#include <algorithm>
+#include <cstdint>
+#include <memory>
+#include <string>
+#include <vector>
+
+
+#if GTEST_CAN_STREAM_RESULTS_
+# include <arpa/inet.h>  // NOLINT
+# include <netdb.h>  // NOLINT
+#endif
+
+#if GTEST_OS_WINDOWS
+# include <windows.h>  // NOLINT
+#endif  // GTEST_OS_WINDOWS
+
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+namespace testing {
+
+// Declares the flags.
+//
+// We don't want the users to modify this flag in the code, but want
+// Google Test's own unit tests to be able to access it. Therefore we
+// declare it here as opposed to in gtest.h.
+GTEST_DECLARE_bool_(death_test_use_fork);
+
+namespace internal {
+
+// The value of GetTestTypeId() as seen from within the Google Test
+// library.  This is solely for testing GetTestTypeId().
+GTEST_API_ extern const TypeId kTestTypeIdInGoogleTest;
+
+// Names of the flags (needed for parsing Google Test flags).
+const char kAlsoRunDisabledTestsFlag[] = "also_run_disabled_tests";
+const char kBreakOnFailureFlag[] = "break_on_failure";
+const char kCatchExceptionsFlag[] = "catch_exceptions";
+const char kColorFlag[] = "color";
+const char kFailFast[] = "fail_fast";
+const char kFilterFlag[] = "filter";
+const char kListTestsFlag[] = "list_tests";
+const char kOutputFlag[] = "output";
+const char kBriefFlag[] = "brief";
+const char kPrintTimeFlag[] = "print_time";
+const char kPrintUTF8Flag[] = "print_utf8";
+const char kRandomSeedFlag[] = "random_seed";
+const char kRepeatFlag[] = "repeat";
+const char kShuffleFlag[] = "shuffle";
+const char kStackTraceDepthFlag[] = "stack_trace_depth";
+const char kStreamResultToFlag[] = "stream_result_to";
+const char kThrowOnFailureFlag[] = "throw_on_failure";
+const char kFlagfileFlag[] = "flagfile";
+
+// A valid random seed must be in [1, kMaxRandomSeed].
+const int kMaxRandomSeed = 99999;
+
+// g_help_flag is true if and only if the --help flag or an equivalent form
+// is specified on the command line.
+GTEST_API_ extern bool g_help_flag;
+
+// Returns the current time in milliseconds.
+GTEST_API_ TimeInMillis GetTimeInMillis();
+
+// Returns true if and only if Google Test should use colors in the output.
+GTEST_API_ bool ShouldUseColor(bool stdout_is_tty);
+
+// Formats the given time in milliseconds as seconds.
+GTEST_API_ std::string FormatTimeInMillisAsSeconds(TimeInMillis ms);
+
+// Converts the given time in milliseconds to a date string in the ISO 8601
+// format, without the timezone information.  N.B.: due to the use the
+// non-reentrant localtime() function, this function is not thread safe.  Do
+// not use it in any code that can be called from multiple threads.
+GTEST_API_ std::string FormatEpochTimeInMillisAsIso8601(TimeInMillis ms);
+
+// Parses a string for an Int32 flag, in the form of "--flag=value".
+//
+// On success, stores the value of the flag in *value, and returns
+// true.  On failure, returns false without changing *value.
+GTEST_API_ bool ParseInt32Flag(
+    const char* str, const char* flag, int32_t* value);
+
+// Returns a random seed in range [1, kMaxRandomSeed] based on the
+// given --gtest_random_seed flag value.
+inline int GetRandomSeedFromFlag(int32_t random_seed_flag) {
+  const unsigned int raw_seed = (random_seed_flag == 0) ?
+      static_cast<unsigned int>(GetTimeInMillis()) :
+      static_cast<unsigned int>(random_seed_flag);
+
+  // Normalizes the actual seed to range [1, kMaxRandomSeed] such that
+  // it's easy to type.
+  const int normalized_seed =
+      static_cast<int>((raw_seed - 1U) %
+                       static_cast<unsigned int>(kMaxRandomSeed)) + 1;
+  return normalized_seed;
+}
+
+// Returns the first valid random seed after 'seed'.  The behavior is
+// undefined if 'seed' is invalid.  The seed after kMaxRandomSeed is
+// considered to be 1.
+inline int GetNextRandomSeed(int seed) {
+  GTEST_CHECK_(1 <= seed && seed <= kMaxRandomSeed)
+      << "Invalid random seed " << seed << " - must be in [1, "
+      << kMaxRandomSeed << "].";
+  const int next_seed = seed + 1;
+  return (next_seed > kMaxRandomSeed) ? 1 : next_seed;
+}
+
+// This class saves the values of all Google Test flags in its c'tor, and
+// restores them in its d'tor.
+class GTestFlagSaver {
+ public:
+  // The c'tor.
+  GTestFlagSaver() {
+    also_run_disabled_tests_ = GTEST_FLAG(also_run_disabled_tests);
+    break_on_failure_ = GTEST_FLAG(break_on_failure);
+    catch_exceptions_ = GTEST_FLAG(catch_exceptions);
+    color_ = GTEST_FLAG(color);
+    death_test_style_ = GTEST_FLAG(death_test_style);
+    death_test_use_fork_ = GTEST_FLAG(death_test_use_fork);
+    fail_fast_ = GTEST_FLAG(fail_fast);
+    filter_ = GTEST_FLAG(filter);
+    internal_run_death_test_ = GTEST_FLAG(internal_run_death_test);
+    list_tests_ = GTEST_FLAG(list_tests);
+    output_ = GTEST_FLAG(output);
+    brief_ = GTEST_FLAG(brief);
+    print_time_ = GTEST_FLAG(print_time);
+    print_utf8_ = GTEST_FLAG(print_utf8);
+    random_seed_ = GTEST_FLAG(random_seed);
+    repeat_ = GTEST_FLAG(repeat);
+    shuffle_ = GTEST_FLAG(shuffle);
+    stack_trace_depth_ = GTEST_FLAG(stack_trace_depth);
+    stream_result_to_ = GTEST_FLAG(stream_result_to);
+    throw_on_failure_ = GTEST_FLAG(throw_on_failure);
+  }
+
+  // The d'tor is not virtual.  DO NOT INHERIT FROM THIS CLASS.
+  ~GTestFlagSaver() {
+    GTEST_FLAG(also_run_disabled_tests) = also_run_disabled_tests_;
+    GTEST_FLAG(break_on_failure) = break_on_failure_;
+    GTEST_FLAG(catch_exceptions) = catch_exceptions_;
+    GTEST_FLAG(color) = color_;
+    GTEST_FLAG(death_test_style) = death_test_style_;
+    GTEST_FLAG(death_test_use_fork) = death_test_use_fork_;
+    GTEST_FLAG(filter) = filter_;
+    GTEST_FLAG(fail_fast) = fail_fast_;
+    GTEST_FLAG(internal_run_death_test) = internal_run_death_test_;
+    GTEST_FLAG(list_tests) = list_tests_;
+    GTEST_FLAG(output) = output_;
+    GTEST_FLAG(brief) = brief_;
+    GTEST_FLAG(print_time) = print_time_;
+    GTEST_FLAG(print_utf8) = print_utf8_;
+    GTEST_FLAG(random_seed) = random_seed_;
+    GTEST_FLAG(repeat) = repeat_;
+    GTEST_FLAG(shuffle) = shuffle_;
+    GTEST_FLAG(stack_trace_depth) = stack_trace_depth_;
+    GTEST_FLAG(stream_result_to) = stream_result_to_;
+    GTEST_FLAG(throw_on_failure) = throw_on_failure_;
+  }
+
+ private:
+  // Fields for saving the original values of flags.
+  bool also_run_disabled_tests_;
+  bool break_on_failure_;
+  bool catch_exceptions_;
+  std::string color_;
+  std::string death_test_style_;
+  bool death_test_use_fork_;
+  bool fail_fast_;
+  std::string filter_;
+  std::string internal_run_death_test_;
+  bool list_tests_;
+  std::string output_;
+  bool brief_;
+  bool print_time_;
+  bool print_utf8_;
+  int32_t random_seed_;
+  int32_t repeat_;
+  bool shuffle_;
+  int32_t stack_trace_depth_;
+  std::string stream_result_to_;
+  bool throw_on_failure_;
+} GTEST_ATTRIBUTE_UNUSED_;
+
+// Converts a Unicode code point to a narrow string in UTF-8 encoding.
+// code_point parameter is of type UInt32 because wchar_t may not be
+// wide enough to contain a code point.
+// If the code_point is not a valid Unicode code point
+// (i.e. outside of Unicode range U+0 to U+10FFFF) it will be converted
+// to "(Invalid Unicode 0xXXXXXXXX)".
+GTEST_API_ std::string CodePointToUtf8(uint32_t code_point);
+
+// Converts a wide string to a narrow string in UTF-8 encoding.
+// The wide string is assumed to have the following encoding:
+//   UTF-16 if sizeof(wchar_t) == 2 (on Windows, Cygwin)
+//   UTF-32 if sizeof(wchar_t) == 4 (on Linux)
+// Parameter str points to a null-terminated wide string.
+// Parameter num_chars may additionally limit the number
+// of wchar_t characters processed. -1 is used when the entire string
+// should be processed.
+// If the string contains code points that are not valid Unicode code points
+// (i.e. outside of Unicode range U+0 to U+10FFFF) they will be output
+// as '(Invalid Unicode 0xXXXXXXXX)'. If the string is in UTF16 encoding
+// and contains invalid UTF-16 surrogate pairs, values in those pairs
+// will be encoded as individual Unicode characters from Basic Normal Plane.
+GTEST_API_ std::string WideStringToUtf8(const wchar_t* str, int num_chars);
+
+// Reads the GTEST_SHARD_STATUS_FILE environment variable, and creates the file
+// if the variable is present. If a file already exists at this location, this
+// function will write over it. If the variable is present, but the file cannot
+// be created, prints an error and exits.
+void WriteToShardStatusFileIfNeeded();
+
+// Checks whether sharding is enabled by examining the relevant
+// environment variable values. If the variables are present,
+// but inconsistent (e.g., shard_index >= total_shards), prints
+// an error and exits. If in_subprocess_for_death_test, sharding is
+// disabled because it must only be applied to the original test
+// process. Otherwise, we could filter out death tests we intended to execute.
+GTEST_API_ bool ShouldShard(const char* total_shards_str,
+                            const char* shard_index_str,
+                            bool in_subprocess_for_death_test);
+
+// Parses the environment variable var as a 32-bit integer. If it is unset,
+// returns default_val. If it is not a 32-bit integer, prints an error and
+// and aborts.
+GTEST_API_ int32_t Int32FromEnvOrDie(const char* env_var, int32_t default_val);
+
+// Given the total number of shards, the shard index, and the test id,
+// returns true if and only if the test should be run on this shard. The test id
+// is some arbitrary but unique non-negative integer assigned to each test
+// method. Assumes that 0 <= shard_index < total_shards.
+GTEST_API_ bool ShouldRunTestOnShard(
+    int total_shards, int shard_index, int test_id);
+
+// STL container utilities.
+
+// Returns the number of elements in the given container that satisfy
+// the given predicate.
+template <class Container, typename Predicate>
+inline int CountIf(const Container& c, Predicate predicate) {
+  // Implemented as an explicit loop since std::count_if() in libCstd on
+  // Solaris has a non-standard signature.
+  int count = 0;
+  for (typename Container::const_iterator it = c.begin(); it != c.end(); ++it) {
+    if (predicate(*it))
+      ++count;
+  }
+  return count;
+}
+
+// Applies a function/functor to each element in the container.
+template <class Container, typename Functor>
+void ForEach(const Container& c, Functor functor) {
+  std::for_each(c.begin(), c.end(), functor);
+}
+
+// Returns the i-th element of the vector, or default_value if i is not
+// in range [0, v.size()).
+template <typename E>
+inline E GetElementOr(const std::vector<E>& v, int i, E default_value) {
+  return (i < 0 || i >= static_cast<int>(v.size())) ? default_value
+                                                    : v[static_cast<size_t>(i)];
+}
+
+// Performs an in-place shuffle of a range of the vector's elements.
+// 'begin' and 'end' are element indices as an STL-style range;
+// i.e. [begin, end) are shuffled, where 'end' == size() means to
+// shuffle to the end of the vector.
+template <typename E>
+void ShuffleRange(internal::Random* random, int begin, int end,
+                  std::vector<E>* v) {
+  const int size = static_cast<int>(v->size());
+  GTEST_CHECK_(0 <= begin && begin <= size)
+      << "Invalid shuffle range start " << begin << ": must be in range [0, "
+      << size << "].";
+  GTEST_CHECK_(begin <= end && end <= size)
+      << "Invalid shuffle range finish " << end << ": must be in range ["
+      << begin << ", " << size << "].";
+
+  // Fisher-Yates shuffle, from
+  // http://en.wikipedia.org/wiki/Fisher-Yates_shuffle
+  for (int range_width = end - begin; range_width >= 2; range_width--) {
+    const int last_in_range = begin + range_width - 1;
+    const int selected =
+        begin +
+        static_cast<int>(random->Generate(static_cast<uint32_t>(range_width)));
+    std::swap((*v)[static_cast<size_t>(selected)],
+              (*v)[static_cast<size_t>(last_in_range)]);
+  }
+}
+
+// Performs an in-place shuffle of the vector's elements.
+template <typename E>
+inline void Shuffle(internal::Random* random, std::vector<E>* v) {
+  ShuffleRange(random, 0, static_cast<int>(v->size()), v);
+}
+
+// A function for deleting an object.  Handy for being used as a
+// functor.
+template <typename T>
+static void Delete(T* x) {
+  delete x;
+}
+
+// A predicate that checks the key of a TestProperty against a known key.
+//
+// TestPropertyKeyIs is copyable.
+class TestPropertyKeyIs {
+ public:
+  // Constructor.
+  //
+  // TestPropertyKeyIs has NO default constructor.
+  explicit TestPropertyKeyIs(const std::string& key) : key_(key) {}
+
+  // Returns true if and only if the test name of test property matches on key_.
+  bool operator()(const TestProperty& test_property) const {
+    return test_property.key() == key_;
+  }
+
+ private:
+  std::string key_;
+};
+
+// Class UnitTestOptions.
+//
+// This class contains functions for processing options the user
+// specifies when running the tests.  It has only static members.
+//
+// In most cases, the user can specify an option using either an
+// environment variable or a command line flag.  E.g. you can set the
+// test filter using either GTEST_FILTER or --gtest_filter.  If both
+// the variable and the flag are present, the latter overrides the
+// former.
+class GTEST_API_ UnitTestOptions {
+ public:
+  // Functions for processing the gtest_output flag.
+
+  // Returns the output format, or "" for normal printed output.
+  static std::string GetOutputFormat();
+
+  // Returns the absolute path of the requested output file, or the
+  // default (test_detail.xml in the original working directory) if
+  // none was explicitly specified.
+  static std::string GetAbsolutePathToOutputFile();
+
+  // Functions for processing the gtest_filter flag.
+
+  // Returns true if and only if the user-specified filter matches the test
+  // suite name and the test name.
+  static bool FilterMatchesTest(const std::string& test_suite_name,
+                                const std::string& test_name);
+
+#if GTEST_OS_WINDOWS
+  // Function for supporting the gtest_catch_exception flag.
+
+  // Returns EXCEPTION_EXECUTE_HANDLER if Google Test should handle the
+  // given SEH exception, or EXCEPTION_CONTINUE_SEARCH otherwise.
+  // This function is useful as an __except condition.
+  static int GTestShouldProcessSEH(DWORD exception_code);
+#endif  // GTEST_OS_WINDOWS
+
+  // Returns true if "name" matches the ':' separated list of glob-style
+  // filters in "filter".
+  static bool MatchesFilter(const std::string& name, const char* filter);
+};
+
+// Returns the current application's name, removing directory path if that
+// is present.  Used by UnitTestOptions::GetOutputFile.
+GTEST_API_ FilePath GetCurrentExecutableName();
+
+// The role interface for getting the OS stack trace as a string.
+class OsStackTraceGetterInterface {
+ public:
+  OsStackTraceGetterInterface() {}
+  virtual ~OsStackTraceGetterInterface() {}
+
+  // Returns the current OS stack trace as an std::string.  Parameters:
+  //
+  //   max_depth  - the maximum number of stack frames to be included
+  //                in the trace.
+  //   skip_count - the number of top frames to be skipped; doesn't count
+  //                against max_depth.
+  virtual std::string CurrentStackTrace(int max_depth, int skip_count) = 0;
+
+  // UponLeavingGTest() should be called immediately before Google Test calls
+  // user code. It saves some information about the current stack that
+  // CurrentStackTrace() will use to find and hide Google Test stack frames.
+  virtual void UponLeavingGTest() = 0;
+
+  // This string is inserted in place of stack frames that are part of
+  // Google Test's implementation.
+  static const char* const kElidedFramesMarker;
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(OsStackTraceGetterInterface);
+};
+
+// A working implementation of the OsStackTraceGetterInterface interface.
+class OsStackTraceGetter : public OsStackTraceGetterInterface {
+ public:
+  OsStackTraceGetter() {}
+
+  std::string CurrentStackTrace(int max_depth, int skip_count) override;
+  void UponLeavingGTest() override;
+
+ private:
+#if GTEST_HAS_ABSL
+  Mutex mutex_;  // Protects all internal state.
+
+  // We save the stack frame below the frame that calls user code.
+  // We do this because the address of the frame immediately below
+  // the user code changes between the call to UponLeavingGTest()
+  // and any calls to the stack trace code from within the user code.
+  void* caller_frame_ = nullptr;
+#endif  // GTEST_HAS_ABSL
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(OsStackTraceGetter);
+};
+
+// Information about a Google Test trace point.
+struct TraceInfo {
+  const char* file;
+  int line;
+  std::string message;
+};
+
+// This is the default global test part result reporter used in UnitTestImpl.
+// This class should only be used by UnitTestImpl.
+class DefaultGlobalTestPartResultReporter
+  : public TestPartResultReporterInterface {
+ public:
+  explicit DefaultGlobalTestPartResultReporter(UnitTestImpl* unit_test);
+  // Implements the TestPartResultReporterInterface. Reports the test part
+  // result in the current test.
+  void ReportTestPartResult(const TestPartResult& result) override;
+
+ private:
+  UnitTestImpl* const unit_test_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(DefaultGlobalTestPartResultReporter);
+};
+
+// This is the default per thread test part result reporter used in
+// UnitTestImpl. This class should only be used by UnitTestImpl.
+class DefaultPerThreadTestPartResultReporter
+    : public TestPartResultReporterInterface {
+ public:
+  explicit DefaultPerThreadTestPartResultReporter(UnitTestImpl* unit_test);
+  // Implements the TestPartResultReporterInterface. The implementation just
+  // delegates to the current global test part result reporter of *unit_test_.
+  void ReportTestPartResult(const TestPartResult& result) override;
+
+ private:
+  UnitTestImpl* const unit_test_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(DefaultPerThreadTestPartResultReporter);
+};
+
+// The private implementation of the UnitTest class.  We don't protect
+// the methods under a mutex, as this class is not accessible by a
+// user and the UnitTest class that delegates work to this class does
+// proper locking.
+class GTEST_API_ UnitTestImpl {
+ public:
+  explicit UnitTestImpl(UnitTest* parent);
+  virtual ~UnitTestImpl();
+
+  // There are two different ways to register your own TestPartResultReporter.
+  // You can register your own repoter to listen either only for test results
+  // from the current thread or for results from all threads.
+  // By default, each per-thread test result repoter just passes a new
+  // TestPartResult to the global test result reporter, which registers the
+  // test part result for the currently running test.
+
+  // Returns the global test part result reporter.
+  TestPartResultReporterInterface* GetGlobalTestPartResultReporter();
+
+  // Sets the global test part result reporter.
+  void SetGlobalTestPartResultReporter(
+      TestPartResultReporterInterface* reporter);
+
+  // Returns the test part result reporter for the current thread.
+  TestPartResultReporterInterface* GetTestPartResultReporterForCurrentThread();
+
+  // Sets the test part result reporter for the current thread.
+  void SetTestPartResultReporterForCurrentThread(
+      TestPartResultReporterInterface* reporter);
+
+  // Gets the number of successful test suites.
+  int successful_test_suite_count() const;
+
+  // Gets the number of failed test suites.
+  int failed_test_suite_count() const;
+
+  // Gets the number of all test suites.
+  int total_test_suite_count() const;
+
+  // Gets the number of all test suites that contain at least one test
+  // that should run.
+  int test_suite_to_run_count() const;
+
+  // Gets the number of successful tests.
+  int successful_test_count() const;
+
+  // Gets the number of skipped tests.
+  int skipped_test_count() const;
+
+  // Gets the number of failed tests.
+  int failed_test_count() const;
+
+  // Gets the number of disabled tests that will be reported in the XML report.
+  int reportable_disabled_test_count() const;
+
+  // Gets the number of disabled tests.
+  int disabled_test_count() const;
+
+  // Gets the number of tests to be printed in the XML report.
+  int reportable_test_count() const;
+
+  // Gets the number of all tests.
+  int total_test_count() const;
+
+  // Gets the number of tests that should run.
+  int test_to_run_count() const;
+
+  // Gets the time of the test program start, in ms from the start of the
+  // UNIX epoch.
+  TimeInMillis start_timestamp() const { return start_timestamp_; }
+
+  // Gets the elapsed time, in milliseconds.
+  TimeInMillis elapsed_time() const { return elapsed_time_; }
+
+  // Returns true if and only if the unit test passed (i.e. all test suites
+  // passed).
+  bool Passed() const { return !Failed(); }
+
+  // Returns true if and only if the unit test failed (i.e. some test suite
+  // failed or something outside of all tests failed).
+  bool Failed() const {
+    return failed_test_suite_count() > 0 || ad_hoc_test_result()->Failed();
+  }
+
+  // Gets the i-th test suite among all the test suites. i can range from 0 to
+  // total_test_suite_count() - 1. If i is not in that range, returns NULL.
+  const TestSuite* GetTestSuite(int i) const {
+    const int index = GetElementOr(test_suite_indices_, i, -1);
+    return index < 0 ? nullptr : test_suites_[static_cast<size_t>(i)];
+  }
+
+  //  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  const TestCase* GetTestCase(int i) const { return GetTestSuite(i); }
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  // Gets the i-th test suite among all the test suites. i can range from 0 to
+  // total_test_suite_count() - 1. If i is not in that range, returns NULL.
+  TestSuite* GetMutableSuiteCase(int i) {
+    const int index = GetElementOr(test_suite_indices_, i, -1);
+    return index < 0 ? nullptr : test_suites_[static_cast<size_t>(index)];
+  }
+
+  // Provides access to the event listener list.
+  TestEventListeners* listeners() { return &listeners_; }
+
+  // Returns the TestResult for the test that's currently running, or
+  // the TestResult for the ad hoc test if no test is running.
+  TestResult* current_test_result();
+
+  // Returns the TestResult for the ad hoc test.
+  const TestResult* ad_hoc_test_result() const { return &ad_hoc_test_result_; }
+
+  // Sets the OS stack trace getter.
+  //
+  // Does nothing if the input and the current OS stack trace getter
+  // are the same; otherwise, deletes the old getter and makes the
+  // input the current getter.
+  void set_os_stack_trace_getter(OsStackTraceGetterInterface* getter);
+
+  // Returns the current OS stack trace getter if it is not NULL;
+  // otherwise, creates an OsStackTraceGetter, makes it the current
+  // getter, and returns it.
+  OsStackTraceGetterInterface* os_stack_trace_getter();
+
+  // Returns the current OS stack trace as an std::string.
+  //
+  // The maximum number of stack frames to be included is specified by
+  // the gtest_stack_trace_depth flag.  The skip_count parameter
+  // specifies the number of top frames to be skipped, which doesn't
+  // count against the number of frames to be included.
+  //
+  // For example, if Foo() calls Bar(), which in turn calls
+  // CurrentOsStackTraceExceptTop(1), Foo() will be included in the
+  // trace but Bar() and CurrentOsStackTraceExceptTop() won't.
+  std::string CurrentOsStackTraceExceptTop(int skip_count) GTEST_NO_INLINE_;
+
+  // Finds and returns a TestSuite with the given name.  If one doesn't
+  // exist, creates one and returns it.
+  //
+  // Arguments:
+  //
+  //   test_suite_name: name of the test suite
+  //   type_param:      the name of the test's type parameter, or NULL if
+  //                    this is not a typed or a type-parameterized test.
+  //   set_up_tc:       pointer to the function that sets up the test suite
+  //   tear_down_tc:    pointer to the function that tears down the test suite
+  TestSuite* GetTestSuite(const char* test_suite_name, const char* type_param,
+                          internal::SetUpTestSuiteFunc set_up_tc,
+                          internal::TearDownTestSuiteFunc tear_down_tc);
+
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  TestCase* GetTestCase(const char* test_case_name, const char* type_param,
+                        internal::SetUpTestSuiteFunc set_up_tc,
+                        internal::TearDownTestSuiteFunc tear_down_tc) {
+    return GetTestSuite(test_case_name, type_param, set_up_tc, tear_down_tc);
+  }
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  // Adds a TestInfo to the unit test.
+  //
+  // Arguments:
+  //
+  //   set_up_tc:    pointer to the function that sets up the test suite
+  //   tear_down_tc: pointer to the function that tears down the test suite
+  //   test_info:    the TestInfo object
+  void AddTestInfo(internal::SetUpTestSuiteFunc set_up_tc,
+                   internal::TearDownTestSuiteFunc tear_down_tc,
+                   TestInfo* test_info) {
+#if GTEST_HAS_DEATH_TEST
+    // In order to support thread-safe death tests, we need to
+    // remember the original working directory when the test program
+    // was first invoked.  We cannot do this in RUN_ALL_TESTS(), as
+    // the user may have changed the current directory before calling
+    // RUN_ALL_TESTS().  Therefore we capture the current directory in
+    // AddTestInfo(), which is called to register a TEST or TEST_F
+    // before main() is reached.
+    if (original_working_dir_.IsEmpty()) {
+      original_working_dir_.Set(FilePath::GetCurrentDir());
+      GTEST_CHECK_(!original_working_dir_.IsEmpty())
+          << "Failed to get the current working directory.";
+    }
+#endif  // GTEST_HAS_DEATH_TEST
+
+    GetTestSuite(test_info->test_suite_name(), test_info->type_param(),
+                 set_up_tc, tear_down_tc)
+        ->AddTestInfo(test_info);
+  }
+
+  // Returns ParameterizedTestSuiteRegistry object used to keep track of
+  // value-parameterized tests and instantiate and register them.
+  internal::ParameterizedTestSuiteRegistry& parameterized_test_registry() {
+    return parameterized_test_registry_;
+  }
+
+  std::set<std::string>* ignored_parameterized_test_suites() {
+    return &ignored_parameterized_test_suites_;
+  }
+
+  // Returns TypeParameterizedTestSuiteRegistry object used to keep track of
+  // type-parameterized tests and instantiations of them.
+  internal::TypeParameterizedTestSuiteRegistry&
+  type_parameterized_test_registry() {
+    return type_parameterized_test_registry_;
+  }
+
+  // Sets the TestSuite object for the test that's currently running.
+  void set_current_test_suite(TestSuite* a_current_test_suite) {
+    current_test_suite_ = a_current_test_suite;
+  }
+
+  // Sets the TestInfo object for the test that's currently running.  If
+  // current_test_info is NULL, the assertion results will be stored in
+  // ad_hoc_test_result_.
+  void set_current_test_info(TestInfo* a_current_test_info) {
+    current_test_info_ = a_current_test_info;
+  }
+
+  // Registers all parameterized tests defined using TEST_P and
+  // INSTANTIATE_TEST_SUITE_P, creating regular tests for each test/parameter
+  // combination. This method can be called more then once; it has guards
+  // protecting from registering the tests more then once.  If
+  // value-parameterized tests are disabled, RegisterParameterizedTests is
+  // present but does nothing.
+  void RegisterParameterizedTests();
+
+  // Runs all tests in this UnitTest object, prints the result, and
+  // returns true if all tests are successful.  If any exception is
+  // thrown during a test, this test is considered to be failed, but
+  // the rest of the tests will still be run.
+  bool RunAllTests();
+
+  // Clears the results of all tests, except the ad hoc tests.
+  void ClearNonAdHocTestResult() {
+    ForEach(test_suites_, TestSuite::ClearTestSuiteResult);
+  }
+
+  // Clears the results of ad-hoc test assertions.
+  void ClearAdHocTestResult() {
+    ad_hoc_test_result_.Clear();
+  }
+
+  // Adds a TestProperty to the current TestResult object when invoked in a
+  // context of a test or a test suite, or to the global property set. If the
+  // result already contains a property with the same key, the value will be
+  // updated.
+  void RecordProperty(const TestProperty& test_property);
+
+  enum ReactionToSharding {
+    HONOR_SHARDING_PROTOCOL,
+    IGNORE_SHARDING_PROTOCOL
+  };
+
+  // Matches the full name of each test against the user-specified
+  // filter to decide whether the test should run, then records the
+  // result in each TestSuite and TestInfo object.
+  // If shard_tests == HONOR_SHARDING_PROTOCOL, further filters tests
+  // based on sharding variables in the environment.
+  // Returns the number of tests that should run.
+  int FilterTests(ReactionToSharding shard_tests);
+
+  // Prints the names of the tests matching the user-specified filter flag.
+  void ListTestsMatchingFilter();
+
+  const TestSuite* current_test_suite() const { return current_test_suite_; }
+  TestInfo* current_test_info() { return current_test_info_; }
+  const TestInfo* current_test_info() const { return current_test_info_; }
+
+  // Returns the vector of environments that need to be set-up/torn-down
+  // before/after the tests are run.
+  std::vector<Environment*>& environments() { return environments_; }
+
+  // Getters for the per-thread Google Test trace stack.
+  std::vector<TraceInfo>& gtest_trace_stack() {
+    return *(gtest_trace_stack_.pointer());
+  }
+  const std::vector<TraceInfo>& gtest_trace_stack() const {
+    return gtest_trace_stack_.get();
+  }
+
+#if GTEST_HAS_DEATH_TEST
+  void InitDeathTestSubprocessControlInfo() {
+    internal_run_death_test_flag_.reset(ParseInternalRunDeathTestFlag());
+  }
+  // Returns a pointer to the parsed --gtest_internal_run_death_test
+  // flag, or NULL if that flag was not specified.
+  // This information is useful only in a death test child process.
+  // Must not be called before a call to InitGoogleTest.
+  const InternalRunDeathTestFlag* internal_run_death_test_flag() const {
+    return internal_run_death_test_flag_.get();
+  }
+
+  // Returns a pointer to the current death test factory.
+  internal::DeathTestFactory* death_test_factory() {
+    return death_test_factory_.get();
+  }
+
+  void SuppressTestEventsIfInSubprocess();
+
+  friend class ReplaceDeathTestFactory;
+#endif  // GTEST_HAS_DEATH_TEST
+
+  // Initializes the event listener performing XML output as specified by
+  // UnitTestOptions. Must not be called before InitGoogleTest.
+  void ConfigureXmlOutput();
+
+#if GTEST_CAN_STREAM_RESULTS_
+  // Initializes the event listener for streaming test results to a socket.
+  // Must not be called before InitGoogleTest.
+  void ConfigureStreamingOutput();
+#endif
+
+  // Performs initialization dependent upon flag values obtained in
+  // ParseGoogleTestFlagsOnly.  Is called from InitGoogleTest after the call to
+  // ParseGoogleTestFlagsOnly.  In case a user neglects to call InitGoogleTest
+  // this function is also called from RunAllTests.  Since this function can be
+  // called more than once, it has to be idempotent.
+  void PostFlagParsingInit();
+
+  // Gets the random seed used at the start of the current test iteration.
+  int random_seed() const { return random_seed_; }
+
+  // Gets the random number generator.
+  internal::Random* random() { return &random_; }
+
+  // Shuffles all test suites, and the tests within each test suite,
+  // making sure that death tests are still run first.
+  void ShuffleTests();
+
+  // Restores the test suites and tests to their order before the first shuffle.
+  void UnshuffleTests();
+
+  // Returns the value of GTEST_FLAG(catch_exceptions) at the moment
+  // UnitTest::Run() starts.
+  bool catch_exceptions() const { return catch_exceptions_; }
+
+ private:
+  friend class ::testing::UnitTest;
+
+  // Used by UnitTest::Run() to capture the state of
+  // GTEST_FLAG(catch_exceptions) at the moment it starts.
+  void set_catch_exceptions(bool value) { catch_exceptions_ = value; }
+
+  // The UnitTest object that owns this implementation object.
+  UnitTest* const parent_;
+
+  // The working directory when the first TEST() or TEST_F() was
+  // executed.
+  internal::FilePath original_working_dir_;
+
+  // The default test part result reporters.
+  DefaultGlobalTestPartResultReporter default_global_test_part_result_reporter_;
+  DefaultPerThreadTestPartResultReporter
+      default_per_thread_test_part_result_reporter_;
+
+  // Points to (but doesn't own) the global test part result reporter.
+  TestPartResultReporterInterface* global_test_part_result_repoter_;
+
+  // Protects read and write access to global_test_part_result_reporter_.
+  internal::Mutex global_test_part_result_reporter_mutex_;
+
+  // Points to (but doesn't own) the per-thread test part result reporter.
+  internal::ThreadLocal<TestPartResultReporterInterface*>
+      per_thread_test_part_result_reporter_;
+
+  // The vector of environments that need to be set-up/torn-down
+  // before/after the tests are run.
+  std::vector<Environment*> environments_;
+
+  // The vector of TestSuites in their original order.  It owns the
+  // elements in the vector.
+  std::vector<TestSuite*> test_suites_;
+
+  // Provides a level of indirection for the test suite list to allow
+  // easy shuffling and restoring the test suite order.  The i-th
+  // element of this vector is the index of the i-th test suite in the
+  // shuffled order.
+  std::vector<int> test_suite_indices_;
+
+  // ParameterizedTestRegistry object used to register value-parameterized
+  // tests.
+  internal::ParameterizedTestSuiteRegistry parameterized_test_registry_;
+  internal::TypeParameterizedTestSuiteRegistry
+      type_parameterized_test_registry_;
+
+  // The set holding the name of parameterized
+  // test suites that may go uninstantiated.
+  std::set<std::string> ignored_parameterized_test_suites_;
+
+  // Indicates whether RegisterParameterizedTests() has been called already.
+  bool parameterized_tests_registered_;
+
+  // Index of the last death test suite registered.  Initially -1.
+  int last_death_test_suite_;
+
+  // This points to the TestSuite for the currently running test.  It
+  // changes as Google Test goes through one test suite after another.
+  // When no test is running, this is set to NULL and Google Test
+  // stores assertion results in ad_hoc_test_result_.  Initially NULL.
+  TestSuite* current_test_suite_;
+
+  // This points to the TestInfo for the currently running test.  It
+  // changes as Google Test goes through one test after another.  When
+  // no test is running, this is set to NULL and Google Test stores
+  // assertion results in ad_hoc_test_result_.  Initially NULL.
+  TestInfo* current_test_info_;
+
+  // Normally, a user only writes assertions inside a TEST or TEST_F,
+  // or inside a function called by a TEST or TEST_F.  Since Google
+  // Test keeps track of which test is current running, it can
+  // associate such an assertion with the test it belongs to.
+  //
+  // If an assertion is encountered when no TEST or TEST_F is running,
+  // Google Test attributes the assertion result to an imaginary "ad hoc"
+  // test, and records the result in ad_hoc_test_result_.
+  TestResult ad_hoc_test_result_;
+
+  // The list of event listeners that can be used to track events inside
+  // Google Test.
+  TestEventListeners listeners_;
+
+  // The OS stack trace getter.  Will be deleted when the UnitTest
+  // object is destructed.  By default, an OsStackTraceGetter is used,
+  // but the user can set this field to use a custom getter if that is
+  // desired.
+  OsStackTraceGetterInterface* os_stack_trace_getter_;
+
+  // True if and only if PostFlagParsingInit() has been called.
+  bool post_flag_parse_init_performed_;
+
+  // The random number seed used at the beginning of the test run.
+  int random_seed_;
+
+  // Our random number generator.
+  internal::Random random_;
+
+  // The time of the test program start, in ms from the start of the
+  // UNIX epoch.
+  TimeInMillis start_timestamp_;
+
+  // How long the test took to run, in milliseconds.
+  TimeInMillis elapsed_time_;
+
+#if GTEST_HAS_DEATH_TEST
+  // The decomposed components of the gtest_internal_run_death_test flag,
+  // parsed when RUN_ALL_TESTS is called.
+  std::unique_ptr<InternalRunDeathTestFlag> internal_run_death_test_flag_;
+  std::unique_ptr<internal::DeathTestFactory> death_test_factory_;
+#endif  // GTEST_HAS_DEATH_TEST
+
+  // A per-thread stack of traces created by the SCOPED_TRACE() macro.
+  internal::ThreadLocal<std::vector<TraceInfo> > gtest_trace_stack_;
+
+  // The value of GTEST_FLAG(catch_exceptions) at the moment RunAllTests()
+  // starts.
+  bool catch_exceptions_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(UnitTestImpl);
+};  // class UnitTestImpl
+
+// Convenience function for accessing the global UnitTest
+// implementation object.
+inline UnitTestImpl* GetUnitTestImpl() {
+  return UnitTest::GetInstance()->impl();
+}
+
+#if GTEST_USES_SIMPLE_RE
+
+// Internal helper functions for implementing the simple regular
+// expression matcher.
+GTEST_API_ bool IsInSet(char ch, const char* str);
+GTEST_API_ bool IsAsciiDigit(char ch);
+GTEST_API_ bool IsAsciiPunct(char ch);
+GTEST_API_ bool IsRepeat(char ch);
+GTEST_API_ bool IsAsciiWhiteSpace(char ch);
+GTEST_API_ bool IsAsciiWordChar(char ch);
+GTEST_API_ bool IsValidEscape(char ch);
+GTEST_API_ bool AtomMatchesChar(bool escaped, char pattern, char ch);
+GTEST_API_ bool ValidateRegex(const char* regex);
+GTEST_API_ bool MatchRegexAtHead(const char* regex, const char* str);
+GTEST_API_ bool MatchRepetitionAndRegexAtHead(
+    bool escaped, char ch, char repeat, const char* regex, const char* str);
+GTEST_API_ bool MatchRegexAnywhere(const char* regex, const char* str);
+
+#endif  // GTEST_USES_SIMPLE_RE
+
+// Parses the command line for Google Test flags, without initializing
+// other parts of Google Test.
+GTEST_API_ void ParseGoogleTestFlagsOnly(int* argc, char** argv);
+GTEST_API_ void ParseGoogleTestFlagsOnly(int* argc, wchar_t** argv);
+
+#if GTEST_HAS_DEATH_TEST
+
+// Returns the message describing the last system error, regardless of the
+// platform.
+GTEST_API_ std::string GetLastErrnoDescription();
+
+// Attempts to parse a string into a positive integer pointed to by the
+// number parameter.  Returns true if that is possible.
+// GTEST_HAS_DEATH_TEST implies that we have ::std::string, so we can use
+// it here.
+template <typename Integer>
+bool ParseNaturalNumber(const ::std::string& str, Integer* number) {
+  // Fail fast if the given string does not begin with a digit;
+  // this bypasses strtoXXX's "optional leading whitespace and plus
+  // or minus sign" semantics, which are undesirable here.
+  if (str.empty() || !IsDigit(str[0])) {
+    return false;
+  }
+  errno = 0;
+
+  char* end;
+  // BiggestConvertible is the largest integer type that system-provided
+  // string-to-number conversion routines can return.
+  using BiggestConvertible = unsigned long long;  // NOLINT
+
+  const BiggestConvertible parsed = strtoull(str.c_str(), &end, 10);  // NOLINT
+  const bool parse_success = *end == '\0' && errno == 0;
+
+  GTEST_CHECK_(sizeof(Integer) <= sizeof(parsed));
+
+  const Integer result = static_cast<Integer>(parsed);
+  if (parse_success && static_cast<BiggestConvertible>(result) == parsed) {
+    *number = result;
+    return true;
+  }
+  return false;
+}
+#endif  // GTEST_HAS_DEATH_TEST
+
+// TestResult contains some private methods that should be hidden from
+// Google Test user but are required for testing. This class allow our tests
+// to access them.
+//
+// This class is supplied only for the purpose of testing Google Test's own
+// constructs. Do not use it in user tests, either directly or indirectly.
+class TestResultAccessor {
+ public:
+  static void RecordProperty(TestResult* test_result,
+                             const std::string& xml_element,
+                             const TestProperty& property) {
+    test_result->RecordProperty(xml_element, property);
+  }
+
+  static void ClearTestPartResults(TestResult* test_result) {
+    test_result->ClearTestPartResults();
+  }
+
+  static const std::vector<testing::TestPartResult>& test_part_results(
+      const TestResult& test_result) {
+    return test_result.test_part_results();
+  }
+};
+
+#if GTEST_CAN_STREAM_RESULTS_
+
+// Streams test results to the given port on the given host machine.
+class StreamingListener : public EmptyTestEventListener {
+ public:
+  // Abstract base class for writing strings to a socket.
+  class AbstractSocketWriter {
+   public:
+    virtual ~AbstractSocketWriter() {}
+
+    // Sends a string to the socket.
+    virtual void Send(const std::string& message) = 0;
+
+    // Closes the socket.
+    virtual void CloseConnection() {}
+
+    // Sends a string and a newline to the socket.
+    void SendLn(const std::string& message) { Send(message + "\n"); }
+  };
+
+  // Concrete class for actually writing strings to a socket.
+  class SocketWriter : public AbstractSocketWriter {
+   public:
+    SocketWriter(const std::string& host, const std::string& port)
+        : sockfd_(-1), host_name_(host), port_num_(port) {
+      MakeConnection();
+    }
+
+    ~SocketWriter() override {
+      if (sockfd_ != -1)
+        CloseConnection();
+    }
+
+    // Sends a string to the socket.
+    void Send(const std::string& message) override {
+      GTEST_CHECK_(sockfd_ != -1)
+          << "Send() can be called only when there is a connection.";
+
+      const auto len = static_cast<size_t>(message.length());
+      if (write(sockfd_, message.c_str(), len) != static_cast<ssize_t>(len)) {
+        GTEST_LOG_(WARNING)
+            << "stream_result_to: failed to stream to "
+            << host_name_ << ":" << port_num_;
+      }
+    }
+
+   private:
+    // Creates a client socket and connects to the server.
+    void MakeConnection();
+
+    // Closes the socket.
+    void CloseConnection() override {
+      GTEST_CHECK_(sockfd_ != -1)
+          << "CloseConnection() can be called only when there is a connection.";
+
+      close(sockfd_);
+      sockfd_ = -1;
+    }
+
+    int sockfd_;  // socket file descriptor
+    const std::string host_name_;
+    const std::string port_num_;
+
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(SocketWriter);
+  };  // class SocketWriter
+
+  // Escapes '=', '&', '%', and '\n' characters in str as "%xx".
+  static std::string UrlEncode(const char* str);
+
+  StreamingListener(const std::string& host, const std::string& port)
+      : socket_writer_(new SocketWriter(host, port)) {
+    Start();
+  }
+
+  explicit StreamingListener(AbstractSocketWriter* socket_writer)
+      : socket_writer_(socket_writer) { Start(); }
+
+  void OnTestProgramStart(const UnitTest& /* unit_test */) override {
+    SendLn("event=TestProgramStart");
+  }
+
+  void OnTestProgramEnd(const UnitTest& unit_test) override {
+    // Note that Google Test current only report elapsed time for each
+    // test iteration, not for the entire test program.
+    SendLn("event=TestProgramEnd&passed=" + FormatBool(unit_test.Passed()));
+
+    // Notify the streaming server to stop.
+    socket_writer_->CloseConnection();
+  }
+
+  void OnTestIterationStart(const UnitTest& /* unit_test */,
+                            int iteration) override {
+    SendLn("event=TestIterationStart&iteration=" +
+           StreamableToString(iteration));
+  }
+
+  void OnTestIterationEnd(const UnitTest& unit_test,
+                          int /* iteration */) override {
+    SendLn("event=TestIterationEnd&passed=" +
+           FormatBool(unit_test.Passed()) + "&elapsed_time=" +
+           StreamableToString(unit_test.elapsed_time()) + "ms");
+  }
+
+  // Note that "event=TestCaseStart" is a wire format and has to remain
+  // "case" for compatibility
+  void OnTestCaseStart(const TestCase& test_case) override {
+    SendLn(std::string("event=TestCaseStart&name=") + test_case.name());
+  }
+
+  // Note that "event=TestCaseEnd" is a wire format and has to remain
+  // "case" for compatibility
+  void OnTestCaseEnd(const TestCase& test_case) override {
+    SendLn("event=TestCaseEnd&passed=" + FormatBool(test_case.Passed()) +
+           "&elapsed_time=" + StreamableToString(test_case.elapsed_time()) +
+           "ms");
+  }
+
+  void OnTestStart(const TestInfo& test_info) override {
+    SendLn(std::string("event=TestStart&name=") + test_info.name());
+  }
+
+  void OnTestEnd(const TestInfo& test_info) override {
+    SendLn("event=TestEnd&passed=" +
+           FormatBool((test_info.result())->Passed()) +
+           "&elapsed_time=" +
+           StreamableToString((test_info.result())->elapsed_time()) + "ms");
+  }
+
+  void OnTestPartResult(const TestPartResult& test_part_result) override {
+    const char* file_name = test_part_result.file_name();
+    if (file_name == nullptr) file_name = "";
+    SendLn("event=TestPartResult&file=" + UrlEncode(file_name) +
+           "&line=" + StreamableToString(test_part_result.line_number()) +
+           "&message=" + UrlEncode(test_part_result.message()));
+  }
+
+ private:
+  // Sends the given message and a newline to the socket.
+  void SendLn(const std::string& message) { socket_writer_->SendLn(message); }
+
+  // Called at the start of streaming to notify the receiver what
+  // protocol we are using.
+  void Start() { SendLn("gtest_streaming_protocol_version=1.0"); }
+
+  std::string FormatBool(bool value) { return value ? "1" : "0"; }
+
+  const std::unique_ptr<AbstractSocketWriter> socket_writer_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(StreamingListener);
+};  // class StreamingListener
+
+#endif  // GTEST_CAN_STREAM_RESULTS_
+
+}  // namespace internal
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+#endif  // GOOGLETEST_SRC_GTEST_INTERNAL_INL_H_
+
+#if GTEST_OS_WINDOWS
+# define vsnprintf _vsnprintf
+#endif  // GTEST_OS_WINDOWS
+
+#if GTEST_OS_MAC
+#ifndef GTEST_OS_IOS
+#include <crt_externs.h>
+#endif
+#endif
+
+#if GTEST_HAS_ABSL
+#include "absl/debugging/failure_signal_handler.h"
+#include "absl/debugging/stacktrace.h"
+#include "absl/debugging/symbolize.h"
+#include "absl/strings/str_cat.h"
+#endif  // GTEST_HAS_ABSL
+
+namespace testing {
+
+using internal::CountIf;
+using internal::ForEach;
+using internal::GetElementOr;
+using internal::Shuffle;
+
+// Constants.
+
+// A test whose test suite name or test name matches this filter is
+// disabled and not run.
+static const char kDisableTestFilter[] = "DISABLED_*:*/DISABLED_*";
+
+// A test suite whose name matches this filter is considered a death
+// test suite and will be run before test suites whose name doesn't
+// match this filter.
+static const char kDeathTestSuiteFilter[] = "*DeathTest:*DeathTest/*";
+
+// A test filter that matches everything.
+static const char kUniversalFilter[] = "*";
+
+// The default output format.
+static const char kDefaultOutputFormat[] = "xml";
+// The default output file.
+static const char kDefaultOutputFile[] = "test_detail";
+
+// The environment variable name for the test shard index.
+static const char kTestShardIndex[] = "GTEST_SHARD_INDEX";
+// The environment variable name for the total number of test shards.
+static const char kTestTotalShards[] = "GTEST_TOTAL_SHARDS";
+// The environment variable name for the test shard status file.
+static const char kTestShardStatusFile[] = "GTEST_SHARD_STATUS_FILE";
+
+namespace internal {
+
+// The text used in failure messages to indicate the start of the
+// stack trace.
+const char kStackTraceMarker[] = "\nStack trace:\n";
+
+// g_help_flag is true if and only if the --help flag or an equivalent form
+// is specified on the command line.
+bool g_help_flag = false;
+
+// Utilty function to Open File for Writing
+static FILE* OpenFileForWriting(const std::string& output_file) {
+  FILE* fileout = nullptr;
+  FilePath output_file_path(output_file);
+  FilePath output_dir(output_file_path.RemoveFileName());
+
+  if (output_dir.CreateDirectoriesRecursively()) {
+    fileout = posix::FOpen(output_file.c_str(), "w");
+  }
+  if (fileout == nullptr) {
+    GTEST_LOG_(FATAL) << "Unable to open file \"" << output_file << "\"";
+  }
+  return fileout;
+}
+
+}  // namespace internal
+
+// Bazel passes in the argument to '--test_filter' via the TESTBRIDGE_TEST_ONLY
+// environment variable.
+static const char* GetDefaultFilter() {
+  const char* const testbridge_test_only =
+      internal::posix::GetEnv("TESTBRIDGE_TEST_ONLY");
+  if (testbridge_test_only != nullptr) {
+    return testbridge_test_only;
+  }
+  return kUniversalFilter;
+}
+
+// Bazel passes in the argument to '--test_runner_fail_fast' via the
+// TESTBRIDGE_TEST_RUNNER_FAIL_FAST environment variable.
+static bool GetDefaultFailFast() {
+  const char* const testbridge_test_runner_fail_fast =
+      internal::posix::GetEnv("TESTBRIDGE_TEST_RUNNER_FAIL_FAST");
+  if (testbridge_test_runner_fail_fast != nullptr) {
+    return strcmp(testbridge_test_runner_fail_fast, "1") == 0;
+  }
+  return false;
+}
+
+GTEST_DEFINE_bool_(
+    fail_fast, internal::BoolFromGTestEnv("fail_fast", GetDefaultFailFast()),
+    "True if and only if a test failure should stop further test execution.");
+
+GTEST_DEFINE_bool_(
+    also_run_disabled_tests,
+    internal::BoolFromGTestEnv("also_run_disabled_tests", false),
+    "Run disabled tests too, in addition to the tests normally being run.");
+
+GTEST_DEFINE_bool_(
+    break_on_failure, internal::BoolFromGTestEnv("break_on_failure", false),
+    "True if and only if a failed assertion should be a debugger "
+    "break-point.");
+
+GTEST_DEFINE_bool_(catch_exceptions,
+                   internal::BoolFromGTestEnv("catch_exceptions", true),
+                   "True if and only if " GTEST_NAME_
+                   " should catch exceptions and treat them as test failures.");
+
+GTEST_DEFINE_string_(
+    color,
+    internal::StringFromGTestEnv("color", "auto"),
+    "Whether to use colors in the output.  Valid values: yes, no, "
+    "and auto.  'auto' means to use colors if the output is "
+    "being sent to a terminal and the TERM environment variable "
+    "is set to a terminal type that supports colors.");
+
+GTEST_DEFINE_string_(
+    filter,
+    internal::StringFromGTestEnv("filter", GetDefaultFilter()),
+    "A colon-separated list of glob (not regex) patterns "
+    "for filtering the tests to run, optionally followed by a "
+    "'-' and a : separated list of negative patterns (tests to "
+    "exclude).  A test is run if it matches one of the positive "
+    "patterns and does not match any of the negative patterns.");
+
+GTEST_DEFINE_bool_(
+    install_failure_signal_handler,
+    internal::BoolFromGTestEnv("install_failure_signal_handler", false),
+    "If true and supported on the current platform, " GTEST_NAME_ " should "
+    "install a signal handler that dumps debugging information when fatal "
+    "signals are raised.");
+
+GTEST_DEFINE_bool_(list_tests, false,
+                   "List all tests without running them.");
+
+// The net priority order after flag processing is thus:
+//   --gtest_output command line flag
+//   GTEST_OUTPUT environment variable
+//   XML_OUTPUT_FILE environment variable
+//   ''
+GTEST_DEFINE_string_(
+    output,
+    internal::StringFromGTestEnv("output",
+      internal::OutputFlagAlsoCheckEnvVar().c_str()),
+    "A format (defaults to \"xml\" but can be specified to be \"json\"), "
+    "optionally followed by a colon and an output file name or directory. "
+    "A directory is indicated by a trailing pathname separator. "
+    "Examples: \"xml:filename.xml\", \"xml::directoryname/\". "
+    "If a directory is specified, output files will be created "
+    "within that directory, with file-names based on the test "
+    "executable's name and, if necessary, made unique by adding "
+    "digits.");
+
+GTEST_DEFINE_bool_(
+    brief, internal::BoolFromGTestEnv("brief", false),
+    "True if only test failures should be displayed in text output.");
+
+GTEST_DEFINE_bool_(print_time, internal::BoolFromGTestEnv("print_time", true),
+                   "True if and only if " GTEST_NAME_
+                   " should display elapsed time in text output.");
+
+GTEST_DEFINE_bool_(print_utf8, internal::BoolFromGTestEnv("print_utf8", true),
+                   "True if and only if " GTEST_NAME_
+                   " prints UTF8 characters as text.");
+
+GTEST_DEFINE_int32_(
+    random_seed,
+    internal::Int32FromGTestEnv("random_seed", 0),
+    "Random number seed to use when shuffling test orders.  Must be in range "
+    "[1, 99999], or 0 to use a seed based on the current time.");
+
+GTEST_DEFINE_int32_(
+    repeat,
+    internal::Int32FromGTestEnv("repeat", 1),
+    "How many times to repeat each test.  Specify a negative number "
+    "for repeating forever.  Useful for shaking out flaky tests.");
+
+GTEST_DEFINE_bool_(show_internal_stack_frames, false,
+                   "True if and only if " GTEST_NAME_
+                   " should include internal stack frames when "
+                   "printing test failure stack traces.");
+
+GTEST_DEFINE_bool_(shuffle, internal::BoolFromGTestEnv("shuffle", false),
+                   "True if and only if " GTEST_NAME_
+                   " should randomize tests' order on every run.");
+
+GTEST_DEFINE_int32_(
+    stack_trace_depth,
+    internal::Int32FromGTestEnv("stack_trace_depth", kMaxStackTraceDepth),
+    "The maximum number of stack frames to print when an "
+    "assertion fails.  The valid range is 0 through 100, inclusive.");
+
+GTEST_DEFINE_string_(
+    stream_result_to,
+    internal::StringFromGTestEnv("stream_result_to", ""),
+    "This flag specifies the host name and the port number on which to stream "
+    "test results. Example: \"localhost:555\". The flag is effective only on "
+    "Linux.");
+
+GTEST_DEFINE_bool_(
+    throw_on_failure,
+    internal::BoolFromGTestEnv("throw_on_failure", false),
+    "When this flag is specified, a failed assertion will throw an exception "
+    "if exceptions are enabled or exit the program with a non-zero code "
+    "otherwise. For use with an external test framework.");
+
+#if GTEST_USE_OWN_FLAGFILE_FLAG_
+GTEST_DEFINE_string_(
+    flagfile,
+    internal::StringFromGTestEnv("flagfile", ""),
+    "This flag specifies the flagfile to read command-line flags from.");
+#endif  // GTEST_USE_OWN_FLAGFILE_FLAG_
+
+namespace internal {
+
+// Generates a random number from [0, range), using a Linear
+// Congruential Generator (LCG).  Crashes if 'range' is 0 or greater
+// than kMaxRange.
+uint32_t Random::Generate(uint32_t range) {
+  // These constants are the same as are used in glibc's rand(3).
+  // Use wider types than necessary to prevent unsigned overflow diagnostics.
+  state_ = static_cast<uint32_t>(1103515245ULL*state_ + 12345U) % kMaxRange;
+
+  GTEST_CHECK_(range > 0)
+      << "Cannot generate a number in the range [0, 0).";
+  GTEST_CHECK_(range <= kMaxRange)
+      << "Generation of a number in [0, " << range << ") was requested, "
+      << "but this can only generate numbers in [0, " << kMaxRange << ").";
+
+  // Converting via modulus introduces a bit of downward bias, but
+  // it's simple, and a linear congruential generator isn't too good
+  // to begin with.
+  return state_ % range;
+}
+
+// GTestIsInitialized() returns true if and only if the user has initialized
+// Google Test.  Useful for catching the user mistake of not initializing
+// Google Test before calling RUN_ALL_TESTS().
+static bool GTestIsInitialized() { return GetArgvs().size() > 0; }
+
+// Iterates over a vector of TestSuites, keeping a running sum of the
+// results of calling a given int-returning method on each.
+// Returns the sum.
+static int SumOverTestSuiteList(const std::vector<TestSuite*>& case_list,
+                                int (TestSuite::*method)() const) {
+  int sum = 0;
+  for (size_t i = 0; i < case_list.size(); i++) {
+    sum += (case_list[i]->*method)();
+  }
+  return sum;
+}
+
+// Returns true if and only if the test suite passed.
+static bool TestSuitePassed(const TestSuite* test_suite) {
+  return test_suite->should_run() && test_suite->Passed();
+}
+
+// Returns true if and only if the test suite failed.
+static bool TestSuiteFailed(const TestSuite* test_suite) {
+  return test_suite->should_run() && test_suite->Failed();
+}
+
+// Returns true if and only if test_suite contains at least one test that
+// should run.
+static bool ShouldRunTestSuite(const TestSuite* test_suite) {
+  return test_suite->should_run();
+}
+
+// AssertHelper constructor.
+AssertHelper::AssertHelper(TestPartResult::Type type,
+                           const char* file,
+                           int line,
+                           const char* message)
+    : data_(new AssertHelperData(type, file, line, message)) {
+}
+
+AssertHelper::~AssertHelper() {
+  delete data_;
+}
+
+// Message assignment, for assertion streaming support.
+void AssertHelper::operator=(const Message& message) const {
+  UnitTest::GetInstance()->
+    AddTestPartResult(data_->type, data_->file, data_->line,
+                      AppendUserMessage(data_->message, message),
+                      UnitTest::GetInstance()->impl()
+                      ->CurrentOsStackTraceExceptTop(1)
+                      // Skips the stack frame for this function itself.
+                      );  // NOLINT
+}
+
+namespace {
+
+// When TEST_P is found without a matching INSTANTIATE_TEST_SUITE_P
+// to creates test cases for it, a syntetic test case is
+// inserted to report ether an error or a log message.
+//
+// This configuration bit will likely be removed at some point.
+constexpr bool kErrorOnUninstantiatedParameterizedTest = true;
+constexpr bool kErrorOnUninstantiatedTypeParameterizedTest = true;
+
+// A test that fails at a given file/line location with a given message.
+class FailureTest : public Test {
+ public:
+  explicit FailureTest(const CodeLocation& loc, std::string error_message,
+                       bool as_error)
+      : loc_(loc),
+        error_message_(std::move(error_message)),
+        as_error_(as_error) {}
+
+  void TestBody() override {
+    if (as_error_) {
+      AssertHelper(TestPartResult::kNonFatalFailure, loc_.file.c_str(),
+                   loc_.line, "") = Message() << error_message_;
+    } else {
+      std::cout << error_message_ << std::endl;
+    }
+  }
+
+ private:
+  const CodeLocation loc_;
+  const std::string error_message_;
+  const bool as_error_;
+};
+
+
+}  // namespace
+
+std::set<std::string>* GetIgnoredParameterizedTestSuites() {
+  return UnitTest::GetInstance()->impl()->ignored_parameterized_test_suites();
+}
+
+// Add a given test_suit to the list of them allow to go un-instantiated.
+MarkAsIgnored::MarkAsIgnored(const char* test_suite) {
+  GetIgnoredParameterizedTestSuites()->insert(test_suite);
+}
+
+// If this parameterized test suite has no instantiations (and that
+// has not been marked as okay), emit a test case reporting that.
+void InsertSyntheticTestCase(const std::string& name, CodeLocation location,
+                             bool has_test_p) {
+  const auto& ignored = *GetIgnoredParameterizedTestSuites();
+  if (ignored.find(name) != ignored.end()) return;
+
+  const char kMissingInstantiation[] =  //
+      " is defined via TEST_P, but never instantiated. None of the test cases "
+      "will run. Either no INSTANTIATE_TEST_SUITE_P is provided or the only "
+      "ones provided expand to nothing."
+      "\n\n"
+      "Ideally, TEST_P definitions should only ever be included as part of "
+      "binaries that intend to use them. (As opposed to, for example, being "
+      "placed in a library that may be linked in to get other utilities.)";
+
+  const char kMissingTestCase[] =  //
+      " is instantiated via INSTANTIATE_TEST_SUITE_P, but no tests are "
+      "defined via TEST_P . No test cases will run."
+      "\n\n"
+      "Ideally, INSTANTIATE_TEST_SUITE_P should only ever be invoked from "
+      "code that always depend on code that provides TEST_P. Failing to do "
+      "so is often an indication of dead code, e.g. the last TEST_P was "
+      "removed but the rest got left behind.";
+
+  std::string message =
+      "Parameterized test suite " + name +
+      (has_test_p ? kMissingInstantiation : kMissingTestCase) +
+      "\n\n"
+      "To suppress this error for this test suite, insert the following line "
+      "(in a non-header) in the namespace it is defined in:"
+      "\n\n"
+      "GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(" + name + ");";
+
+  std::string full_name = "UninstantiatedParameterizedTestSuite<" + name + ">";
+  RegisterTest(  //
+      "GoogleTestVerification", full_name.c_str(),
+      nullptr,  // No type parameter.
+      nullptr,  // No value parameter.
+      location.file.c_str(), location.line, [message, location] {
+        return new FailureTest(location, message,
+                               kErrorOnUninstantiatedParameterizedTest);
+      });
+}
+
+void RegisterTypeParameterizedTestSuite(const char* test_suite_name,
+                                        CodeLocation code_location) {
+  GetUnitTestImpl()->type_parameterized_test_registry().RegisterTestSuite(
+      test_suite_name, code_location);
+}
+
+void RegisterTypeParameterizedTestSuiteInstantiation(const char* case_name) {
+  GetUnitTestImpl()
+      ->type_parameterized_test_registry()
+      .RegisterInstantiation(case_name);
+}
+
+void TypeParameterizedTestSuiteRegistry::RegisterTestSuite(
+    const char* test_suite_name, CodeLocation code_location) {
+  suites_.emplace(std::string(test_suite_name),
+                 TypeParameterizedTestSuiteInfo(code_location));
+}
+
+void TypeParameterizedTestSuiteRegistry::RegisterInstantiation(
+        const char* test_suite_name) {
+  auto it = suites_.find(std::string(test_suite_name));
+  if (it != suites_.end()) {
+    it->second.instantiated = true;
+  } else {
+    GTEST_LOG_(ERROR) << "Unknown type parameterized test suit '"
+                      << test_suite_name << "'";
+  }
+}
+
+void TypeParameterizedTestSuiteRegistry::CheckForInstantiations() {
+  const auto& ignored = *GetIgnoredParameterizedTestSuites();
+  for (const auto& testcase : suites_) {
+    if (testcase.second.instantiated) continue;
+    if (ignored.find(testcase.first) != ignored.end()) continue;
+
+    std::string message =
+        "Type parameterized test suite " + testcase.first +
+        " is defined via REGISTER_TYPED_TEST_SUITE_P, but never instantiated "
+        "via INSTANTIATE_TYPED_TEST_SUITE_P. None of the test cases will run."
+        "\n\n"
+        "Ideally, TYPED_TEST_P definitions should only ever be included as "
+        "part of binaries that intend to use them. (As opposed to, for "
+        "example, being placed in a library that may be linked in to get other "
+        "utilities.)"
+        "\n\n"
+        "To suppress this error for this test suite, insert the following line "
+        "(in a non-header) in the namespace it is defined in:"
+        "\n\n"
+        "GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(" +
+        testcase.first + ");";
+
+    std::string full_name =
+        "UninstantiatedTypeParameterizedTestSuite<" + testcase.first + ">";
+    RegisterTest(  //
+        "GoogleTestVerification", full_name.c_str(),
+        nullptr,  // No type parameter.
+        nullptr,  // No value parameter.
+        testcase.second.code_location.file.c_str(),
+        testcase.second.code_location.line, [message, testcase] {
+          return new FailureTest(testcase.second.code_location, message,
+                                 kErrorOnUninstantiatedTypeParameterizedTest);
+        });
+  }
+}
+
+// A copy of all command line arguments.  Set by InitGoogleTest().
+static ::std::vector<std::string> g_argvs;
+
+::std::vector<std::string> GetArgvs() {
+#if defined(GTEST_CUSTOM_GET_ARGVS_)
+  // GTEST_CUSTOM_GET_ARGVS_() may return a container of std::string or
+  // ::string. This code converts it to the appropriate type.
+  const auto& custom = GTEST_CUSTOM_GET_ARGVS_();
+  return ::std::vector<std::string>(custom.begin(), custom.end());
+#else   // defined(GTEST_CUSTOM_GET_ARGVS_)
+  return g_argvs;
+#endif  // defined(GTEST_CUSTOM_GET_ARGVS_)
+}
+
+// Returns the current application's name, removing directory path if that
+// is present.
+FilePath GetCurrentExecutableName() {
+  FilePath result;
+
+#if GTEST_OS_WINDOWS || GTEST_OS_OS2
+  result.Set(FilePath(GetArgvs()[0]).RemoveExtension("exe"));
+#else
+  result.Set(FilePath(GetArgvs()[0]));
+#endif  // GTEST_OS_WINDOWS
+
+  return result.RemoveDirectoryName();
+}
+
+// Functions for processing the gtest_output flag.
+
+// Returns the output format, or "" for normal printed output.
+std::string UnitTestOptions::GetOutputFormat() {
+  const char* const gtest_output_flag = GTEST_FLAG(output).c_str();
+  const char* const colon = strchr(gtest_output_flag, ':');
+  return (colon == nullptr)
+             ? std::string(gtest_output_flag)
+             : std::string(gtest_output_flag,
+                           static_cast<size_t>(colon - gtest_output_flag));
+}
+
+// Returns the name of the requested output file, or the default if none
+// was explicitly specified.
+std::string UnitTestOptions::GetAbsolutePathToOutputFile() {
+  const char* const gtest_output_flag = GTEST_FLAG(output).c_str();
+
+  std::string format = GetOutputFormat();
+  if (format.empty())
+    format = std::string(kDefaultOutputFormat);
+
+  const char* const colon = strchr(gtest_output_flag, ':');
+  if (colon == nullptr)
+    return internal::FilePath::MakeFileName(
+        internal::FilePath(
+            UnitTest::GetInstance()->original_working_dir()),
+        internal::FilePath(kDefaultOutputFile), 0,
+        format.c_str()).string();
+
+  internal::FilePath output_name(colon + 1);
+  if (!output_name.IsAbsolutePath())
+    output_name = internal::FilePath::ConcatPaths(
+        internal::FilePath(UnitTest::GetInstance()->original_working_dir()),
+        internal::FilePath(colon + 1));
+
+  if (!output_name.IsDirectory())
+    return output_name.string();
+
+  internal::FilePath result(internal::FilePath::GenerateUniqueFileName(
+      output_name, internal::GetCurrentExecutableName(),
+      GetOutputFormat().c_str()));
+  return result.string();
+}
+
+// Returns true if and only if the wildcard pattern matches the string. Each
+// pattern consists of regular characters, single-character wildcards (?), and
+// multi-character wildcards (*).
+//
+// This function implements a linear-time string globbing algorithm based on
+// https://research.swtch.com/glob.
+static bool PatternMatchesString(const std::string& name_str,
+                                 const char* pattern, const char* pattern_end) {
+  const char* name = name_str.c_str();
+  const char* const name_begin = name;
+  const char* const name_end = name + name_str.size();
+
+  const char* pattern_next = pattern;
+  const char* name_next = name;
+
+  while (pattern < pattern_end || name < name_end) {
+    if (pattern < pattern_end) {
+      switch (*pattern) {
+        default:  // Match an ordinary character.
+          if (name < name_end && *name == *pattern) {
+            ++pattern;
+            ++name;
+            continue;
+          }
+          break;
+        case '?':  // Match any single character.
+          if (name < name_end) {
+            ++pattern;
+            ++name;
+            continue;
+          }
+          break;
+        case '*':
+          // Match zero or more characters. Start by skipping over the wildcard
+          // and matching zero characters from name. If that fails, restart and
+          // match one more character than the last attempt.
+          pattern_next = pattern;
+          name_next = name + 1;
+          ++pattern;
+          continue;
+      }
+    }
+    // Failed to match a character. Restart if possible.
+    if (name_begin < name_next && name_next <= name_end) {
+      pattern = pattern_next;
+      name = name_next;
+      continue;
+    }
+    return false;
+  }
+  return true;
+}
+
+bool UnitTestOptions::MatchesFilter(const std::string& name_str,
+                                    const char* filter) {
+  // The filter is a list of patterns separated by colons (:).
+  const char* pattern = filter;
+  while (true) {
+    // Find the bounds of this pattern.
+    const char* const next_sep = strchr(pattern, ':');
+    const char* const pattern_end =
+        next_sep != nullptr ? next_sep : pattern + strlen(pattern);
+
+    // Check if this pattern matches name_str.
+    if (PatternMatchesString(name_str, pattern, pattern_end)) {
+      break;
+    }
+
+    // Give up on this pattern. However, if we found a pattern separator (:),
+    // advance to the next pattern (skipping over the separator) and restart.
+    if (next_sep == nullptr) {
+      return false;
+    }
+    pattern = next_sep + 1;
+  }
+  return true;
+}
+
+// Returns true if and only if the user-specified filter matches the test
+// suite name and the test name.
+bool UnitTestOptions::FilterMatchesTest(const std::string& test_suite_name,
+                                        const std::string& test_name) {
+  const std::string& full_name = test_suite_name + "." + test_name.c_str();
+
+  // Split --gtest_filter at '-', if there is one, to separate into
+  // positive filter and negative filter portions
+  const char* const p = GTEST_FLAG(filter).c_str();
+  const char* const dash = strchr(p, '-');
+  std::string positive;
+  std::string negative;
+  if (dash == nullptr) {
+    positive = GTEST_FLAG(filter).c_str();  // Whole string is a positive filter
+    negative = "";
+  } else {
+    positive = std::string(p, dash);   // Everything up to the dash
+    negative = std::string(dash + 1);  // Everything after the dash
+    if (positive.empty()) {
+      // Treat '-test1' as the same as '*-test1'
+      positive = kUniversalFilter;
+    }
+  }
+
+  // A filter is a colon-separated list of patterns.  It matches a
+  // test if any pattern in it matches the test.
+  return (MatchesFilter(full_name, positive.c_str()) &&
+          !MatchesFilter(full_name, negative.c_str()));
+}
+
+#if GTEST_HAS_SEH
+// Returns EXCEPTION_EXECUTE_HANDLER if Google Test should handle the
+// given SEH exception, or EXCEPTION_CONTINUE_SEARCH otherwise.
+// This function is useful as an __except condition.
+int UnitTestOptions::GTestShouldProcessSEH(DWORD exception_code) {
+  // Google Test should handle a SEH exception if:
+  //   1. the user wants it to, AND
+  //   2. this is not a breakpoint exception, AND
+  //   3. this is not a C++ exception (VC++ implements them via SEH,
+  //      apparently).
+  //
+  // SEH exception code for C++ exceptions.
+  // (see http://support.microsoft.com/kb/185294 for more information).
+  const DWORD kCxxExceptionCode = 0xe06d7363;
+
+  bool should_handle = true;
+
+  if (!GTEST_FLAG(catch_exceptions))
+    should_handle = false;
+  else if (exception_code == EXCEPTION_BREAKPOINT)
+    should_handle = false;
+  else if (exception_code == kCxxExceptionCode)
+    should_handle = false;
+
+  return should_handle ? EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH;
+}
+#endif  // GTEST_HAS_SEH
+
+}  // namespace internal
+
+// The c'tor sets this object as the test part result reporter used by
+// Google Test.  The 'result' parameter specifies where to report the
+// results. Intercepts only failures from the current thread.
+ScopedFakeTestPartResultReporter::ScopedFakeTestPartResultReporter(
+    TestPartResultArray* result)
+    : intercept_mode_(INTERCEPT_ONLY_CURRENT_THREAD),
+      result_(result) {
+  Init();
+}
+
+// The c'tor sets this object as the test part result reporter used by
+// Google Test.  The 'result' parameter specifies where to report the
+// results.
+ScopedFakeTestPartResultReporter::ScopedFakeTestPartResultReporter(
+    InterceptMode intercept_mode, TestPartResultArray* result)
+    : intercept_mode_(intercept_mode),
+      result_(result) {
+  Init();
+}
+
+void ScopedFakeTestPartResultReporter::Init() {
+  internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
+  if (intercept_mode_ == INTERCEPT_ALL_THREADS) {
+    old_reporter_ = impl->GetGlobalTestPartResultReporter();
+    impl->SetGlobalTestPartResultReporter(this);
+  } else {
+    old_reporter_ = impl->GetTestPartResultReporterForCurrentThread();
+    impl->SetTestPartResultReporterForCurrentThread(this);
+  }
+}
+
+// The d'tor restores the test part result reporter used by Google Test
+// before.
+ScopedFakeTestPartResultReporter::~ScopedFakeTestPartResultReporter() {
+  internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
+  if (intercept_mode_ == INTERCEPT_ALL_THREADS) {
+    impl->SetGlobalTestPartResultReporter(old_reporter_);
+  } else {
+    impl->SetTestPartResultReporterForCurrentThread(old_reporter_);
+  }
+}
+
+// Increments the test part result count and remembers the result.
+// This method is from the TestPartResultReporterInterface interface.
+void ScopedFakeTestPartResultReporter::ReportTestPartResult(
+    const TestPartResult& result) {
+  result_->Append(result);
+}
+
+namespace internal {
+
+// Returns the type ID of ::testing::Test.  We should always call this
+// instead of GetTypeId< ::testing::Test>() to get the type ID of
+// testing::Test.  This is to work around a suspected linker bug when
+// using Google Test as a framework on Mac OS X.  The bug causes
+// GetTypeId< ::testing::Test>() to return different values depending
+// on whether the call is from the Google Test framework itself or
+// from user test code.  GetTestTypeId() is guaranteed to always
+// return the same value, as it always calls GetTypeId<>() from the
+// gtest.cc, which is within the Google Test framework.
+TypeId GetTestTypeId() {
+  return GetTypeId<Test>();
+}
+
+// The value of GetTestTypeId() as seen from within the Google Test
+// library.  This is solely for testing GetTestTypeId().
+extern const TypeId kTestTypeIdInGoogleTest = GetTestTypeId();
+
+// This predicate-formatter checks that 'results' contains a test part
+// failure of the given type and that the failure message contains the
+// given substring.
+static AssertionResult HasOneFailure(const char* /* results_expr */,
+                                     const char* /* type_expr */,
+                                     const char* /* substr_expr */,
+                                     const TestPartResultArray& results,
+                                     TestPartResult::Type type,
+                                     const std::string& substr) {
+  const std::string expected(type == TestPartResult::kFatalFailure ?
+                        "1 fatal failure" :
+                        "1 non-fatal failure");
+  Message msg;
+  if (results.size() != 1) {
+    msg << "Expected: " << expected << "\n"
+        << "  Actual: " << results.size() << " failures";
+    for (int i = 0; i < results.size(); i++) {
+      msg << "\n" << results.GetTestPartResult(i);
+    }
+    return AssertionFailure() << msg;
+  }
+
+  const TestPartResult& r = results.GetTestPartResult(0);
+  if (r.type() != type) {
+    return AssertionFailure() << "Expected: " << expected << "\n"
+                              << "  Actual:\n"
+                              << r;
+  }
+
+  if (strstr(r.message(), substr.c_str()) == nullptr) {
+    return AssertionFailure() << "Expected: " << expected << " containing \""
+                              << substr << "\"\n"
+                              << "  Actual:\n"
+                              << r;
+  }
+
+  return AssertionSuccess();
+}
+
+// The constructor of SingleFailureChecker remembers where to look up
+// test part results, what type of failure we expect, and what
+// substring the failure message should contain.
+SingleFailureChecker::SingleFailureChecker(const TestPartResultArray* results,
+                                           TestPartResult::Type type,
+                                           const std::string& substr)
+    : results_(results), type_(type), substr_(substr) {}
+
+// The destructor of SingleFailureChecker verifies that the given
+// TestPartResultArray contains exactly one failure that has the given
+// type and contains the given substring.  If that's not the case, a
+// non-fatal failure will be generated.
+SingleFailureChecker::~SingleFailureChecker() {
+  EXPECT_PRED_FORMAT3(HasOneFailure, *results_, type_, substr_);
+}
+
+DefaultGlobalTestPartResultReporter::DefaultGlobalTestPartResultReporter(
+    UnitTestImpl* unit_test) : unit_test_(unit_test) {}
+
+void DefaultGlobalTestPartResultReporter::ReportTestPartResult(
+    const TestPartResult& result) {
+  unit_test_->current_test_result()->AddTestPartResult(result);
+  unit_test_->listeners()->repeater()->OnTestPartResult(result);
+}
+
+DefaultPerThreadTestPartResultReporter::DefaultPerThreadTestPartResultReporter(
+    UnitTestImpl* unit_test) : unit_test_(unit_test) {}
+
+void DefaultPerThreadTestPartResultReporter::ReportTestPartResult(
+    const TestPartResult& result) {
+  unit_test_->GetGlobalTestPartResultReporter()->ReportTestPartResult(result);
+}
+
+// Returns the global test part result reporter.
+TestPartResultReporterInterface*
+UnitTestImpl::GetGlobalTestPartResultReporter() {
+  internal::MutexLock lock(&global_test_part_result_reporter_mutex_);
+  return global_test_part_result_repoter_;
+}
+
+// Sets the global test part result reporter.
+void UnitTestImpl::SetGlobalTestPartResultReporter(
+    TestPartResultReporterInterface* reporter) {
+  internal::MutexLock lock(&global_test_part_result_reporter_mutex_);
+  global_test_part_result_repoter_ = reporter;
+}
+
+// Returns the test part result reporter for the current thread.
+TestPartResultReporterInterface*
+UnitTestImpl::GetTestPartResultReporterForCurrentThread() {
+  return per_thread_test_part_result_reporter_.get();
+}
+
+// Sets the test part result reporter for the current thread.
+void UnitTestImpl::SetTestPartResultReporterForCurrentThread(
+    TestPartResultReporterInterface* reporter) {
+  per_thread_test_part_result_reporter_.set(reporter);
+}
+
+// Gets the number of successful test suites.
+int UnitTestImpl::successful_test_suite_count() const {
+  return CountIf(test_suites_, TestSuitePassed);
+}
+
+// Gets the number of failed test suites.
+int UnitTestImpl::failed_test_suite_count() const {
+  return CountIf(test_suites_, TestSuiteFailed);
+}
+
+// Gets the number of all test suites.
+int UnitTestImpl::total_test_suite_count() const {
+  return static_cast<int>(test_suites_.size());
+}
+
+// Gets the number of all test suites that contain at least one test
+// that should run.
+int UnitTestImpl::test_suite_to_run_count() const {
+  return CountIf(test_suites_, ShouldRunTestSuite);
+}
+
+// Gets the number of successful tests.
+int UnitTestImpl::successful_test_count() const {
+  return SumOverTestSuiteList(test_suites_, &TestSuite::successful_test_count);
+}
+
+// Gets the number of skipped tests.
+int UnitTestImpl::skipped_test_count() const {
+  return SumOverTestSuiteList(test_suites_, &TestSuite::skipped_test_count);
+}
+
+// Gets the number of failed tests.
+int UnitTestImpl::failed_test_count() const {
+  return SumOverTestSuiteList(test_suites_, &TestSuite::failed_test_count);
+}
+
+// Gets the number of disabled tests that will be reported in the XML report.
+int UnitTestImpl::reportable_disabled_test_count() const {
+  return SumOverTestSuiteList(test_suites_,
+                              &TestSuite::reportable_disabled_test_count);
+}
+
+// Gets the number of disabled tests.
+int UnitTestImpl::disabled_test_count() const {
+  return SumOverTestSuiteList(test_suites_, &TestSuite::disabled_test_count);
+}
+
+// Gets the number of tests to be printed in the XML report.
+int UnitTestImpl::reportable_test_count() const {
+  return SumOverTestSuiteList(test_suites_, &TestSuite::reportable_test_count);
+}
+
+// Gets the number of all tests.
+int UnitTestImpl::total_test_count() const {
+  return SumOverTestSuiteList(test_suites_, &TestSuite::total_test_count);
+}
+
+// Gets the number of tests that should run.
+int UnitTestImpl::test_to_run_count() const {
+  return SumOverTestSuiteList(test_suites_, &TestSuite::test_to_run_count);
+}
+
+// Returns the current OS stack trace as an std::string.
+//
+// The maximum number of stack frames to be included is specified by
+// the gtest_stack_trace_depth flag.  The skip_count parameter
+// specifies the number of top frames to be skipped, which doesn't
+// count against the number of frames to be included.
+//
+// For example, if Foo() calls Bar(), which in turn calls
+// CurrentOsStackTraceExceptTop(1), Foo() will be included in the
+// trace but Bar() and CurrentOsStackTraceExceptTop() won't.
+std::string UnitTestImpl::CurrentOsStackTraceExceptTop(int skip_count) {
+  return os_stack_trace_getter()->CurrentStackTrace(
+      static_cast<int>(GTEST_FLAG(stack_trace_depth)),
+      skip_count + 1
+      // Skips the user-specified number of frames plus this function
+      // itself.
+      );  // NOLINT
+}
+
+// A helper class for measuring elapsed times.
+class Timer {
+ public:
+  Timer() : start_(std::chrono::steady_clock::now()) {}
+
+  // Return time elapsed in milliseconds since the timer was created.
+  TimeInMillis Elapsed() {
+    return std::chrono::duration_cast<std::chrono::milliseconds>(
+               std::chrono::steady_clock::now() - start_)
+        .count();
+  }
+
+ private:
+  std::chrono::steady_clock::time_point start_;
+};
+
+// Returns a timestamp as milliseconds since the epoch. Note this time may jump
+// around subject to adjustments by the system, to measure elapsed time use
+// Timer instead.
+TimeInMillis GetTimeInMillis() {
+  return std::chrono::duration_cast<std::chrono::milliseconds>(
+             std::chrono::system_clock::now() -
+             std::chrono::system_clock::from_time_t(0))
+      .count();
+}
+
+// Utilities
+
+// class String.
+
+#if GTEST_OS_WINDOWS_MOBILE
+// Creates a UTF-16 wide string from the given ANSI string, allocating
+// memory using new. The caller is responsible for deleting the return
+// value using delete[]. Returns the wide string, or NULL if the
+// input is NULL.
+LPCWSTR String::AnsiToUtf16(const char* ansi) {
+  if (!ansi) return nullptr;
+  const int length = strlen(ansi);
+  const int unicode_length =
+      MultiByteToWideChar(CP_ACP, 0, ansi, length, nullptr, 0);
+  WCHAR* unicode = new WCHAR[unicode_length + 1];
+  MultiByteToWideChar(CP_ACP, 0, ansi, length,
+                      unicode, unicode_length);
+  unicode[unicode_length] = 0;
+  return unicode;
+}
+
+// Creates an ANSI string from the given wide string, allocating
+// memory using new. The caller is responsible for deleting the return
+// value using delete[]. Returns the ANSI string, or NULL if the
+// input is NULL.
+const char* String::Utf16ToAnsi(LPCWSTR utf16_str)  {
+  if (!utf16_str) return nullptr;
+  const int ansi_length = WideCharToMultiByte(CP_ACP, 0, utf16_str, -1, nullptr,
+                                              0, nullptr, nullptr);
+  char* ansi = new char[ansi_length + 1];
+  WideCharToMultiByte(CP_ACP, 0, utf16_str, -1, ansi, ansi_length, nullptr,
+                      nullptr);
+  ansi[ansi_length] = 0;
+  return ansi;
+}
+
+#endif  // GTEST_OS_WINDOWS_MOBILE
+
+// Compares two C strings.  Returns true if and only if they have the same
+// content.
+//
+// Unlike strcmp(), this function can handle NULL argument(s).  A NULL
+// C string is considered different to any non-NULL C string,
+// including the empty string.
+bool String::CStringEquals(const char * lhs, const char * rhs) {
+  if (lhs == nullptr) return rhs == nullptr;
+
+  if (rhs == nullptr) return false;
+
+  return strcmp(lhs, rhs) == 0;
+}
+
+#if GTEST_HAS_STD_WSTRING
+
+// Converts an array of wide chars to a narrow string using the UTF-8
+// encoding, and streams the result to the given Message object.
+static void StreamWideCharsToMessage(const wchar_t* wstr, size_t length,
+                                     Message* msg) {
+  for (size_t i = 0; i != length; ) {  // NOLINT
+    if (wstr[i] != L'\0') {
+      *msg << WideStringToUtf8(wstr + i, static_cast<int>(length - i));
+      while (i != length && wstr[i] != L'\0')
+        i++;
+    } else {
+      *msg << '\0';
+      i++;
+    }
+  }
+}
+
+#endif  // GTEST_HAS_STD_WSTRING
+
+void SplitString(const ::std::string& str, char delimiter,
+                 ::std::vector< ::std::string>* dest) {
+  ::std::vector< ::std::string> parsed;
+  ::std::string::size_type pos = 0;
+  while (::testing::internal::AlwaysTrue()) {
+    const ::std::string::size_type colon = str.find(delimiter, pos);
+    if (colon == ::std::string::npos) {
+      parsed.push_back(str.substr(pos));
+      break;
+    } else {
+      parsed.push_back(str.substr(pos, colon - pos));
+      pos = colon + 1;
+    }
+  }
+  dest->swap(parsed);
+}
+
+}  // namespace internal
+
+// Constructs an empty Message.
+// We allocate the stringstream separately because otherwise each use of
+// ASSERT/EXPECT in a procedure adds over 200 bytes to the procedure's
+// stack frame leading to huge stack frames in some cases; gcc does not reuse
+// the stack space.
+Message::Message() : ss_(new ::std::stringstream) {
+  // By default, we want there to be enough precision when printing
+  // a double to a Message.
+  *ss_ << std::setprecision(std::numeric_limits<double>::digits10 + 2);
+}
+
+// These two overloads allow streaming a wide C string to a Message
+// using the UTF-8 encoding.
+Message& Message::operator <<(const wchar_t* wide_c_str) {
+  return *this << internal::String::ShowWideCString(wide_c_str);
+}
+Message& Message::operator <<(wchar_t* wide_c_str) {
+  return *this << internal::String::ShowWideCString(wide_c_str);
+}
+
+#if GTEST_HAS_STD_WSTRING
+// Converts the given wide string to a narrow string using the UTF-8
+// encoding, and streams the result to this Message object.
+Message& Message::operator <<(const ::std::wstring& wstr) {
+  internal::StreamWideCharsToMessage(wstr.c_str(), wstr.length(), this);
+  return *this;
+}
+#endif  // GTEST_HAS_STD_WSTRING
+
+// Gets the text streamed to this object so far as an std::string.
+// Each '\0' character in the buffer is replaced with "\\0".
+std::string Message::GetString() const {
+  return internal::StringStreamToString(ss_.get());
+}
+
+// AssertionResult constructors.
+// Used in EXPECT_TRUE/FALSE(assertion_result).
+AssertionResult::AssertionResult(const AssertionResult& other)
+    : success_(other.success_),
+      message_(other.message_.get() != nullptr
+                   ? new ::std::string(*other.message_)
+                   : static_cast< ::std::string*>(nullptr)) {}
+
+// Swaps two AssertionResults.
+void AssertionResult::swap(AssertionResult& other) {
+  using std::swap;
+  swap(success_, other.success_);
+  swap(message_, other.message_);
+}
+
+// Returns the assertion's negation. Used with EXPECT/ASSERT_FALSE.
+AssertionResult AssertionResult::operator!() const {
+  AssertionResult negation(!success_);
+  if (message_.get() != nullptr) negation << *message_;
+  return negation;
+}
+
+// Makes a successful assertion result.
+AssertionResult AssertionSuccess() {
+  return AssertionResult(true);
+}
+
+// Makes a failed assertion result.
+AssertionResult AssertionFailure() {
+  return AssertionResult(false);
+}
+
+// Makes a failed assertion result with the given failure message.
+// Deprecated; use AssertionFailure() << message.
+AssertionResult AssertionFailure(const Message& message) {
+  return AssertionFailure() << message;
+}
+
+namespace internal {
+
+namespace edit_distance {
+std::vector<EditType> CalculateOptimalEdits(const std::vector<size_t>& left,
+                                            const std::vector<size_t>& right) {
+  std::vector<std::vector<double> > costs(
+      left.size() + 1, std::vector<double>(right.size() + 1));
+  std::vector<std::vector<EditType> > best_move(
+      left.size() + 1, std::vector<EditType>(right.size() + 1));
+
+  // Populate for empty right.
+  for (size_t l_i = 0; l_i < costs.size(); ++l_i) {
+    costs[l_i][0] = static_cast<double>(l_i);
+    best_move[l_i][0] = kRemove;
+  }
+  // Populate for empty left.
+  for (size_t r_i = 1; r_i < costs[0].size(); ++r_i) {
+    costs[0][r_i] = static_cast<double>(r_i);
+    best_move[0][r_i] = kAdd;
+  }
+
+  for (size_t l_i = 0; l_i < left.size(); ++l_i) {
+    for (size_t r_i = 0; r_i < right.size(); ++r_i) {
+      if (left[l_i] == right[r_i]) {
+        // Found a match. Consume it.
+        costs[l_i + 1][r_i + 1] = costs[l_i][r_i];
+        best_move[l_i + 1][r_i + 1] = kMatch;
+        continue;
+      }
+
+      const double add = costs[l_i + 1][r_i];
+      const double remove = costs[l_i][r_i + 1];
+      const double replace = costs[l_i][r_i];
+      if (add < remove && add < replace) {
+        costs[l_i + 1][r_i + 1] = add + 1;
+        best_move[l_i + 1][r_i + 1] = kAdd;
+      } else if (remove < add && remove < replace) {
+        costs[l_i + 1][r_i + 1] = remove + 1;
+        best_move[l_i + 1][r_i + 1] = kRemove;
+      } else {
+        // We make replace a little more expensive than add/remove to lower
+        // their priority.
+        costs[l_i + 1][r_i + 1] = replace + 1.00001;
+        best_move[l_i + 1][r_i + 1] = kReplace;
+      }
+    }
+  }
+
+  // Reconstruct the best path. We do it in reverse order.
+  std::vector<EditType> best_path;
+  for (size_t l_i = left.size(), r_i = right.size(); l_i > 0 || r_i > 0;) {
+    EditType move = best_move[l_i][r_i];
+    best_path.push_back(move);
+    l_i -= move != kAdd;
+    r_i -= move != kRemove;
+  }
+  std::reverse(best_path.begin(), best_path.end());
+  return best_path;
+}
+
+namespace {
+
+// Helper class to convert string into ids with deduplication.
+class InternalStrings {
+ public:
+  size_t GetId(const std::string& str) {
+    IdMap::iterator it = ids_.find(str);
+    if (it != ids_.end()) return it->second;
+    size_t id = ids_.size();
+    return ids_[str] = id;
+  }
+
+ private:
+  typedef std::map<std::string, size_t> IdMap;
+  IdMap ids_;
+};
+
+}  // namespace
+
+std::vector<EditType> CalculateOptimalEdits(
+    const std::vector<std::string>& left,
+    const std::vector<std::string>& right) {
+  std::vector<size_t> left_ids, right_ids;
+  {
+    InternalStrings intern_table;
+    for (size_t i = 0; i < left.size(); ++i) {
+      left_ids.push_back(intern_table.GetId(left[i]));
+    }
+    for (size_t i = 0; i < right.size(); ++i) {
+      right_ids.push_back(intern_table.GetId(right[i]));
+    }
+  }
+  return CalculateOptimalEdits(left_ids, right_ids);
+}
+
+namespace {
+
+// Helper class that holds the state for one hunk and prints it out to the
+// stream.
+// It reorders adds/removes when possible to group all removes before all
+// adds. It also adds the hunk header before printint into the stream.
+class Hunk {
+ public:
+  Hunk(size_t left_start, size_t right_start)
+      : left_start_(left_start),
+        right_start_(right_start),
+        adds_(),
+        removes_(),
+        common_() {}
+
+  void PushLine(char edit, const char* line) {
+    switch (edit) {
+      case ' ':
+        ++common_;
+        FlushEdits();
+        hunk_.push_back(std::make_pair(' ', line));
+        break;
+      case '-':
+        ++removes_;
+        hunk_removes_.push_back(std::make_pair('-', line));
+        break;
+      case '+':
+        ++adds_;
+        hunk_adds_.push_back(std::make_pair('+', line));
+        break;
+    }
+  }
+
+  void PrintTo(std::ostream* os) {
+    PrintHeader(os);
+    FlushEdits();
+    for (std::list<std::pair<char, const char*> >::const_iterator it =
+             hunk_.begin();
+         it != hunk_.end(); ++it) {
+      *os << it->first << it->second << "\n";
+    }
+  }
+
+  bool has_edits() const { return adds_ || removes_; }
+
+ private:
+  void FlushEdits() {
+    hunk_.splice(hunk_.end(), hunk_removes_);
+    hunk_.splice(hunk_.end(), hunk_adds_);
+  }
+
+  // Print a unified diff header for one hunk.
+  // The format is
+  //   "@@ -<left_start>,<left_length> +<right_start>,<right_length> @@"
+  // where the left/right parts are omitted if unnecessary.
+  void PrintHeader(std::ostream* ss) const {
+    *ss << "@@ ";
+    if (removes_) {
+      *ss << "-" << left_start_ << "," << (removes_ + common_);
+    }
+    if (removes_ && adds_) {
+      *ss << " ";
+    }
+    if (adds_) {
+      *ss << "+" << right_start_ << "," << (adds_ + common_);
+    }
+    *ss << " @@\n";
+  }
+
+  size_t left_start_, right_start_;
+  size_t adds_, removes_, common_;
+  std::list<std::pair<char, const char*> > hunk_, hunk_adds_, hunk_removes_;
+};
+
+}  // namespace
+
+// Create a list of diff hunks in Unified diff format.
+// Each hunk has a header generated by PrintHeader above plus a body with
+// lines prefixed with ' ' for no change, '-' for deletion and '+' for
+// addition.
+// 'context' represents the desired unchanged prefix/suffix around the diff.
+// If two hunks are close enough that their contexts overlap, then they are
+// joined into one hunk.
+std::string CreateUnifiedDiff(const std::vector<std::string>& left,
+                              const std::vector<std::string>& right,
+                              size_t context) {
+  const std::vector<EditType> edits = CalculateOptimalEdits(left, right);
+
+  size_t l_i = 0, r_i = 0, edit_i = 0;
+  std::stringstream ss;
+  while (edit_i < edits.size()) {
+    // Find first edit.
+    while (edit_i < edits.size() && edits[edit_i] == kMatch) {
+      ++l_i;
+      ++r_i;
+      ++edit_i;
+    }
+
+    // Find the first line to include in the hunk.
+    const size_t prefix_context = std::min(l_i, context);
+    Hunk hunk(l_i - prefix_context + 1, r_i - prefix_context + 1);
+    for (size_t i = prefix_context; i > 0; --i) {
+      hunk.PushLine(' ', left[l_i - i].c_str());
+    }
+
+    // Iterate the edits until we found enough suffix for the hunk or the input
+    // is over.
+    size_t n_suffix = 0;
+    for (; edit_i < edits.size(); ++edit_i) {
+      if (n_suffix >= context) {
+        // Continue only if the next hunk is very close.
+        auto it = edits.begin() + static_cast<int>(edit_i);
+        while (it != edits.end() && *it == kMatch) ++it;
+        if (it == edits.end() ||
+            static_cast<size_t>(it - edits.begin()) - edit_i >= context) {
+          // There is no next edit or it is too far away.
+          break;
+        }
+      }
+
+      EditType edit = edits[edit_i];
+      // Reset count when a non match is found.
+      n_suffix = edit == kMatch ? n_suffix + 1 : 0;
+
+      if (edit == kMatch || edit == kRemove || edit == kReplace) {
+        hunk.PushLine(edit == kMatch ? ' ' : '-', left[l_i].c_str());
+      }
+      if (edit == kAdd || edit == kReplace) {
+        hunk.PushLine('+', right[r_i].c_str());
+      }
+
+      // Advance indices, depending on edit type.
+      l_i += edit != kAdd;
+      r_i += edit != kRemove;
+    }
+
+    if (!hunk.has_edits()) {
+      // We are done. We don't want this hunk.
+      break;
+    }
+
+    hunk.PrintTo(&ss);
+  }
+  return ss.str();
+}
+
+}  // namespace edit_distance
+
+namespace {
+
+// The string representation of the values received in EqFailure() are already
+// escaped. Split them on escaped '\n' boundaries. Leave all other escaped
+// characters the same.
+std::vector<std::string> SplitEscapedString(const std::string& str) {
+  std::vector<std::string> lines;
+  size_t start = 0, end = str.size();
+  if (end > 2 && str[0] == '"' && str[end - 1] == '"') {
+    ++start;
+    --end;
+  }
+  bool escaped = false;
+  for (size_t i = start; i + 1 < end; ++i) {
+    if (escaped) {
+      escaped = false;
+      if (str[i] == 'n') {
+        lines.push_back(str.substr(start, i - start - 1));
+        start = i + 1;
+      }
+    } else {
+      escaped = str[i] == '\\';
+    }
+  }
+  lines.push_back(str.substr(start, end - start));
+  return lines;
+}
+
+}  // namespace
+
+// Constructs and returns the message for an equality assertion
+// (e.g. ASSERT_EQ, EXPECT_STREQ, etc) failure.
+//
+// The first four parameters are the expressions used in the assertion
+// and their values, as strings.  For example, for ASSERT_EQ(foo, bar)
+// where foo is 5 and bar is 6, we have:
+//
+//   lhs_expression: "foo"
+//   rhs_expression: "bar"
+//   lhs_value:      "5"
+//   rhs_value:      "6"
+//
+// The ignoring_case parameter is true if and only if the assertion is a
+// *_STRCASEEQ*.  When it's true, the string "Ignoring case" will
+// be inserted into the message.
+AssertionResult EqFailure(const char* lhs_expression,
+                          const char* rhs_expression,
+                          const std::string& lhs_value,
+                          const std::string& rhs_value,
+                          bool ignoring_case) {
+  Message msg;
+  msg << "Expected equality of these values:";
+  msg << "\n  " << lhs_expression;
+  if (lhs_value != lhs_expression) {
+    msg << "\n    Which is: " << lhs_value;
+  }
+  msg << "\n  " << rhs_expression;
+  if (rhs_value != rhs_expression) {
+    msg << "\n    Which is: " << rhs_value;
+  }
+
+  if (ignoring_case) {
+    msg << "\nIgnoring case";
+  }
+
+  if (!lhs_value.empty() && !rhs_value.empty()) {
+    const std::vector<std::string> lhs_lines =
+        SplitEscapedString(lhs_value);
+    const std::vector<std::string> rhs_lines =
+        SplitEscapedString(rhs_value);
+    if (lhs_lines.size() > 1 || rhs_lines.size() > 1) {
+      msg << "\nWith diff:\n"
+          << edit_distance::CreateUnifiedDiff(lhs_lines, rhs_lines);
+    }
+  }
+
+  return AssertionFailure() << msg;
+}
+
+// Constructs a failure message for Boolean assertions such as EXPECT_TRUE.
+std::string GetBoolAssertionFailureMessage(
+    const AssertionResult& assertion_result,
+    const char* expression_text,
+    const char* actual_predicate_value,
+    const char* expected_predicate_value) {
+  const char* actual_message = assertion_result.message();
+  Message msg;
+  msg << "Value of: " << expression_text
+      << "\n  Actual: " << actual_predicate_value;
+  if (actual_message[0] != '\0')
+    msg << " (" << actual_message << ")";
+  msg << "\nExpected: " << expected_predicate_value;
+  return msg.GetString();
+}
+
+// Helper function for implementing ASSERT_NEAR.
+AssertionResult DoubleNearPredFormat(const char* expr1,
+                                     const char* expr2,
+                                     const char* abs_error_expr,
+                                     double val1,
+                                     double val2,
+                                     double abs_error) {
+  const double diff = fabs(val1 - val2);
+  if (diff <= abs_error) return AssertionSuccess();
+
+  // Find the value which is closest to zero.
+  const double min_abs = std::min(fabs(val1), fabs(val2));
+  // Find the distance to the next double from that value.
+  const double epsilon =
+      nextafter(min_abs, std::numeric_limits<double>::infinity()) - min_abs;
+  // Detect the case where abs_error is so small that EXPECT_NEAR is
+  // effectively the same as EXPECT_EQUAL, and give an informative error
+  // message so that the situation can be more easily understood without
+  // requiring exotic floating-point knowledge.
+  // Don't do an epsilon check if abs_error is zero because that implies
+  // that an equality check was actually intended.
+  if (!(std::isnan)(val1) && !(std::isnan)(val2) && abs_error > 0 &&
+      abs_error < epsilon) {
+    return AssertionFailure()
+           << "The difference between " << expr1 << " and " << expr2 << " is "
+           << diff << ", where\n"
+           << expr1 << " evaluates to " << val1 << ",\n"
+           << expr2 << " evaluates to " << val2 << ".\nThe abs_error parameter "
+           << abs_error_expr << " evaluates to " << abs_error
+           << " which is smaller than the minimum distance between doubles for "
+              "numbers of this magnitude which is "
+           << epsilon
+           << ", thus making this EXPECT_NEAR check equivalent to "
+              "EXPECT_EQUAL. Consider using EXPECT_DOUBLE_EQ instead.";
+  }
+  return AssertionFailure()
+      << "The difference between " << expr1 << " and " << expr2
+      << " is " << diff << ", which exceeds " << abs_error_expr << ", where\n"
+      << expr1 << " evaluates to " << val1 << ",\n"
+      << expr2 << " evaluates to " << val2 << ", and\n"
+      << abs_error_expr << " evaluates to " << abs_error << ".";
+}
+
+
+// Helper template for implementing FloatLE() and DoubleLE().
+template <typename RawType>
+AssertionResult FloatingPointLE(const char* expr1,
+                                const char* expr2,
+                                RawType val1,
+                                RawType val2) {
+  // Returns success if val1 is less than val2,
+  if (val1 < val2) {
+    return AssertionSuccess();
+  }
+
+  // or if val1 is almost equal to val2.
+  const FloatingPoint<RawType> lhs(val1), rhs(val2);
+  if (lhs.AlmostEquals(rhs)) {
+    return AssertionSuccess();
+  }
+
+  // Note that the above two checks will both fail if either val1 or
+  // val2 is NaN, as the IEEE floating-point standard requires that
+  // any predicate involving a NaN must return false.
+
+  ::std::stringstream val1_ss;
+  val1_ss << std::setprecision(std::numeric_limits<RawType>::digits10 + 2)
+          << val1;
+
+  ::std::stringstream val2_ss;
+  val2_ss << std::setprecision(std::numeric_limits<RawType>::digits10 + 2)
+          << val2;
+
+  return AssertionFailure()
+      << "Expected: (" << expr1 << ") <= (" << expr2 << ")\n"
+      << "  Actual: " << StringStreamToString(&val1_ss) << " vs "
+      << StringStreamToString(&val2_ss);
+}
+
+}  // namespace internal
+
+// Asserts that val1 is less than, or almost equal to, val2.  Fails
+// otherwise.  In particular, it fails if either val1 or val2 is NaN.
+AssertionResult FloatLE(const char* expr1, const char* expr2,
+                        float val1, float val2) {
+  return internal::FloatingPointLE<float>(expr1, expr2, val1, val2);
+}
+
+// Asserts that val1 is less than, or almost equal to, val2.  Fails
+// otherwise.  In particular, it fails if either val1 or val2 is NaN.
+AssertionResult DoubleLE(const char* expr1, const char* expr2,
+                         double val1, double val2) {
+  return internal::FloatingPointLE<double>(expr1, expr2, val1, val2);
+}
+
+namespace internal {
+
+// The helper function for {ASSERT|EXPECT}_STREQ.
+AssertionResult CmpHelperSTREQ(const char* lhs_expression,
+                               const char* rhs_expression,
+                               const char* lhs,
+                               const char* rhs) {
+  if (String::CStringEquals(lhs, rhs)) {
+    return AssertionSuccess();
+  }
+
+  return EqFailure(lhs_expression,
+                   rhs_expression,
+                   PrintToString(lhs),
+                   PrintToString(rhs),
+                   false);
+}
+
+// The helper function for {ASSERT|EXPECT}_STRCASEEQ.
+AssertionResult CmpHelperSTRCASEEQ(const char* lhs_expression,
+                                   const char* rhs_expression,
+                                   const char* lhs,
+                                   const char* rhs) {
+  if (String::CaseInsensitiveCStringEquals(lhs, rhs)) {
+    return AssertionSuccess();
+  }
+
+  return EqFailure(lhs_expression,
+                   rhs_expression,
+                   PrintToString(lhs),
+                   PrintToString(rhs),
+                   true);
+}
+
+// The helper function for {ASSERT|EXPECT}_STRNE.
+AssertionResult CmpHelperSTRNE(const char* s1_expression,
+                               const char* s2_expression,
+                               const char* s1,
+                               const char* s2) {
+  if (!String::CStringEquals(s1, s2)) {
+    return AssertionSuccess();
+  } else {
+    return AssertionFailure() << "Expected: (" << s1_expression << ") != ("
+                              << s2_expression << "), actual: \""
+                              << s1 << "\" vs \"" << s2 << "\"";
+  }
+}
+
+// The helper function for {ASSERT|EXPECT}_STRCASENE.
+AssertionResult CmpHelperSTRCASENE(const char* s1_expression,
+                                   const char* s2_expression,
+                                   const char* s1,
+                                   const char* s2) {
+  if (!String::CaseInsensitiveCStringEquals(s1, s2)) {
+    return AssertionSuccess();
+  } else {
+    return AssertionFailure()
+        << "Expected: (" << s1_expression << ") != ("
+        << s2_expression << ") (ignoring case), actual: \""
+        << s1 << "\" vs \"" << s2 << "\"";
+  }
+}
+
+}  // namespace internal
+
+namespace {
+
+// Helper functions for implementing IsSubString() and IsNotSubstring().
+
+// This group of overloaded functions return true if and only if needle
+// is a substring of haystack.  NULL is considered a substring of
+// itself only.
+
+bool IsSubstringPred(const char* needle, const char* haystack) {
+  if (needle == nullptr || haystack == nullptr) return needle == haystack;
+
+  return strstr(haystack, needle) != nullptr;
+}
+
+bool IsSubstringPred(const wchar_t* needle, const wchar_t* haystack) {
+  if (needle == nullptr || haystack == nullptr) return needle == haystack;
+
+  return wcsstr(haystack, needle) != nullptr;
+}
+
+// StringType here can be either ::std::string or ::std::wstring.
+template <typename StringType>
+bool IsSubstringPred(const StringType& needle,
+                     const StringType& haystack) {
+  return haystack.find(needle) != StringType::npos;
+}
+
+// This function implements either IsSubstring() or IsNotSubstring(),
+// depending on the value of the expected_to_be_substring parameter.
+// StringType here can be const char*, const wchar_t*, ::std::string,
+// or ::std::wstring.
+template <typename StringType>
+AssertionResult IsSubstringImpl(
+    bool expected_to_be_substring,
+    const char* needle_expr, const char* haystack_expr,
+    const StringType& needle, const StringType& haystack) {
+  if (IsSubstringPred(needle, haystack) == expected_to_be_substring)
+    return AssertionSuccess();
+
+  const bool is_wide_string = sizeof(needle[0]) > 1;
+  const char* const begin_string_quote = is_wide_string ? "L\"" : "\"";
+  return AssertionFailure()
+      << "Value of: " << needle_expr << "\n"
+      << "  Actual: " << begin_string_quote << needle << "\"\n"
+      << "Expected: " << (expected_to_be_substring ? "" : "not ")
+      << "a substring of " << haystack_expr << "\n"
+      << "Which is: " << begin_string_quote << haystack << "\"";
+}
+
+}  // namespace
+
+// IsSubstring() and IsNotSubstring() check whether needle is a
+// substring of haystack (NULL is considered a substring of itself
+// only), and return an appropriate error message when they fail.
+
+AssertionResult IsSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const char* needle, const char* haystack) {
+  return IsSubstringImpl(true, needle_expr, haystack_expr, needle, haystack);
+}
+
+AssertionResult IsSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const wchar_t* needle, const wchar_t* haystack) {
+  return IsSubstringImpl(true, needle_expr, haystack_expr, needle, haystack);
+}
+
+AssertionResult IsNotSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const char* needle, const char* haystack) {
+  return IsSubstringImpl(false, needle_expr, haystack_expr, needle, haystack);
+}
+
+AssertionResult IsNotSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const wchar_t* needle, const wchar_t* haystack) {
+  return IsSubstringImpl(false, needle_expr, haystack_expr, needle, haystack);
+}
+
+AssertionResult IsSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const ::std::string& needle, const ::std::string& haystack) {
+  return IsSubstringImpl(true, needle_expr, haystack_expr, needle, haystack);
+}
+
+AssertionResult IsNotSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const ::std::string& needle, const ::std::string& haystack) {
+  return IsSubstringImpl(false, needle_expr, haystack_expr, needle, haystack);
+}
+
+#if GTEST_HAS_STD_WSTRING
+AssertionResult IsSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const ::std::wstring& needle, const ::std::wstring& haystack) {
+  return IsSubstringImpl(true, needle_expr, haystack_expr, needle, haystack);
+}
+
+AssertionResult IsNotSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const ::std::wstring& needle, const ::std::wstring& haystack) {
+  return IsSubstringImpl(false, needle_expr, haystack_expr, needle, haystack);
+}
+#endif  // GTEST_HAS_STD_WSTRING
+
+namespace internal {
+
+#if GTEST_OS_WINDOWS
+
+namespace {
+
+// Helper function for IsHRESULT{SuccessFailure} predicates
+AssertionResult HRESULTFailureHelper(const char* expr,
+                                     const char* expected,
+                                     long hr) {  // NOLINT
+# if GTEST_OS_WINDOWS_MOBILE || GTEST_OS_WINDOWS_TV_TITLE
+
+  // Windows CE doesn't support FormatMessage.
+  const char error_text[] = "";
+
+# else
+
+  // Looks up the human-readable system message for the HRESULT code
+  // and since we're not passing any params to FormatMessage, we don't
+  // want inserts expanded.
+  const DWORD kFlags = FORMAT_MESSAGE_FROM_SYSTEM |
+                       FORMAT_MESSAGE_IGNORE_INSERTS;
+  const DWORD kBufSize = 4096;
+  // Gets the system's human readable message string for this HRESULT.
+  char error_text[kBufSize] = { '\0' };
+  DWORD message_length = ::FormatMessageA(kFlags,
+                                          0,   // no source, we're asking system
+                                          static_cast<DWORD>(hr),  // the error
+                                          0,   // no line width restrictions
+                                          error_text,  // output buffer
+                                          kBufSize,    // buf size
+                                          nullptr);  // no arguments for inserts
+  // Trims tailing white space (FormatMessage leaves a trailing CR-LF)
+  for (; message_length && IsSpace(error_text[message_length - 1]);
+          --message_length) {
+    error_text[message_length - 1] = '\0';
+  }
+
+# endif  // GTEST_OS_WINDOWS_MOBILE
+
+  const std::string error_hex("0x" + String::FormatHexInt(hr));
+  return ::testing::AssertionFailure()
+      << "Expected: " << expr << " " << expected << ".\n"
+      << "  Actual: " << error_hex << " " << error_text << "\n";
+}
+
+}  // namespace
+
+AssertionResult IsHRESULTSuccess(const char* expr, long hr) {  // NOLINT
+  if (SUCCEEDED(hr)) {
+    return AssertionSuccess();
+  }
+  return HRESULTFailureHelper(expr, "succeeds", hr);
+}
+
+AssertionResult IsHRESULTFailure(const char* expr, long hr) {  // NOLINT
+  if (FAILED(hr)) {
+    return AssertionSuccess();
+  }
+  return HRESULTFailureHelper(expr, "fails", hr);
+}
+
+#endif  // GTEST_OS_WINDOWS
+
+// Utility functions for encoding Unicode text (wide strings) in
+// UTF-8.
+
+// A Unicode code-point can have up to 21 bits, and is encoded in UTF-8
+// like this:
+//
+// Code-point length   Encoding
+//   0 -  7 bits       0xxxxxxx
+//   8 - 11 bits       110xxxxx 10xxxxxx
+//  12 - 16 bits       1110xxxx 10xxxxxx 10xxxxxx
+//  17 - 21 bits       11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+
+// The maximum code-point a one-byte UTF-8 sequence can represent.
+constexpr uint32_t kMaxCodePoint1 = (static_cast<uint32_t>(1) <<  7) - 1;
+
+// The maximum code-point a two-byte UTF-8 sequence can represent.
+constexpr uint32_t kMaxCodePoint2 = (static_cast<uint32_t>(1) << (5 + 6)) - 1;
+
+// The maximum code-point a three-byte UTF-8 sequence can represent.
+constexpr uint32_t kMaxCodePoint3 = (static_cast<uint32_t>(1) << (4 + 2*6)) - 1;
+
+// The maximum code-point a four-byte UTF-8 sequence can represent.
+constexpr uint32_t kMaxCodePoint4 = (static_cast<uint32_t>(1) << (3 + 3*6)) - 1;
+
+// Chops off the n lowest bits from a bit pattern.  Returns the n
+// lowest bits.  As a side effect, the original bit pattern will be
+// shifted to the right by n bits.
+inline uint32_t ChopLowBits(uint32_t* bits, int n) {
+  const uint32_t low_bits = *bits & ((static_cast<uint32_t>(1) << n) - 1);
+  *bits >>= n;
+  return low_bits;
+}
+
+// Converts a Unicode code point to a narrow string in UTF-8 encoding.
+// code_point parameter is of type uint32_t because wchar_t may not be
+// wide enough to contain a code point.
+// If the code_point is not a valid Unicode code point
+// (i.e. outside of Unicode range U+0 to U+10FFFF) it will be converted
+// to "(Invalid Unicode 0xXXXXXXXX)".
+std::string CodePointToUtf8(uint32_t code_point) {
+  if (code_point > kMaxCodePoint4) {
+    return "(Invalid Unicode 0x" + String::FormatHexUInt32(code_point) + ")";
+  }
+
+  char str[5];  // Big enough for the largest valid code point.
+  if (code_point <= kMaxCodePoint1) {
+    str[1] = '\0';
+    str[0] = static_cast<char>(code_point);                          // 0xxxxxxx
+  } else if (code_point <= kMaxCodePoint2) {
+    str[2] = '\0';
+    str[1] = static_cast<char>(0x80 | ChopLowBits(&code_point, 6));  // 10xxxxxx
+    str[0] = static_cast<char>(0xC0 | code_point);                   // 110xxxxx
+  } else if (code_point <= kMaxCodePoint3) {
+    str[3] = '\0';
+    str[2] = static_cast<char>(0x80 | ChopLowBits(&code_point, 6));  // 10xxxxxx
+    str[1] = static_cast<char>(0x80 | ChopLowBits(&code_point, 6));  // 10xxxxxx
+    str[0] = static_cast<char>(0xE0 | code_point);                   // 1110xxxx
+  } else {  // code_point <= kMaxCodePoint4
+    str[4] = '\0';
+    str[3] = static_cast<char>(0x80 | ChopLowBits(&code_point, 6));  // 10xxxxxx
+    str[2] = static_cast<char>(0x80 | ChopLowBits(&code_point, 6));  // 10xxxxxx
+    str[1] = static_cast<char>(0x80 | ChopLowBits(&code_point, 6));  // 10xxxxxx
+    str[0] = static_cast<char>(0xF0 | code_point);                   // 11110xxx
+  }
+  return str;
+}
+
+// The following two functions only make sense if the system
+// uses UTF-16 for wide string encoding. All supported systems
+// with 16 bit wchar_t (Windows, Cygwin) do use UTF-16.
+
+// Determines if the arguments constitute UTF-16 surrogate pair
+// and thus should be combined into a single Unicode code point
+// using CreateCodePointFromUtf16SurrogatePair.
+inline bool IsUtf16SurrogatePair(wchar_t first, wchar_t second) {
+  return sizeof(wchar_t) == 2 &&
+      (first & 0xFC00) == 0xD800 && (second & 0xFC00) == 0xDC00;
+}
+
+// Creates a Unicode code point from UTF16 surrogate pair.
+inline uint32_t CreateCodePointFromUtf16SurrogatePair(wchar_t first,
+                                                      wchar_t second) {
+  const auto first_u = static_cast<uint32_t>(first);
+  const auto second_u = static_cast<uint32_t>(second);
+  const uint32_t mask = (1 << 10) - 1;
+  return (sizeof(wchar_t) == 2)
+             ? (((first_u & mask) << 10) | (second_u & mask)) + 0x10000
+             :
+             // This function should not be called when the condition is
+             // false, but we provide a sensible default in case it is.
+             first_u;
+}
+
+// Converts a wide string to a narrow string in UTF-8 encoding.
+// The wide string is assumed to have the following encoding:
+//   UTF-16 if sizeof(wchar_t) == 2 (on Windows, Cygwin)
+//   UTF-32 if sizeof(wchar_t) == 4 (on Linux)
+// Parameter str points to a null-terminated wide string.
+// Parameter num_chars may additionally limit the number
+// of wchar_t characters processed. -1 is used when the entire string
+// should be processed.
+// If the string contains code points that are not valid Unicode code points
+// (i.e. outside of Unicode range U+0 to U+10FFFF) they will be output
+// as '(Invalid Unicode 0xXXXXXXXX)'. If the string is in UTF16 encoding
+// and contains invalid UTF-16 surrogate pairs, values in those pairs
+// will be encoded as individual Unicode characters from Basic Normal Plane.
+std::string WideStringToUtf8(const wchar_t* str, int num_chars) {
+  if (num_chars == -1)
+    num_chars = static_cast<int>(wcslen(str));
+
+  ::std::stringstream stream;
+  for (int i = 0; i < num_chars; ++i) {
+    uint32_t unicode_code_point;
+
+    if (str[i] == L'\0') {
+      break;
+    } else if (i + 1 < num_chars && IsUtf16SurrogatePair(str[i], str[i + 1])) {
+      unicode_code_point = CreateCodePointFromUtf16SurrogatePair(str[i],
+                                                                 str[i + 1]);
+      i++;
+    } else {
+      unicode_code_point = static_cast<uint32_t>(str[i]);
+    }
+
+    stream << CodePointToUtf8(unicode_code_point);
+  }
+  return StringStreamToString(&stream);
+}
+
+// Converts a wide C string to an std::string using the UTF-8 encoding.
+// NULL will be converted to "(null)".
+std::string String::ShowWideCString(const wchar_t * wide_c_str) {
+  if (wide_c_str == nullptr) return "(null)";
+
+  return internal::WideStringToUtf8(wide_c_str, -1);
+}
+
+// Compares two wide C strings.  Returns true if and only if they have the
+// same content.
+//
+// Unlike wcscmp(), this function can handle NULL argument(s).  A NULL
+// C string is considered different to any non-NULL C string,
+// including the empty string.
+bool String::WideCStringEquals(const wchar_t * lhs, const wchar_t * rhs) {
+  if (lhs == nullptr) return rhs == nullptr;
+
+  if (rhs == nullptr) return false;
+
+  return wcscmp(lhs, rhs) == 0;
+}
+
+// Helper function for *_STREQ on wide strings.
+AssertionResult CmpHelperSTREQ(const char* lhs_expression,
+                               const char* rhs_expression,
+                               const wchar_t* lhs,
+                               const wchar_t* rhs) {
+  if (String::WideCStringEquals(lhs, rhs)) {
+    return AssertionSuccess();
+  }
+
+  return EqFailure(lhs_expression,
+                   rhs_expression,
+                   PrintToString(lhs),
+                   PrintToString(rhs),
+                   false);
+}
+
+// Helper function for *_STRNE on wide strings.
+AssertionResult CmpHelperSTRNE(const char* s1_expression,
+                               const char* s2_expression,
+                               const wchar_t* s1,
+                               const wchar_t* s2) {
+  if (!String::WideCStringEquals(s1, s2)) {
+    return AssertionSuccess();
+  }
+
+  return AssertionFailure() << "Expected: (" << s1_expression << ") != ("
+                            << s2_expression << "), actual: "
+                            << PrintToString(s1)
+                            << " vs " << PrintToString(s2);
+}
+
+// Compares two C strings, ignoring case.  Returns true if and only if they have
+// the same content.
+//
+// Unlike strcasecmp(), this function can handle NULL argument(s).  A
+// NULL C string is considered different to any non-NULL C string,
+// including the empty string.
+bool String::CaseInsensitiveCStringEquals(const char * lhs, const char * rhs) {
+  if (lhs == nullptr) return rhs == nullptr;
+  if (rhs == nullptr) return false;
+  return posix::StrCaseCmp(lhs, rhs) == 0;
+}
+
+// Compares two wide C strings, ignoring case.  Returns true if and only if they
+// have the same content.
+//
+// Unlike wcscasecmp(), this function can handle NULL argument(s).
+// A NULL C string is considered different to any non-NULL wide C string,
+// including the empty string.
+// NB: The implementations on different platforms slightly differ.
+// On windows, this method uses _wcsicmp which compares according to LC_CTYPE
+// environment variable. On GNU platform this method uses wcscasecmp
+// which compares according to LC_CTYPE category of the current locale.
+// On MacOS X, it uses towlower, which also uses LC_CTYPE category of the
+// current locale.
+bool String::CaseInsensitiveWideCStringEquals(const wchar_t* lhs,
+                                              const wchar_t* rhs) {
+  if (lhs == nullptr) return rhs == nullptr;
+
+  if (rhs == nullptr) return false;
+
+#if GTEST_OS_WINDOWS
+  return _wcsicmp(lhs, rhs) == 0;
+#elif GTEST_OS_LINUX && !GTEST_OS_LINUX_ANDROID
+  return wcscasecmp(lhs, rhs) == 0;
+#else
+  // Android, Mac OS X and Cygwin don't define wcscasecmp.
+  // Other unknown OSes may not define it either.
+  wint_t left, right;
+  do {
+    left = towlower(static_cast<wint_t>(*lhs++));
+    right = towlower(static_cast<wint_t>(*rhs++));
+  } while (left && left == right);
+  return left == right;
+#endif  // OS selector
+}
+
+// Returns true if and only if str ends with the given suffix, ignoring case.
+// Any string is considered to end with an empty suffix.
+bool String::EndsWithCaseInsensitive(
+    const std::string& str, const std::string& suffix) {
+  const size_t str_len = str.length();
+  const size_t suffix_len = suffix.length();
+  return (str_len >= suffix_len) &&
+         CaseInsensitiveCStringEquals(str.c_str() + str_len - suffix_len,
+                                      suffix.c_str());
+}
+
+// Formats an int value as "%02d".
+std::string String::FormatIntWidth2(int value) {
+  return FormatIntWidthN(value, 2);
+}
+
+// Formats an int value to given width with leading zeros.
+std::string String::FormatIntWidthN(int value, int width) {
+  std::stringstream ss;
+  ss << std::setfill('0') << std::setw(width) << value;
+  return ss.str();
+}
+
+// Formats an int value as "%X".
+std::string String::FormatHexUInt32(uint32_t value) {
+  std::stringstream ss;
+  ss << std::hex << std::uppercase << value;
+  return ss.str();
+}
+
+// Formats an int value as "%X".
+std::string String::FormatHexInt(int value) {
+  return FormatHexUInt32(static_cast<uint32_t>(value));
+}
+
+// Formats a byte as "%02X".
+std::string String::FormatByte(unsigned char value) {
+  std::stringstream ss;
+  ss << std::setfill('0') << std::setw(2) << std::hex << std::uppercase
+     << static_cast<unsigned int>(value);
+  return ss.str();
+}
+
+// Converts the buffer in a stringstream to an std::string, converting NUL
+// bytes to "\\0" along the way.
+std::string StringStreamToString(::std::stringstream* ss) {
+  const ::std::string& str = ss->str();
+  const char* const start = str.c_str();
+  const char* const end = start + str.length();
+
+  std::string result;
+  result.reserve(static_cast<size_t>(2 * (end - start)));
+  for (const char* ch = start; ch != end; ++ch) {
+    if (*ch == '\0') {
+      result += "\\0";  // Replaces NUL with "\\0";
+    } else {
+      result += *ch;
+    }
+  }
+
+  return result;
+}
+
+// Appends the user-supplied message to the Google-Test-generated message.
+std::string AppendUserMessage(const std::string& gtest_msg,
+                              const Message& user_msg) {
+  // Appends the user message if it's non-empty.
+  const std::string user_msg_string = user_msg.GetString();
+  if (user_msg_string.empty()) {
+    return gtest_msg;
+  }
+  if (gtest_msg.empty()) {
+    return user_msg_string;
+  }
+  return gtest_msg + "\n" + user_msg_string;
+}
+
+}  // namespace internal
+
+// class TestResult
+
+// Creates an empty TestResult.
+TestResult::TestResult()
+    : death_test_count_(0), start_timestamp_(0), elapsed_time_(0) {}
+
+// D'tor.
+TestResult::~TestResult() {
+}
+
+// Returns the i-th test part result among all the results. i can
+// range from 0 to total_part_count() - 1. If i is not in that range,
+// aborts the program.
+const TestPartResult& TestResult::GetTestPartResult(int i) const {
+  if (i < 0 || i >= total_part_count())
+    internal::posix::Abort();
+  return test_part_results_.at(static_cast<size_t>(i));
+}
+
+// Returns the i-th test property. i can range from 0 to
+// test_property_count() - 1. If i is not in that range, aborts the
+// program.
+const TestProperty& TestResult::GetTestProperty(int i) const {
+  if (i < 0 || i >= test_property_count())
+    internal::posix::Abort();
+  return test_properties_.at(static_cast<size_t>(i));
+}
+
+// Clears the test part results.
+void TestResult::ClearTestPartResults() {
+  test_part_results_.clear();
+}
+
+// Adds a test part result to the list.
+void TestResult::AddTestPartResult(const TestPartResult& test_part_result) {
+  test_part_results_.push_back(test_part_result);
+}
+
+// Adds a test property to the list. If a property with the same key as the
+// supplied property is already represented, the value of this test_property
+// replaces the old value for that key.
+void TestResult::RecordProperty(const std::string& xml_element,
+                                const TestProperty& test_property) {
+  if (!ValidateTestProperty(xml_element, test_property)) {
+    return;
+  }
+  internal::MutexLock lock(&test_properties_mutex_);
+  const std::vector<TestProperty>::iterator property_with_matching_key =
+      std::find_if(test_properties_.begin(), test_properties_.end(),
+                   internal::TestPropertyKeyIs(test_property.key()));
+  if (property_with_matching_key == test_properties_.end()) {
+    test_properties_.push_back(test_property);
+    return;
+  }
+  property_with_matching_key->SetValue(test_property.value());
+}
+
+// The list of reserved attributes used in the <testsuites> element of XML
+// output.
+static const char* const kReservedTestSuitesAttributes[] = {
+  "disabled",
+  "errors",
+  "failures",
+  "name",
+  "random_seed",
+  "tests",
+  "time",
+  "timestamp"
+};
+
+// The list of reserved attributes used in the <testsuite> element of XML
+// output.
+static const char* const kReservedTestSuiteAttributes[] = {
+    "disabled", "errors", "failures",  "name",
+    "tests",    "time",   "timestamp", "skipped"};
+
+// The list of reserved attributes used in the <testcase> element of XML output.
+static const char* const kReservedTestCaseAttributes[] = {
+    "classname",   "name", "status", "time",  "type_param",
+    "value_param", "file", "line"};
+
+// Use a slightly different set for allowed output to ensure existing tests can
+// still RecordProperty("result") or "RecordProperty(timestamp")
+static const char* const kReservedOutputTestCaseAttributes[] = {
+    "classname",   "name", "status", "time",   "type_param",
+    "value_param", "file", "line",   "result", "timestamp"};
+
+template <size_t kSize>
+std::vector<std::string> ArrayAsVector(const char* const (&array)[kSize]) {
+  return std::vector<std::string>(array, array + kSize);
+}
+
+static std::vector<std::string> GetReservedAttributesForElement(
+    const std::string& xml_element) {
+  if (xml_element == "testsuites") {
+    return ArrayAsVector(kReservedTestSuitesAttributes);
+  } else if (xml_element == "testsuite") {
+    return ArrayAsVector(kReservedTestSuiteAttributes);
+  } else if (xml_element == "testcase") {
+    return ArrayAsVector(kReservedTestCaseAttributes);
+  } else {
+    GTEST_CHECK_(false) << "Unrecognized xml_element provided: " << xml_element;
+  }
+  // This code is unreachable but some compilers may not realizes that.
+  return std::vector<std::string>();
+}
+
+// TODO(jdesprez): Merge the two getReserved attributes once skip is improved
+static std::vector<std::string> GetReservedOutputAttributesForElement(
+    const std::string& xml_element) {
+  if (xml_element == "testsuites") {
+    return ArrayAsVector(kReservedTestSuitesAttributes);
+  } else if (xml_element == "testsuite") {
+    return ArrayAsVector(kReservedTestSuiteAttributes);
+  } else if (xml_element == "testcase") {
+    return ArrayAsVector(kReservedOutputTestCaseAttributes);
+  } else {
+    GTEST_CHECK_(false) << "Unrecognized xml_element provided: " << xml_element;
+  }
+  // This code is unreachable but some compilers may not realizes that.
+  return std::vector<std::string>();
+}
+
+static std::string FormatWordList(const std::vector<std::string>& words) {
+  Message word_list;
+  for (size_t i = 0; i < words.size(); ++i) {
+    if (i > 0 && words.size() > 2) {
+      word_list << ", ";
+    }
+    if (i == words.size() - 1) {
+      word_list << "and ";
+    }
+    word_list << "'" << words[i] << "'";
+  }
+  return word_list.GetString();
+}
+
+static bool ValidateTestPropertyName(
+    const std::string& property_name,
+    const std::vector<std::string>& reserved_names) {
+  if (std::find(reserved_names.begin(), reserved_names.end(), property_name) !=
+          reserved_names.end()) {
+    ADD_FAILURE() << "Reserved key used in RecordProperty(): " << property_name
+                  << " (" << FormatWordList(reserved_names)
+                  << " are reserved by " << GTEST_NAME_ << ")";
+    return false;
+  }
+  return true;
+}
+
+// Adds a failure if the key is a reserved attribute of the element named
+// xml_element.  Returns true if the property is valid.
+bool TestResult::ValidateTestProperty(const std::string& xml_element,
+                                      const TestProperty& test_property) {
+  return ValidateTestPropertyName(test_property.key(),
+                                  GetReservedAttributesForElement(xml_element));
+}
+
+// Clears the object.
+void TestResult::Clear() {
+  test_part_results_.clear();
+  test_properties_.clear();
+  death_test_count_ = 0;
+  elapsed_time_ = 0;
+}
+
+// Returns true off the test part was skipped.
+static bool TestPartSkipped(const TestPartResult& result) {
+  return result.skipped();
+}
+
+// Returns true if and only if the test was skipped.
+bool TestResult::Skipped() const {
+  return !Failed() && CountIf(test_part_results_, TestPartSkipped) > 0;
+}
+
+// Returns true if and only if the test failed.
+bool TestResult::Failed() const {
+  for (int i = 0; i < total_part_count(); ++i) {
+    if (GetTestPartResult(i).failed())
+      return true;
+  }
+  return false;
+}
+
+// Returns true if and only if the test part fatally failed.
+static bool TestPartFatallyFailed(const TestPartResult& result) {
+  return result.fatally_failed();
+}
+
+// Returns true if and only if the test fatally failed.
+bool TestResult::HasFatalFailure() const {
+  return CountIf(test_part_results_, TestPartFatallyFailed) > 0;
+}
+
+// Returns true if and only if the test part non-fatally failed.
+static bool TestPartNonfatallyFailed(const TestPartResult& result) {
+  return result.nonfatally_failed();
+}
+
+// Returns true if and only if the test has a non-fatal failure.
+bool TestResult::HasNonfatalFailure() const {
+  return CountIf(test_part_results_, TestPartNonfatallyFailed) > 0;
+}
+
+// Gets the number of all test parts.  This is the sum of the number
+// of successful test parts and the number of failed test parts.
+int TestResult::total_part_count() const {
+  return static_cast<int>(test_part_results_.size());
+}
+
+// Returns the number of the test properties.
+int TestResult::test_property_count() const {
+  return static_cast<int>(test_properties_.size());
+}
+
+// class Test
+
+// Creates a Test object.
+
+// The c'tor saves the states of all flags.
+Test::Test()
+    : gtest_flag_saver_(new GTEST_FLAG_SAVER_) {
+}
+
+// The d'tor restores the states of all flags.  The actual work is
+// done by the d'tor of the gtest_flag_saver_ field, and thus not
+// visible here.
+Test::~Test() {
+}
+
+// Sets up the test fixture.
+//
+// A sub-class may override this.
+void Test::SetUp() {
+}
+
+// Tears down the test fixture.
+//
+// A sub-class may override this.
+void Test::TearDown() {
+}
+
+// Allows user supplied key value pairs to be recorded for later output.
+void Test::RecordProperty(const std::string& key, const std::string& value) {
+  UnitTest::GetInstance()->RecordProperty(key, value);
+}
+
+// Allows user supplied key value pairs to be recorded for later output.
+void Test::RecordProperty(const std::string& key, int value) {
+  Message value_message;
+  value_message << value;
+  RecordProperty(key, value_message.GetString().c_str());
+}
+
+namespace internal {
+
+void ReportFailureInUnknownLocation(TestPartResult::Type result_type,
+                                    const std::string& message) {
+  // This function is a friend of UnitTest and as such has access to
+  // AddTestPartResult.
+  UnitTest::GetInstance()->AddTestPartResult(
+      result_type,
+      nullptr,  // No info about the source file where the exception occurred.
+      -1,       // We have no info on which line caused the exception.
+      message,
+      "");  // No stack trace, either.
+}
+
+}  // namespace internal
+
+// Google Test requires all tests in the same test suite to use the same test
+// fixture class.  This function checks if the current test has the
+// same fixture class as the first test in the current test suite.  If
+// yes, it returns true; otherwise it generates a Google Test failure and
+// returns false.
+bool Test::HasSameFixtureClass() {
+  internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
+  const TestSuite* const test_suite = impl->current_test_suite();
+
+  // Info about the first test in the current test suite.
+  const TestInfo* const first_test_info = test_suite->test_info_list()[0];
+  const internal::TypeId first_fixture_id = first_test_info->fixture_class_id_;
+  const char* const first_test_name = first_test_info->name();
+
+  // Info about the current test.
+  const TestInfo* const this_test_info = impl->current_test_info();
+  const internal::TypeId this_fixture_id = this_test_info->fixture_class_id_;
+  const char* const this_test_name = this_test_info->name();
+
+  if (this_fixture_id != first_fixture_id) {
+    // Is the first test defined using TEST?
+    const bool first_is_TEST = first_fixture_id == internal::GetTestTypeId();
+    // Is this test defined using TEST?
+    const bool this_is_TEST = this_fixture_id == internal::GetTestTypeId();
+
+    if (first_is_TEST || this_is_TEST) {
+      // Both TEST and TEST_F appear in same test suite, which is incorrect.
+      // Tell the user how to fix this.
+
+      // Gets the name of the TEST and the name of the TEST_F.  Note
+      // that first_is_TEST and this_is_TEST cannot both be true, as
+      // the fixture IDs are different for the two tests.
+      const char* const TEST_name =
+          first_is_TEST ? first_test_name : this_test_name;
+      const char* const TEST_F_name =
+          first_is_TEST ? this_test_name : first_test_name;
+
+      ADD_FAILURE()
+          << "All tests in the same test suite must use the same test fixture\n"
+          << "class, so mixing TEST_F and TEST in the same test suite is\n"
+          << "illegal.  In test suite " << this_test_info->test_suite_name()
+          << ",\n"
+          << "test " << TEST_F_name << " is defined using TEST_F but\n"
+          << "test " << TEST_name << " is defined using TEST.  You probably\n"
+          << "want to change the TEST to TEST_F or move it to another test\n"
+          << "case.";
+    } else {
+      // Two fixture classes with the same name appear in two different
+      // namespaces, which is not allowed. Tell the user how to fix this.
+      ADD_FAILURE()
+          << "All tests in the same test suite must use the same test fixture\n"
+          << "class.  However, in test suite "
+          << this_test_info->test_suite_name() << ",\n"
+          << "you defined test " << first_test_name << " and test "
+          << this_test_name << "\n"
+          << "using two different test fixture classes.  This can happen if\n"
+          << "the two classes are from different namespaces or translation\n"
+          << "units and have the same name.  You should probably rename one\n"
+          << "of the classes to put the tests into different test suites.";
+    }
+    return false;
+  }
+
+  return true;
+}
+
+#if GTEST_HAS_SEH
+
+// Adds an "exception thrown" fatal failure to the current test.  This
+// function returns its result via an output parameter pointer because VC++
+// prohibits creation of objects with destructors on stack in functions
+// using __try (see error C2712).
+static std::string* FormatSehExceptionMessage(DWORD exception_code,
+                                              const char* location) {
+  Message message;
+  message << "SEH exception with code 0x" << std::setbase(16) <<
+    exception_code << std::setbase(10) << " thrown in " << location << ".";
+
+  return new std::string(message.GetString());
+}
+
+#endif  // GTEST_HAS_SEH
+
+namespace internal {
+
+#if GTEST_HAS_EXCEPTIONS
+
+// Adds an "exception thrown" fatal failure to the current test.
+static std::string FormatCxxExceptionMessage(const char* description,
+                                             const char* location) {
+  Message message;
+  if (description != nullptr) {
+    message << "C++ exception with description \"" << description << "\"";
+  } else {
+    message << "Unknown C++ exception";
+  }
+  message << " thrown in " << location << ".";
+
+  return message.GetString();
+}
+
+static std::string PrintTestPartResultToString(
+    const TestPartResult& test_part_result);
+
+GoogleTestFailureException::GoogleTestFailureException(
+    const TestPartResult& failure)
+    : ::std::runtime_error(PrintTestPartResultToString(failure).c_str()) {}
+
+#endif  // GTEST_HAS_EXCEPTIONS
+
+// We put these helper functions in the internal namespace as IBM's xlC
+// compiler rejects the code if they were declared static.
+
+// Runs the given method and handles SEH exceptions it throws, when
+// SEH is supported; returns the 0-value for type Result in case of an
+// SEH exception.  (Microsoft compilers cannot handle SEH and C++
+// exceptions in the same function.  Therefore, we provide a separate
+// wrapper function for handling SEH exceptions.)
+template <class T, typename Result>
+Result HandleSehExceptionsInMethodIfSupported(
+    T* object, Result (T::*method)(), const char* location) {
+#if GTEST_HAS_SEH
+  __try {
+    return (object->*method)();
+  } __except (internal::UnitTestOptions::GTestShouldProcessSEH(  // NOLINT
+      GetExceptionCode())) {
+    // We create the exception message on the heap because VC++ prohibits
+    // creation of objects with destructors on stack in functions using __try
+    // (see error C2712).
+    std::string* exception_message = FormatSehExceptionMessage(
+        GetExceptionCode(), location);
+    internal::ReportFailureInUnknownLocation(TestPartResult::kFatalFailure,
+                                             *exception_message);
+    delete exception_message;
+    return static_cast<Result>(0);
+  }
+#else
+  (void)location;
+  return (object->*method)();
+#endif  // GTEST_HAS_SEH
+}
+
+// Runs the given method and catches and reports C++ and/or SEH-style
+// exceptions, if they are supported; returns the 0-value for type
+// Result in case of an SEH exception.
+template <class T, typename Result>
+Result HandleExceptionsInMethodIfSupported(
+    T* object, Result (T::*method)(), const char* location) {
+  // NOTE: The user code can affect the way in which Google Test handles
+  // exceptions by setting GTEST_FLAG(catch_exceptions), but only before
+  // RUN_ALL_TESTS() starts. It is technically possible to check the flag
+  // after the exception is caught and either report or re-throw the
+  // exception based on the flag's value:
+  //
+  // try {
+  //   // Perform the test method.
+  // } catch (...) {
+  //   if (GTEST_FLAG(catch_exceptions))
+  //     // Report the exception as failure.
+  //   else
+  //     throw;  // Re-throws the original exception.
+  // }
+  //
+  // However, the purpose of this flag is to allow the program to drop into
+  // the debugger when the exception is thrown. On most platforms, once the
+  // control enters the catch block, the exception origin information is
+  // lost and the debugger will stop the program at the point of the
+  // re-throw in this function -- instead of at the point of the original
+  // throw statement in the code under test.  For this reason, we perform
+  // the check early, sacrificing the ability to affect Google Test's
+  // exception handling in the method where the exception is thrown.
+  if (internal::GetUnitTestImpl()->catch_exceptions()) {
+#if GTEST_HAS_EXCEPTIONS
+    try {
+      return HandleSehExceptionsInMethodIfSupported(object, method, location);
+    } catch (const AssertionException&) {  // NOLINT
+      // This failure was reported already.
+    } catch (const internal::GoogleTestFailureException&) {  // NOLINT
+      // This exception type can only be thrown by a failed Google
+      // Test assertion with the intention of letting another testing
+      // framework catch it.  Therefore we just re-throw it.
+      throw;
+    } catch (const std::exception& e) {  // NOLINT
+      internal::ReportFailureInUnknownLocation(
+          TestPartResult::kFatalFailure,
+          FormatCxxExceptionMessage(e.what(), location));
+    } catch (...) {  // NOLINT
+      internal::ReportFailureInUnknownLocation(
+          TestPartResult::kFatalFailure,
+          FormatCxxExceptionMessage(nullptr, location));
+    }
+    return static_cast<Result>(0);
+#else
+    return HandleSehExceptionsInMethodIfSupported(object, method, location);
+#endif  // GTEST_HAS_EXCEPTIONS
+  } else {
+    return (object->*method)();
+  }
+}
+
+}  // namespace internal
+
+// Runs the test and updates the test result.
+void Test::Run() {
+  if (!HasSameFixtureClass()) return;
+
+  internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
+  impl->os_stack_trace_getter()->UponLeavingGTest();
+  internal::HandleExceptionsInMethodIfSupported(this, &Test::SetUp, "SetUp()");
+  // We will run the test only if SetUp() was successful and didn't call
+  // GTEST_SKIP().
+  if (!HasFatalFailure() && !IsSkipped()) {
+    impl->os_stack_trace_getter()->UponLeavingGTest();
+    internal::HandleExceptionsInMethodIfSupported(
+        this, &Test::TestBody, "the test body");
+  }
+
+  // However, we want to clean up as much as possible.  Hence we will
+  // always call TearDown(), even if SetUp() or the test body has
+  // failed.
+  impl->os_stack_trace_getter()->UponLeavingGTest();
+  internal::HandleExceptionsInMethodIfSupported(
+      this, &Test::TearDown, "TearDown()");
+}
+
+// Returns true if and only if the current test has a fatal failure.
+bool Test::HasFatalFailure() {
+  return internal::GetUnitTestImpl()->current_test_result()->HasFatalFailure();
+}
+
+// Returns true if and only if the current test has a non-fatal failure.
+bool Test::HasNonfatalFailure() {
+  return internal::GetUnitTestImpl()->current_test_result()->
+      HasNonfatalFailure();
+}
+
+// Returns true if and only if the current test was skipped.
+bool Test::IsSkipped() {
+  return internal::GetUnitTestImpl()->current_test_result()->Skipped();
+}
+
+// class TestInfo
+
+// Constructs a TestInfo object. It assumes ownership of the test factory
+// object.
+TestInfo::TestInfo(const std::string& a_test_suite_name,
+                   const std::string& a_name, const char* a_type_param,
+                   const char* a_value_param,
+                   internal::CodeLocation a_code_location,
+                   internal::TypeId fixture_class_id,
+                   internal::TestFactoryBase* factory)
+    : test_suite_name_(a_test_suite_name),
+      name_(a_name),
+      type_param_(a_type_param ? new std::string(a_type_param) : nullptr),
+      value_param_(a_value_param ? new std::string(a_value_param) : nullptr),
+      location_(a_code_location),
+      fixture_class_id_(fixture_class_id),
+      should_run_(false),
+      is_disabled_(false),
+      matches_filter_(false),
+      is_in_another_shard_(false),
+      factory_(factory),
+      result_() {}
+
+// Destructs a TestInfo object.
+TestInfo::~TestInfo() { delete factory_; }
+
+namespace internal {
+
+// Creates a new TestInfo object and registers it with Google Test;
+// returns the created object.
+//
+// Arguments:
+//
+//   test_suite_name:  name of the test suite
+//   name:             name of the test
+//   type_param:       the name of the test's type parameter, or NULL if
+//                     this is not a typed or a type-parameterized test.
+//   value_param:      text representation of the test's value parameter,
+//                     or NULL if this is not a value-parameterized test.
+//   code_location:    code location where the test is defined
+//   fixture_class_id: ID of the test fixture class
+//   set_up_tc:        pointer to the function that sets up the test suite
+//   tear_down_tc:     pointer to the function that tears down the test suite
+//   factory:          pointer to the factory that creates a test object.
+//                     The newly created TestInfo instance will assume
+//                     ownership of the factory object.
+TestInfo* MakeAndRegisterTestInfo(
+    const char* test_suite_name, const char* name, const char* type_param,
+    const char* value_param, CodeLocation code_location,
+    TypeId fixture_class_id, SetUpTestSuiteFunc set_up_tc,
+    TearDownTestSuiteFunc tear_down_tc, TestFactoryBase* factory) {
+  TestInfo* const test_info =
+      new TestInfo(test_suite_name, name, type_param, value_param,
+                   code_location, fixture_class_id, factory);
+  GetUnitTestImpl()->AddTestInfo(set_up_tc, tear_down_tc, test_info);
+  return test_info;
+}
+
+void ReportInvalidTestSuiteType(const char* test_suite_name,
+                                CodeLocation code_location) {
+  Message errors;
+  errors
+      << "Attempted redefinition of test suite " << test_suite_name << ".\n"
+      << "All tests in the same test suite must use the same test fixture\n"
+      << "class.  However, in test suite " << test_suite_name << ", you tried\n"
+      << "to define a test using a fixture class different from the one\n"
+      << "used earlier. This can happen if the two fixture classes are\n"
+      << "from different namespaces and have the same name. You should\n"
+      << "probably rename one of the classes to put the tests into different\n"
+      << "test suites.";
+
+  GTEST_LOG_(ERROR) << FormatFileLocation(code_location.file.c_str(),
+                                          code_location.line)
+                    << " " << errors.GetString();
+}
+}  // namespace internal
+
+namespace {
+
+// A predicate that checks the test name of a TestInfo against a known
+// value.
+//
+// This is used for implementation of the TestSuite class only.  We put
+// it in the anonymous namespace to prevent polluting the outer
+// namespace.
+//
+// TestNameIs is copyable.
+class TestNameIs {
+ public:
+  // Constructor.
+  //
+  // TestNameIs has NO default constructor.
+  explicit TestNameIs(const char* name)
+      : name_(name) {}
+
+  // Returns true if and only if the test name of test_info matches name_.
+  bool operator()(const TestInfo * test_info) const {
+    return test_info && test_info->name() == name_;
+  }
+
+ private:
+  std::string name_;
+};
+
+}  // namespace
+
+namespace internal {
+
+// This method expands all parameterized tests registered with macros TEST_P
+// and INSTANTIATE_TEST_SUITE_P into regular tests and registers those.
+// This will be done just once during the program runtime.
+void UnitTestImpl::RegisterParameterizedTests() {
+  if (!parameterized_tests_registered_) {
+    parameterized_test_registry_.RegisterTests();
+    type_parameterized_test_registry_.CheckForInstantiations();
+    parameterized_tests_registered_ = true;
+  }
+}
+
+}  // namespace internal
+
+// Creates the test object, runs it, records its result, and then
+// deletes it.
+void TestInfo::Run() {
+  if (!should_run_) return;
+
+  // Tells UnitTest where to store test result.
+  internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
+  impl->set_current_test_info(this);
+
+  TestEventListener* repeater = UnitTest::GetInstance()->listeners().repeater();
+
+  // Notifies the unit test event listeners that a test is about to start.
+  repeater->OnTestStart(*this);
+
+  result_.set_start_timestamp(internal::GetTimeInMillis());
+  internal::Timer timer;
+
+  impl->os_stack_trace_getter()->UponLeavingGTest();
+
+  // Creates the test object.
+  Test* const test = internal::HandleExceptionsInMethodIfSupported(
+      factory_, &internal::TestFactoryBase::CreateTest,
+      "the test fixture's constructor");
+
+  // Runs the test if the constructor didn't generate a fatal failure or invoke
+  // GTEST_SKIP().
+  // Note that the object will not be null
+  if (!Test::HasFatalFailure() && !Test::IsSkipped()) {
+    // This doesn't throw as all user code that can throw are wrapped into
+    // exception handling code.
+    test->Run();
+  }
+
+  if (test != nullptr) {
+    // Deletes the test object.
+    impl->os_stack_trace_getter()->UponLeavingGTest();
+    internal::HandleExceptionsInMethodIfSupported(
+        test, &Test::DeleteSelf_, "the test fixture's destructor");
+  }
+
+  result_.set_elapsed_time(timer.Elapsed());
+
+  // Notifies the unit test event listener that a test has just finished.
+  repeater->OnTestEnd(*this);
+
+  // Tells UnitTest to stop associating assertion results to this
+  // test.
+  impl->set_current_test_info(nullptr);
+}
+
+// Skip and records a skipped test result for this object.
+void TestInfo::Skip() {
+  if (!should_run_) return;
+
+  internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
+  impl->set_current_test_info(this);
+
+  TestEventListener* repeater = UnitTest::GetInstance()->listeners().repeater();
+
+  // Notifies the unit test event listeners that a test is about to start.
+  repeater->OnTestStart(*this);
+
+  const TestPartResult test_part_result =
+      TestPartResult(TestPartResult::kSkip, this->file(), this->line(), "");
+  impl->GetTestPartResultReporterForCurrentThread()->ReportTestPartResult(
+      test_part_result);
+
+  // Notifies the unit test event listener that a test has just finished.
+  repeater->OnTestEnd(*this);
+  impl->set_current_test_info(nullptr);
+}
+
+// class TestSuite
+
+// Gets the number of successful tests in this test suite.
+int TestSuite::successful_test_count() const {
+  return CountIf(test_info_list_, TestPassed);
+}
+
+// Gets the number of successful tests in this test suite.
+int TestSuite::skipped_test_count() const {
+  return CountIf(test_info_list_, TestSkipped);
+}
+
+// Gets the number of failed tests in this test suite.
+int TestSuite::failed_test_count() const {
+  return CountIf(test_info_list_, TestFailed);
+}
+
+// Gets the number of disabled tests that will be reported in the XML report.
+int TestSuite::reportable_disabled_test_count() const {
+  return CountIf(test_info_list_, TestReportableDisabled);
+}
+
+// Gets the number of disabled tests in this test suite.
+int TestSuite::disabled_test_count() const {
+  return CountIf(test_info_list_, TestDisabled);
+}
+
+// Gets the number of tests to be printed in the XML report.
+int TestSuite::reportable_test_count() const {
+  return CountIf(test_info_list_, TestReportable);
+}
+
+// Get the number of tests in this test suite that should run.
+int TestSuite::test_to_run_count() const {
+  return CountIf(test_info_list_, ShouldRunTest);
+}
+
+// Gets the number of all tests.
+int TestSuite::total_test_count() const {
+  return static_cast<int>(test_info_list_.size());
+}
+
+// Creates a TestSuite with the given name.
+//
+// Arguments:
+//
+//   a_name:       name of the test suite
+//   a_type_param: the name of the test suite's type parameter, or NULL if
+//                 this is not a typed or a type-parameterized test suite.
+//   set_up_tc:    pointer to the function that sets up the test suite
+//   tear_down_tc: pointer to the function that tears down the test suite
+TestSuite::TestSuite(const char* a_name, const char* a_type_param,
+                     internal::SetUpTestSuiteFunc set_up_tc,
+                     internal::TearDownTestSuiteFunc tear_down_tc)
+    : name_(a_name),
+      type_param_(a_type_param ? new std::string(a_type_param) : nullptr),
+      set_up_tc_(set_up_tc),
+      tear_down_tc_(tear_down_tc),
+      should_run_(false),
+      start_timestamp_(0),
+      elapsed_time_(0) {}
+
+// Destructor of TestSuite.
+TestSuite::~TestSuite() {
+  // Deletes every Test in the collection.
+  ForEach(test_info_list_, internal::Delete<TestInfo>);
+}
+
+// Returns the i-th test among all the tests. i can range from 0 to
+// total_test_count() - 1. If i is not in that range, returns NULL.
+const TestInfo* TestSuite::GetTestInfo(int i) const {
+  const int index = GetElementOr(test_indices_, i, -1);
+  return index < 0 ? nullptr : test_info_list_[static_cast<size_t>(index)];
+}
+
+// Returns the i-th test among all the tests. i can range from 0 to
+// total_test_count() - 1. If i is not in that range, returns NULL.
+TestInfo* TestSuite::GetMutableTestInfo(int i) {
+  const int index = GetElementOr(test_indices_, i, -1);
+  return index < 0 ? nullptr : test_info_list_[static_cast<size_t>(index)];
+}
+
+// Adds a test to this test suite.  Will delete the test upon
+// destruction of the TestSuite object.
+void TestSuite::AddTestInfo(TestInfo* test_info) {
+  test_info_list_.push_back(test_info);
+  test_indices_.push_back(static_cast<int>(test_indices_.size()));
+}
+
+// Runs every test in this TestSuite.
+void TestSuite::Run() {
+  if (!should_run_) return;
+
+  internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
+  impl->set_current_test_suite(this);
+
+  TestEventListener* repeater = UnitTest::GetInstance()->listeners().repeater();
+
+  // Call both legacy and the new API
+  repeater->OnTestSuiteStart(*this);
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  repeater->OnTestCaseStart(*this);
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  impl->os_stack_trace_getter()->UponLeavingGTest();
+  internal::HandleExceptionsInMethodIfSupported(
+      this, &TestSuite::RunSetUpTestSuite, "SetUpTestSuite()");
+
+  start_timestamp_ = internal::GetTimeInMillis();
+  internal::Timer timer;
+  for (int i = 0; i < total_test_count(); i++) {
+    GetMutableTestInfo(i)->Run();
+    if (GTEST_FLAG(fail_fast) && GetMutableTestInfo(i)->result()->Failed()) {
+      for (int j = i + 1; j < total_test_count(); j++) {
+        GetMutableTestInfo(j)->Skip();
+      }
+      break;
+    }
+  }
+  elapsed_time_ = timer.Elapsed();
+
+  impl->os_stack_trace_getter()->UponLeavingGTest();
+  internal::HandleExceptionsInMethodIfSupported(
+      this, &TestSuite::RunTearDownTestSuite, "TearDownTestSuite()");
+
+  // Call both legacy and the new API
+  repeater->OnTestSuiteEnd(*this);
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  repeater->OnTestCaseEnd(*this);
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  impl->set_current_test_suite(nullptr);
+}
+
+// Skips all tests under this TestSuite.
+void TestSuite::Skip() {
+  if (!should_run_) return;
+
+  internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
+  impl->set_current_test_suite(this);
+
+  TestEventListener* repeater = UnitTest::GetInstance()->listeners().repeater();
+
+  // Call both legacy and the new API
+  repeater->OnTestSuiteStart(*this);
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  repeater->OnTestCaseStart(*this);
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  for (int i = 0; i < total_test_count(); i++) {
+    GetMutableTestInfo(i)->Skip();
+  }
+
+  // Call both legacy and the new API
+  repeater->OnTestSuiteEnd(*this);
+  // Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  repeater->OnTestCaseEnd(*this);
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  impl->set_current_test_suite(nullptr);
+}
+
+// Clears the results of all tests in this test suite.
+void TestSuite::ClearResult() {
+  ad_hoc_test_result_.Clear();
+  ForEach(test_info_list_, TestInfo::ClearTestResult);
+}
+
+// Shuffles the tests in this test suite.
+void TestSuite::ShuffleTests(internal::Random* random) {
+  Shuffle(random, &test_indices_);
+}
+
+// Restores the test order to before the first shuffle.
+void TestSuite::UnshuffleTests() {
+  for (size_t i = 0; i < test_indices_.size(); i++) {
+    test_indices_[i] = static_cast<int>(i);
+  }
+}
+
+// Formats a countable noun.  Depending on its quantity, either the
+// singular form or the plural form is used. e.g.
+//
+// FormatCountableNoun(1, "formula", "formuli") returns "1 formula".
+// FormatCountableNoun(5, "book", "books") returns "5 books".
+static std::string FormatCountableNoun(int count,
+                                       const char * singular_form,
+                                       const char * plural_form) {
+  return internal::StreamableToString(count) + " " +
+      (count == 1 ? singular_form : plural_form);
+}
+
+// Formats the count of tests.
+static std::string FormatTestCount(int test_count) {
+  return FormatCountableNoun(test_count, "test", "tests");
+}
+
+// Formats the count of test suites.
+static std::string FormatTestSuiteCount(int test_suite_count) {
+  return FormatCountableNoun(test_suite_count, "test suite", "test suites");
+}
+
+// Converts a TestPartResult::Type enum to human-friendly string
+// representation.  Both kNonFatalFailure and kFatalFailure are translated
+// to "Failure", as the user usually doesn't care about the difference
+// between the two when viewing the test result.
+static const char * TestPartResultTypeToString(TestPartResult::Type type) {
+  switch (type) {
+    case TestPartResult::kSkip:
+      return "Skipped\n";
+    case TestPartResult::kSuccess:
+      return "Success";
+
+    case TestPartResult::kNonFatalFailure:
+    case TestPartResult::kFatalFailure:
+#ifdef _MSC_VER
+      return "error: ";
+#else
+      return "Failure\n";
+#endif
+    default:
+      return "Unknown result type";
+  }
+}
+
+namespace internal {
+namespace {
+enum class GTestColor { kDefault, kRed, kGreen, kYellow };
+}  // namespace
+
+// Prints a TestPartResult to an std::string.
+static std::string PrintTestPartResultToString(
+    const TestPartResult& test_part_result) {
+  return (Message()
+          << internal::FormatFileLocation(test_part_result.file_name(),
+                                          test_part_result.line_number())
+          << " " << TestPartResultTypeToString(test_part_result.type())
+          << test_part_result.message()).GetString();
+}
+
+// Prints a TestPartResult.
+static void PrintTestPartResult(const TestPartResult& test_part_result) {
+  const std::string& result =
+      PrintTestPartResultToString(test_part_result);
+  printf("%s\n", result.c_str());
+  fflush(stdout);
+  // If the test program runs in Visual Studio or a debugger, the
+  // following statements add the test part result message to the Output
+  // window such that the user can double-click on it to jump to the
+  // corresponding source code location; otherwise they do nothing.
+#if GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MOBILE
+  // We don't call OutputDebugString*() on Windows Mobile, as printing
+  // to stdout is done by OutputDebugString() there already - we don't
+  // want the same message printed twice.
+  ::OutputDebugStringA(result.c_str());
+  ::OutputDebugStringA("\n");
+#endif
+}
+
+// class PrettyUnitTestResultPrinter
+#if GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MOBILE && \
+    !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT && !GTEST_OS_WINDOWS_MINGW
+
+// Returns the character attribute for the given color.
+static WORD GetColorAttribute(GTestColor color) {
+  switch (color) {
+    case GTestColor::kRed:
+      return FOREGROUND_RED;
+    case GTestColor::kGreen:
+      return FOREGROUND_GREEN;
+    case GTestColor::kYellow:
+      return FOREGROUND_RED | FOREGROUND_GREEN;
+    default:           return 0;
+  }
+}
+
+static int GetBitOffset(WORD color_mask) {
+  if (color_mask == 0) return 0;
+
+  int bitOffset = 0;
+  while ((color_mask & 1) == 0) {
+    color_mask >>= 1;
+    ++bitOffset;
+  }
+  return bitOffset;
+}
+
+static WORD GetNewColor(GTestColor color, WORD old_color_attrs) {
+  // Let's reuse the BG
+  static const WORD background_mask = BACKGROUND_BLUE | BACKGROUND_GREEN |
+                                      BACKGROUND_RED | BACKGROUND_INTENSITY;
+  static const WORD foreground_mask = FOREGROUND_BLUE | FOREGROUND_GREEN |
+                                      FOREGROUND_RED | FOREGROUND_INTENSITY;
+  const WORD existing_bg = old_color_attrs & background_mask;
+
+  WORD new_color =
+      GetColorAttribute(color) | existing_bg | FOREGROUND_INTENSITY;
+  static const int bg_bitOffset = GetBitOffset(background_mask);
+  static const int fg_bitOffset = GetBitOffset(foreground_mask);
+
+  if (((new_color & background_mask) >> bg_bitOffset) ==
+      ((new_color & foreground_mask) >> fg_bitOffset)) {
+    new_color ^= FOREGROUND_INTENSITY;  // invert intensity
+  }
+  return new_color;
+}
+
+#else
+
+// Returns the ANSI color code for the given color. GTestColor::kDefault is
+// an invalid input.
+static const char* GetAnsiColorCode(GTestColor color) {
+  switch (color) {
+    case GTestColor::kRed:
+      return "1";
+    case GTestColor::kGreen:
+      return "2";
+    case GTestColor::kYellow:
+      return "3";
+    default:
+      return nullptr;
+  }
+}
+
+#endif  // GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MOBILE
+
+// Returns true if and only if Google Test should use colors in the output.
+bool ShouldUseColor(bool stdout_is_tty) {
+  const char* const gtest_color = GTEST_FLAG(color).c_str();
+
+  if (String::CaseInsensitiveCStringEquals(gtest_color, "auto")) {
+#if GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MINGW
+    // On Windows the TERM variable is usually not set, but the
+    // console there does support colors.
+    return stdout_is_tty;
+#else
+    // On non-Windows platforms, we rely on the TERM variable.
+    const char* const term = posix::GetEnv("TERM");
+    const bool term_supports_color =
+        String::CStringEquals(term, "xterm") ||
+        String::CStringEquals(term, "xterm-color") ||
+        String::CStringEquals(term, "xterm-256color") ||
+        String::CStringEquals(term, "screen") ||
+        String::CStringEquals(term, "screen-256color") ||
+        String::CStringEquals(term, "tmux") ||
+        String::CStringEquals(term, "tmux-256color") ||
+        String::CStringEquals(term, "rxvt-unicode") ||
+        String::CStringEquals(term, "rxvt-unicode-256color") ||
+        String::CStringEquals(term, "linux") ||
+        String::CStringEquals(term, "cygwin");
+    return stdout_is_tty && term_supports_color;
+#endif  // GTEST_OS_WINDOWS
+  }
+
+  return String::CaseInsensitiveCStringEquals(gtest_color, "yes") ||
+      String::CaseInsensitiveCStringEquals(gtest_color, "true") ||
+      String::CaseInsensitiveCStringEquals(gtest_color, "t") ||
+      String::CStringEquals(gtest_color, "1");
+  // We take "yes", "true", "t", and "1" as meaning "yes".  If the
+  // value is neither one of these nor "auto", we treat it as "no" to
+  // be conservative.
+}
+
+// Helpers for printing colored strings to stdout. Note that on Windows, we
+// cannot simply emit special characters and have the terminal change colors.
+// This routine must actually emit the characters rather than return a string
+// that would be colored when printed, as can be done on Linux.
+
+GTEST_ATTRIBUTE_PRINTF_(2, 3)
+static void ColoredPrintf(GTestColor color, const char *fmt, ...) {
+  va_list args;
+  va_start(args, fmt);
+
+#if GTEST_OS_WINDOWS_MOBILE || GTEST_OS_ZOS || GTEST_OS_IOS || \
+    GTEST_OS_WINDOWS_PHONE || GTEST_OS_WINDOWS_RT || defined(ESP_PLATFORM)
+  const bool use_color = AlwaysFalse();
+#else
+  static const bool in_color_mode =
+      ShouldUseColor(posix::IsATTY(posix::FileNo(stdout)) != 0);
+  const bool use_color = in_color_mode && (color != GTestColor::kDefault);
+#endif  // GTEST_OS_WINDOWS_MOBILE || GTEST_OS_ZOS
+
+  if (!use_color) {
+    vprintf(fmt, args);
+    va_end(args);
+    return;
+  }
+
+#if GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MOBILE && \
+    !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT && !GTEST_OS_WINDOWS_MINGW
+  const HANDLE stdout_handle = GetStdHandle(STD_OUTPUT_HANDLE);
+
+  // Gets the current text color.
+  CONSOLE_SCREEN_BUFFER_INFO buffer_info;
+  GetConsoleScreenBufferInfo(stdout_handle, &buffer_info);
+  const WORD old_color_attrs = buffer_info.wAttributes;
+  const WORD new_color = GetNewColor(color, old_color_attrs);
+
+  // We need to flush the stream buffers into the console before each
+  // SetConsoleTextAttribute call lest it affect the text that is already
+  // printed but has not yet reached the console.
+  fflush(stdout);
+  SetConsoleTextAttribute(stdout_handle, new_color);
+
+  vprintf(fmt, args);
+
+  fflush(stdout);
+  // Restores the text color.
+  SetConsoleTextAttribute(stdout_handle, old_color_attrs);
+#else
+  printf("\033[0;3%sm", GetAnsiColorCode(color));
+  vprintf(fmt, args);
+  printf("\033[m");  // Resets the terminal to default.
+#endif  // GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MOBILE
+  va_end(args);
+}
+
+// Text printed in Google Test's text output and --gtest_list_tests
+// output to label the type parameter and value parameter for a test.
+static const char kTypeParamLabel[] = "TypeParam";
+static const char kValueParamLabel[] = "GetParam()";
+
+static void PrintFullTestCommentIfPresent(const TestInfo& test_info) {
+  const char* const type_param = test_info.type_param();
+  const char* const value_param = test_info.value_param();
+
+  if (type_param != nullptr || value_param != nullptr) {
+    printf(", where ");
+    if (type_param != nullptr) {
+      printf("%s = %s", kTypeParamLabel, type_param);
+      if (value_param != nullptr) printf(" and ");
+    }
+    if (value_param != nullptr) {
+      printf("%s = %s", kValueParamLabel, value_param);
+    }
+  }
+}
+
+// This class implements the TestEventListener interface.
+//
+// Class PrettyUnitTestResultPrinter is copyable.
+class PrettyUnitTestResultPrinter : public TestEventListener {
+ public:
+  PrettyUnitTestResultPrinter() {}
+  static void PrintTestName(const char* test_suite, const char* test) {
+    printf("%s.%s", test_suite, test);
+  }
+
+  // The following methods override what's in the TestEventListener class.
+  void OnTestProgramStart(const UnitTest& /*unit_test*/) override {}
+  void OnTestIterationStart(const UnitTest& unit_test, int iteration) override;
+  void OnEnvironmentsSetUpStart(const UnitTest& unit_test) override;
+  void OnEnvironmentsSetUpEnd(const UnitTest& /*unit_test*/) override {}
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestCaseStart(const TestCase& test_case) override;
+#else
+  void OnTestSuiteStart(const TestSuite& test_suite) override;
+#endif  // OnTestCaseStart
+
+  void OnTestStart(const TestInfo& test_info) override;
+
+  void OnTestPartResult(const TestPartResult& result) override;
+  void OnTestEnd(const TestInfo& test_info) override;
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestCaseEnd(const TestCase& test_case) override;
+#else
+  void OnTestSuiteEnd(const TestSuite& test_suite) override;
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  void OnEnvironmentsTearDownStart(const UnitTest& unit_test) override;
+  void OnEnvironmentsTearDownEnd(const UnitTest& /*unit_test*/) override {}
+  void OnTestIterationEnd(const UnitTest& unit_test, int iteration) override;
+  void OnTestProgramEnd(const UnitTest& /*unit_test*/) override {}
+
+ private:
+  static void PrintFailedTests(const UnitTest& unit_test);
+  static void PrintFailedTestSuites(const UnitTest& unit_test);
+  static void PrintSkippedTests(const UnitTest& unit_test);
+};
+
+  // Fired before each iteration of tests starts.
+void PrettyUnitTestResultPrinter::OnTestIterationStart(
+    const UnitTest& unit_test, int iteration) {
+  if (GTEST_FLAG(repeat) != 1)
+    printf("\nRepeating all tests (iteration %d) . . .\n\n", iteration + 1);
+
+  const char* const filter = GTEST_FLAG(filter).c_str();
+
+  // Prints the filter if it's not *.  This reminds the user that some
+  // tests may be skipped.
+  if (!String::CStringEquals(filter, kUniversalFilter)) {
+    ColoredPrintf(GTestColor::kYellow, "Note: %s filter = %s\n", GTEST_NAME_,
+                  filter);
+  }
+
+  if (internal::ShouldShard(kTestTotalShards, kTestShardIndex, false)) {
+    const int32_t shard_index = Int32FromEnvOrDie(kTestShardIndex, -1);
+    ColoredPrintf(GTestColor::kYellow, "Note: This is test shard %d of %s.\n",
+                  static_cast<int>(shard_index) + 1,
+                  internal::posix::GetEnv(kTestTotalShards));
+  }
+
+  if (GTEST_FLAG(shuffle)) {
+    ColoredPrintf(GTestColor::kYellow,
+                  "Note: Randomizing tests' orders with a seed of %d .\n",
+                  unit_test.random_seed());
+  }
+
+  ColoredPrintf(GTestColor::kGreen, "[==========] ");
+  printf("Running %s from %s.\n",
+         FormatTestCount(unit_test.test_to_run_count()).c_str(),
+         FormatTestSuiteCount(unit_test.test_suite_to_run_count()).c_str());
+  fflush(stdout);
+}
+
+void PrettyUnitTestResultPrinter::OnEnvironmentsSetUpStart(
+    const UnitTest& /*unit_test*/) {
+  ColoredPrintf(GTestColor::kGreen, "[----------] ");
+  printf("Global test environment set-up.\n");
+  fflush(stdout);
+}
+
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+void PrettyUnitTestResultPrinter::OnTestCaseStart(const TestCase& test_case) {
+  const std::string counts =
+      FormatCountableNoun(test_case.test_to_run_count(), "test", "tests");
+  ColoredPrintf(GTestColor::kGreen, "[----------] ");
+  printf("%s from %s", counts.c_str(), test_case.name());
+  if (test_case.type_param() == nullptr) {
+    printf("\n");
+  } else {
+    printf(", where %s = %s\n", kTypeParamLabel, test_case.type_param());
+  }
+  fflush(stdout);
+}
+#else
+void PrettyUnitTestResultPrinter::OnTestSuiteStart(
+    const TestSuite& test_suite) {
+  const std::string counts =
+      FormatCountableNoun(test_suite.test_to_run_count(), "test", "tests");
+  ColoredPrintf(GTestColor::kGreen, "[----------] ");
+  printf("%s from %s", counts.c_str(), test_suite.name());
+  if (test_suite.type_param() == nullptr) {
+    printf("\n");
+  } else {
+    printf(", where %s = %s\n", kTypeParamLabel, test_suite.type_param());
+  }
+  fflush(stdout);
+}
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+void PrettyUnitTestResultPrinter::OnTestStart(const TestInfo& test_info) {
+  ColoredPrintf(GTestColor::kGreen, "[ RUN      ] ");
+  PrintTestName(test_info.test_suite_name(), test_info.name());
+  printf("\n");
+  fflush(stdout);
+}
+
+// Called after an assertion failure.
+void PrettyUnitTestResultPrinter::OnTestPartResult(
+    const TestPartResult& result) {
+  switch (result.type()) {
+    // If the test part succeeded, we don't need to do anything.
+    case TestPartResult::kSuccess:
+      return;
+    default:
+      // Print failure message from the assertion
+      // (e.g. expected this and got that).
+      PrintTestPartResult(result);
+      fflush(stdout);
+  }
+}
+
+void PrettyUnitTestResultPrinter::OnTestEnd(const TestInfo& test_info) {
+  if (test_info.result()->Passed()) {
+    ColoredPrintf(GTestColor::kGreen, "[       OK ] ");
+  } else if (test_info.result()->Skipped()) {
+    ColoredPrintf(GTestColor::kGreen, "[  SKIPPED ] ");
+  } else {
+    ColoredPrintf(GTestColor::kRed, "[  FAILED  ] ");
+  }
+  PrintTestName(test_info.test_suite_name(), test_info.name());
+  if (test_info.result()->Failed())
+    PrintFullTestCommentIfPresent(test_info);
+
+  if (GTEST_FLAG(print_time)) {
+    printf(" (%s ms)\n", internal::StreamableToString(
+           test_info.result()->elapsed_time()).c_str());
+  } else {
+    printf("\n");
+  }
+  fflush(stdout);
+}
+
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+void PrettyUnitTestResultPrinter::OnTestCaseEnd(const TestCase& test_case) {
+  if (!GTEST_FLAG(print_time)) return;
+
+  const std::string counts =
+      FormatCountableNoun(test_case.test_to_run_count(), "test", "tests");
+  ColoredPrintf(GTestColor::kGreen, "[----------] ");
+  printf("%s from %s (%s ms total)\n\n", counts.c_str(), test_case.name(),
+         internal::StreamableToString(test_case.elapsed_time()).c_str());
+  fflush(stdout);
+}
+#else
+void PrettyUnitTestResultPrinter::OnTestSuiteEnd(const TestSuite& test_suite) {
+  if (!GTEST_FLAG(print_time)) return;
+
+  const std::string counts =
+      FormatCountableNoun(test_suite.test_to_run_count(), "test", "tests");
+  ColoredPrintf(GTestColor::kGreen, "[----------] ");
+  printf("%s from %s (%s ms total)\n\n", counts.c_str(), test_suite.name(),
+         internal::StreamableToString(test_suite.elapsed_time()).c_str());
+  fflush(stdout);
+}
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+void PrettyUnitTestResultPrinter::OnEnvironmentsTearDownStart(
+    const UnitTest& /*unit_test*/) {
+  ColoredPrintf(GTestColor::kGreen, "[----------] ");
+  printf("Global test environment tear-down\n");
+  fflush(stdout);
+}
+
+// Internal helper for printing the list of failed tests.
+void PrettyUnitTestResultPrinter::PrintFailedTests(const UnitTest& unit_test) {
+  const int failed_test_count = unit_test.failed_test_count();
+  ColoredPrintf(GTestColor::kRed, "[  FAILED  ] ");
+  printf("%s, listed below:\n", FormatTestCount(failed_test_count).c_str());
+
+  for (int i = 0; i < unit_test.total_test_suite_count(); ++i) {
+    const TestSuite& test_suite = *unit_test.GetTestSuite(i);
+    if (!test_suite.should_run() || (test_suite.failed_test_count() == 0)) {
+      continue;
+    }
+    for (int j = 0; j < test_suite.total_test_count(); ++j) {
+      const TestInfo& test_info = *test_suite.GetTestInfo(j);
+      if (!test_info.should_run() || !test_info.result()->Failed()) {
+        continue;
+      }
+      ColoredPrintf(GTestColor::kRed, "[  FAILED  ] ");
+      printf("%s.%s", test_suite.name(), test_info.name());
+      PrintFullTestCommentIfPresent(test_info);
+      printf("\n");
+    }
+  }
+  printf("\n%2d FAILED %s\n", failed_test_count,
+         failed_test_count == 1 ? "TEST" : "TESTS");
+}
+
+// Internal helper for printing the list of test suite failures not covered by
+// PrintFailedTests.
+void PrettyUnitTestResultPrinter::PrintFailedTestSuites(
+    const UnitTest& unit_test) {
+  int suite_failure_count = 0;
+  for (int i = 0; i < unit_test.total_test_suite_count(); ++i) {
+    const TestSuite& test_suite = *unit_test.GetTestSuite(i);
+    if (!test_suite.should_run()) {
+      continue;
+    }
+    if (test_suite.ad_hoc_test_result().Failed()) {
+      ColoredPrintf(GTestColor::kRed, "[  FAILED  ] ");
+      printf("%s: SetUpTestSuite or TearDownTestSuite\n", test_suite.name());
+      ++suite_failure_count;
+    }
+  }
+  if (suite_failure_count > 0) {
+    printf("\n%2d FAILED TEST %s\n", suite_failure_count,
+           suite_failure_count == 1 ? "SUITE" : "SUITES");
+  }
+}
+
+// Internal helper for printing the list of skipped tests.
+void PrettyUnitTestResultPrinter::PrintSkippedTests(const UnitTest& unit_test) {
+  const int skipped_test_count = unit_test.skipped_test_count();
+  if (skipped_test_count == 0) {
+    return;
+  }
+
+  for (int i = 0; i < unit_test.total_test_suite_count(); ++i) {
+    const TestSuite& test_suite = *unit_test.GetTestSuite(i);
+    if (!test_suite.should_run() || (test_suite.skipped_test_count() == 0)) {
+      continue;
+    }
+    for (int j = 0; j < test_suite.total_test_count(); ++j) {
+      const TestInfo& test_info = *test_suite.GetTestInfo(j);
+      if (!test_info.should_run() || !test_info.result()->Skipped()) {
+        continue;
+      }
+      ColoredPrintf(GTestColor::kGreen, "[  SKIPPED ] ");
+      printf("%s.%s", test_suite.name(), test_info.name());
+      printf("\n");
+    }
+  }
+}
+
+void PrettyUnitTestResultPrinter::OnTestIterationEnd(const UnitTest& unit_test,
+                                                     int /*iteration*/) {
+  ColoredPrintf(GTestColor::kGreen, "[==========] ");
+  printf("%s from %s ran.",
+         FormatTestCount(unit_test.test_to_run_count()).c_str(),
+         FormatTestSuiteCount(unit_test.test_suite_to_run_count()).c_str());
+  if (GTEST_FLAG(print_time)) {
+    printf(" (%s ms total)",
+           internal::StreamableToString(unit_test.elapsed_time()).c_str());
+  }
+  printf("\n");
+  ColoredPrintf(GTestColor::kGreen, "[  PASSED  ] ");
+  printf("%s.\n", FormatTestCount(unit_test.successful_test_count()).c_str());
+
+  const int skipped_test_count = unit_test.skipped_test_count();
+  if (skipped_test_count > 0) {
+    ColoredPrintf(GTestColor::kGreen, "[  SKIPPED ] ");
+    printf("%s, listed below:\n", FormatTestCount(skipped_test_count).c_str());
+    PrintSkippedTests(unit_test);
+  }
+
+  if (!unit_test.Passed()) {
+    PrintFailedTests(unit_test);
+    PrintFailedTestSuites(unit_test);
+  }
+
+  int num_disabled = unit_test.reportable_disabled_test_count();
+  if (num_disabled && !GTEST_FLAG(also_run_disabled_tests)) {
+    if (unit_test.Passed()) {
+      printf("\n");  // Add a spacer if no FAILURE banner is displayed.
+    }
+    ColoredPrintf(GTestColor::kYellow, "  YOU HAVE %d DISABLED %s\n\n",
+                  num_disabled, num_disabled == 1 ? "TEST" : "TESTS");
+  }
+  // Ensure that Google Test output is printed before, e.g., heapchecker output.
+  fflush(stdout);
+}
+
+// End PrettyUnitTestResultPrinter
+
+// This class implements the TestEventListener interface.
+//
+// Class BriefUnitTestResultPrinter is copyable.
+class BriefUnitTestResultPrinter : public TestEventListener {
+ public:
+  BriefUnitTestResultPrinter() {}
+  static void PrintTestName(const char* test_suite, const char* test) {
+    printf("%s.%s", test_suite, test);
+  }
+
+  // The following methods override what's in the TestEventListener class.
+  void OnTestProgramStart(const UnitTest& /*unit_test*/) override {}
+  void OnTestIterationStart(const UnitTest& /*unit_test*/,
+                            int /*iteration*/) override {}
+  void OnEnvironmentsSetUpStart(const UnitTest& /*unit_test*/) override {}
+  void OnEnvironmentsSetUpEnd(const UnitTest& /*unit_test*/) override {}
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestCaseStart(const TestCase& /*test_case*/) override {}
+#else
+  void OnTestSuiteStart(const TestSuite& /*test_suite*/) override {}
+#endif  // OnTestCaseStart
+
+  void OnTestStart(const TestInfo& /*test_info*/) override {}
+
+  void OnTestPartResult(const TestPartResult& result) override;
+  void OnTestEnd(const TestInfo& test_info) override;
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestCaseEnd(const TestCase& /*test_case*/) override {}
+#else
+  void OnTestSuiteEnd(const TestSuite& /*test_suite*/) override {}
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  void OnEnvironmentsTearDownStart(const UnitTest& /*unit_test*/) override {}
+  void OnEnvironmentsTearDownEnd(const UnitTest& /*unit_test*/) override {}
+  void OnTestIterationEnd(const UnitTest& unit_test, int iteration) override;
+  void OnTestProgramEnd(const UnitTest& /*unit_test*/) override {}
+};
+
+// Called after an assertion failure.
+void BriefUnitTestResultPrinter::OnTestPartResult(
+    const TestPartResult& result) {
+  switch (result.type()) {
+    // If the test part succeeded, we don't need to do anything.
+    case TestPartResult::kSuccess:
+      return;
+    default:
+      // Print failure message from the assertion
+      // (e.g. expected this and got that).
+      PrintTestPartResult(result);
+      fflush(stdout);
+  }
+}
+
+void BriefUnitTestResultPrinter::OnTestEnd(const TestInfo& test_info) {
+  if (test_info.result()->Failed()) {
+    ColoredPrintf(GTestColor::kRed, "[  FAILED  ] ");
+    PrintTestName(test_info.test_suite_name(), test_info.name());
+    PrintFullTestCommentIfPresent(test_info);
+
+    if (GTEST_FLAG(print_time)) {
+      printf(" (%s ms)\n",
+             internal::StreamableToString(test_info.result()->elapsed_time())
+                 .c_str());
+    } else {
+      printf("\n");
+    }
+    fflush(stdout);
+  }
+}
+
+void BriefUnitTestResultPrinter::OnTestIterationEnd(const UnitTest& unit_test,
+                                                    int /*iteration*/) {
+  ColoredPrintf(GTestColor::kGreen, "[==========] ");
+  printf("%s from %s ran.",
+         FormatTestCount(unit_test.test_to_run_count()).c_str(),
+         FormatTestSuiteCount(unit_test.test_suite_to_run_count()).c_str());
+  if (GTEST_FLAG(print_time)) {
+    printf(" (%s ms total)",
+           internal::StreamableToString(unit_test.elapsed_time()).c_str());
+  }
+  printf("\n");
+  ColoredPrintf(GTestColor::kGreen, "[  PASSED  ] ");
+  printf("%s.\n", FormatTestCount(unit_test.successful_test_count()).c_str());
+
+  const int skipped_test_count = unit_test.skipped_test_count();
+  if (skipped_test_count > 0) {
+    ColoredPrintf(GTestColor::kGreen, "[  SKIPPED ] ");
+    printf("%s.\n", FormatTestCount(skipped_test_count).c_str());
+  }
+
+  int num_disabled = unit_test.reportable_disabled_test_count();
+  if (num_disabled && !GTEST_FLAG(also_run_disabled_tests)) {
+    if (unit_test.Passed()) {
+      printf("\n");  // Add a spacer if no FAILURE banner is displayed.
+    }
+    ColoredPrintf(GTestColor::kYellow, "  YOU HAVE %d DISABLED %s\n\n",
+                  num_disabled, num_disabled == 1 ? "TEST" : "TESTS");
+  }
+  // Ensure that Google Test output is printed before, e.g., heapchecker output.
+  fflush(stdout);
+}
+
+// End BriefUnitTestResultPrinter
+
+// class TestEventRepeater
+//
+// This class forwards events to other event listeners.
+class TestEventRepeater : public TestEventListener {
+ public:
+  TestEventRepeater() : forwarding_enabled_(true) {}
+  ~TestEventRepeater() override;
+  void Append(TestEventListener *listener);
+  TestEventListener* Release(TestEventListener* listener);
+
+  // Controls whether events will be forwarded to listeners_. Set to false
+  // in death test child processes.
+  bool forwarding_enabled() const { return forwarding_enabled_; }
+  void set_forwarding_enabled(bool enable) { forwarding_enabled_ = enable; }
+
+  void OnTestProgramStart(const UnitTest& unit_test) override;
+  void OnTestIterationStart(const UnitTest& unit_test, int iteration) override;
+  void OnEnvironmentsSetUpStart(const UnitTest& unit_test) override;
+  void OnEnvironmentsSetUpEnd(const UnitTest& unit_test) override;
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestCaseStart(const TestSuite& parameter) override;
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestSuiteStart(const TestSuite& parameter) override;
+  void OnTestStart(const TestInfo& test_info) override;
+  void OnTestPartResult(const TestPartResult& result) override;
+  void OnTestEnd(const TestInfo& test_info) override;
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestCaseEnd(const TestCase& parameter) override;
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestSuiteEnd(const TestSuite& parameter) override;
+  void OnEnvironmentsTearDownStart(const UnitTest& unit_test) override;
+  void OnEnvironmentsTearDownEnd(const UnitTest& unit_test) override;
+  void OnTestIterationEnd(const UnitTest& unit_test, int iteration) override;
+  void OnTestProgramEnd(const UnitTest& unit_test) override;
+
+ private:
+  // Controls whether events will be forwarded to listeners_. Set to false
+  // in death test child processes.
+  bool forwarding_enabled_;
+  // The list of listeners that receive events.
+  std::vector<TestEventListener*> listeners_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestEventRepeater);
+};
+
+TestEventRepeater::~TestEventRepeater() {
+  ForEach(listeners_, Delete<TestEventListener>);
+}
+
+void TestEventRepeater::Append(TestEventListener *listener) {
+  listeners_.push_back(listener);
+}
+
+TestEventListener* TestEventRepeater::Release(TestEventListener *listener) {
+  for (size_t i = 0; i < listeners_.size(); ++i) {
+    if (listeners_[i] == listener) {
+      listeners_.erase(listeners_.begin() + static_cast<int>(i));
+      return listener;
+    }
+  }
+
+  return nullptr;
+}
+
+// Since most methods are very similar, use macros to reduce boilerplate.
+// This defines a member that forwards the call to all listeners.
+#define GTEST_REPEATER_METHOD_(Name, Type) \
+void TestEventRepeater::Name(const Type& parameter) { \
+  if (forwarding_enabled_) { \
+    for (size_t i = 0; i < listeners_.size(); i++) { \
+      listeners_[i]->Name(parameter); \
+    } \
+  } \
+}
+// This defines a member that forwards the call to all listeners in reverse
+// order.
+#define GTEST_REVERSE_REPEATER_METHOD_(Name, Type)      \
+  void TestEventRepeater::Name(const Type& parameter) { \
+    if (forwarding_enabled_) {                          \
+      for (size_t i = listeners_.size(); i != 0; i--) { \
+        listeners_[i - 1]->Name(parameter);             \
+      }                                                 \
+    }                                                   \
+  }
+
+GTEST_REPEATER_METHOD_(OnTestProgramStart, UnitTest)
+GTEST_REPEATER_METHOD_(OnEnvironmentsSetUpStart, UnitTest)
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+GTEST_REPEATER_METHOD_(OnTestCaseStart, TestSuite)
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+GTEST_REPEATER_METHOD_(OnTestSuiteStart, TestSuite)
+GTEST_REPEATER_METHOD_(OnTestStart, TestInfo)
+GTEST_REPEATER_METHOD_(OnTestPartResult, TestPartResult)
+GTEST_REPEATER_METHOD_(OnEnvironmentsTearDownStart, UnitTest)
+GTEST_REVERSE_REPEATER_METHOD_(OnEnvironmentsSetUpEnd, UnitTest)
+GTEST_REVERSE_REPEATER_METHOD_(OnEnvironmentsTearDownEnd, UnitTest)
+GTEST_REVERSE_REPEATER_METHOD_(OnTestEnd, TestInfo)
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+GTEST_REVERSE_REPEATER_METHOD_(OnTestCaseEnd, TestSuite)
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+GTEST_REVERSE_REPEATER_METHOD_(OnTestSuiteEnd, TestSuite)
+GTEST_REVERSE_REPEATER_METHOD_(OnTestProgramEnd, UnitTest)
+
+#undef GTEST_REPEATER_METHOD_
+#undef GTEST_REVERSE_REPEATER_METHOD_
+
+void TestEventRepeater::OnTestIterationStart(const UnitTest& unit_test,
+                                             int iteration) {
+  if (forwarding_enabled_) {
+    for (size_t i = 0; i < listeners_.size(); i++) {
+      listeners_[i]->OnTestIterationStart(unit_test, iteration);
+    }
+  }
+}
+
+void TestEventRepeater::OnTestIterationEnd(const UnitTest& unit_test,
+                                           int iteration) {
+  if (forwarding_enabled_) {
+    for (size_t i = listeners_.size(); i > 0; i--) {
+      listeners_[i - 1]->OnTestIterationEnd(unit_test, iteration);
+    }
+  }
+}
+
+// End TestEventRepeater
+
+// This class generates an XML output file.
+class XmlUnitTestResultPrinter : public EmptyTestEventListener {
+ public:
+  explicit XmlUnitTestResultPrinter(const char* output_file);
+
+  void OnTestIterationEnd(const UnitTest& unit_test, int iteration) override;
+  void ListTestsMatchingFilter(const std::vector<TestSuite*>& test_suites);
+
+  // Prints an XML summary of all unit tests.
+  static void PrintXmlTestsList(std::ostream* stream,
+                                const std::vector<TestSuite*>& test_suites);
+
+ private:
+  // Is c a whitespace character that is normalized to a space character
+  // when it appears in an XML attribute value?
+  static bool IsNormalizableWhitespace(char c) {
+    return c == 0x9 || c == 0xA || c == 0xD;
+  }
+
+  // May c appear in a well-formed XML document?
+  static bool IsValidXmlCharacter(char c) {
+    return IsNormalizableWhitespace(c) || c >= 0x20;
+  }
+
+  // Returns an XML-escaped copy of the input string str.  If
+  // is_attribute is true, the text is meant to appear as an attribute
+  // value, and normalizable whitespace is preserved by replacing it
+  // with character references.
+  static std::string EscapeXml(const std::string& str, bool is_attribute);
+
+  // Returns the given string with all characters invalid in XML removed.
+  static std::string RemoveInvalidXmlCharacters(const std::string& str);
+
+  // Convenience wrapper around EscapeXml when str is an attribute value.
+  static std::string EscapeXmlAttribute(const std::string& str) {
+    return EscapeXml(str, true);
+  }
+
+  // Convenience wrapper around EscapeXml when str is not an attribute value.
+  static std::string EscapeXmlText(const char* str) {
+    return EscapeXml(str, false);
+  }
+
+  // Verifies that the given attribute belongs to the given element and
+  // streams the attribute as XML.
+  static void OutputXmlAttribute(std::ostream* stream,
+                                 const std::string& element_name,
+                                 const std::string& name,
+                                 const std::string& value);
+
+  // Streams an XML CDATA section, escaping invalid CDATA sequences as needed.
+  static void OutputXmlCDataSection(::std::ostream* stream, const char* data);
+
+  // Streams a test suite XML stanza containing the given test result.
+  //
+  // Requires: result.Failed()
+  static void OutputXmlTestSuiteForTestResult(::std::ostream* stream,
+                                              const TestResult& result);
+
+  // Streams an XML representation of a TestResult object.
+  static void OutputXmlTestResult(::std::ostream* stream,
+                                  const TestResult& result);
+
+  // Streams an XML representation of a TestInfo object.
+  static void OutputXmlTestInfo(::std::ostream* stream,
+                                const char* test_suite_name,
+                                const TestInfo& test_info);
+
+  // Prints an XML representation of a TestSuite object
+  static void PrintXmlTestSuite(::std::ostream* stream,
+                                const TestSuite& test_suite);
+
+  // Prints an XML summary of unit_test to output stream out.
+  static void PrintXmlUnitTest(::std::ostream* stream,
+                               const UnitTest& unit_test);
+
+  // Produces a string representing the test properties in a result as space
+  // delimited XML attributes based on the property key="value" pairs.
+  // When the std::string is not empty, it includes a space at the beginning,
+  // to delimit this attribute from prior attributes.
+  static std::string TestPropertiesAsXmlAttributes(const TestResult& result);
+
+  // Streams an XML representation of the test properties of a TestResult
+  // object.
+  static void OutputXmlTestProperties(std::ostream* stream,
+                                      const TestResult& result);
+
+  // The output file.
+  const std::string output_file_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(XmlUnitTestResultPrinter);
+};
+
+// Creates a new XmlUnitTestResultPrinter.
+XmlUnitTestResultPrinter::XmlUnitTestResultPrinter(const char* output_file)
+    : output_file_(output_file) {
+  if (output_file_.empty()) {
+    GTEST_LOG_(FATAL) << "XML output file may not be null";
+  }
+}
+
+// Called after the unit test ends.
+void XmlUnitTestResultPrinter::OnTestIterationEnd(const UnitTest& unit_test,
+                                                  int /*iteration*/) {
+  FILE* xmlout = OpenFileForWriting(output_file_);
+  std::stringstream stream;
+  PrintXmlUnitTest(&stream, unit_test);
+  fprintf(xmlout, "%s", StringStreamToString(&stream).c_str());
+  fclose(xmlout);
+}
+
+void XmlUnitTestResultPrinter::ListTestsMatchingFilter(
+    const std::vector<TestSuite*>& test_suites) {
+  FILE* xmlout = OpenFileForWriting(output_file_);
+  std::stringstream stream;
+  PrintXmlTestsList(&stream, test_suites);
+  fprintf(xmlout, "%s", StringStreamToString(&stream).c_str());
+  fclose(xmlout);
+}
+
+// Returns an XML-escaped copy of the input string str.  If is_attribute
+// is true, the text is meant to appear as an attribute value, and
+// normalizable whitespace is preserved by replacing it with character
+// references.
+//
+// Invalid XML characters in str, if any, are stripped from the output.
+// It is expected that most, if not all, of the text processed by this
+// module will consist of ordinary English text.
+// If this module is ever modified to produce version 1.1 XML output,
+// most invalid characters can be retained using character references.
+std::string XmlUnitTestResultPrinter::EscapeXml(
+    const std::string& str, bool is_attribute) {
+  Message m;
+
+  for (size_t i = 0; i < str.size(); ++i) {
+    const char ch = str[i];
+    switch (ch) {
+      case '<':
+        m << "&lt;";
+        break;
+      case '>':
+        m << "&gt;";
+        break;
+      case '&':
+        m << "&amp;";
+        break;
+      case '\'':
+        if (is_attribute)
+          m << "&apos;";
+        else
+          m << '\'';
+        break;
+      case '"':
+        if (is_attribute)
+          m << "&quot;";
+        else
+          m << '"';
+        break;
+      default:
+        if (IsValidXmlCharacter(ch)) {
+          if (is_attribute && IsNormalizableWhitespace(ch))
+            m << "&#x" << String::FormatByte(static_cast<unsigned char>(ch))
+              << ";";
+          else
+            m << ch;
+        }
+        break;
+    }
+  }
+
+  return m.GetString();
+}
+
+// Returns the given string with all characters invalid in XML removed.
+// Currently invalid characters are dropped from the string. An
+// alternative is to replace them with certain characters such as . or ?.
+std::string XmlUnitTestResultPrinter::RemoveInvalidXmlCharacters(
+    const std::string& str) {
+  std::string output;
+  output.reserve(str.size());
+  for (std::string::const_iterator it = str.begin(); it != str.end(); ++it)
+    if (IsValidXmlCharacter(*it))
+      output.push_back(*it);
+
+  return output;
+}
+
+// The following routines generate an XML representation of a UnitTest
+// object.
+// GOOGLETEST_CM0009 DO NOT DELETE
+//
+// This is how Google Test concepts map to the DTD:
+//
+// <testsuites name="AllTests">        <-- corresponds to a UnitTest object
+//   <testsuite name="testcase-name">  <-- corresponds to a TestSuite object
+//     <testcase name="test-name">     <-- corresponds to a TestInfo object
+//       <failure message="...">...</failure>
+//       <failure message="...">...</failure>
+//       <failure message="...">...</failure>
+//                                     <-- individual assertion failures
+//     </testcase>
+//   </testsuite>
+// </testsuites>
+
+// Formats the given time in milliseconds as seconds.
+std::string FormatTimeInMillisAsSeconds(TimeInMillis ms) {
+  ::std::stringstream ss;
+  ss << (static_cast<double>(ms) * 1e-3);
+  return ss.str();
+}
+
+static bool PortableLocaltime(time_t seconds, struct tm* out) {
+#if defined(_MSC_VER)
+  return localtime_s(out, &seconds) == 0;
+#elif defined(__MINGW32__) || defined(__MINGW64__)
+  // MINGW <time.h> provides neither localtime_r nor localtime_s, but uses
+  // Windows' localtime(), which has a thread-local tm buffer.
+  struct tm* tm_ptr = localtime(&seconds);  // NOLINT
+  if (tm_ptr == nullptr) return false;
+  *out = *tm_ptr;
+  return true;
+#elif defined(__STDC_LIB_EXT1__)
+  // Uses localtime_s when available as localtime_r is only available from
+  // C23 standard.
+  return localtime_s(&seconds, out) != nullptr;
+#else
+  return localtime_r(&seconds, out) != nullptr;
+#endif
+}
+
+// Converts the given epoch time in milliseconds to a date string in the ISO
+// 8601 format, without the timezone information.
+std::string FormatEpochTimeInMillisAsIso8601(TimeInMillis ms) {
+  struct tm time_struct;
+  if (!PortableLocaltime(static_cast<time_t>(ms / 1000), &time_struct))
+    return "";
+  // YYYY-MM-DDThh:mm:ss.sss
+  return StreamableToString(time_struct.tm_year + 1900) + "-" +
+      String::FormatIntWidth2(time_struct.tm_mon + 1) + "-" +
+      String::FormatIntWidth2(time_struct.tm_mday) + "T" +
+      String::FormatIntWidth2(time_struct.tm_hour) + ":" +
+      String::FormatIntWidth2(time_struct.tm_min) + ":" +
+      String::FormatIntWidth2(time_struct.tm_sec) + "." +
+      String::FormatIntWidthN(static_cast<int>(ms % 1000), 3);
+}
+
+// Streams an XML CDATA section, escaping invalid CDATA sequences as needed.
+void XmlUnitTestResultPrinter::OutputXmlCDataSection(::std::ostream* stream,
+                                                     const char* data) {
+  const char* segment = data;
+  *stream << "<![CDATA[";
+  for (;;) {
+    const char* const next_segment = strstr(segment, "]]>");
+    if (next_segment != nullptr) {
+      stream->write(
+          segment, static_cast<std::streamsize>(next_segment - segment));
+      *stream << "]]>]]&gt;<![CDATA[";
+      segment = next_segment + strlen("]]>");
+    } else {
+      *stream << segment;
+      break;
+    }
+  }
+  *stream << "]]>";
+}
+
+void XmlUnitTestResultPrinter::OutputXmlAttribute(
+    std::ostream* stream,
+    const std::string& element_name,
+    const std::string& name,
+    const std::string& value) {
+  const std::vector<std::string>& allowed_names =
+      GetReservedOutputAttributesForElement(element_name);
+
+  GTEST_CHECK_(std::find(allowed_names.begin(), allowed_names.end(), name) !=
+                   allowed_names.end())
+      << "Attribute " << name << " is not allowed for element <" << element_name
+      << ">.";
+
+  *stream << " " << name << "=\"" << EscapeXmlAttribute(value) << "\"";
+}
+
+// Streams a test suite XML stanza containing the given test result.
+void XmlUnitTestResultPrinter::OutputXmlTestSuiteForTestResult(
+    ::std::ostream* stream, const TestResult& result) {
+  // Output the boilerplate for a minimal test suite with one test.
+  *stream << "  <testsuite";
+  OutputXmlAttribute(stream, "testsuite", "name", "NonTestSuiteFailure");
+  OutputXmlAttribute(stream, "testsuite", "tests", "1");
+  OutputXmlAttribute(stream, "testsuite", "failures", "1");
+  OutputXmlAttribute(stream, "testsuite", "disabled", "0");
+  OutputXmlAttribute(stream, "testsuite", "skipped", "0");
+  OutputXmlAttribute(stream, "testsuite", "errors", "0");
+  OutputXmlAttribute(stream, "testsuite", "time",
+                     FormatTimeInMillisAsSeconds(result.elapsed_time()));
+  OutputXmlAttribute(
+      stream, "testsuite", "timestamp",
+      FormatEpochTimeInMillisAsIso8601(result.start_timestamp()));
+  *stream << ">";
+
+  // Output the boilerplate for a minimal test case with a single test.
+  *stream << "    <testcase";
+  OutputXmlAttribute(stream, "testcase", "name", "");
+  OutputXmlAttribute(stream, "testcase", "status", "run");
+  OutputXmlAttribute(stream, "testcase", "result", "completed");
+  OutputXmlAttribute(stream, "testcase", "classname", "");
+  OutputXmlAttribute(stream, "testcase", "time",
+                     FormatTimeInMillisAsSeconds(result.elapsed_time()));
+  OutputXmlAttribute(
+      stream, "testcase", "timestamp",
+      FormatEpochTimeInMillisAsIso8601(result.start_timestamp()));
+
+  // Output the actual test result.
+  OutputXmlTestResult(stream, result);
+
+  // Complete the test suite.
+  *stream << "  </testsuite>\n";
+}
+
+// Prints an XML representation of a TestInfo object.
+void XmlUnitTestResultPrinter::OutputXmlTestInfo(::std::ostream* stream,
+                                                 const char* test_suite_name,
+                                                 const TestInfo& test_info) {
+  const TestResult& result = *test_info.result();
+  const std::string kTestsuite = "testcase";
+
+  if (test_info.is_in_another_shard()) {
+    return;
+  }
+
+  *stream << "    <testcase";
+  OutputXmlAttribute(stream, kTestsuite, "name", test_info.name());
+
+  if (test_info.value_param() != nullptr) {
+    OutputXmlAttribute(stream, kTestsuite, "value_param",
+                       test_info.value_param());
+  }
+  if (test_info.type_param() != nullptr) {
+    OutputXmlAttribute(stream, kTestsuite, "type_param",
+                       test_info.type_param());
+  }
+  if (GTEST_FLAG(list_tests)) {
+    OutputXmlAttribute(stream, kTestsuite, "file", test_info.file());
+    OutputXmlAttribute(stream, kTestsuite, "line",
+                       StreamableToString(test_info.line()));
+    *stream << " />\n";
+    return;
+  }
+
+  OutputXmlAttribute(stream, kTestsuite, "status",
+                     test_info.should_run() ? "run" : "notrun");
+  OutputXmlAttribute(stream, kTestsuite, "result",
+                     test_info.should_run()
+                         ? (result.Skipped() ? "skipped" : "completed")
+                         : "suppressed");
+  OutputXmlAttribute(stream, kTestsuite, "time",
+                     FormatTimeInMillisAsSeconds(result.elapsed_time()));
+  OutputXmlAttribute(
+      stream, kTestsuite, "timestamp",
+      FormatEpochTimeInMillisAsIso8601(result.start_timestamp()));
+  OutputXmlAttribute(stream, kTestsuite, "classname", test_suite_name);
+
+  OutputXmlTestResult(stream, result);
+}
+
+void XmlUnitTestResultPrinter::OutputXmlTestResult(::std::ostream* stream,
+                                                   const TestResult& result) {
+  int failures = 0;
+  int skips = 0;
+  for (int i = 0; i < result.total_part_count(); ++i) {
+    const TestPartResult& part = result.GetTestPartResult(i);
+    if (part.failed()) {
+      if (++failures == 1 && skips == 0) {
+        *stream << ">\n";
+      }
+      const std::string location =
+          internal::FormatCompilerIndependentFileLocation(part.file_name(),
+                                                          part.line_number());
+      const std::string summary = location + "\n" + part.summary();
+      *stream << "      <failure message=\""
+              << EscapeXmlAttribute(summary)
+              << "\" type=\"\">";
+      const std::string detail = location + "\n" + part.message();
+      OutputXmlCDataSection(stream, RemoveInvalidXmlCharacters(detail).c_str());
+      *stream << "</failure>\n";
+    } else if (part.skipped()) {
+      if (++skips == 1 && failures == 0) {
+        *stream << ">\n";
+      }
+      const std::string location =
+          internal::FormatCompilerIndependentFileLocation(part.file_name(),
+                                                          part.line_number());
+      const std::string summary = location + "\n" + part.summary();
+      *stream << "      <skipped message=\""
+              << EscapeXmlAttribute(summary.c_str()) << "\">";
+      const std::string detail = location + "\n" + part.message();
+      OutputXmlCDataSection(stream, RemoveInvalidXmlCharacters(detail).c_str());
+      *stream << "</skipped>\n";
+    }
+  }
+
+  if (failures == 0 && skips == 0 && result.test_property_count() == 0) {
+    *stream << " />\n";
+  } else {
+    if (failures == 0 && skips == 0) {
+      *stream << ">\n";
+    }
+    OutputXmlTestProperties(stream, result);
+    *stream << "    </testcase>\n";
+  }
+}
+
+// Prints an XML representation of a TestSuite object
+void XmlUnitTestResultPrinter::PrintXmlTestSuite(std::ostream* stream,
+                                                 const TestSuite& test_suite) {
+  const std::string kTestsuite = "testsuite";
+  *stream << "  <" << kTestsuite;
+  OutputXmlAttribute(stream, kTestsuite, "name", test_suite.name());
+  OutputXmlAttribute(stream, kTestsuite, "tests",
+                     StreamableToString(test_suite.reportable_test_count()));
+  if (!GTEST_FLAG(list_tests)) {
+    OutputXmlAttribute(stream, kTestsuite, "failures",
+                       StreamableToString(test_suite.failed_test_count()));
+    OutputXmlAttribute(
+        stream, kTestsuite, "disabled",
+        StreamableToString(test_suite.reportable_disabled_test_count()));
+    OutputXmlAttribute(stream, kTestsuite, "skipped",
+                       StreamableToString(test_suite.skipped_test_count()));
+
+    OutputXmlAttribute(stream, kTestsuite, "errors", "0");
+
+    OutputXmlAttribute(stream, kTestsuite, "time",
+                       FormatTimeInMillisAsSeconds(test_suite.elapsed_time()));
+    OutputXmlAttribute(
+        stream, kTestsuite, "timestamp",
+        FormatEpochTimeInMillisAsIso8601(test_suite.start_timestamp()));
+    *stream << TestPropertiesAsXmlAttributes(test_suite.ad_hoc_test_result());
+  }
+  *stream << ">\n";
+  for (int i = 0; i < test_suite.total_test_count(); ++i) {
+    if (test_suite.GetTestInfo(i)->is_reportable())
+      OutputXmlTestInfo(stream, test_suite.name(), *test_suite.GetTestInfo(i));
+  }
+  *stream << "  </" << kTestsuite << ">\n";
+}
+
+// Prints an XML summary of unit_test to output stream out.
+void XmlUnitTestResultPrinter::PrintXmlUnitTest(std::ostream* stream,
+                                                const UnitTest& unit_test) {
+  const std::string kTestsuites = "testsuites";
+
+  *stream << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
+  *stream << "<" << kTestsuites;
+
+  OutputXmlAttribute(stream, kTestsuites, "tests",
+                     StreamableToString(unit_test.reportable_test_count()));
+  OutputXmlAttribute(stream, kTestsuites, "failures",
+                     StreamableToString(unit_test.failed_test_count()));
+  OutputXmlAttribute(
+      stream, kTestsuites, "disabled",
+      StreamableToString(unit_test.reportable_disabled_test_count()));
+  OutputXmlAttribute(stream, kTestsuites, "errors", "0");
+  OutputXmlAttribute(stream, kTestsuites, "time",
+                     FormatTimeInMillisAsSeconds(unit_test.elapsed_time()));
+  OutputXmlAttribute(
+      stream, kTestsuites, "timestamp",
+      FormatEpochTimeInMillisAsIso8601(unit_test.start_timestamp()));
+
+  if (GTEST_FLAG(shuffle)) {
+    OutputXmlAttribute(stream, kTestsuites, "random_seed",
+                       StreamableToString(unit_test.random_seed()));
+  }
+  *stream << TestPropertiesAsXmlAttributes(unit_test.ad_hoc_test_result());
+
+  OutputXmlAttribute(stream, kTestsuites, "name", "AllTests");
+  *stream << ">\n";
+
+  for (int i = 0; i < unit_test.total_test_suite_count(); ++i) {
+    if (unit_test.GetTestSuite(i)->reportable_test_count() > 0)
+      PrintXmlTestSuite(stream, *unit_test.GetTestSuite(i));
+  }
+
+  // If there was a test failure outside of one of the test suites (like in a
+  // test environment) include that in the output.
+  if (unit_test.ad_hoc_test_result().Failed()) {
+    OutputXmlTestSuiteForTestResult(stream, unit_test.ad_hoc_test_result());
+  }
+
+  *stream << "</" << kTestsuites << ">\n";
+}
+
+void XmlUnitTestResultPrinter::PrintXmlTestsList(
+    std::ostream* stream, const std::vector<TestSuite*>& test_suites) {
+  const std::string kTestsuites = "testsuites";
+
+  *stream << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
+  *stream << "<" << kTestsuites;
+
+  int total_tests = 0;
+  for (auto test_suite : test_suites) {
+    total_tests += test_suite->total_test_count();
+  }
+  OutputXmlAttribute(stream, kTestsuites, "tests",
+                     StreamableToString(total_tests));
+  OutputXmlAttribute(stream, kTestsuites, "name", "AllTests");
+  *stream << ">\n";
+
+  for (auto test_suite : test_suites) {
+    PrintXmlTestSuite(stream, *test_suite);
+  }
+  *stream << "</" << kTestsuites << ">\n";
+}
+
+// Produces a string representing the test properties in a result as space
+// delimited XML attributes based on the property key="value" pairs.
+std::string XmlUnitTestResultPrinter::TestPropertiesAsXmlAttributes(
+    const TestResult& result) {
+  Message attributes;
+  for (int i = 0; i < result.test_property_count(); ++i) {
+    const TestProperty& property = result.GetTestProperty(i);
+    attributes << " " << property.key() << "="
+        << "\"" << EscapeXmlAttribute(property.value()) << "\"";
+  }
+  return attributes.GetString();
+}
+
+void XmlUnitTestResultPrinter::OutputXmlTestProperties(
+    std::ostream* stream, const TestResult& result) {
+  const std::string kProperties = "properties";
+  const std::string kProperty = "property";
+
+  if (result.test_property_count() <= 0) {
+    return;
+  }
+
+  *stream << "<" << kProperties << ">\n";
+  for (int i = 0; i < result.test_property_count(); ++i) {
+    const TestProperty& property = result.GetTestProperty(i);
+    *stream << "<" << kProperty;
+    *stream << " name=\"" << EscapeXmlAttribute(property.key()) << "\"";
+    *stream << " value=\"" << EscapeXmlAttribute(property.value()) << "\"";
+    *stream << "/>\n";
+  }
+  *stream << "</" << kProperties << ">\n";
+}
+
+// End XmlUnitTestResultPrinter
+
+// This class generates an JSON output file.
+class JsonUnitTestResultPrinter : public EmptyTestEventListener {
+ public:
+  explicit JsonUnitTestResultPrinter(const char* output_file);
+
+  void OnTestIterationEnd(const UnitTest& unit_test, int iteration) override;
+
+  // Prints an JSON summary of all unit tests.
+  static void PrintJsonTestList(::std::ostream* stream,
+                                const std::vector<TestSuite*>& test_suites);
+
+ private:
+  // Returns an JSON-escaped copy of the input string str.
+  static std::string EscapeJson(const std::string& str);
+
+  //// Verifies that the given attribute belongs to the given element and
+  //// streams the attribute as JSON.
+  static void OutputJsonKey(std::ostream* stream,
+                            const std::string& element_name,
+                            const std::string& name,
+                            const std::string& value,
+                            const std::string& indent,
+                            bool comma = true);
+  static void OutputJsonKey(std::ostream* stream,
+                            const std::string& element_name,
+                            const std::string& name,
+                            int value,
+                            const std::string& indent,
+                            bool comma = true);
+
+  // Streams a test suite JSON stanza containing the given test result.
+  //
+  // Requires: result.Failed()
+  static void OutputJsonTestSuiteForTestResult(::std::ostream* stream,
+                                               const TestResult& result);
+
+  // Streams a JSON representation of a TestResult object.
+  static void OutputJsonTestResult(::std::ostream* stream,
+                                   const TestResult& result);
+
+  // Streams a JSON representation of a TestInfo object.
+  static void OutputJsonTestInfo(::std::ostream* stream,
+                                 const char* test_suite_name,
+                                 const TestInfo& test_info);
+
+  // Prints a JSON representation of a TestSuite object
+  static void PrintJsonTestSuite(::std::ostream* stream,
+                                 const TestSuite& test_suite);
+
+  // Prints a JSON summary of unit_test to output stream out.
+  static void PrintJsonUnitTest(::std::ostream* stream,
+                                const UnitTest& unit_test);
+
+  // Produces a string representing the test properties in a result as
+  // a JSON dictionary.
+  static std::string TestPropertiesAsJson(const TestResult& result,
+                                          const std::string& indent);
+
+  // The output file.
+  const std::string output_file_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(JsonUnitTestResultPrinter);
+};
+
+// Creates a new JsonUnitTestResultPrinter.
+JsonUnitTestResultPrinter::JsonUnitTestResultPrinter(const char* output_file)
+    : output_file_(output_file) {
+  if (output_file_.empty()) {
+    GTEST_LOG_(FATAL) << "JSON output file may not be null";
+  }
+}
+
+void JsonUnitTestResultPrinter::OnTestIterationEnd(const UnitTest& unit_test,
+                                                  int /*iteration*/) {
+  FILE* jsonout = OpenFileForWriting(output_file_);
+  std::stringstream stream;
+  PrintJsonUnitTest(&stream, unit_test);
+  fprintf(jsonout, "%s", StringStreamToString(&stream).c_str());
+  fclose(jsonout);
+}
+
+// Returns an JSON-escaped copy of the input string str.
+std::string JsonUnitTestResultPrinter::EscapeJson(const std::string& str) {
+  Message m;
+
+  for (size_t i = 0; i < str.size(); ++i) {
+    const char ch = str[i];
+    switch (ch) {
+      case '\\':
+      case '"':
+      case '/':
+        m << '\\' << ch;
+        break;
+      case '\b':
+        m << "\\b";
+        break;
+      case '\t':
+        m << "\\t";
+        break;
+      case '\n':
+        m << "\\n";
+        break;
+      case '\f':
+        m << "\\f";
+        break;
+      case '\r':
+        m << "\\r";
+        break;
+      default:
+        if (ch < ' ') {
+          m << "\\u00" << String::FormatByte(static_cast<unsigned char>(ch));
+        } else {
+          m << ch;
+        }
+        break;
+    }
+  }
+
+  return m.GetString();
+}
+
+// The following routines generate an JSON representation of a UnitTest
+// object.
+
+// Formats the given time in milliseconds as seconds.
+static std::string FormatTimeInMillisAsDuration(TimeInMillis ms) {
+  ::std::stringstream ss;
+  ss << (static_cast<double>(ms) * 1e-3) << "s";
+  return ss.str();
+}
+
+// Converts the given epoch time in milliseconds to a date string in the
+// RFC3339 format, without the timezone information.
+static std::string FormatEpochTimeInMillisAsRFC3339(TimeInMillis ms) {
+  struct tm time_struct;
+  if (!PortableLocaltime(static_cast<time_t>(ms / 1000), &time_struct))
+    return "";
+  // YYYY-MM-DDThh:mm:ss
+  return StreamableToString(time_struct.tm_year + 1900) + "-" +
+      String::FormatIntWidth2(time_struct.tm_mon + 1) + "-" +
+      String::FormatIntWidth2(time_struct.tm_mday) + "T" +
+      String::FormatIntWidth2(time_struct.tm_hour) + ":" +
+      String::FormatIntWidth2(time_struct.tm_min) + ":" +
+      String::FormatIntWidth2(time_struct.tm_sec) + "Z";
+}
+
+static inline std::string Indent(size_t width) {
+  return std::string(width, ' ');
+}
+
+void JsonUnitTestResultPrinter::OutputJsonKey(
+    std::ostream* stream,
+    const std::string& element_name,
+    const std::string& name,
+    const std::string& value,
+    const std::string& indent,
+    bool comma) {
+  const std::vector<std::string>& allowed_names =
+      GetReservedOutputAttributesForElement(element_name);
+
+  GTEST_CHECK_(std::find(allowed_names.begin(), allowed_names.end(), name) !=
+                   allowed_names.end())
+      << "Key \"" << name << "\" is not allowed for value \"" << element_name
+      << "\".";
+
+  *stream << indent << "\"" << name << "\": \"" << EscapeJson(value) << "\"";
+  if (comma)
+    *stream << ",\n";
+}
+
+void JsonUnitTestResultPrinter::OutputJsonKey(
+    std::ostream* stream,
+    const std::string& element_name,
+    const std::string& name,
+    int value,
+    const std::string& indent,
+    bool comma) {
+  const std::vector<std::string>& allowed_names =
+      GetReservedOutputAttributesForElement(element_name);
+
+  GTEST_CHECK_(std::find(allowed_names.begin(), allowed_names.end(), name) !=
+                   allowed_names.end())
+      << "Key \"" << name << "\" is not allowed for value \"" << element_name
+      << "\".";
+
+  *stream << indent << "\"" << name << "\": " << StreamableToString(value);
+  if (comma)
+    *stream << ",\n";
+}
+
+// Streams a test suite JSON stanza containing the given test result.
+void JsonUnitTestResultPrinter::OutputJsonTestSuiteForTestResult(
+    ::std::ostream* stream, const TestResult& result) {
+  // Output the boilerplate for a new test suite.
+  *stream << Indent(4) << "{\n";
+  OutputJsonKey(stream, "testsuite", "name", "NonTestSuiteFailure", Indent(6));
+  OutputJsonKey(stream, "testsuite", "tests", 1, Indent(6));
+  if (!GTEST_FLAG(list_tests)) {
+    OutputJsonKey(stream, "testsuite", "failures", 1, Indent(6));
+    OutputJsonKey(stream, "testsuite", "disabled", 0, Indent(6));
+    OutputJsonKey(stream, "testsuite", "skipped", 0, Indent(6));
+    OutputJsonKey(stream, "testsuite", "errors", 0, Indent(6));
+    OutputJsonKey(stream, "testsuite", "time",
+                  FormatTimeInMillisAsDuration(result.elapsed_time()),
+                  Indent(6));
+    OutputJsonKey(stream, "testsuite", "timestamp",
+                  FormatEpochTimeInMillisAsRFC3339(result.start_timestamp()),
+                  Indent(6));
+  }
+  *stream << Indent(6) << "\"testsuite\": [\n";
+
+  // Output the boilerplate for a new test case.
+  *stream << Indent(8) << "{\n";
+  OutputJsonKey(stream, "testcase", "name", "", Indent(10));
+  OutputJsonKey(stream, "testcase", "status", "RUN", Indent(10));
+  OutputJsonKey(stream, "testcase", "result", "COMPLETED", Indent(10));
+  OutputJsonKey(stream, "testcase", "timestamp",
+                FormatEpochTimeInMillisAsRFC3339(result.start_timestamp()),
+                Indent(10));
+  OutputJsonKey(stream, "testcase", "time",
+                FormatTimeInMillisAsDuration(result.elapsed_time()),
+                Indent(10));
+  OutputJsonKey(stream, "testcase", "classname", "", Indent(10), false);
+  *stream << TestPropertiesAsJson(result, Indent(10));
+
+  // Output the actual test result.
+  OutputJsonTestResult(stream, result);
+
+  // Finish the test suite.
+  *stream << "\n" << Indent(6) << "]\n" << Indent(4) << "}";
+}
+
+// Prints a JSON representation of a TestInfo object.
+void JsonUnitTestResultPrinter::OutputJsonTestInfo(::std::ostream* stream,
+                                                   const char* test_suite_name,
+                                                   const TestInfo& test_info) {
+  const TestResult& result = *test_info.result();
+  const std::string kTestsuite = "testcase";
+  const std::string kIndent = Indent(10);
+
+  *stream << Indent(8) << "{\n";
+  OutputJsonKey(stream, kTestsuite, "name", test_info.name(), kIndent);
+
+  if (test_info.value_param() != nullptr) {
+    OutputJsonKey(stream, kTestsuite, "value_param", test_info.value_param(),
+                  kIndent);
+  }
+  if (test_info.type_param() != nullptr) {
+    OutputJsonKey(stream, kTestsuite, "type_param", test_info.type_param(),
+                  kIndent);
+  }
+  if (GTEST_FLAG(list_tests)) {
+    OutputJsonKey(stream, kTestsuite, "file", test_info.file(), kIndent);
+    OutputJsonKey(stream, kTestsuite, "line", test_info.line(), kIndent, false);
+    *stream << "\n" << Indent(8) << "}";
+    return;
+  }
+
+  OutputJsonKey(stream, kTestsuite, "status",
+                test_info.should_run() ? "RUN" : "NOTRUN", kIndent);
+  OutputJsonKey(stream, kTestsuite, "result",
+                test_info.should_run()
+                    ? (result.Skipped() ? "SKIPPED" : "COMPLETED")
+                    : "SUPPRESSED",
+                kIndent);
+  OutputJsonKey(stream, kTestsuite, "timestamp",
+                FormatEpochTimeInMillisAsRFC3339(result.start_timestamp()),
+                kIndent);
+  OutputJsonKey(stream, kTestsuite, "time",
+                FormatTimeInMillisAsDuration(result.elapsed_time()), kIndent);
+  OutputJsonKey(stream, kTestsuite, "classname", test_suite_name, kIndent,
+                false);
+  *stream << TestPropertiesAsJson(result, kIndent);
+
+  OutputJsonTestResult(stream, result);
+}
+
+void JsonUnitTestResultPrinter::OutputJsonTestResult(::std::ostream* stream,
+                                                     const TestResult& result) {
+  const std::string kIndent = Indent(10);
+
+  int failures = 0;
+  for (int i = 0; i < result.total_part_count(); ++i) {
+    const TestPartResult& part = result.GetTestPartResult(i);
+    if (part.failed()) {
+      *stream << ",\n";
+      if (++failures == 1) {
+        *stream << kIndent << "\"" << "failures" << "\": [\n";
+      }
+      const std::string location =
+          internal::FormatCompilerIndependentFileLocation(part.file_name(),
+                                                          part.line_number());
+      const std::string message = EscapeJson(location + "\n" + part.message());
+      *stream << kIndent << "  {\n"
+              << kIndent << "    \"failure\": \"" << message << "\",\n"
+              << kIndent << "    \"type\": \"\"\n"
+              << kIndent << "  }";
+    }
+  }
+
+  if (failures > 0)
+    *stream << "\n" << kIndent << "]";
+  *stream << "\n" << Indent(8) << "}";
+}
+
+// Prints an JSON representation of a TestSuite object
+void JsonUnitTestResultPrinter::PrintJsonTestSuite(
+    std::ostream* stream, const TestSuite& test_suite) {
+  const std::string kTestsuite = "testsuite";
+  const std::string kIndent = Indent(6);
+
+  *stream << Indent(4) << "{\n";
+  OutputJsonKey(stream, kTestsuite, "name", test_suite.name(), kIndent);
+  OutputJsonKey(stream, kTestsuite, "tests", test_suite.reportable_test_count(),
+                kIndent);
+  if (!GTEST_FLAG(list_tests)) {
+    OutputJsonKey(stream, kTestsuite, "failures",
+                  test_suite.failed_test_count(), kIndent);
+    OutputJsonKey(stream, kTestsuite, "disabled",
+                  test_suite.reportable_disabled_test_count(), kIndent);
+    OutputJsonKey(stream, kTestsuite, "errors", 0, kIndent);
+    OutputJsonKey(
+        stream, kTestsuite, "timestamp",
+        FormatEpochTimeInMillisAsRFC3339(test_suite.start_timestamp()),
+        kIndent);
+    OutputJsonKey(stream, kTestsuite, "time",
+                  FormatTimeInMillisAsDuration(test_suite.elapsed_time()),
+                  kIndent, false);
+    *stream << TestPropertiesAsJson(test_suite.ad_hoc_test_result(), kIndent)
+            << ",\n";
+  }
+
+  *stream << kIndent << "\"" << kTestsuite << "\": [\n";
+
+  bool comma = false;
+  for (int i = 0; i < test_suite.total_test_count(); ++i) {
+    if (test_suite.GetTestInfo(i)->is_reportable()) {
+      if (comma) {
+        *stream << ",\n";
+      } else {
+        comma = true;
+      }
+      OutputJsonTestInfo(stream, test_suite.name(), *test_suite.GetTestInfo(i));
+    }
+  }
+  *stream << "\n" << kIndent << "]\n" << Indent(4) << "}";
+}
+
+// Prints a JSON summary of unit_test to output stream out.
+void JsonUnitTestResultPrinter::PrintJsonUnitTest(std::ostream* stream,
+                                                  const UnitTest& unit_test) {
+  const std::string kTestsuites = "testsuites";
+  const std::string kIndent = Indent(2);
+  *stream << "{\n";
+
+  OutputJsonKey(stream, kTestsuites, "tests", unit_test.reportable_test_count(),
+                kIndent);
+  OutputJsonKey(stream, kTestsuites, "failures", unit_test.failed_test_count(),
+                kIndent);
+  OutputJsonKey(stream, kTestsuites, "disabled",
+                unit_test.reportable_disabled_test_count(), kIndent);
+  OutputJsonKey(stream, kTestsuites, "errors", 0, kIndent);
+  if (GTEST_FLAG(shuffle)) {
+    OutputJsonKey(stream, kTestsuites, "random_seed", unit_test.random_seed(),
+                  kIndent);
+  }
+  OutputJsonKey(stream, kTestsuites, "timestamp",
+                FormatEpochTimeInMillisAsRFC3339(unit_test.start_timestamp()),
+                kIndent);
+  OutputJsonKey(stream, kTestsuites, "time",
+                FormatTimeInMillisAsDuration(unit_test.elapsed_time()), kIndent,
+                false);
+
+  *stream << TestPropertiesAsJson(unit_test.ad_hoc_test_result(), kIndent)
+          << ",\n";
+
+  OutputJsonKey(stream, kTestsuites, "name", "AllTests", kIndent);
+  *stream << kIndent << "\"" << kTestsuites << "\": [\n";
+
+  bool comma = false;
+  for (int i = 0; i < unit_test.total_test_suite_count(); ++i) {
+    if (unit_test.GetTestSuite(i)->reportable_test_count() > 0) {
+      if (comma) {
+        *stream << ",\n";
+      } else {
+        comma = true;
+      }
+      PrintJsonTestSuite(stream, *unit_test.GetTestSuite(i));
+    }
+  }
+
+  // If there was a test failure outside of one of the test suites (like in a
+  // test environment) include that in the output.
+  if (unit_test.ad_hoc_test_result().Failed()) {
+    OutputJsonTestSuiteForTestResult(stream, unit_test.ad_hoc_test_result());
+  }
+
+  *stream << "\n" << kIndent << "]\n" << "}\n";
+}
+
+void JsonUnitTestResultPrinter::PrintJsonTestList(
+    std::ostream* stream, const std::vector<TestSuite*>& test_suites) {
+  const std::string kTestsuites = "testsuites";
+  const std::string kIndent = Indent(2);
+  *stream << "{\n";
+  int total_tests = 0;
+  for (auto test_suite : test_suites) {
+    total_tests += test_suite->total_test_count();
+  }
+  OutputJsonKey(stream, kTestsuites, "tests", total_tests, kIndent);
+
+  OutputJsonKey(stream, kTestsuites, "name", "AllTests", kIndent);
+  *stream << kIndent << "\"" << kTestsuites << "\": [\n";
+
+  for (size_t i = 0; i < test_suites.size(); ++i) {
+    if (i != 0) {
+      *stream << ",\n";
+    }
+    PrintJsonTestSuite(stream, *test_suites[i]);
+  }
+
+  *stream << "\n"
+          << kIndent << "]\n"
+          << "}\n";
+}
+// Produces a string representing the test properties in a result as
+// a JSON dictionary.
+std::string JsonUnitTestResultPrinter::TestPropertiesAsJson(
+    const TestResult& result, const std::string& indent) {
+  Message attributes;
+  for (int i = 0; i < result.test_property_count(); ++i) {
+    const TestProperty& property = result.GetTestProperty(i);
+    attributes << ",\n" << indent << "\"" << property.key() << "\": "
+               << "\"" << EscapeJson(property.value()) << "\"";
+  }
+  return attributes.GetString();
+}
+
+// End JsonUnitTestResultPrinter
+
+#if GTEST_CAN_STREAM_RESULTS_
+
+// Checks if str contains '=', '&', '%' or '\n' characters. If yes,
+// replaces them by "%xx" where xx is their hexadecimal value. For
+// example, replaces "=" with "%3D".  This algorithm is O(strlen(str))
+// in both time and space -- important as the input str may contain an
+// arbitrarily long test failure message and stack trace.
+std::string StreamingListener::UrlEncode(const char* str) {
+  std::string result;
+  result.reserve(strlen(str) + 1);
+  for (char ch = *str; ch != '\0'; ch = *++str) {
+    switch (ch) {
+      case '%':
+      case '=':
+      case '&':
+      case '\n':
+        result.append("%" + String::FormatByte(static_cast<unsigned char>(ch)));
+        break;
+      default:
+        result.push_back(ch);
+        break;
+    }
+  }
+  return result;
+}
+
+void StreamingListener::SocketWriter::MakeConnection() {
+  GTEST_CHECK_(sockfd_ == -1)
+      << "MakeConnection() can't be called when there is already a connection.";
+
+  addrinfo hints;
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_UNSPEC;    // To allow both IPv4 and IPv6 addresses.
+  hints.ai_socktype = SOCK_STREAM;
+  addrinfo* servinfo = nullptr;
+
+  // Use the getaddrinfo() to get a linked list of IP addresses for
+  // the given host name.
+  const int error_num = getaddrinfo(
+      host_name_.c_str(), port_num_.c_str(), &hints, &servinfo);
+  if (error_num != 0) {
+    GTEST_LOG_(WARNING) << "stream_result_to: getaddrinfo() failed: "
+                        << gai_strerror(error_num);
+  }
+
+  // Loop through all the results and connect to the first we can.
+  for (addrinfo* cur_addr = servinfo; sockfd_ == -1 && cur_addr != nullptr;
+       cur_addr = cur_addr->ai_next) {
+    sockfd_ = socket(
+        cur_addr->ai_family, cur_addr->ai_socktype, cur_addr->ai_protocol);
+    if (sockfd_ != -1) {
+      // Connect the client socket to the server socket.
+      if (connect(sockfd_, cur_addr->ai_addr, cur_addr->ai_addrlen) == -1) {
+        close(sockfd_);
+        sockfd_ = -1;
+      }
+    }
+  }
+
+  freeaddrinfo(servinfo);  // all done with this structure
+
+  if (sockfd_ == -1) {
+    GTEST_LOG_(WARNING) << "stream_result_to: failed to connect to "
+                        << host_name_ << ":" << port_num_;
+  }
+}
+
+// End of class Streaming Listener
+#endif  // GTEST_CAN_STREAM_RESULTS__
+
+// class OsStackTraceGetter
+
+const char* const OsStackTraceGetterInterface::kElidedFramesMarker =
+    "... " GTEST_NAME_ " internal frames ...";
+
+std::string OsStackTraceGetter::CurrentStackTrace(int max_depth, int skip_count)
+    GTEST_LOCK_EXCLUDED_(mutex_) {
+#if GTEST_HAS_ABSL
+  std::string result;
+
+  if (max_depth <= 0) {
+    return result;
+  }
+
+  max_depth = std::min(max_depth, kMaxStackTraceDepth);
+
+  std::vector<void*> raw_stack(max_depth);
+  // Skips the frames requested by the caller, plus this function.
+  const int raw_stack_size =
+      absl::GetStackTrace(&raw_stack[0], max_depth, skip_count + 1);
+
+  void* caller_frame = nullptr;
+  {
+    MutexLock lock(&mutex_);
+    caller_frame = caller_frame_;
+  }
+
+  for (int i = 0; i < raw_stack_size; ++i) {
+    if (raw_stack[i] == caller_frame &&
+        !GTEST_FLAG(show_internal_stack_frames)) {
+      // Add a marker to the trace and stop adding frames.
+      absl::StrAppend(&result, kElidedFramesMarker, "\n");
+      break;
+    }
+
+    char tmp[1024];
+    const char* symbol = "(unknown)";
+    if (absl::Symbolize(raw_stack[i], tmp, sizeof(tmp))) {
+      symbol = tmp;
+    }
+
+    char line[1024];
+    snprintf(line, sizeof(line), "  %p: %s\n", raw_stack[i], symbol);
+    result += line;
+  }
+
+  return result;
+
+#else  // !GTEST_HAS_ABSL
+  static_cast<void>(max_depth);
+  static_cast<void>(skip_count);
+  return "";
+#endif  // GTEST_HAS_ABSL
+}
+
+void OsStackTraceGetter::UponLeavingGTest() GTEST_LOCK_EXCLUDED_(mutex_) {
+#if GTEST_HAS_ABSL
+  void* caller_frame = nullptr;
+  if (absl::GetStackTrace(&caller_frame, 1, 3) <= 0) {
+    caller_frame = nullptr;
+  }
+
+  MutexLock lock(&mutex_);
+  caller_frame_ = caller_frame;
+#endif  // GTEST_HAS_ABSL
+}
+
+// A helper class that creates the premature-exit file in its
+// constructor and deletes the file in its destructor.
+class ScopedPrematureExitFile {
+ public:
+  explicit ScopedPrematureExitFile(const char* premature_exit_filepath)
+      : premature_exit_filepath_(premature_exit_filepath ?
+                                 premature_exit_filepath : "") {
+    // If a path to the premature-exit file is specified...
+    if (!premature_exit_filepath_.empty()) {
+      // create the file with a single "0" character in it.  I/O
+      // errors are ignored as there's nothing better we can do and we
+      // don't want to fail the test because of this.
+      FILE* pfile = posix::FOpen(premature_exit_filepath, "w");
+      fwrite("0", 1, 1, pfile);
+      fclose(pfile);
+    }
+  }
+
+  ~ScopedPrematureExitFile() {
+#if !defined GTEST_OS_ESP8266
+    if (!premature_exit_filepath_.empty()) {
+      int retval = remove(premature_exit_filepath_.c_str());
+      if (retval) {
+        GTEST_LOG_(ERROR) << "Failed to remove premature exit filepath \""
+                          << premature_exit_filepath_ << "\" with error "
+                          << retval;
+      }
+    }
+#endif
+  }
+
+ private:
+  const std::string premature_exit_filepath_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ScopedPrematureExitFile);
+};
+
+}  // namespace internal
+
+// class TestEventListeners
+
+TestEventListeners::TestEventListeners()
+    : repeater_(new internal::TestEventRepeater()),
+      default_result_printer_(nullptr),
+      default_xml_generator_(nullptr) {}
+
+TestEventListeners::~TestEventListeners() { delete repeater_; }
+
+// Returns the standard listener responsible for the default console
+// output.  Can be removed from the listeners list to shut down default
+// console output.  Note that removing this object from the listener list
+// with Release transfers its ownership to the user.
+void TestEventListeners::Append(TestEventListener* listener) {
+  repeater_->Append(listener);
+}
+
+// Removes the given event listener from the list and returns it.  It then
+// becomes the caller's responsibility to delete the listener. Returns
+// NULL if the listener is not found in the list.
+TestEventListener* TestEventListeners::Release(TestEventListener* listener) {
+  if (listener == default_result_printer_)
+    default_result_printer_ = nullptr;
+  else if (listener == default_xml_generator_)
+    default_xml_generator_ = nullptr;
+  return repeater_->Release(listener);
+}
+
+// Returns repeater that broadcasts the TestEventListener events to all
+// subscribers.
+TestEventListener* TestEventListeners::repeater() { return repeater_; }
+
+// Sets the default_result_printer attribute to the provided listener.
+// The listener is also added to the listener list and previous
+// default_result_printer is removed from it and deleted. The listener can
+// also be NULL in which case it will not be added to the list. Does
+// nothing if the previous and the current listener objects are the same.
+void TestEventListeners::SetDefaultResultPrinter(TestEventListener* listener) {
+  if (default_result_printer_ != listener) {
+    // It is an error to pass this method a listener that is already in the
+    // list.
+    delete Release(default_result_printer_);
+    default_result_printer_ = listener;
+    if (listener != nullptr) Append(listener);
+  }
+}
+
+// Sets the default_xml_generator attribute to the provided listener.  The
+// listener is also added to the listener list and previous
+// default_xml_generator is removed from it and deleted. The listener can
+// also be NULL in which case it will not be added to the list. Does
+// nothing if the previous and the current listener objects are the same.
+void TestEventListeners::SetDefaultXmlGenerator(TestEventListener* listener) {
+  if (default_xml_generator_ != listener) {
+    // It is an error to pass this method a listener that is already in the
+    // list.
+    delete Release(default_xml_generator_);
+    default_xml_generator_ = listener;
+    if (listener != nullptr) Append(listener);
+  }
+}
+
+// Controls whether events will be forwarded by the repeater to the
+// listeners in the list.
+bool TestEventListeners::EventForwardingEnabled() const {
+  return repeater_->forwarding_enabled();
+}
+
+void TestEventListeners::SuppressEventForwarding() {
+  repeater_->set_forwarding_enabled(false);
+}
+
+// class UnitTest
+
+// Gets the singleton UnitTest object.  The first time this method is
+// called, a UnitTest object is constructed and returned.  Consecutive
+// calls will return the same object.
+//
+// We don't protect this under mutex_ as a user is not supposed to
+// call this before main() starts, from which point on the return
+// value will never change.
+UnitTest* UnitTest::GetInstance() {
+  // CodeGear C++Builder insists on a public destructor for the
+  // default implementation.  Use this implementation to keep good OO
+  // design with private destructor.
+
+#if defined(__BORLANDC__)
+  static UnitTest* const instance = new UnitTest;
+  return instance;
+#else
+  static UnitTest instance;
+  return &instance;
+#endif  // defined(__BORLANDC__)
+}
+
+// Gets the number of successful test suites.
+int UnitTest::successful_test_suite_count() const {
+  return impl()->successful_test_suite_count();
+}
+
+// Gets the number of failed test suites.
+int UnitTest::failed_test_suite_count() const {
+  return impl()->failed_test_suite_count();
+}
+
+// Gets the number of all test suites.
+int UnitTest::total_test_suite_count() const {
+  return impl()->total_test_suite_count();
+}
+
+// Gets the number of all test suites that contain at least one test
+// that should run.
+int UnitTest::test_suite_to_run_count() const {
+  return impl()->test_suite_to_run_count();
+}
+
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+int UnitTest::successful_test_case_count() const {
+  return impl()->successful_test_suite_count();
+}
+int UnitTest::failed_test_case_count() const {
+  return impl()->failed_test_suite_count();
+}
+int UnitTest::total_test_case_count() const {
+  return impl()->total_test_suite_count();
+}
+int UnitTest::test_case_to_run_count() const {
+  return impl()->test_suite_to_run_count();
+}
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+// Gets the number of successful tests.
+int UnitTest::successful_test_count() const {
+  return impl()->successful_test_count();
+}
+
+// Gets the number of skipped tests.
+int UnitTest::skipped_test_count() const {
+  return impl()->skipped_test_count();
+}
+
+// Gets the number of failed tests.
+int UnitTest::failed_test_count() const { return impl()->failed_test_count(); }
+
+// Gets the number of disabled tests that will be reported in the XML report.
+int UnitTest::reportable_disabled_test_count() const {
+  return impl()->reportable_disabled_test_count();
+}
+
+// Gets the number of disabled tests.
+int UnitTest::disabled_test_count() const {
+  return impl()->disabled_test_count();
+}
+
+// Gets the number of tests to be printed in the XML report.
+int UnitTest::reportable_test_count() const {
+  return impl()->reportable_test_count();
+}
+
+// Gets the number of all tests.
+int UnitTest::total_test_count() const { return impl()->total_test_count(); }
+
+// Gets the number of tests that should run.
+int UnitTest::test_to_run_count() const { return impl()->test_to_run_count(); }
+
+// Gets the time of the test program start, in ms from the start of the
+// UNIX epoch.
+internal::TimeInMillis UnitTest::start_timestamp() const {
+    return impl()->start_timestamp();
+}
+
+// Gets the elapsed time, in milliseconds.
+internal::TimeInMillis UnitTest::elapsed_time() const {
+  return impl()->elapsed_time();
+}
+
+// Returns true if and only if the unit test passed (i.e. all test suites
+// passed).
+bool UnitTest::Passed() const { return impl()->Passed(); }
+
+// Returns true if and only if the unit test failed (i.e. some test suite
+// failed or something outside of all tests failed).
+bool UnitTest::Failed() const { return impl()->Failed(); }
+
+// Gets the i-th test suite among all the test suites. i can range from 0 to
+// total_test_suite_count() - 1. If i is not in that range, returns NULL.
+const TestSuite* UnitTest::GetTestSuite(int i) const {
+  return impl()->GetTestSuite(i);
+}
+
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+const TestCase* UnitTest::GetTestCase(int i) const {
+  return impl()->GetTestCase(i);
+}
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+// Returns the TestResult containing information on test failures and
+// properties logged outside of individual test suites.
+const TestResult& UnitTest::ad_hoc_test_result() const {
+  return *impl()->ad_hoc_test_result();
+}
+
+// Gets the i-th test suite among all the test suites. i can range from 0 to
+// total_test_suite_count() - 1. If i is not in that range, returns NULL.
+TestSuite* UnitTest::GetMutableTestSuite(int i) {
+  return impl()->GetMutableSuiteCase(i);
+}
+
+// Returns the list of event listeners that can be used to track events
+// inside Google Test.
+TestEventListeners& UnitTest::listeners() {
+  return *impl()->listeners();
+}
+
+// Registers and returns a global test environment.  When a test
+// program is run, all global test environments will be set-up in the
+// order they were registered.  After all tests in the program have
+// finished, all global test environments will be torn-down in the
+// *reverse* order they were registered.
+//
+// The UnitTest object takes ownership of the given environment.
+//
+// We don't protect this under mutex_, as we only support calling it
+// from the main thread.
+Environment* UnitTest::AddEnvironment(Environment* env) {
+  if (env == nullptr) {
+    return nullptr;
+  }
+
+  impl_->environments().push_back(env);
+  return env;
+}
+
+// Adds a TestPartResult to the current TestResult object.  All Google Test
+// assertion macros (e.g. ASSERT_TRUE, EXPECT_EQ, etc) eventually call
+// this to report their results.  The user code should use the
+// assertion macros instead of calling this directly.
+void UnitTest::AddTestPartResult(
+    TestPartResult::Type result_type,
+    const char* file_name,
+    int line_number,
+    const std::string& message,
+    const std::string& os_stack_trace) GTEST_LOCK_EXCLUDED_(mutex_) {
+  Message msg;
+  msg << message;
+
+  internal::MutexLock lock(&mutex_);
+  if (impl_->gtest_trace_stack().size() > 0) {
+    msg << "\n" << GTEST_NAME_ << " trace:";
+
+    for (size_t i = impl_->gtest_trace_stack().size(); i > 0; --i) {
+      const internal::TraceInfo& trace = impl_->gtest_trace_stack()[i - 1];
+      msg << "\n" << internal::FormatFileLocation(trace.file, trace.line)
+          << " " << trace.message;
+    }
+  }
+
+  if (os_stack_trace.c_str() != nullptr && !os_stack_trace.empty()) {
+    msg << internal::kStackTraceMarker << os_stack_trace;
+  }
+
+  const TestPartResult result = TestPartResult(
+      result_type, file_name, line_number, msg.GetString().c_str());
+  impl_->GetTestPartResultReporterForCurrentThread()->
+      ReportTestPartResult(result);
+
+  if (result_type != TestPartResult::kSuccess &&
+      result_type != TestPartResult::kSkip) {
+    // gtest_break_on_failure takes precedence over
+    // gtest_throw_on_failure.  This allows a user to set the latter
+    // in the code (perhaps in order to use Google Test assertions
+    // with another testing framework) and specify the former on the
+    // command line for debugging.
+    if (GTEST_FLAG(break_on_failure)) {
+#if GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT
+      // Using DebugBreak on Windows allows gtest to still break into a debugger
+      // when a failure happens and both the --gtest_break_on_failure and
+      // the --gtest_catch_exceptions flags are specified.
+      DebugBreak();
+#elif (!defined(__native_client__)) &&            \
+    ((defined(__clang__) || defined(__GNUC__)) && \
+     (defined(__x86_64__) || defined(__i386__)))
+      // with clang/gcc we can achieve the same effect on x86 by invoking int3
+      asm("int3");
+#else
+      // Dereference nullptr through a volatile pointer to prevent the compiler
+      // from removing. We use this rather than abort() or __builtin_trap() for
+      // portability: some debuggers don't correctly trap abort().
+      *static_cast<volatile int*>(nullptr) = 1;
+#endif  // GTEST_OS_WINDOWS
+    } else if (GTEST_FLAG(throw_on_failure)) {
+#if GTEST_HAS_EXCEPTIONS
+      throw internal::GoogleTestFailureException(result);
+#else
+      // We cannot call abort() as it generates a pop-up in debug mode
+      // that cannot be suppressed in VC 7.1 or below.
+      exit(1);
+#endif
+    }
+  }
+}
+
+// Adds a TestProperty to the current TestResult object when invoked from
+// inside a test, to current TestSuite's ad_hoc_test_result_ when invoked
+// from SetUpTestSuite or TearDownTestSuite, or to the global property set
+// when invoked elsewhere.  If the result already contains a property with
+// the same key, the value will be updated.
+void UnitTest::RecordProperty(const std::string& key,
+                              const std::string& value) {
+  impl_->RecordProperty(TestProperty(key, value));
+}
+
+// Runs all tests in this UnitTest object and prints the result.
+// Returns 0 if successful, or 1 otherwise.
+//
+// We don't protect this under mutex_, as we only support calling it
+// from the main thread.
+int UnitTest::Run() {
+  const bool in_death_test_child_process =
+      internal::GTEST_FLAG(internal_run_death_test).length() > 0;
+
+  // Google Test implements this protocol for catching that a test
+  // program exits before returning control to Google Test:
+  //
+  //   1. Upon start, Google Test creates a file whose absolute path
+  //      is specified by the environment variable
+  //      TEST_PREMATURE_EXIT_FILE.
+  //   2. When Google Test has finished its work, it deletes the file.
+  //
+  // This allows a test runner to set TEST_PREMATURE_EXIT_FILE before
+  // running a Google-Test-based test program and check the existence
+  // of the file at the end of the test execution to see if it has
+  // exited prematurely.
+
+  // If we are in the child process of a death test, don't
+  // create/delete the premature exit file, as doing so is unnecessary
+  // and will confuse the parent process.  Otherwise, create/delete
+  // the file upon entering/leaving this function.  If the program
+  // somehow exits before this function has a chance to return, the
+  // premature-exit file will be left undeleted, causing a test runner
+  // that understands the premature-exit-file protocol to report the
+  // test as having failed.
+  const internal::ScopedPrematureExitFile premature_exit_file(
+      in_death_test_child_process
+          ? nullptr
+          : internal::posix::GetEnv("TEST_PREMATURE_EXIT_FILE"));
+
+  // Captures the value of GTEST_FLAG(catch_exceptions).  This value will be
+  // used for the duration of the program.
+  impl()->set_catch_exceptions(GTEST_FLAG(catch_exceptions));
+
+#if GTEST_OS_WINDOWS
+  // Either the user wants Google Test to catch exceptions thrown by the
+  // tests or this is executing in the context of death test child
+  // process. In either case the user does not want to see pop-up dialogs
+  // about crashes - they are expected.
+  if (impl()->catch_exceptions() || in_death_test_child_process) {
+# if !GTEST_OS_WINDOWS_MOBILE && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT
+    // SetErrorMode doesn't exist on CE.
+    SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOALIGNMENTFAULTEXCEPT |
+                 SEM_NOGPFAULTERRORBOX | SEM_NOOPENFILEERRORBOX);
+# endif  // !GTEST_OS_WINDOWS_MOBILE
+
+# if (defined(_MSC_VER) || GTEST_OS_WINDOWS_MINGW) && !GTEST_OS_WINDOWS_MOBILE
+    // Death test children can be terminated with _abort().  On Windows,
+    // _abort() can show a dialog with a warning message.  This forces the
+    // abort message to go to stderr instead.
+    _set_error_mode(_OUT_TO_STDERR);
+# endif
+
+# if defined(_MSC_VER) && !GTEST_OS_WINDOWS_MOBILE
+    // In the debug version, Visual Studio pops up a separate dialog
+    // offering a choice to debug the aborted program. We need to suppress
+    // this dialog or it will pop up for every EXPECT/ASSERT_DEATH statement
+    // executed. Google Test will notify the user of any unexpected
+    // failure via stderr.
+    if (!GTEST_FLAG(break_on_failure))
+      _set_abort_behavior(
+          0x0,                                    // Clear the following flags:
+          _WRITE_ABORT_MSG | _CALL_REPORTFAULT);  // pop-up window, core dump.
+
+    // In debug mode, the Windows CRT can crash with an assertion over invalid
+    // input (e.g. passing an invalid file descriptor).  The default handling
+    // for these assertions is to pop up a dialog and wait for user input.
+    // Instead ask the CRT to dump such assertions to stderr non-interactively.
+    if (!IsDebuggerPresent()) {
+      (void)_CrtSetReportMode(_CRT_ASSERT,
+                              _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
+      (void)_CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR);
+    }
+# endif
+  }
+#endif  // GTEST_OS_WINDOWS
+
+  return internal::HandleExceptionsInMethodIfSupported(
+      impl(),
+      &internal::UnitTestImpl::RunAllTests,
+      "auxiliary test code (environments or event listeners)") ? 0 : 1;
+}
+
+// Returns the working directory when the first TEST() or TEST_F() was
+// executed.
+const char* UnitTest::original_working_dir() const {
+  return impl_->original_working_dir_.c_str();
+}
+
+// Returns the TestSuite object for the test that's currently running,
+// or NULL if no test is running.
+const TestSuite* UnitTest::current_test_suite() const
+    GTEST_LOCK_EXCLUDED_(mutex_) {
+  internal::MutexLock lock(&mutex_);
+  return impl_->current_test_suite();
+}
+
+// Legacy API is still available but deprecated
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+const TestCase* UnitTest::current_test_case() const
+    GTEST_LOCK_EXCLUDED_(mutex_) {
+  internal::MutexLock lock(&mutex_);
+  return impl_->current_test_suite();
+}
+#endif
+
+// Returns the TestInfo object for the test that's currently running,
+// or NULL if no test is running.
+const TestInfo* UnitTest::current_test_info() const
+    GTEST_LOCK_EXCLUDED_(mutex_) {
+  internal::MutexLock lock(&mutex_);
+  return impl_->current_test_info();
+}
+
+// Returns the random seed used at the start of the current test run.
+int UnitTest::random_seed() const { return impl_->random_seed(); }
+
+// Returns ParameterizedTestSuiteRegistry object used to keep track of
+// value-parameterized tests and instantiate and register them.
+internal::ParameterizedTestSuiteRegistry&
+UnitTest::parameterized_test_registry() GTEST_LOCK_EXCLUDED_(mutex_) {
+  return impl_->parameterized_test_registry();
+}
+
+// Creates an empty UnitTest.
+UnitTest::UnitTest() {
+  impl_ = new internal::UnitTestImpl(this);
+}
+
+// Destructor of UnitTest.
+UnitTest::~UnitTest() {
+  delete impl_;
+}
+
+// Pushes a trace defined by SCOPED_TRACE() on to the per-thread
+// Google Test trace stack.
+void UnitTest::PushGTestTrace(const internal::TraceInfo& trace)
+    GTEST_LOCK_EXCLUDED_(mutex_) {
+  internal::MutexLock lock(&mutex_);
+  impl_->gtest_trace_stack().push_back(trace);
+}
+
+// Pops a trace from the per-thread Google Test trace stack.
+void UnitTest::PopGTestTrace()
+    GTEST_LOCK_EXCLUDED_(mutex_) {
+  internal::MutexLock lock(&mutex_);
+  impl_->gtest_trace_stack().pop_back();
+}
+
+namespace internal {
+
+UnitTestImpl::UnitTestImpl(UnitTest* parent)
+    : parent_(parent),
+      GTEST_DISABLE_MSC_WARNINGS_PUSH_(4355 /* using this in initializer */)
+          default_global_test_part_result_reporter_(this),
+      default_per_thread_test_part_result_reporter_(this),
+      GTEST_DISABLE_MSC_WARNINGS_POP_() global_test_part_result_repoter_(
+          &default_global_test_part_result_reporter_),
+      per_thread_test_part_result_reporter_(
+          &default_per_thread_test_part_result_reporter_),
+      parameterized_test_registry_(),
+      parameterized_tests_registered_(false),
+      last_death_test_suite_(-1),
+      current_test_suite_(nullptr),
+      current_test_info_(nullptr),
+      ad_hoc_test_result_(),
+      os_stack_trace_getter_(nullptr),
+      post_flag_parse_init_performed_(false),
+      random_seed_(0),  // Will be overridden by the flag before first use.
+      random_(0),       // Will be reseeded before first use.
+      start_timestamp_(0),
+      elapsed_time_(0),
+#if GTEST_HAS_DEATH_TEST
+      death_test_factory_(new DefaultDeathTestFactory),
+#endif
+      // Will be overridden by the flag before first use.
+      catch_exceptions_(false) {
+  listeners()->SetDefaultResultPrinter(new PrettyUnitTestResultPrinter);
+}
+
+UnitTestImpl::~UnitTestImpl() {
+  // Deletes every TestSuite.
+  ForEach(test_suites_, internal::Delete<TestSuite>);
+
+  // Deletes every Environment.
+  ForEach(environments_, internal::Delete<Environment>);
+
+  delete os_stack_trace_getter_;
+}
+
+// Adds a TestProperty to the current TestResult object when invoked in a
+// context of a test, to current test suite's ad_hoc_test_result when invoke
+// from SetUpTestSuite/TearDownTestSuite, or to the global property set
+// otherwise.  If the result already contains a property with the same key,
+// the value will be updated.
+void UnitTestImpl::RecordProperty(const TestProperty& test_property) {
+  std::string xml_element;
+  TestResult* test_result;  // TestResult appropriate for property recording.
+
+  if (current_test_info_ != nullptr) {
+    xml_element = "testcase";
+    test_result = &(current_test_info_->result_);
+  } else if (current_test_suite_ != nullptr) {
+    xml_element = "testsuite";
+    test_result = &(current_test_suite_->ad_hoc_test_result_);
+  } else {
+    xml_element = "testsuites";
+    test_result = &ad_hoc_test_result_;
+  }
+  test_result->RecordProperty(xml_element, test_property);
+}
+
+#if GTEST_HAS_DEATH_TEST
+// Disables event forwarding if the control is currently in a death test
+// subprocess. Must not be called before InitGoogleTest.
+void UnitTestImpl::SuppressTestEventsIfInSubprocess() {
+  if (internal_run_death_test_flag_.get() != nullptr)
+    listeners()->SuppressEventForwarding();
+}
+#endif  // GTEST_HAS_DEATH_TEST
+
+// Initializes event listeners performing XML output as specified by
+// UnitTestOptions. Must not be called before InitGoogleTest.
+void UnitTestImpl::ConfigureXmlOutput() {
+  const std::string& output_format = UnitTestOptions::GetOutputFormat();
+  if (output_format == "xml") {
+    listeners()->SetDefaultXmlGenerator(new XmlUnitTestResultPrinter(
+        UnitTestOptions::GetAbsolutePathToOutputFile().c_str()));
+  } else if (output_format == "json") {
+    listeners()->SetDefaultXmlGenerator(new JsonUnitTestResultPrinter(
+        UnitTestOptions::GetAbsolutePathToOutputFile().c_str()));
+  } else if (output_format != "") {
+    GTEST_LOG_(WARNING) << "WARNING: unrecognized output format \""
+                        << output_format << "\" ignored.";
+  }
+}
+
+#if GTEST_CAN_STREAM_RESULTS_
+// Initializes event listeners for streaming test results in string form.
+// Must not be called before InitGoogleTest.
+void UnitTestImpl::ConfigureStreamingOutput() {
+  const std::string& target = GTEST_FLAG(stream_result_to);
+  if (!target.empty()) {
+    const size_t pos = target.find(':');
+    if (pos != std::string::npos) {
+      listeners()->Append(new StreamingListener(target.substr(0, pos),
+                                                target.substr(pos+1)));
+    } else {
+      GTEST_LOG_(WARNING) << "unrecognized streaming target \"" << target
+                          << "\" ignored.";
+    }
+  }
+}
+#endif  // GTEST_CAN_STREAM_RESULTS_
+
+// Performs initialization dependent upon flag values obtained in
+// ParseGoogleTestFlagsOnly.  Is called from InitGoogleTest after the call to
+// ParseGoogleTestFlagsOnly.  In case a user neglects to call InitGoogleTest
+// this function is also called from RunAllTests.  Since this function can be
+// called more than once, it has to be idempotent.
+void UnitTestImpl::PostFlagParsingInit() {
+  // Ensures that this function does not execute more than once.
+  if (!post_flag_parse_init_performed_) {
+    post_flag_parse_init_performed_ = true;
+
+#if defined(GTEST_CUSTOM_TEST_EVENT_LISTENER_)
+    // Register to send notifications about key process state changes.
+    listeners()->Append(new GTEST_CUSTOM_TEST_EVENT_LISTENER_());
+#endif  // defined(GTEST_CUSTOM_TEST_EVENT_LISTENER_)
+
+#if GTEST_HAS_DEATH_TEST
+    InitDeathTestSubprocessControlInfo();
+    SuppressTestEventsIfInSubprocess();
+#endif  // GTEST_HAS_DEATH_TEST
+
+    // Registers parameterized tests. This makes parameterized tests
+    // available to the UnitTest reflection API without running
+    // RUN_ALL_TESTS.
+    RegisterParameterizedTests();
+
+    // Configures listeners for XML output. This makes it possible for users
+    // to shut down the default XML output before invoking RUN_ALL_TESTS.
+    ConfigureXmlOutput();
+
+    if (GTEST_FLAG(brief)) {
+      listeners()->SetDefaultResultPrinter(new BriefUnitTestResultPrinter);
+    }
+
+#if GTEST_CAN_STREAM_RESULTS_
+    // Configures listeners for streaming test results to the specified server.
+    ConfigureStreamingOutput();
+#endif  // GTEST_CAN_STREAM_RESULTS_
+
+#if GTEST_HAS_ABSL
+    if (GTEST_FLAG(install_failure_signal_handler)) {
+      absl::FailureSignalHandlerOptions options;
+      absl::InstallFailureSignalHandler(options);
+    }
+#endif  // GTEST_HAS_ABSL
+  }
+}
+
+// A predicate that checks the name of a TestSuite against a known
+// value.
+//
+// This is used for implementation of the UnitTest class only.  We put
+// it in the anonymous namespace to prevent polluting the outer
+// namespace.
+//
+// TestSuiteNameIs is copyable.
+class TestSuiteNameIs {
+ public:
+  // Constructor.
+  explicit TestSuiteNameIs(const std::string& name) : name_(name) {}
+
+  // Returns true if and only if the name of test_suite matches name_.
+  bool operator()(const TestSuite* test_suite) const {
+    return test_suite != nullptr &&
+           strcmp(test_suite->name(), name_.c_str()) == 0;
+  }
+
+ private:
+  std::string name_;
+};
+
+// Finds and returns a TestSuite with the given name.  If one doesn't
+// exist, creates one and returns it.  It's the CALLER'S
+// RESPONSIBILITY to ensure that this function is only called WHEN THE
+// TESTS ARE NOT SHUFFLED.
+//
+// Arguments:
+//
+//   test_suite_name: name of the test suite
+//   type_param:      the name of the test suite's type parameter, or NULL if
+//                    this is not a typed or a type-parameterized test suite.
+//   set_up_tc:       pointer to the function that sets up the test suite
+//   tear_down_tc:    pointer to the function that tears down the test suite
+TestSuite* UnitTestImpl::GetTestSuite(
+    const char* test_suite_name, const char* type_param,
+    internal::SetUpTestSuiteFunc set_up_tc,
+    internal::TearDownTestSuiteFunc tear_down_tc) {
+  // Can we find a TestSuite with the given name?
+  const auto test_suite =
+      std::find_if(test_suites_.rbegin(), test_suites_.rend(),
+                   TestSuiteNameIs(test_suite_name));
+
+  if (test_suite != test_suites_.rend()) return *test_suite;
+
+  // No.  Let's create one.
+  auto* const new_test_suite =
+      new TestSuite(test_suite_name, type_param, set_up_tc, tear_down_tc);
+
+  // Is this a death test suite?
+  if (internal::UnitTestOptions::MatchesFilter(test_suite_name,
+                                               kDeathTestSuiteFilter)) {
+    // Yes.  Inserts the test suite after the last death test suite
+    // defined so far.  This only works when the test suites haven't
+    // been shuffled.  Otherwise we may end up running a death test
+    // after a non-death test.
+    ++last_death_test_suite_;
+    test_suites_.insert(test_suites_.begin() + last_death_test_suite_,
+                        new_test_suite);
+  } else {
+    // No.  Appends to the end of the list.
+    test_suites_.push_back(new_test_suite);
+  }
+
+  test_suite_indices_.push_back(static_cast<int>(test_suite_indices_.size()));
+  return new_test_suite;
+}
+
+// Helpers for setting up / tearing down the given environment.  They
+// are for use in the ForEach() function.
+static void SetUpEnvironment(Environment* env) { env->SetUp(); }
+static void TearDownEnvironment(Environment* env) { env->TearDown(); }
+
+// Runs all tests in this UnitTest object, prints the result, and
+// returns true if all tests are successful.  If any exception is
+// thrown during a test, the test is considered to be failed, but the
+// rest of the tests will still be run.
+//
+// When parameterized tests are enabled, it expands and registers
+// parameterized tests first in RegisterParameterizedTests().
+// All other functions called from RunAllTests() may safely assume that
+// parameterized tests are ready to be counted and run.
+bool UnitTestImpl::RunAllTests() {
+  // True if and only if Google Test is initialized before RUN_ALL_TESTS() is
+  // called.
+  const bool gtest_is_initialized_before_run_all_tests = GTestIsInitialized();
+
+  // Do not run any test if the --help flag was specified.
+  if (g_help_flag)
+    return true;
+
+  // Repeats the call to the post-flag parsing initialization in case the
+  // user didn't call InitGoogleTest.
+  PostFlagParsingInit();
+
+  // Even if sharding is not on, test runners may want to use the
+  // GTEST_SHARD_STATUS_FILE to query whether the test supports the sharding
+  // protocol.
+  internal::WriteToShardStatusFileIfNeeded();
+
+  // True if and only if we are in a subprocess for running a thread-safe-style
+  // death test.
+  bool in_subprocess_for_death_test = false;
+
+#if GTEST_HAS_DEATH_TEST
+  in_subprocess_for_death_test =
+      (internal_run_death_test_flag_.get() != nullptr);
+# if defined(GTEST_EXTRA_DEATH_TEST_CHILD_SETUP_)
+  if (in_subprocess_for_death_test) {
+    GTEST_EXTRA_DEATH_TEST_CHILD_SETUP_();
+  }
+# endif  // defined(GTEST_EXTRA_DEATH_TEST_CHILD_SETUP_)
+#endif  // GTEST_HAS_DEATH_TEST
+
+  const bool should_shard = ShouldShard(kTestTotalShards, kTestShardIndex,
+                                        in_subprocess_for_death_test);
+
+  // Compares the full test names with the filter to decide which
+  // tests to run.
+  const bool has_tests_to_run = FilterTests(should_shard
+                                              ? HONOR_SHARDING_PROTOCOL
+                                              : IGNORE_SHARDING_PROTOCOL) > 0;
+
+  // Lists the tests and exits if the --gtest_list_tests flag was specified.
+  if (GTEST_FLAG(list_tests)) {
+    // This must be called *after* FilterTests() has been called.
+    ListTestsMatchingFilter();
+    return true;
+  }
+
+  random_seed_ = GTEST_FLAG(shuffle) ?
+      GetRandomSeedFromFlag(GTEST_FLAG(random_seed)) : 0;
+
+  // True if and only if at least one test has failed.
+  bool failed = false;
+
+  TestEventListener* repeater = listeners()->repeater();
+
+  start_timestamp_ = GetTimeInMillis();
+  repeater->OnTestProgramStart(*parent_);
+
+  // How many times to repeat the tests?  We don't want to repeat them
+  // when we are inside the subprocess of a death test.
+  const int repeat = in_subprocess_for_death_test ? 1 : GTEST_FLAG(repeat);
+  // Repeats forever if the repeat count is negative.
+  const bool gtest_repeat_forever = repeat < 0;
+  for (int i = 0; gtest_repeat_forever || i != repeat; i++) {
+    // We want to preserve failures generated by ad-hoc test
+    // assertions executed before RUN_ALL_TESTS().
+    ClearNonAdHocTestResult();
+
+    Timer timer;
+
+    // Shuffles test suites and tests if requested.
+    if (has_tests_to_run && GTEST_FLAG(shuffle)) {
+      random()->Reseed(static_cast<uint32_t>(random_seed_));
+      // This should be done before calling OnTestIterationStart(),
+      // such that a test event listener can see the actual test order
+      // in the event.
+      ShuffleTests();
+    }
+
+    // Tells the unit test event listeners that the tests are about to start.
+    repeater->OnTestIterationStart(*parent_, i);
+
+    // Runs each test suite if there is at least one test to run.
+    if (has_tests_to_run) {
+      // Sets up all environments beforehand.
+      repeater->OnEnvironmentsSetUpStart(*parent_);
+      ForEach(environments_, SetUpEnvironment);
+      repeater->OnEnvironmentsSetUpEnd(*parent_);
+
+      // Runs the tests only if there was no fatal failure or skip triggered
+      // during global set-up.
+      if (Test::IsSkipped()) {
+        // Emit diagnostics when global set-up calls skip, as it will not be
+        // emitted by default.
+        TestResult& test_result =
+            *internal::GetUnitTestImpl()->current_test_result();
+        for (int j = 0; j < test_result.total_part_count(); ++j) {
+          const TestPartResult& test_part_result =
+              test_result.GetTestPartResult(j);
+          if (test_part_result.type() == TestPartResult::kSkip) {
+            const std::string& result = test_part_result.message();
+            printf("%s\n", result.c_str());
+          }
+        }
+        fflush(stdout);
+      } else if (!Test::HasFatalFailure()) {
+        for (int test_index = 0; test_index < total_test_suite_count();
+             test_index++) {
+          GetMutableSuiteCase(test_index)->Run();
+          if (GTEST_FLAG(fail_fast) &&
+              GetMutableSuiteCase(test_index)->Failed()) {
+            for (int j = test_index + 1; j < total_test_suite_count(); j++) {
+              GetMutableSuiteCase(j)->Skip();
+            }
+            break;
+          }
+        }
+      } else if (Test::HasFatalFailure()) {
+        // If there was a fatal failure during the global setup then we know we
+        // aren't going to run any tests. Explicitly mark all of the tests as
+        // skipped to make this obvious in the output.
+        for (int test_index = 0; test_index < total_test_suite_count();
+             test_index++) {
+          GetMutableSuiteCase(test_index)->Skip();
+        }
+      }
+
+      // Tears down all environments in reverse order afterwards.
+      repeater->OnEnvironmentsTearDownStart(*parent_);
+      std::for_each(environments_.rbegin(), environments_.rend(),
+                    TearDownEnvironment);
+      repeater->OnEnvironmentsTearDownEnd(*parent_);
+    }
+
+    elapsed_time_ = timer.Elapsed();
+
+    // Tells the unit test event listener that the tests have just finished.
+    repeater->OnTestIterationEnd(*parent_, i);
+
+    // Gets the result and clears it.
+    if (!Passed()) {
+      failed = true;
+    }
+
+    // Restores the original test order after the iteration.  This
+    // allows the user to quickly repro a failure that happens in the
+    // N-th iteration without repeating the first (N - 1) iterations.
+    // This is not enclosed in "if (GTEST_FLAG(shuffle)) { ... }", in
+    // case the user somehow changes the value of the flag somewhere
+    // (it's always safe to unshuffle the tests).
+    UnshuffleTests();
+
+    if (GTEST_FLAG(shuffle)) {
+      // Picks a new random seed for each iteration.
+      random_seed_ = GetNextRandomSeed(random_seed_);
+    }
+  }
+
+  repeater->OnTestProgramEnd(*parent_);
+
+  if (!gtest_is_initialized_before_run_all_tests) {
+    ColoredPrintf(
+        GTestColor::kRed,
+        "\nIMPORTANT NOTICE - DO NOT IGNORE:\n"
+        "This test program did NOT call " GTEST_INIT_GOOGLE_TEST_NAME_
+        "() before calling RUN_ALL_TESTS(). This is INVALID. Soon " GTEST_NAME_
+        " will start to enforce the valid usage. "
+        "Please fix it ASAP, or IT WILL START TO FAIL.\n");  // NOLINT
+#if GTEST_FOR_GOOGLE_
+    ColoredPrintf(GTestColor::kRed,
+                  "For more details, see http://wiki/Main/ValidGUnitMain.\n");
+#endif  // GTEST_FOR_GOOGLE_
+  }
+
+  return !failed;
+}
+
+// Reads the GTEST_SHARD_STATUS_FILE environment variable, and creates the file
+// if the variable is present. If a file already exists at this location, this
+// function will write over it. If the variable is present, but the file cannot
+// be created, prints an error and exits.
+void WriteToShardStatusFileIfNeeded() {
+  const char* const test_shard_file = posix::GetEnv(kTestShardStatusFile);
+  if (test_shard_file != nullptr) {
+    FILE* const file = posix::FOpen(test_shard_file, "w");
+    if (file == nullptr) {
+      ColoredPrintf(GTestColor::kRed,
+                    "Could not write to the test shard status file \"%s\" "
+                    "specified by the %s environment variable.\n",
+                    test_shard_file, kTestShardStatusFile);
+      fflush(stdout);
+      exit(EXIT_FAILURE);
+    }
+    fclose(file);
+  }
+}
+
+// Checks whether sharding is enabled by examining the relevant
+// environment variable values. If the variables are present,
+// but inconsistent (i.e., shard_index >= total_shards), prints
+// an error and exits. If in_subprocess_for_death_test, sharding is
+// disabled because it must only be applied to the original test
+// process. Otherwise, we could filter out death tests we intended to execute.
+bool ShouldShard(const char* total_shards_env,
+                 const char* shard_index_env,
+                 bool in_subprocess_for_death_test) {
+  if (in_subprocess_for_death_test) {
+    return false;
+  }
+
+  const int32_t total_shards = Int32FromEnvOrDie(total_shards_env, -1);
+  const int32_t shard_index = Int32FromEnvOrDie(shard_index_env, -1);
+
+  if (total_shards == -1 && shard_index == -1) {
+    return false;
+  } else if (total_shards == -1 && shard_index != -1) {
+    const Message msg = Message()
+      << "Invalid environment variables: you have "
+      << kTestShardIndex << " = " << shard_index
+      << ", but have left " << kTestTotalShards << " unset.\n";
+    ColoredPrintf(GTestColor::kRed, "%s", msg.GetString().c_str());
+    fflush(stdout);
+    exit(EXIT_FAILURE);
+  } else if (total_shards != -1 && shard_index == -1) {
+    const Message msg = Message()
+      << "Invalid environment variables: you have "
+      << kTestTotalShards << " = " << total_shards
+      << ", but have left " << kTestShardIndex << " unset.\n";
+    ColoredPrintf(GTestColor::kRed, "%s", msg.GetString().c_str());
+    fflush(stdout);
+    exit(EXIT_FAILURE);
+  } else if (shard_index < 0 || shard_index >= total_shards) {
+    const Message msg = Message()
+      << "Invalid environment variables: we require 0 <= "
+      << kTestShardIndex << " < " << kTestTotalShards
+      << ", but you have " << kTestShardIndex << "=" << shard_index
+      << ", " << kTestTotalShards << "=" << total_shards << ".\n";
+    ColoredPrintf(GTestColor::kRed, "%s", msg.GetString().c_str());
+    fflush(stdout);
+    exit(EXIT_FAILURE);
+  }
+
+  return total_shards > 1;
+}
+
+// Parses the environment variable var as an Int32. If it is unset,
+// returns default_val. If it is not an Int32, prints an error
+// and aborts.
+int32_t Int32FromEnvOrDie(const char* var, int32_t default_val) {
+  const char* str_val = posix::GetEnv(var);
+  if (str_val == nullptr) {
+    return default_val;
+  }
+
+  int32_t result;
+  if (!ParseInt32(Message() << "The value of environment variable " << var,
+                  str_val, &result)) {
+    exit(EXIT_FAILURE);
+  }
+  return result;
+}
+
+// Given the total number of shards, the shard index, and the test id,
+// returns true if and only if the test should be run on this shard. The test id
+// is some arbitrary but unique non-negative integer assigned to each test
+// method. Assumes that 0 <= shard_index < total_shards.
+bool ShouldRunTestOnShard(int total_shards, int shard_index, int test_id) {
+  return (test_id % total_shards) == shard_index;
+}
+
+// Compares the name of each test with the user-specified filter to
+// decide whether the test should be run, then records the result in
+// each TestSuite and TestInfo object.
+// If shard_tests == true, further filters tests based on sharding
+// variables in the environment - see
+// https://github.com/google/googletest/blob/master/googletest/docs/advanced.md
+// . Returns the number of tests that should run.
+int UnitTestImpl::FilterTests(ReactionToSharding shard_tests) {
+  const int32_t total_shards = shard_tests == HONOR_SHARDING_PROTOCOL ?
+      Int32FromEnvOrDie(kTestTotalShards, -1) : -1;
+  const int32_t shard_index = shard_tests == HONOR_SHARDING_PROTOCOL ?
+      Int32FromEnvOrDie(kTestShardIndex, -1) : -1;
+
+  // num_runnable_tests are the number of tests that will
+  // run across all shards (i.e., match filter and are not disabled).
+  // num_selected_tests are the number of tests to be run on
+  // this shard.
+  int num_runnable_tests = 0;
+  int num_selected_tests = 0;
+  for (auto* test_suite : test_suites_) {
+    const std::string& test_suite_name = test_suite->name();
+    test_suite->set_should_run(false);
+
+    for (size_t j = 0; j < test_suite->test_info_list().size(); j++) {
+      TestInfo* const test_info = test_suite->test_info_list()[j];
+      const std::string test_name(test_info->name());
+      // A test is disabled if test suite name or test name matches
+      // kDisableTestFilter.
+      const bool is_disabled = internal::UnitTestOptions::MatchesFilter(
+                                   test_suite_name, kDisableTestFilter) ||
+                               internal::UnitTestOptions::MatchesFilter(
+                                   test_name, kDisableTestFilter);
+      test_info->is_disabled_ = is_disabled;
+
+      const bool matches_filter = internal::UnitTestOptions::FilterMatchesTest(
+          test_suite_name, test_name);
+      test_info->matches_filter_ = matches_filter;
+
+      const bool is_runnable =
+          (GTEST_FLAG(also_run_disabled_tests) || !is_disabled) &&
+          matches_filter;
+
+      const bool is_in_another_shard =
+          shard_tests != IGNORE_SHARDING_PROTOCOL &&
+          !ShouldRunTestOnShard(total_shards, shard_index, num_runnable_tests);
+      test_info->is_in_another_shard_ = is_in_another_shard;
+      const bool is_selected = is_runnable && !is_in_another_shard;
+
+      num_runnable_tests += is_runnable;
+      num_selected_tests += is_selected;
+
+      test_info->should_run_ = is_selected;
+      test_suite->set_should_run(test_suite->should_run() || is_selected);
+    }
+  }
+  return num_selected_tests;
+}
+
+// Prints the given C-string on a single line by replacing all '\n'
+// characters with string "\\n".  If the output takes more than
+// max_length characters, only prints the first max_length characters
+// and "...".
+static void PrintOnOneLine(const char* str, int max_length) {
+  if (str != nullptr) {
+    for (int i = 0; *str != '\0'; ++str) {
+      if (i >= max_length) {
+        printf("...");
+        break;
+      }
+      if (*str == '\n') {
+        printf("\\n");
+        i += 2;
+      } else {
+        printf("%c", *str);
+        ++i;
+      }
+    }
+  }
+}
+
+// Prints the names of the tests matching the user-specified filter flag.
+void UnitTestImpl::ListTestsMatchingFilter() {
+  // Print at most this many characters for each type/value parameter.
+  const int kMaxParamLength = 250;
+
+  for (auto* test_suite : test_suites_) {
+    bool printed_test_suite_name = false;
+
+    for (size_t j = 0; j < test_suite->test_info_list().size(); j++) {
+      const TestInfo* const test_info = test_suite->test_info_list()[j];
+      if (test_info->matches_filter_) {
+        if (!printed_test_suite_name) {
+          printed_test_suite_name = true;
+          printf("%s.", test_suite->name());
+          if (test_suite->type_param() != nullptr) {
+            printf("  # %s = ", kTypeParamLabel);
+            // We print the type parameter on a single line to make
+            // the output easy to parse by a program.
+            PrintOnOneLine(test_suite->type_param(), kMaxParamLength);
+          }
+          printf("\n");
+        }
+        printf("  %s", test_info->name());
+        if (test_info->value_param() != nullptr) {
+          printf("  # %s = ", kValueParamLabel);
+          // We print the value parameter on a single line to make the
+          // output easy to parse by a program.
+          PrintOnOneLine(test_info->value_param(), kMaxParamLength);
+        }
+        printf("\n");
+      }
+    }
+  }
+  fflush(stdout);
+  const std::string& output_format = UnitTestOptions::GetOutputFormat();
+  if (output_format == "xml" || output_format == "json") {
+    FILE* fileout = OpenFileForWriting(
+        UnitTestOptions::GetAbsolutePathToOutputFile().c_str());
+    std::stringstream stream;
+    if (output_format == "xml") {
+      XmlUnitTestResultPrinter(
+          UnitTestOptions::GetAbsolutePathToOutputFile().c_str())
+          .PrintXmlTestsList(&stream, test_suites_);
+    } else if (output_format == "json") {
+      JsonUnitTestResultPrinter(
+          UnitTestOptions::GetAbsolutePathToOutputFile().c_str())
+          .PrintJsonTestList(&stream, test_suites_);
+    }
+    fprintf(fileout, "%s", StringStreamToString(&stream).c_str());
+    fclose(fileout);
+  }
+}
+
+// Sets the OS stack trace getter.
+//
+// Does nothing if the input and the current OS stack trace getter are
+// the same; otherwise, deletes the old getter and makes the input the
+// current getter.
+void UnitTestImpl::set_os_stack_trace_getter(
+    OsStackTraceGetterInterface* getter) {
+  if (os_stack_trace_getter_ != getter) {
+    delete os_stack_trace_getter_;
+    os_stack_trace_getter_ = getter;
+  }
+}
+
+// Returns the current OS stack trace getter if it is not NULL;
+// otherwise, creates an OsStackTraceGetter, makes it the current
+// getter, and returns it.
+OsStackTraceGetterInterface* UnitTestImpl::os_stack_trace_getter() {
+  if (os_stack_trace_getter_ == nullptr) {
+#ifdef GTEST_OS_STACK_TRACE_GETTER_
+    os_stack_trace_getter_ = new GTEST_OS_STACK_TRACE_GETTER_;
+#else
+    os_stack_trace_getter_ = new OsStackTraceGetter;
+#endif  // GTEST_OS_STACK_TRACE_GETTER_
+  }
+
+  return os_stack_trace_getter_;
+}
+
+// Returns the most specific TestResult currently running.
+TestResult* UnitTestImpl::current_test_result() {
+  if (current_test_info_ != nullptr) {
+    return &current_test_info_->result_;
+  }
+  if (current_test_suite_ != nullptr) {
+    return &current_test_suite_->ad_hoc_test_result_;
+  }
+  return &ad_hoc_test_result_;
+}
+
+// Shuffles all test suites, and the tests within each test suite,
+// making sure that death tests are still run first.
+void UnitTestImpl::ShuffleTests() {
+  // Shuffles the death test suites.
+  ShuffleRange(random(), 0, last_death_test_suite_ + 1, &test_suite_indices_);
+
+  // Shuffles the non-death test suites.
+  ShuffleRange(random(), last_death_test_suite_ + 1,
+               static_cast<int>(test_suites_.size()), &test_suite_indices_);
+
+  // Shuffles the tests inside each test suite.
+  for (auto& test_suite : test_suites_) {
+    test_suite->ShuffleTests(random());
+  }
+}
+
+// Restores the test suites and tests to their order before the first shuffle.
+void UnitTestImpl::UnshuffleTests() {
+  for (size_t i = 0; i < test_suites_.size(); i++) {
+    // Unshuffles the tests in each test suite.
+    test_suites_[i]->UnshuffleTests();
+    // Resets the index of each test suite.
+    test_suite_indices_[i] = static_cast<int>(i);
+  }
+}
+
+// Returns the current OS stack trace as an std::string.
+//
+// The maximum number of stack frames to be included is specified by
+// the gtest_stack_trace_depth flag.  The skip_count parameter
+// specifies the number of top frames to be skipped, which doesn't
+// count against the number of frames to be included.
+//
+// For example, if Foo() calls Bar(), which in turn calls
+// GetCurrentOsStackTraceExceptTop(..., 1), Foo() will be included in
+// the trace but Bar() and GetCurrentOsStackTraceExceptTop() won't.
+std::string GetCurrentOsStackTraceExceptTop(UnitTest* /*unit_test*/,
+                                            int skip_count) {
+  // We pass skip_count + 1 to skip this wrapper function in addition
+  // to what the user really wants to skip.
+  return GetUnitTestImpl()->CurrentOsStackTraceExceptTop(skip_count + 1);
+}
+
+// Used by the GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_ macro to
+// suppress unreachable code warnings.
+namespace {
+class ClassUniqueToAlwaysTrue {};
+}
+
+bool IsTrue(bool condition) { return condition; }
+
+bool AlwaysTrue() {
+#if GTEST_HAS_EXCEPTIONS
+  // This condition is always false so AlwaysTrue() never actually throws,
+  // but it makes the compiler think that it may throw.
+  if (IsTrue(false))
+    throw ClassUniqueToAlwaysTrue();
+#endif  // GTEST_HAS_EXCEPTIONS
+  return true;
+}
+
+// If *pstr starts with the given prefix, modifies *pstr to be right
+// past the prefix and returns true; otherwise leaves *pstr unchanged
+// and returns false.  None of pstr, *pstr, and prefix can be NULL.
+bool SkipPrefix(const char* prefix, const char** pstr) {
+  const size_t prefix_len = strlen(prefix);
+  if (strncmp(*pstr, prefix, prefix_len) == 0) {
+    *pstr += prefix_len;
+    return true;
+  }
+  return false;
+}
+
+// Parses a string as a command line flag.  The string should have
+// the format "--flag=value".  When def_optional is true, the "=value"
+// part can be omitted.
+//
+// Returns the value of the flag, or NULL if the parsing failed.
+static const char* ParseFlagValue(const char* str, const char* flag,
+                                  bool def_optional) {
+  // str and flag must not be NULL.
+  if (str == nullptr || flag == nullptr) return nullptr;
+
+  // The flag must start with "--" followed by GTEST_FLAG_PREFIX_.
+  const std::string flag_str = std::string("--") + GTEST_FLAG_PREFIX_ + flag;
+  const size_t flag_len = flag_str.length();
+  if (strncmp(str, flag_str.c_str(), flag_len) != 0) return nullptr;
+
+  // Skips the flag name.
+  const char* flag_end = str + flag_len;
+
+  // When def_optional is true, it's OK to not have a "=value" part.
+  if (def_optional && (flag_end[0] == '\0')) {
+    return flag_end;
+  }
+
+  // If def_optional is true and there are more characters after the
+  // flag name, or if def_optional is false, there must be a '=' after
+  // the flag name.
+  if (flag_end[0] != '=') return nullptr;
+
+  // Returns the string after "=".
+  return flag_end + 1;
+}
+
+// Parses a string for a bool flag, in the form of either
+// "--flag=value" or "--flag".
+//
+// In the former case, the value is taken as true as long as it does
+// not start with '0', 'f', or 'F'.
+//
+// In the latter case, the value is taken as true.
+//
+// On success, stores the value of the flag in *value, and returns
+// true.  On failure, returns false without changing *value.
+static bool ParseBoolFlag(const char* str, const char* flag, bool* value) {
+  // Gets the value of the flag as a string.
+  const char* const value_str = ParseFlagValue(str, flag, true);
+
+  // Aborts if the parsing failed.
+  if (value_str == nullptr) return false;
+
+  // Converts the string value to a bool.
+  *value = !(*value_str == '0' || *value_str == 'f' || *value_str == 'F');
+  return true;
+}
+
+// Parses a string for an int32_t flag, in the form of "--flag=value".
+//
+// On success, stores the value of the flag in *value, and returns
+// true.  On failure, returns false without changing *value.
+bool ParseInt32Flag(const char* str, const char* flag, int32_t* value) {
+  // Gets the value of the flag as a string.
+  const char* const value_str = ParseFlagValue(str, flag, false);
+
+  // Aborts if the parsing failed.
+  if (value_str == nullptr) return false;
+
+  // Sets *value to the value of the flag.
+  return ParseInt32(Message() << "The value of flag --" << flag,
+                    value_str, value);
+}
+
+// Parses a string for a string flag, in the form of "--flag=value".
+//
+// On success, stores the value of the flag in *value, and returns
+// true.  On failure, returns false without changing *value.
+template <typename String>
+static bool ParseStringFlag(const char* str, const char* flag, String* value) {
+  // Gets the value of the flag as a string.
+  const char* const value_str = ParseFlagValue(str, flag, false);
+
+  // Aborts if the parsing failed.
+  if (value_str == nullptr) return false;
+
+  // Sets *value to the value of the flag.
+  *value = value_str;
+  return true;
+}
+
+// Determines whether a string has a prefix that Google Test uses for its
+// flags, i.e., starts with GTEST_FLAG_PREFIX_ or GTEST_FLAG_PREFIX_DASH_.
+// If Google Test detects that a command line flag has its prefix but is not
+// recognized, it will print its help message. Flags starting with
+// GTEST_INTERNAL_PREFIX_ followed by "internal_" are considered Google Test
+// internal flags and do not trigger the help message.
+static bool HasGoogleTestFlagPrefix(const char* str) {
+  return (SkipPrefix("--", &str) ||
+          SkipPrefix("-", &str) ||
+          SkipPrefix("/", &str)) &&
+         !SkipPrefix(GTEST_FLAG_PREFIX_ "internal_", &str) &&
+         (SkipPrefix(GTEST_FLAG_PREFIX_, &str) ||
+          SkipPrefix(GTEST_FLAG_PREFIX_DASH_, &str));
+}
+
+// Prints a string containing code-encoded text.  The following escape
+// sequences can be used in the string to control the text color:
+//
+//   @@    prints a single '@' character.
+//   @R    changes the color to red.
+//   @G    changes the color to green.
+//   @Y    changes the color to yellow.
+//   @D    changes to the default terminal text color.
+//
+static void PrintColorEncoded(const char* str) {
+  GTestColor color = GTestColor::kDefault;  // The current color.
+
+  // Conceptually, we split the string into segments divided by escape
+  // sequences.  Then we print one segment at a time.  At the end of
+  // each iteration, the str pointer advances to the beginning of the
+  // next segment.
+  for (;;) {
+    const char* p = strchr(str, '@');
+    if (p == nullptr) {
+      ColoredPrintf(color, "%s", str);
+      return;
+    }
+
+    ColoredPrintf(color, "%s", std::string(str, p).c_str());
+
+    const char ch = p[1];
+    str = p + 2;
+    if (ch == '@') {
+      ColoredPrintf(color, "@");
+    } else if (ch == 'D') {
+      color = GTestColor::kDefault;
+    } else if (ch == 'R') {
+      color = GTestColor::kRed;
+    } else if (ch == 'G') {
+      color = GTestColor::kGreen;
+    } else if (ch == 'Y') {
+      color = GTestColor::kYellow;
+    } else {
+      --str;
+    }
+  }
+}
+
+static const char kColorEncodedHelpMessage[] =
+    "This program contains tests written using " GTEST_NAME_
+    ". You can use the\n"
+    "following command line flags to control its behavior:\n"
+    "\n"
+    "Test Selection:\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "list_tests@D\n"
+    "      List the names of all tests instead of running them. The name of\n"
+    "      TEST(Foo, Bar) is \"Foo.Bar\".\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "filter=@YPOSITIVE_PATTERNS"
+    "[@G-@YNEGATIVE_PATTERNS]@D\n"
+    "      Run only the tests whose name matches one of the positive patterns "
+    "but\n"
+    "      none of the negative patterns. '?' matches any single character; "
+    "'*'\n"
+    "      matches any substring; ':' separates two patterns.\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "also_run_disabled_tests@D\n"
+    "      Run all disabled tests too.\n"
+    "\n"
+    "Test Execution:\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "repeat=@Y[COUNT]@D\n"
+    "      Run the tests repeatedly; use a negative count to repeat forever.\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "shuffle@D\n"
+    "      Randomize tests' orders on every iteration.\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "random_seed=@Y[NUMBER]@D\n"
+    "      Random number seed to use for shuffling test orders (between 1 and\n"
+    "      99999, or 0 to use a seed based on the current time).\n"
+    "\n"
+    "Test Output:\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "color=@Y(@Gyes@Y|@Gno@Y|@Gauto@Y)@D\n"
+    "      Enable/disable colored output. The default is @Gauto@D.\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "brief=1@D\n"
+    "      Only print test failures.\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "print_time=0@D\n"
+    "      Don't print the elapsed time of each test.\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "output=@Y(@Gjson@Y|@Gxml@Y)[@G:@YDIRECTORY_PATH@G" GTEST_PATH_SEP_
+    "@Y|@G:@YFILE_PATH]@D\n"
+    "      Generate a JSON or XML report in the given directory or with the "
+    "given\n"
+    "      file name. @YFILE_PATH@D defaults to @Gtest_detail.xml@D.\n"
+# if GTEST_CAN_STREAM_RESULTS_
+    "  @G--" GTEST_FLAG_PREFIX_
+    "stream_result_to=@YHOST@G:@YPORT@D\n"
+    "      Stream test results to the given server.\n"
+# endif  // GTEST_CAN_STREAM_RESULTS_
+    "\n"
+    "Assertion Behavior:\n"
+# if GTEST_HAS_DEATH_TEST && !GTEST_OS_WINDOWS
+    "  @G--" GTEST_FLAG_PREFIX_
+    "death_test_style=@Y(@Gfast@Y|@Gthreadsafe@Y)@D\n"
+    "      Set the default death test style.\n"
+# endif  // GTEST_HAS_DEATH_TEST && !GTEST_OS_WINDOWS
+    "  @G--" GTEST_FLAG_PREFIX_
+    "break_on_failure@D\n"
+    "      Turn assertion failures into debugger break-points.\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "throw_on_failure@D\n"
+    "      Turn assertion failures into C++ exceptions for use by an external\n"
+    "      test framework.\n"
+    "  @G--" GTEST_FLAG_PREFIX_
+    "catch_exceptions=0@D\n"
+    "      Do not report exceptions as test failures. Instead, allow them\n"
+    "      to crash the program or throw a pop-up (on Windows).\n"
+    "\n"
+    "Except for @G--" GTEST_FLAG_PREFIX_
+    "list_tests@D, you can alternatively set "
+    "the corresponding\n"
+    "environment variable of a flag (all letters in upper-case). For example, "
+    "to\n"
+    "disable colored text output, you can either specify "
+    "@G--" GTEST_FLAG_PREFIX_
+    "color=no@D or set\n"
+    "the @G" GTEST_FLAG_PREFIX_UPPER_
+    "COLOR@D environment variable to @Gno@D.\n"
+    "\n"
+    "For more information, please read the " GTEST_NAME_
+    " documentation at\n"
+    "@G" GTEST_PROJECT_URL_ "@D. If you find a bug in " GTEST_NAME_
+    "\n"
+    "(not one in your own code or tests), please report it to\n"
+    "@G<" GTEST_DEV_EMAIL_ ">@D.\n";
+
+static bool ParseGoogleTestFlag(const char* const arg) {
+  return ParseBoolFlag(arg, kAlsoRunDisabledTestsFlag,
+                       &GTEST_FLAG(also_run_disabled_tests)) ||
+         ParseBoolFlag(arg, kBreakOnFailureFlag,
+                       &GTEST_FLAG(break_on_failure)) ||
+         ParseBoolFlag(arg, kCatchExceptionsFlag,
+                       &GTEST_FLAG(catch_exceptions)) ||
+         ParseStringFlag(arg, kColorFlag, &GTEST_FLAG(color)) ||
+         ParseStringFlag(arg, kDeathTestStyleFlag,
+                         &GTEST_FLAG(death_test_style)) ||
+         ParseBoolFlag(arg, kDeathTestUseFork,
+                       &GTEST_FLAG(death_test_use_fork)) ||
+         ParseBoolFlag(arg, kFailFast, &GTEST_FLAG(fail_fast)) ||
+         ParseStringFlag(arg, kFilterFlag, &GTEST_FLAG(filter)) ||
+         ParseStringFlag(arg, kInternalRunDeathTestFlag,
+                         &GTEST_FLAG(internal_run_death_test)) ||
+         ParseBoolFlag(arg, kListTestsFlag, &GTEST_FLAG(list_tests)) ||
+         ParseStringFlag(arg, kOutputFlag, &GTEST_FLAG(output)) ||
+         ParseBoolFlag(arg, kBriefFlag, &GTEST_FLAG(brief)) ||
+         ParseBoolFlag(arg, kPrintTimeFlag, &GTEST_FLAG(print_time)) ||
+         ParseBoolFlag(arg, kPrintUTF8Flag, &GTEST_FLAG(print_utf8)) ||
+         ParseInt32Flag(arg, kRandomSeedFlag, &GTEST_FLAG(random_seed)) ||
+         ParseInt32Flag(arg, kRepeatFlag, &GTEST_FLAG(repeat)) ||
+         ParseBoolFlag(arg, kShuffleFlag, &GTEST_FLAG(shuffle)) ||
+         ParseInt32Flag(arg, kStackTraceDepthFlag,
+                        &GTEST_FLAG(stack_trace_depth)) ||
+         ParseStringFlag(arg, kStreamResultToFlag,
+                         &GTEST_FLAG(stream_result_to)) ||
+         ParseBoolFlag(arg, kThrowOnFailureFlag, &GTEST_FLAG(throw_on_failure));
+}
+
+#if GTEST_USE_OWN_FLAGFILE_FLAG_
+static void LoadFlagsFromFile(const std::string& path) {
+  FILE* flagfile = posix::FOpen(path.c_str(), "r");
+  if (!flagfile) {
+    GTEST_LOG_(FATAL) << "Unable to open file \"" << GTEST_FLAG(flagfile)
+                      << "\"";
+  }
+  std::string contents(ReadEntireFile(flagfile));
+  posix::FClose(flagfile);
+  std::vector<std::string> lines;
+  SplitString(contents, '\n', &lines);
+  for (size_t i = 0; i < lines.size(); ++i) {
+    if (lines[i].empty())
+      continue;
+    if (!ParseGoogleTestFlag(lines[i].c_str()))
+      g_help_flag = true;
+  }
+}
+#endif  // GTEST_USE_OWN_FLAGFILE_FLAG_
+
+// Parses the command line for Google Test flags, without initializing
+// other parts of Google Test.  The type parameter CharType can be
+// instantiated to either char or wchar_t.
+template <typename CharType>
+void ParseGoogleTestFlagsOnlyImpl(int* argc, CharType** argv) {
+  for (int i = 1; i < *argc; i++) {
+    const std::string arg_string = StreamableToString(argv[i]);
+    const char* const arg = arg_string.c_str();
+
+    using internal::ParseBoolFlag;
+    using internal::ParseInt32Flag;
+    using internal::ParseStringFlag;
+
+    bool remove_flag = false;
+    if (ParseGoogleTestFlag(arg)) {
+      remove_flag = true;
+#if GTEST_USE_OWN_FLAGFILE_FLAG_
+    } else if (ParseStringFlag(arg, kFlagfileFlag, &GTEST_FLAG(flagfile))) {
+      LoadFlagsFromFile(GTEST_FLAG(flagfile));
+      remove_flag = true;
+#endif  // GTEST_USE_OWN_FLAGFILE_FLAG_
+    } else if (arg_string == "--help" || arg_string == "-h" ||
+               arg_string == "-?" || arg_string == "/?" ||
+               HasGoogleTestFlagPrefix(arg)) {
+      // Both help flag and unrecognized Google Test flags (excluding
+      // internal ones) trigger help display.
+      g_help_flag = true;
+    }
+
+    if (remove_flag) {
+      // Shift the remainder of the argv list left by one.  Note
+      // that argv has (*argc + 1) elements, the last one always being
+      // NULL.  The following loop moves the trailing NULL element as
+      // well.
+      for (int j = i; j != *argc; j++) {
+        argv[j] = argv[j + 1];
+      }
+
+      // Decrements the argument count.
+      (*argc)--;
+
+      // We also need to decrement the iterator as we just removed
+      // an element.
+      i--;
+    }
+  }
+
+  if (g_help_flag) {
+    // We print the help here instead of in RUN_ALL_TESTS(), as the
+    // latter may not be called at all if the user is using Google
+    // Test with another testing framework.
+    PrintColorEncoded(kColorEncodedHelpMessage);
+  }
+}
+
+// Parses the command line for Google Test flags, without initializing
+// other parts of Google Test.
+void ParseGoogleTestFlagsOnly(int* argc, char** argv) {
+  ParseGoogleTestFlagsOnlyImpl(argc, argv);
+
+  // Fix the value of *_NSGetArgc() on macOS, but if and only if
+  // *_NSGetArgv() == argv
+  // Only applicable to char** version of argv
+#if GTEST_OS_MAC
+#ifndef GTEST_OS_IOS
+  if (*_NSGetArgv() == argv) {
+    *_NSGetArgc() = *argc;
+  }
+#endif
+#endif
+}
+void ParseGoogleTestFlagsOnly(int* argc, wchar_t** argv) {
+  ParseGoogleTestFlagsOnlyImpl(argc, argv);
+}
+
+// The internal implementation of InitGoogleTest().
+//
+// The type parameter CharType can be instantiated to either char or
+// wchar_t.
+template <typename CharType>
+void InitGoogleTestImpl(int* argc, CharType** argv) {
+  // We don't want to run the initialization code twice.
+  if (GTestIsInitialized()) return;
+
+  if (*argc <= 0) return;
+
+  g_argvs.clear();
+  for (int i = 0; i != *argc; i++) {
+    g_argvs.push_back(StreamableToString(argv[i]));
+  }
+
+#if GTEST_HAS_ABSL
+  absl::InitializeSymbolizer(g_argvs[0].c_str());
+#endif  // GTEST_HAS_ABSL
+
+  ParseGoogleTestFlagsOnly(argc, argv);
+  GetUnitTestImpl()->PostFlagParsingInit();
+}
+
+}  // namespace internal
+
+// Initializes Google Test.  This must be called before calling
+// RUN_ALL_TESTS().  In particular, it parses a command line for the
+// flags that Google Test recognizes.  Whenever a Google Test flag is
+// seen, it is removed from argv, and *argc is decremented.
+//
+// No value is returned.  Instead, the Google Test flag variables are
+// updated.
+//
+// Calling the function for the second time has no user-visible effect.
+void InitGoogleTest(int* argc, char** argv) {
+#if defined(GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_)
+  GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_(argc, argv);
+#else  // defined(GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_)
+  internal::InitGoogleTestImpl(argc, argv);
+#endif  // defined(GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_)
+}
+
+// This overloaded version can be used in Windows programs compiled in
+// UNICODE mode.
+void InitGoogleTest(int* argc, wchar_t** argv) {
+#if defined(GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_)
+  GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_(argc, argv);
+#else  // defined(GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_)
+  internal::InitGoogleTestImpl(argc, argv);
+#endif  // defined(GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_)
+}
+
+// This overloaded version can be used on Arduino/embedded platforms where
+// there is no argc/argv.
+void InitGoogleTest() {
+  // Since Arduino doesn't have a command line, fake out the argc/argv arguments
+  int argc = 1;
+  const auto arg0 = "dummy";
+  char* argv0 = const_cast<char*>(arg0);
+  char** argv = &argv0;
+
+#if defined(GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_)
+  GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_(&argc, argv);
+#else  // defined(GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_)
+  internal::InitGoogleTestImpl(&argc, argv);
+#endif  // defined(GTEST_CUSTOM_INIT_GOOGLE_TEST_FUNCTION_)
+}
+
+std::string TempDir() {
+#if defined(GTEST_CUSTOM_TEMPDIR_FUNCTION_)
+  return GTEST_CUSTOM_TEMPDIR_FUNCTION_();
+#elif GTEST_OS_WINDOWS_MOBILE
+  return "\\temp\\";
+#elif GTEST_OS_WINDOWS
+  const char* temp_dir = internal::posix::GetEnv("TEMP");
+  if (temp_dir == nullptr || temp_dir[0] == '\0') {
+    return "\\temp\\";
+  } else if (temp_dir[strlen(temp_dir) - 1] == '\\') {
+    return temp_dir;
+  } else {
+    return std::string(temp_dir) + "\\";
+  }
+#elif GTEST_OS_LINUX_ANDROID
+  const char* temp_dir = internal::posix::GetEnv("TEST_TMPDIR");
+  if (temp_dir == nullptr || temp_dir[0] == '\0') {
+    return "/data/local/tmp/";
+  } else {
+    return temp_dir;
+  }
+#elif GTEST_OS_LINUX
+  const char* temp_dir = internal::posix::GetEnv("TEST_TMPDIR");
+  if (temp_dir == nullptr || temp_dir[0] == '\0') {
+    return "/tmp/";
+  } else {
+    return temp_dir;
+  }
+#else
+  return "/tmp/";
+#endif  // GTEST_OS_WINDOWS_MOBILE
+}
+
+// Class ScopedTrace
+
+// Pushes the given source file location and message onto a per-thread
+// trace stack maintained by Google Test.
+void ScopedTrace::PushTrace(const char* file, int line, std::string message) {
+  internal::TraceInfo trace;
+  trace.file = file;
+  trace.line = line;
+  trace.message.swap(message);
+
+  UnitTest::GetInstance()->PushGTestTrace(trace);
+}
+
+// Pops the info pushed by the c'tor.
+ScopedTrace::~ScopedTrace()
+    GTEST_LOCK_EXCLUDED_(&UnitTest::mutex_) {
+  UnitTest::GetInstance()->PopGTestTrace();
+}
+
+}  // namespace testing
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// This file implements death tests.
+
+
+#include <functional>
+#include <utility>
+
+
+#if GTEST_HAS_DEATH_TEST
+
+# if GTEST_OS_MAC
+#  include <crt_externs.h>
+# endif  // GTEST_OS_MAC
+
+# include <errno.h>
+# include <fcntl.h>
+# include <limits.h>
+
+# if GTEST_OS_LINUX
+#  include <signal.h>
+# endif  // GTEST_OS_LINUX
+
+# include <stdarg.h>
+
+# if GTEST_OS_WINDOWS
+#  include <windows.h>
+# else
+#  include <sys/mman.h>
+#  include <sys/wait.h>
+# endif  // GTEST_OS_WINDOWS
+
+# if GTEST_OS_QNX
+#  include <spawn.h>
+# endif  // GTEST_OS_QNX
+
+# if GTEST_OS_FUCHSIA
+#  include <lib/fdio/fd.h>
+#  include <lib/fdio/io.h>
+#  include <lib/fdio/spawn.h>
+#  include <lib/zx/channel.h>
+#  include <lib/zx/port.h>
+#  include <lib/zx/process.h>
+#  include <lib/zx/socket.h>
+#  include <zircon/processargs.h>
+#  include <zircon/syscalls.h>
+#  include <zircon/syscalls/policy.h>
+#  include <zircon/syscalls/port.h>
+# endif  // GTEST_OS_FUCHSIA
+
+#endif  // GTEST_HAS_DEATH_TEST
+
+
+namespace testing {
+
+// Constants.
+
+// The default death test style.
+//
+// This is defined in internal/gtest-port.h as "fast", but can be overridden by
+// a definition in internal/custom/gtest-port.h. The recommended value, which is
+// used internally at Google, is "threadsafe".
+static const char kDefaultDeathTestStyle[] = GTEST_DEFAULT_DEATH_TEST_STYLE;
+
+GTEST_DEFINE_string_(
+    death_test_style,
+    internal::StringFromGTestEnv("death_test_style", kDefaultDeathTestStyle),
+    "Indicates how to run a death test in a forked child process: "
+    "\"threadsafe\" (child process re-executes the test binary "
+    "from the beginning, running only the specific death test) or "
+    "\"fast\" (child process runs the death test immediately "
+    "after forking).");
+
+GTEST_DEFINE_bool_(
+    death_test_use_fork,
+    internal::BoolFromGTestEnv("death_test_use_fork", false),
+    "Instructs to use fork()/_exit() instead of clone() in death tests. "
+    "Ignored and always uses fork() on POSIX systems where clone() is not "
+    "implemented. Useful when running under valgrind or similar tools if "
+    "those do not support clone(). Valgrind 3.3.1 will just fail if "
+    "it sees an unsupported combination of clone() flags. "
+    "It is not recommended to use this flag w/o valgrind though it will "
+    "work in 99% of the cases. Once valgrind is fixed, this flag will "
+    "most likely be removed.");
+
+namespace internal {
+GTEST_DEFINE_string_(
+    internal_run_death_test, "",
+    "Indicates the file, line number, temporal index of "
+    "the single death test to run, and a file descriptor to "
+    "which a success code may be sent, all separated by "
+    "the '|' characters.  This flag is specified if and only if the "
+    "current process is a sub-process launched for running a thread-safe "
+    "death test.  FOR INTERNAL USE ONLY.");
+}  // namespace internal
+
+#if GTEST_HAS_DEATH_TEST
+
+namespace internal {
+
+// Valid only for fast death tests. Indicates the code is running in the
+// child process of a fast style death test.
+# if !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA
+static bool g_in_fast_death_test_child = false;
+# endif
+
+// Returns a Boolean value indicating whether the caller is currently
+// executing in the context of the death test child process.  Tools such as
+// Valgrind heap checkers may need this to modify their behavior in death
+// tests.  IMPORTANT: This is an internal utility.  Using it may break the
+// implementation of death tests.  User code MUST NOT use it.
+bool InDeathTestChild() {
+# if GTEST_OS_WINDOWS || GTEST_OS_FUCHSIA
+
+  // On Windows and Fuchsia, death tests are thread-safe regardless of the value
+  // of the death_test_style flag.
+  return !GTEST_FLAG(internal_run_death_test).empty();
+
+# else
+
+  if (GTEST_FLAG(death_test_style) == "threadsafe")
+    return !GTEST_FLAG(internal_run_death_test).empty();
+  else
+    return g_in_fast_death_test_child;
+#endif
+}
+
+}  // namespace internal
+
+// ExitedWithCode constructor.
+ExitedWithCode::ExitedWithCode(int exit_code) : exit_code_(exit_code) {
+}
+
+// ExitedWithCode function-call operator.
+bool ExitedWithCode::operator()(int exit_status) const {
+# if GTEST_OS_WINDOWS || GTEST_OS_FUCHSIA
+
+  return exit_status == exit_code_;
+
+# else
+
+  return WIFEXITED(exit_status) && WEXITSTATUS(exit_status) == exit_code_;
+
+# endif  // GTEST_OS_WINDOWS || GTEST_OS_FUCHSIA
+}
+
+# if !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA
+// KilledBySignal constructor.
+KilledBySignal::KilledBySignal(int signum) : signum_(signum) {
+}
+
+// KilledBySignal function-call operator.
+bool KilledBySignal::operator()(int exit_status) const {
+#  if defined(GTEST_KILLED_BY_SIGNAL_OVERRIDE_)
+  {
+    bool result;
+    if (GTEST_KILLED_BY_SIGNAL_OVERRIDE_(signum_, exit_status, &result)) {
+      return result;
+    }
+  }
+#  endif  // defined(GTEST_KILLED_BY_SIGNAL_OVERRIDE_)
+  return WIFSIGNALED(exit_status) && WTERMSIG(exit_status) == signum_;
+}
+# endif  // !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA
+
+namespace internal {
+
+// Utilities needed for death tests.
+
+// Generates a textual description of a given exit code, in the format
+// specified by wait(2).
+static std::string ExitSummary(int exit_code) {
+  Message m;
+
+# if GTEST_OS_WINDOWS || GTEST_OS_FUCHSIA
+
+  m << "Exited with exit status " << exit_code;
+
+# else
+
+  if (WIFEXITED(exit_code)) {
+    m << "Exited with exit status " << WEXITSTATUS(exit_code);
+  } else if (WIFSIGNALED(exit_code)) {
+    m << "Terminated by signal " << WTERMSIG(exit_code);
+  }
+#  ifdef WCOREDUMP
+  if (WCOREDUMP(exit_code)) {
+    m << " (core dumped)";
+  }
+#  endif
+# endif  // GTEST_OS_WINDOWS || GTEST_OS_FUCHSIA
+
+  return m.GetString();
+}
+
+// Returns true if exit_status describes a process that was terminated
+// by a signal, or exited normally with a nonzero exit code.
+bool ExitedUnsuccessfully(int exit_status) {
+  return !ExitedWithCode(0)(exit_status);
+}
+
+# if !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA
+// Generates a textual failure message when a death test finds more than
+// one thread running, or cannot determine the number of threads, prior
+// to executing the given statement.  It is the responsibility of the
+// caller not to pass a thread_count of 1.
+static std::string DeathTestThreadWarning(size_t thread_count) {
+  Message msg;
+  msg << "Death tests use fork(), which is unsafe particularly"
+      << " in a threaded context. For this test, " << GTEST_NAME_ << " ";
+  if (thread_count == 0) {
+    msg << "couldn't detect the number of threads.";
+  } else {
+    msg << "detected " << thread_count << " threads.";
+  }
+  msg << " See "
+         "https://github.com/google/googletest/blob/master/docs/"
+         "advanced.md#death-tests-and-threads"
+      << " for more explanation and suggested solutions, especially if"
+      << " this is the last message you see before your test times out.";
+  return msg.GetString();
+}
+# endif  // !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA
+
+// Flag characters for reporting a death test that did not die.
+static const char kDeathTestLived = 'L';
+static const char kDeathTestReturned = 'R';
+static const char kDeathTestThrew = 'T';
+static const char kDeathTestInternalError = 'I';
+
+#if GTEST_OS_FUCHSIA
+
+// File descriptor used for the pipe in the child process.
+static const int kFuchsiaReadPipeFd = 3;
+
+#endif
+
+// An enumeration describing all of the possible ways that a death test can
+// conclude.  DIED means that the process died while executing the test
+// code; LIVED means that process lived beyond the end of the test code;
+// RETURNED means that the test statement attempted to execute a return
+// statement, which is not allowed; THREW means that the test statement
+// returned control by throwing an exception.  IN_PROGRESS means the test
+// has not yet concluded.
+enum DeathTestOutcome { IN_PROGRESS, DIED, LIVED, RETURNED, THREW };
+
+// Routine for aborting the program which is safe to call from an
+// exec-style death test child process, in which case the error
+// message is propagated back to the parent process.  Otherwise, the
+// message is simply printed to stderr.  In either case, the program
+// then exits with status 1.
+static void DeathTestAbort(const std::string& message) {
+  // On a POSIX system, this function may be called from a threadsafe-style
+  // death test child process, which operates on a very small stack.  Use
+  // the heap for any additional non-minuscule memory requirements.
+  const InternalRunDeathTestFlag* const flag =
+      GetUnitTestImpl()->internal_run_death_test_flag();
+  if (flag != nullptr) {
+    FILE* parent = posix::FDOpen(flag->write_fd(), "w");
+    fputc(kDeathTestInternalError, parent);
+    fprintf(parent, "%s", message.c_str());
+    fflush(parent);
+    _exit(1);
+  } else {
+    fprintf(stderr, "%s", message.c_str());
+    fflush(stderr);
+    posix::Abort();
+  }
+}
+
+// A replacement for CHECK that calls DeathTestAbort if the assertion
+// fails.
+# define GTEST_DEATH_TEST_CHECK_(expression) \
+  do { \
+    if (!::testing::internal::IsTrue(expression)) { \
+      DeathTestAbort( \
+          ::std::string("CHECK failed: File ") + __FILE__ +  ", line " \
+          + ::testing::internal::StreamableToString(__LINE__) + ": " \
+          + #expression); \
+    } \
+  } while (::testing::internal::AlwaysFalse())
+
+// This macro is similar to GTEST_DEATH_TEST_CHECK_, but it is meant for
+// evaluating any system call that fulfills two conditions: it must return
+// -1 on failure, and set errno to EINTR when it is interrupted and
+// should be tried again.  The macro expands to a loop that repeatedly
+// evaluates the expression as long as it evaluates to -1 and sets
+// errno to EINTR.  If the expression evaluates to -1 but errno is
+// something other than EINTR, DeathTestAbort is called.
+# define GTEST_DEATH_TEST_CHECK_SYSCALL_(expression) \
+  do { \
+    int gtest_retval; \
+    do { \
+      gtest_retval = (expression); \
+    } while (gtest_retval == -1 && errno == EINTR); \
+    if (gtest_retval == -1) { \
+      DeathTestAbort( \
+          ::std::string("CHECK failed: File ") + __FILE__ + ", line " \
+          + ::testing::internal::StreamableToString(__LINE__) + ": " \
+          + #expression + " != -1"); \
+    } \
+  } while (::testing::internal::AlwaysFalse())
+
+// Returns the message describing the last system error in errno.
+std::string GetLastErrnoDescription() {
+    return errno == 0 ? "" : posix::StrError(errno);
+}
+
+// This is called from a death test parent process to read a failure
+// message from the death test child process and log it with the FATAL
+// severity. On Windows, the message is read from a pipe handle. On other
+// platforms, it is read from a file descriptor.
+static void FailFromInternalError(int fd) {
+  Message error;
+  char buffer[256];
+  int num_read;
+
+  do {
+    while ((num_read = posix::Read(fd, buffer, 255)) > 0) {
+      buffer[num_read] = '\0';
+      error << buffer;
+    }
+  } while (num_read == -1 && errno == EINTR);
+
+  if (num_read == 0) {
+    GTEST_LOG_(FATAL) << error.GetString();
+  } else {
+    const int last_error = errno;
+    GTEST_LOG_(FATAL) << "Error while reading death test internal: "
+                      << GetLastErrnoDescription() << " [" << last_error << "]";
+  }
+}
+
+// Death test constructor.  Increments the running death test count
+// for the current test.
+DeathTest::DeathTest() {
+  TestInfo* const info = GetUnitTestImpl()->current_test_info();
+  if (info == nullptr) {
+    DeathTestAbort("Cannot run a death test outside of a TEST or "
+                   "TEST_F construct");
+  }
+}
+
+// Creates and returns a death test by dispatching to the current
+// death test factory.
+bool DeathTest::Create(const char* statement,
+                       Matcher<const std::string&> matcher, const char* file,
+                       int line, DeathTest** test) {
+  return GetUnitTestImpl()->death_test_factory()->Create(
+      statement, std::move(matcher), file, line, test);
+}
+
+const char* DeathTest::LastMessage() {
+  return last_death_test_message_.c_str();
+}
+
+void DeathTest::set_last_death_test_message(const std::string& message) {
+  last_death_test_message_ = message;
+}
+
+std::string DeathTest::last_death_test_message_;
+
+// Provides cross platform implementation for some death functionality.
+class DeathTestImpl : public DeathTest {
+ protected:
+  DeathTestImpl(const char* a_statement, Matcher<const std::string&> matcher)
+      : statement_(a_statement),
+        matcher_(std::move(matcher)),
+        spawned_(false),
+        status_(-1),
+        outcome_(IN_PROGRESS),
+        read_fd_(-1),
+        write_fd_(-1) {}
+
+  // read_fd_ is expected to be closed and cleared by a derived class.
+  ~DeathTestImpl() override { GTEST_DEATH_TEST_CHECK_(read_fd_ == -1); }
+
+  void Abort(AbortReason reason) override;
+  bool Passed(bool status_ok) override;
+
+  const char* statement() const { return statement_; }
+  bool spawned() const { return spawned_; }
+  void set_spawned(bool is_spawned) { spawned_ = is_spawned; }
+  int status() const { return status_; }
+  void set_status(int a_status) { status_ = a_status; }
+  DeathTestOutcome outcome() const { return outcome_; }
+  void set_outcome(DeathTestOutcome an_outcome) { outcome_ = an_outcome; }
+  int read_fd() const { return read_fd_; }
+  void set_read_fd(int fd) { read_fd_ = fd; }
+  int write_fd() const { return write_fd_; }
+  void set_write_fd(int fd) { write_fd_ = fd; }
+
+  // Called in the parent process only. Reads the result code of the death
+  // test child process via a pipe, interprets it to set the outcome_
+  // member, and closes read_fd_.  Outputs diagnostics and terminates in
+  // case of unexpected codes.
+  void ReadAndInterpretStatusByte();
+
+  // Returns stderr output from the child process.
+  virtual std::string GetErrorLogs();
+
+ private:
+  // The textual content of the code this object is testing.  This class
+  // doesn't own this string and should not attempt to delete it.
+  const char* const statement_;
+  // A matcher that's expected to match the stderr output by the child process.
+  Matcher<const std::string&> matcher_;
+  // True if the death test child process has been successfully spawned.
+  bool spawned_;
+  // The exit status of the child process.
+  int status_;
+  // How the death test concluded.
+  DeathTestOutcome outcome_;
+  // Descriptor to the read end of the pipe to the child process.  It is
+  // always -1 in the child process.  The child keeps its write end of the
+  // pipe in write_fd_.
+  int read_fd_;
+  // Descriptor to the child's write end of the pipe to the parent process.
+  // It is always -1 in the parent process.  The parent keeps its end of the
+  // pipe in read_fd_.
+  int write_fd_;
+};
+
+// Called in the parent process only. Reads the result code of the death
+// test child process via a pipe, interprets it to set the outcome_
+// member, and closes read_fd_.  Outputs diagnostics and terminates in
+// case of unexpected codes.
+void DeathTestImpl::ReadAndInterpretStatusByte() {
+  char flag;
+  int bytes_read;
+
+  // The read() here blocks until data is available (signifying the
+  // failure of the death test) or until the pipe is closed (signifying
+  // its success), so it's okay to call this in the parent before
+  // the child process has exited.
+  do {
+    bytes_read = posix::Read(read_fd(), &flag, 1);
+  } while (bytes_read == -1 && errno == EINTR);
+
+  if (bytes_read == 0) {
+    set_outcome(DIED);
+  } else if (bytes_read == 1) {
+    switch (flag) {
+      case kDeathTestReturned:
+        set_outcome(RETURNED);
+        break;
+      case kDeathTestThrew:
+        set_outcome(THREW);
+        break;
+      case kDeathTestLived:
+        set_outcome(LIVED);
+        break;
+      case kDeathTestInternalError:
+        FailFromInternalError(read_fd());  // Does not return.
+        break;
+      default:
+        GTEST_LOG_(FATAL) << "Death test child process reported "
+                          << "unexpected status byte ("
+                          << static_cast<unsigned int>(flag) << ")";
+    }
+  } else {
+    GTEST_LOG_(FATAL) << "Read from death test child process failed: "
+                      << GetLastErrnoDescription();
+  }
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(posix::Close(read_fd()));
+  set_read_fd(-1);
+}
+
+std::string DeathTestImpl::GetErrorLogs() {
+  return GetCapturedStderr();
+}
+
+// Signals that the death test code which should have exited, didn't.
+// Should be called only in a death test child process.
+// Writes a status byte to the child's status file descriptor, then
+// calls _exit(1).
+void DeathTestImpl::Abort(AbortReason reason) {
+  // The parent process considers the death test to be a failure if
+  // it finds any data in our pipe.  So, here we write a single flag byte
+  // to the pipe, then exit.
+  const char status_ch =
+      reason == TEST_DID_NOT_DIE ? kDeathTestLived :
+      reason == TEST_THREW_EXCEPTION ? kDeathTestThrew : kDeathTestReturned;
+
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(posix::Write(write_fd(), &status_ch, 1));
+  // We are leaking the descriptor here because on some platforms (i.e.,
+  // when built as Windows DLL), destructors of global objects will still
+  // run after calling _exit(). On such systems, write_fd_ will be
+  // indirectly closed from the destructor of UnitTestImpl, causing double
+  // close if it is also closed here. On debug configurations, double close
+  // may assert. As there are no in-process buffers to flush here, we are
+  // relying on the OS to close the descriptor after the process terminates
+  // when the destructors are not run.
+  _exit(1);  // Exits w/o any normal exit hooks (we were supposed to crash)
+}
+
+// Returns an indented copy of stderr output for a death test.
+// This makes distinguishing death test output lines from regular log lines
+// much easier.
+static ::std::string FormatDeathTestOutput(const ::std::string& output) {
+  ::std::string ret;
+  for (size_t at = 0; ; ) {
+    const size_t line_end = output.find('\n', at);
+    ret += "[  DEATH   ] ";
+    if (line_end == ::std::string::npos) {
+      ret += output.substr(at);
+      break;
+    }
+    ret += output.substr(at, line_end + 1 - at);
+    at = line_end + 1;
+  }
+  return ret;
+}
+
+// Assesses the success or failure of a death test, using both private
+// members which have previously been set, and one argument:
+//
+// Private data members:
+//   outcome:  An enumeration describing how the death test
+//             concluded: DIED, LIVED, THREW, or RETURNED.  The death test
+//             fails in the latter three cases.
+//   status:   The exit status of the child process. On *nix, it is in the
+//             in the format specified by wait(2). On Windows, this is the
+//             value supplied to the ExitProcess() API or a numeric code
+//             of the exception that terminated the program.
+//   matcher_: A matcher that's expected to match the stderr output by the child
+//             process.
+//
+// Argument:
+//   status_ok: true if exit_status is acceptable in the context of
+//              this particular death test, which fails if it is false
+//
+// Returns true if and only if all of the above conditions are met.  Otherwise,
+// the first failing condition, in the order given above, is the one that is
+// reported. Also sets the last death test message string.
+bool DeathTestImpl::Passed(bool status_ok) {
+  if (!spawned())
+    return false;
+
+  const std::string error_message = GetErrorLogs();
+
+  bool success = false;
+  Message buffer;
+
+  buffer << "Death test: " << statement() << "\n";
+  switch (outcome()) {
+    case LIVED:
+      buffer << "    Result: failed to die.\n"
+             << " Error msg:\n" << FormatDeathTestOutput(error_message);
+      break;
+    case THREW:
+      buffer << "    Result: threw an exception.\n"
+             << " Error msg:\n" << FormatDeathTestOutput(error_message);
+      break;
+    case RETURNED:
+      buffer << "    Result: illegal return in test statement.\n"
+             << " Error msg:\n" << FormatDeathTestOutput(error_message);
+      break;
+    case DIED:
+      if (status_ok) {
+        if (matcher_.Matches(error_message)) {
+          success = true;
+        } else {
+          std::ostringstream stream;
+          matcher_.DescribeTo(&stream);
+          buffer << "    Result: died but not with expected error.\n"
+                 << "  Expected: " << stream.str() << "\n"
+                 << "Actual msg:\n"
+                 << FormatDeathTestOutput(error_message);
+        }
+      } else {
+        buffer << "    Result: died but not with expected exit code:\n"
+               << "            " << ExitSummary(status()) << "\n"
+               << "Actual msg:\n" << FormatDeathTestOutput(error_message);
+      }
+      break;
+    case IN_PROGRESS:
+    default:
+      GTEST_LOG_(FATAL)
+          << "DeathTest::Passed somehow called before conclusion of test";
+  }
+
+  DeathTest::set_last_death_test_message(buffer.GetString());
+  return success;
+}
+
+# if GTEST_OS_WINDOWS
+// WindowsDeathTest implements death tests on Windows. Due to the
+// specifics of starting new processes on Windows, death tests there are
+// always threadsafe, and Google Test considers the
+// --gtest_death_test_style=fast setting to be equivalent to
+// --gtest_death_test_style=threadsafe there.
+//
+// A few implementation notes:  Like the Linux version, the Windows
+// implementation uses pipes for child-to-parent communication. But due to
+// the specifics of pipes on Windows, some extra steps are required:
+//
+// 1. The parent creates a communication pipe and stores handles to both
+//    ends of it.
+// 2. The parent starts the child and provides it with the information
+//    necessary to acquire the handle to the write end of the pipe.
+// 3. The child acquires the write end of the pipe and signals the parent
+//    using a Windows event.
+// 4. Now the parent can release the write end of the pipe on its side. If
+//    this is done before step 3, the object's reference count goes down to
+//    0 and it is destroyed, preventing the child from acquiring it. The
+//    parent now has to release it, or read operations on the read end of
+//    the pipe will not return when the child terminates.
+// 5. The parent reads child's output through the pipe (outcome code and
+//    any possible error messages) from the pipe, and its stderr and then
+//    determines whether to fail the test.
+//
+// Note: to distinguish Win32 API calls from the local method and function
+// calls, the former are explicitly resolved in the global namespace.
+//
+class WindowsDeathTest : public DeathTestImpl {
+ public:
+  WindowsDeathTest(const char* a_statement, Matcher<const std::string&> matcher,
+                   const char* file, int line)
+      : DeathTestImpl(a_statement, std::move(matcher)),
+        file_(file),
+        line_(line) {}
+
+  // All of these virtual functions are inherited from DeathTest.
+  virtual int Wait();
+  virtual TestRole AssumeRole();
+
+ private:
+  // The name of the file in which the death test is located.
+  const char* const file_;
+  // The line number on which the death test is located.
+  const int line_;
+  // Handle to the write end of the pipe to the child process.
+  AutoHandle write_handle_;
+  // Child process handle.
+  AutoHandle child_handle_;
+  // Event the child process uses to signal the parent that it has
+  // acquired the handle to the write end of the pipe. After seeing this
+  // event the parent can release its own handles to make sure its
+  // ReadFile() calls return when the child terminates.
+  AutoHandle event_handle_;
+};
+
+// Waits for the child in a death test to exit, returning its exit
+// status, or 0 if no child process exists.  As a side effect, sets the
+// outcome data member.
+int WindowsDeathTest::Wait() {
+  if (!spawned())
+    return 0;
+
+  // Wait until the child either signals that it has acquired the write end
+  // of the pipe or it dies.
+  const HANDLE wait_handles[2] = { child_handle_.Get(), event_handle_.Get() };
+  switch (::WaitForMultipleObjects(2,
+                                   wait_handles,
+                                   FALSE,  // Waits for any of the handles.
+                                   INFINITE)) {
+    case WAIT_OBJECT_0:
+    case WAIT_OBJECT_0 + 1:
+      break;
+    default:
+      GTEST_DEATH_TEST_CHECK_(false);  // Should not get here.
+  }
+
+  // The child has acquired the write end of the pipe or exited.
+  // We release the handle on our side and continue.
+  write_handle_.Reset();
+  event_handle_.Reset();
+
+  ReadAndInterpretStatusByte();
+
+  // Waits for the child process to exit if it haven't already. This
+  // returns immediately if the child has already exited, regardless of
+  // whether previous calls to WaitForMultipleObjects synchronized on this
+  // handle or not.
+  GTEST_DEATH_TEST_CHECK_(
+      WAIT_OBJECT_0 == ::WaitForSingleObject(child_handle_.Get(),
+                                             INFINITE));
+  DWORD status_code;
+  GTEST_DEATH_TEST_CHECK_(
+      ::GetExitCodeProcess(child_handle_.Get(), &status_code) != FALSE);
+  child_handle_.Reset();
+  set_status(static_cast<int>(status_code));
+  return status();
+}
+
+// The AssumeRole process for a Windows death test.  It creates a child
+// process with the same executable as the current process to run the
+// death test.  The child process is given the --gtest_filter and
+// --gtest_internal_run_death_test flags such that it knows to run the
+// current death test only.
+DeathTest::TestRole WindowsDeathTest::AssumeRole() {
+  const UnitTestImpl* const impl = GetUnitTestImpl();
+  const InternalRunDeathTestFlag* const flag =
+      impl->internal_run_death_test_flag();
+  const TestInfo* const info = impl->current_test_info();
+  const int death_test_index = info->result()->death_test_count();
+
+  if (flag != nullptr) {
+    // ParseInternalRunDeathTestFlag() has performed all the necessary
+    // processing.
+    set_write_fd(flag->write_fd());
+    return EXECUTE_TEST;
+  }
+
+  // WindowsDeathTest uses an anonymous pipe to communicate results of
+  // a death test.
+  SECURITY_ATTRIBUTES handles_are_inheritable = {sizeof(SECURITY_ATTRIBUTES),
+                                                 nullptr, TRUE};
+  HANDLE read_handle, write_handle;
+  GTEST_DEATH_TEST_CHECK_(
+      ::CreatePipe(&read_handle, &write_handle, &handles_are_inheritable,
+                   0)  // Default buffer size.
+      != FALSE);
+  set_read_fd(::_open_osfhandle(reinterpret_cast<intptr_t>(read_handle),
+                                O_RDONLY));
+  write_handle_.Reset(write_handle);
+  event_handle_.Reset(::CreateEvent(
+      &handles_are_inheritable,
+      TRUE,       // The event will automatically reset to non-signaled state.
+      FALSE,      // The initial state is non-signalled.
+      nullptr));  // The even is unnamed.
+  GTEST_DEATH_TEST_CHECK_(event_handle_.Get() != nullptr);
+  const std::string filter_flag = std::string("--") + GTEST_FLAG_PREFIX_ +
+                                  kFilterFlag + "=" + info->test_suite_name() +
+                                  "." + info->name();
+  const std::string internal_flag =
+      std::string("--") + GTEST_FLAG_PREFIX_ + kInternalRunDeathTestFlag +
+      "=" + file_ + "|" + StreamableToString(line_) + "|" +
+      StreamableToString(death_test_index) + "|" +
+      StreamableToString(static_cast<unsigned int>(::GetCurrentProcessId())) +
+      // size_t has the same width as pointers on both 32-bit and 64-bit
+      // Windows platforms.
+      // See http://msdn.microsoft.com/en-us/library/tcxf1dw6.aspx.
+      "|" + StreamableToString(reinterpret_cast<size_t>(write_handle)) +
+      "|" + StreamableToString(reinterpret_cast<size_t>(event_handle_.Get()));
+
+  char executable_path[_MAX_PATH + 1];  // NOLINT
+  GTEST_DEATH_TEST_CHECK_(_MAX_PATH + 1 != ::GetModuleFileNameA(nullptr,
+                                                                executable_path,
+                                                                _MAX_PATH));
+
+  std::string command_line =
+      std::string(::GetCommandLineA()) + " " + filter_flag + " \"" +
+      internal_flag + "\"";
+
+  DeathTest::set_last_death_test_message("");
+
+  CaptureStderr();
+  // Flush the log buffers since the log streams are shared with the child.
+  FlushInfoLog();
+
+  // The child process will share the standard handles with the parent.
+  STARTUPINFOA startup_info;
+  memset(&startup_info, 0, sizeof(STARTUPINFO));
+  startup_info.dwFlags = STARTF_USESTDHANDLES;
+  startup_info.hStdInput = ::GetStdHandle(STD_INPUT_HANDLE);
+  startup_info.hStdOutput = ::GetStdHandle(STD_OUTPUT_HANDLE);
+  startup_info.hStdError = ::GetStdHandle(STD_ERROR_HANDLE);
+
+  PROCESS_INFORMATION process_info;
+  GTEST_DEATH_TEST_CHECK_(
+      ::CreateProcessA(
+          executable_path, const_cast<char*>(command_line.c_str()),
+          nullptr,  // Retuned process handle is not inheritable.
+          nullptr,  // Retuned thread handle is not inheritable.
+          TRUE,  // Child inherits all inheritable handles (for write_handle_).
+          0x0,   // Default creation flags.
+          nullptr,  // Inherit the parent's environment.
+          UnitTest::GetInstance()->original_working_dir(), &startup_info,
+          &process_info) != FALSE);
+  child_handle_.Reset(process_info.hProcess);
+  ::CloseHandle(process_info.hThread);
+  set_spawned(true);
+  return OVERSEE_TEST;
+}
+
+# elif GTEST_OS_FUCHSIA
+
+class FuchsiaDeathTest : public DeathTestImpl {
+ public:
+  FuchsiaDeathTest(const char* a_statement, Matcher<const std::string&> matcher,
+                   const char* file, int line)
+      : DeathTestImpl(a_statement, std::move(matcher)),
+        file_(file),
+        line_(line) {}
+
+  // All of these virtual functions are inherited from DeathTest.
+  int Wait() override;
+  TestRole AssumeRole() override;
+  std::string GetErrorLogs() override;
+
+ private:
+  // The name of the file in which the death test is located.
+  const char* const file_;
+  // The line number on which the death test is located.
+  const int line_;
+  // The stderr data captured by the child process.
+  std::string captured_stderr_;
+
+  zx::process child_process_;
+  zx::channel exception_channel_;
+  zx::socket stderr_socket_;
+};
+
+// Utility class for accumulating command-line arguments.
+class Arguments {
+ public:
+  Arguments() { args_.push_back(nullptr); }
+
+  ~Arguments() {
+    for (std::vector<char*>::iterator i = args_.begin(); i != args_.end();
+         ++i) {
+      free(*i);
+    }
+  }
+  void AddArgument(const char* argument) {
+    args_.insert(args_.end() - 1, posix::StrDup(argument));
+  }
+
+  template <typename Str>
+  void AddArguments(const ::std::vector<Str>& arguments) {
+    for (typename ::std::vector<Str>::const_iterator i = arguments.begin();
+         i != arguments.end();
+         ++i) {
+      args_.insert(args_.end() - 1, posix::StrDup(i->c_str()));
+    }
+  }
+  char* const* Argv() {
+    return &args_[0];
+  }
+
+  int size() {
+    return static_cast<int>(args_.size()) - 1;
+  }
+
+ private:
+  std::vector<char*> args_;
+};
+
+// Waits for the child in a death test to exit, returning its exit
+// status, or 0 if no child process exists.  As a side effect, sets the
+// outcome data member.
+int FuchsiaDeathTest::Wait() {
+  const int kProcessKey = 0;
+  const int kSocketKey = 1;
+  const int kExceptionKey = 2;
+
+  if (!spawned())
+    return 0;
+
+  // Create a port to wait for socket/task/exception events.
+  zx_status_t status_zx;
+  zx::port port;
+  status_zx = zx::port::create(0, &port);
+  GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
+
+  // Register to wait for the child process to terminate.
+  status_zx = child_process_.wait_async(
+      port, kProcessKey, ZX_PROCESS_TERMINATED, 0);
+  GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
+
+  // Register to wait for the socket to be readable or closed.
+  status_zx = stderr_socket_.wait_async(
+      port, kSocketKey, ZX_SOCKET_READABLE | ZX_SOCKET_PEER_CLOSED, 0);
+  GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
+
+  // Register to wait for an exception.
+  status_zx = exception_channel_.wait_async(
+      port, kExceptionKey, ZX_CHANNEL_READABLE, 0);
+  GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
+
+  bool process_terminated = false;
+  bool socket_closed = false;
+  do {
+    zx_port_packet_t packet = {};
+    status_zx = port.wait(zx::time::infinite(), &packet);
+    GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
+
+    if (packet.key == kExceptionKey) {
+      // Process encountered an exception. Kill it directly rather than
+      // letting other handlers process the event. We will get a kProcessKey
+      // event when the process actually terminates.
+      status_zx = child_process_.kill();
+      GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
+    } else if (packet.key == kProcessKey) {
+      // Process terminated.
+      GTEST_DEATH_TEST_CHECK_(ZX_PKT_IS_SIGNAL_ONE(packet.type));
+      GTEST_DEATH_TEST_CHECK_(packet.signal.observed & ZX_PROCESS_TERMINATED);
+      process_terminated = true;
+    } else if (packet.key == kSocketKey) {
+      GTEST_DEATH_TEST_CHECK_(ZX_PKT_IS_SIGNAL_ONE(packet.type));
+      if (packet.signal.observed & ZX_SOCKET_READABLE) {
+        // Read data from the socket.
+        constexpr size_t kBufferSize = 1024;
+        do {
+          size_t old_length = captured_stderr_.length();
+          size_t bytes_read = 0;
+          captured_stderr_.resize(old_length + kBufferSize);
+          status_zx = stderr_socket_.read(
+              0, &captured_stderr_.front() + old_length, kBufferSize,
+              &bytes_read);
+          captured_stderr_.resize(old_length + bytes_read);
+        } while (status_zx == ZX_OK);
+        if (status_zx == ZX_ERR_PEER_CLOSED) {
+          socket_closed = true;
+        } else {
+          GTEST_DEATH_TEST_CHECK_(status_zx == ZX_ERR_SHOULD_WAIT);
+          status_zx = stderr_socket_.wait_async(
+              port, kSocketKey, ZX_SOCKET_READABLE | ZX_SOCKET_PEER_CLOSED, 0);
+          GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
+        }
+      } else {
+        GTEST_DEATH_TEST_CHECK_(packet.signal.observed & ZX_SOCKET_PEER_CLOSED);
+        socket_closed = true;
+      }
+    }
+  } while (!process_terminated && !socket_closed);
+
+  ReadAndInterpretStatusByte();
+
+  zx_info_process_v2_t buffer;
+  status_zx = child_process_.get_info(
+      ZX_INFO_PROCESS_V2, &buffer, sizeof(buffer), nullptr, nullptr);
+  GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
+
+  GTEST_DEATH_TEST_CHECK_(buffer.flags & ZX_INFO_PROCESS_FLAG_EXITED);
+  set_status(static_cast<int>(buffer.return_code));
+  return status();
+}
+
+// The AssumeRole process for a Fuchsia death test.  It creates a child
+// process with the same executable as the current process to run the
+// death test.  The child process is given the --gtest_filter and
+// --gtest_internal_run_death_test flags such that it knows to run the
+// current death test only.
+DeathTest::TestRole FuchsiaDeathTest::AssumeRole() {
+  const UnitTestImpl* const impl = GetUnitTestImpl();
+  const InternalRunDeathTestFlag* const flag =
+      impl->internal_run_death_test_flag();
+  const TestInfo* const info = impl->current_test_info();
+  const int death_test_index = info->result()->death_test_count();
+
+  if (flag != nullptr) {
+    // ParseInternalRunDeathTestFlag() has performed all the necessary
+    // processing.
+    set_write_fd(kFuchsiaReadPipeFd);
+    return EXECUTE_TEST;
+  }
+
+  // Flush the log buffers since the log streams are shared with the child.
+  FlushInfoLog();
+
+  // Build the child process command line.
+  const std::string filter_flag = std::string("--") + GTEST_FLAG_PREFIX_ +
+                                  kFilterFlag + "=" + info->test_suite_name() +
+                                  "." + info->name();
+  const std::string internal_flag =
+      std::string("--") + GTEST_FLAG_PREFIX_ + kInternalRunDeathTestFlag + "="
+      + file_ + "|"
+      + StreamableToString(line_) + "|"
+      + StreamableToString(death_test_index);
+  Arguments args;
+  args.AddArguments(GetInjectableArgvs());
+  args.AddArgument(filter_flag.c_str());
+  args.AddArgument(internal_flag.c_str());
+
+  // Build the pipe for communication with the child.
+  zx_status_t status;
+  zx_handle_t child_pipe_handle;
+  int child_pipe_fd;
+  status = fdio_pipe_half(&child_pipe_fd, &child_pipe_handle);
+  GTEST_DEATH_TEST_CHECK_(status == ZX_OK);
+  set_read_fd(child_pipe_fd);
+
+  // Set the pipe handle for the child.
+  fdio_spawn_action_t spawn_actions[2] = {};
+  fdio_spawn_action_t* add_handle_action = &spawn_actions[0];
+  add_handle_action->action = FDIO_SPAWN_ACTION_ADD_HANDLE;
+  add_handle_action->h.id = PA_HND(PA_FD, kFuchsiaReadPipeFd);
+  add_handle_action->h.handle = child_pipe_handle;
+
+  // Create a socket pair will be used to receive the child process' stderr.
+  zx::socket stderr_producer_socket;
+  status =
+      zx::socket::create(0, &stderr_producer_socket, &stderr_socket_);
+  GTEST_DEATH_TEST_CHECK_(status >= 0);
+  int stderr_producer_fd = -1;
+  status =
+      fdio_fd_create(stderr_producer_socket.release(), &stderr_producer_fd);
+  GTEST_DEATH_TEST_CHECK_(status >= 0);
+
+  // Make the stderr socket nonblocking.
+  GTEST_DEATH_TEST_CHECK_(fcntl(stderr_producer_fd, F_SETFL, 0) == 0);
+
+  fdio_spawn_action_t* add_stderr_action = &spawn_actions[1];
+  add_stderr_action->action = FDIO_SPAWN_ACTION_CLONE_FD;
+  add_stderr_action->fd.local_fd = stderr_producer_fd;
+  add_stderr_action->fd.target_fd = STDERR_FILENO;
+
+  // Create a child job.
+  zx_handle_t child_job = ZX_HANDLE_INVALID;
+  status = zx_job_create(zx_job_default(), 0, & child_job);
+  GTEST_DEATH_TEST_CHECK_(status == ZX_OK);
+  zx_policy_basic_t policy;
+  policy.condition = ZX_POL_NEW_ANY;
+  policy.policy = ZX_POL_ACTION_ALLOW;
+  status = zx_job_set_policy(
+      child_job, ZX_JOB_POL_RELATIVE, ZX_JOB_POL_BASIC, &policy, 1);
+  GTEST_DEATH_TEST_CHECK_(status == ZX_OK);
+
+  // Create an exception channel attached to the |child_job|, to allow
+  // us to suppress the system default exception handler from firing.
+  status =
+      zx_task_create_exception_channel(
+          child_job, 0, exception_channel_.reset_and_get_address());
+  GTEST_DEATH_TEST_CHECK_(status == ZX_OK);
+
+  // Spawn the child process.
+  status = fdio_spawn_etc(
+      child_job, FDIO_SPAWN_CLONE_ALL, args.Argv()[0], args.Argv(), nullptr,
+      2, spawn_actions, child_process_.reset_and_get_address(), nullptr);
+  GTEST_DEATH_TEST_CHECK_(status == ZX_OK);
+
+  set_spawned(true);
+  return OVERSEE_TEST;
+}
+
+std::string FuchsiaDeathTest::GetErrorLogs() {
+  return captured_stderr_;
+}
+
+#else  // We are neither on Windows, nor on Fuchsia.
+
+// ForkingDeathTest provides implementations for most of the abstract
+// methods of the DeathTest interface.  Only the AssumeRole method is
+// left undefined.
+class ForkingDeathTest : public DeathTestImpl {
+ public:
+  ForkingDeathTest(const char* statement, Matcher<const std::string&> matcher);
+
+  // All of these virtual functions are inherited from DeathTest.
+  int Wait() override;
+
+ protected:
+  void set_child_pid(pid_t child_pid) { child_pid_ = child_pid; }
+
+ private:
+  // PID of child process during death test; 0 in the child process itself.
+  pid_t child_pid_;
+};
+
+// Constructs a ForkingDeathTest.
+ForkingDeathTest::ForkingDeathTest(const char* a_statement,
+                                   Matcher<const std::string&> matcher)
+    : DeathTestImpl(a_statement, std::move(matcher)), child_pid_(-1) {}
+
+// Waits for the child in a death test to exit, returning its exit
+// status, or 0 if no child process exists.  As a side effect, sets the
+// outcome data member.
+int ForkingDeathTest::Wait() {
+  if (!spawned())
+    return 0;
+
+  ReadAndInterpretStatusByte();
+
+  int status_value;
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(waitpid(child_pid_, &status_value, 0));
+  set_status(status_value);
+  return status_value;
+}
+
+// A concrete death test class that forks, then immediately runs the test
+// in the child process.
+class NoExecDeathTest : public ForkingDeathTest {
+ public:
+  NoExecDeathTest(const char* a_statement, Matcher<const std::string&> matcher)
+      : ForkingDeathTest(a_statement, std::move(matcher)) {}
+  TestRole AssumeRole() override;
+};
+
+// The AssumeRole process for a fork-and-run death test.  It implements a
+// straightforward fork, with a simple pipe to transmit the status byte.
+DeathTest::TestRole NoExecDeathTest::AssumeRole() {
+  const size_t thread_count = GetThreadCount();
+  if (thread_count != 1) {
+    GTEST_LOG_(WARNING) << DeathTestThreadWarning(thread_count);
+  }
+
+  int pipe_fd[2];
+  GTEST_DEATH_TEST_CHECK_(pipe(pipe_fd) != -1);
+
+  DeathTest::set_last_death_test_message("");
+  CaptureStderr();
+  // When we fork the process below, the log file buffers are copied, but the
+  // file descriptors are shared.  We flush all log files here so that closing
+  // the file descriptors in the child process doesn't throw off the
+  // synchronization between descriptors and buffers in the parent process.
+  // This is as close to the fork as possible to avoid a race condition in case
+  // there are multiple threads running before the death test, and another
+  // thread writes to the log file.
+  FlushInfoLog();
+
+  const pid_t child_pid = fork();
+  GTEST_DEATH_TEST_CHECK_(child_pid != -1);
+  set_child_pid(child_pid);
+  if (child_pid == 0) {
+    GTEST_DEATH_TEST_CHECK_SYSCALL_(close(pipe_fd[0]));
+    set_write_fd(pipe_fd[1]);
+    // Redirects all logging to stderr in the child process to prevent
+    // concurrent writes to the log files.  We capture stderr in the parent
+    // process and append the child process' output to a log.
+    LogToStderr();
+    // Event forwarding to the listeners of event listener API mush be shut
+    // down in death test subprocesses.
+    GetUnitTestImpl()->listeners()->SuppressEventForwarding();
+    g_in_fast_death_test_child = true;
+    return EXECUTE_TEST;
+  } else {
+    GTEST_DEATH_TEST_CHECK_SYSCALL_(close(pipe_fd[1]));
+    set_read_fd(pipe_fd[0]);
+    set_spawned(true);
+    return OVERSEE_TEST;
+  }
+}
+
+// A concrete death test class that forks and re-executes the main
+// program from the beginning, with command-line flags set that cause
+// only this specific death test to be run.
+class ExecDeathTest : public ForkingDeathTest {
+ public:
+  ExecDeathTest(const char* a_statement, Matcher<const std::string&> matcher,
+                const char* file, int line)
+      : ForkingDeathTest(a_statement, std::move(matcher)),
+        file_(file),
+        line_(line) {}
+  TestRole AssumeRole() override;
+
+ private:
+  static ::std::vector<std::string> GetArgvsForDeathTestChildProcess() {
+    ::std::vector<std::string> args = GetInjectableArgvs();
+#  if defined(GTEST_EXTRA_DEATH_TEST_COMMAND_LINE_ARGS_)
+    ::std::vector<std::string> extra_args =
+        GTEST_EXTRA_DEATH_TEST_COMMAND_LINE_ARGS_();
+    args.insert(args.end(), extra_args.begin(), extra_args.end());
+#  endif  // defined(GTEST_EXTRA_DEATH_TEST_COMMAND_LINE_ARGS_)
+    return args;
+  }
+  // The name of the file in which the death test is located.
+  const char* const file_;
+  // The line number on which the death test is located.
+  const int line_;
+};
+
+// Utility class for accumulating command-line arguments.
+class Arguments {
+ public:
+  Arguments() { args_.push_back(nullptr); }
+
+  ~Arguments() {
+    for (std::vector<char*>::iterator i = args_.begin(); i != args_.end();
+         ++i) {
+      free(*i);
+    }
+  }
+  void AddArgument(const char* argument) {
+    args_.insert(args_.end() - 1, posix::StrDup(argument));
+  }
+
+  template <typename Str>
+  void AddArguments(const ::std::vector<Str>& arguments) {
+    for (typename ::std::vector<Str>::const_iterator i = arguments.begin();
+         i != arguments.end();
+         ++i) {
+      args_.insert(args_.end() - 1, posix::StrDup(i->c_str()));
+    }
+  }
+  char* const* Argv() {
+    return &args_[0];
+  }
+
+ private:
+  std::vector<char*> args_;
+};
+
+// A struct that encompasses the arguments to the child process of a
+// threadsafe-style death test process.
+struct ExecDeathTestArgs {
+  char* const* argv;  // Command-line arguments for the child's call to exec
+  int close_fd;       // File descriptor to close; the read end of a pipe
+};
+
+#  if GTEST_OS_QNX
+extern "C" char** environ;
+#  else  // GTEST_OS_QNX
+// The main function for a threadsafe-style death test child process.
+// This function is called in a clone()-ed process and thus must avoid
+// any potentially unsafe operations like malloc or libc functions.
+static int ExecDeathTestChildMain(void* child_arg) {
+  ExecDeathTestArgs* const args = static_cast<ExecDeathTestArgs*>(child_arg);
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(close(args->close_fd));
+
+  // We need to execute the test program in the same environment where
+  // it was originally invoked.  Therefore we change to the original
+  // working directory first.
+  const char* const original_dir =
+      UnitTest::GetInstance()->original_working_dir();
+  // We can safely call chdir() as it's a direct system call.
+  if (chdir(original_dir) != 0) {
+    DeathTestAbort(std::string("chdir(\"") + original_dir + "\") failed: " +
+                   GetLastErrnoDescription());
+    return EXIT_FAILURE;
+  }
+
+  // We can safely call execv() as it's almost a direct system call. We
+  // cannot use execvp() as it's a libc function and thus potentially
+  // unsafe.  Since execv() doesn't search the PATH, the user must
+  // invoke the test program via a valid path that contains at least
+  // one path separator.
+  execv(args->argv[0], args->argv);
+  DeathTestAbort(std::string("execv(") + args->argv[0] + ", ...) in " +
+                 original_dir + " failed: " +
+                 GetLastErrnoDescription());
+  return EXIT_FAILURE;
+}
+#  endif  // GTEST_OS_QNX
+
+#  if GTEST_HAS_CLONE
+// Two utility routines that together determine the direction the stack
+// grows.
+// This could be accomplished more elegantly by a single recursive
+// function, but we want to guard against the unlikely possibility of
+// a smart compiler optimizing the recursion away.
+//
+// GTEST_NO_INLINE_ is required to prevent GCC 4.6 from inlining
+// StackLowerThanAddress into StackGrowsDown, which then doesn't give
+// correct answer.
+static void StackLowerThanAddress(const void* ptr,
+                                  bool* result) GTEST_NO_INLINE_;
+// Make sure sanitizers do not tamper with the stack here.
+// Ideally, we want to use `__builtin_frame_address` instead of a local variable
+// address with sanitizer disabled, but it does not work when the
+// compiler optimizes the stack frame out, which happens on PowerPC targets.
+// HWAddressSanitizer add a random tag to the MSB of the local variable address,
+// making comparison result unpredictable.
+GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
+GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_
+static void StackLowerThanAddress(const void* ptr, bool* result) {
+  int dummy = 0;
+  *result = std::less<const void*>()(&dummy, ptr);
+}
+
+// Make sure AddressSanitizer does not tamper with the stack here.
+GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
+GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_
+static bool StackGrowsDown() {
+  int dummy = 0;
+  bool result;
+  StackLowerThanAddress(&dummy, &result);
+  return result;
+}
+#  endif  // GTEST_HAS_CLONE
+
+// Spawns a child process with the same executable as the current process in
+// a thread-safe manner and instructs it to run the death test.  The
+// implementation uses fork(2) + exec.  On systems where clone(2) is
+// available, it is used instead, being slightly more thread-safe.  On QNX,
+// fork supports only single-threaded environments, so this function uses
+// spawn(2) there instead.  The function dies with an error message if
+// anything goes wrong.
+static pid_t ExecDeathTestSpawnChild(char* const* argv, int close_fd) {
+  ExecDeathTestArgs args = { argv, close_fd };
+  pid_t child_pid = -1;
+
+#  if GTEST_OS_QNX
+  // Obtains the current directory and sets it to be closed in the child
+  // process.
+  const int cwd_fd = open(".", O_RDONLY);
+  GTEST_DEATH_TEST_CHECK_(cwd_fd != -1);
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(fcntl(cwd_fd, F_SETFD, FD_CLOEXEC));
+  // We need to execute the test program in the same environment where
+  // it was originally invoked.  Therefore we change to the original
+  // working directory first.
+  const char* const original_dir =
+      UnitTest::GetInstance()->original_working_dir();
+  // We can safely call chdir() as it's a direct system call.
+  if (chdir(original_dir) != 0) {
+    DeathTestAbort(std::string("chdir(\"") + original_dir + "\") failed: " +
+                   GetLastErrnoDescription());
+    return EXIT_FAILURE;
+  }
+
+  int fd_flags;
+  // Set close_fd to be closed after spawn.
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(fd_flags = fcntl(close_fd, F_GETFD));
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(fcntl(close_fd, F_SETFD,
+                                        fd_flags | FD_CLOEXEC));
+  struct inheritance inherit = {0};
+  // spawn is a system call.
+  child_pid = spawn(args.argv[0], 0, nullptr, &inherit, args.argv, environ);
+  // Restores the current working directory.
+  GTEST_DEATH_TEST_CHECK_(fchdir(cwd_fd) != -1);
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(close(cwd_fd));
+
+#  else   // GTEST_OS_QNX
+#   if GTEST_OS_LINUX
+  // When a SIGPROF signal is received while fork() or clone() are executing,
+  // the process may hang. To avoid this, we ignore SIGPROF here and re-enable
+  // it after the call to fork()/clone() is complete.
+  struct sigaction saved_sigprof_action;
+  struct sigaction ignore_sigprof_action;
+  memset(&ignore_sigprof_action, 0, sizeof(ignore_sigprof_action));
+  sigemptyset(&ignore_sigprof_action.sa_mask);
+  ignore_sigprof_action.sa_handler = SIG_IGN;
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(sigaction(
+      SIGPROF, &ignore_sigprof_action, &saved_sigprof_action));
+#   endif  // GTEST_OS_LINUX
+
+#   if GTEST_HAS_CLONE
+  const bool use_fork = GTEST_FLAG(death_test_use_fork);
+
+  if (!use_fork) {
+    static const bool stack_grows_down = StackGrowsDown();
+    const auto stack_size = static_cast<size_t>(getpagesize() * 2);
+    // MMAP_ANONYMOUS is not defined on Mac, so we use MAP_ANON instead.
+    void* const stack = mmap(nullptr, stack_size, PROT_READ | PROT_WRITE,
+                             MAP_ANON | MAP_PRIVATE, -1, 0);
+    GTEST_DEATH_TEST_CHECK_(stack != MAP_FAILED);
+
+    // Maximum stack alignment in bytes:  For a downward-growing stack, this
+    // amount is subtracted from size of the stack space to get an address
+    // that is within the stack space and is aligned on all systems we care
+    // about.  As far as I know there is no ABI with stack alignment greater
+    // than 64.  We assume stack and stack_size already have alignment of
+    // kMaxStackAlignment.
+    const size_t kMaxStackAlignment = 64;
+    void* const stack_top =
+        static_cast<char*>(stack) +
+            (stack_grows_down ? stack_size - kMaxStackAlignment : 0);
+    GTEST_DEATH_TEST_CHECK_(
+        static_cast<size_t>(stack_size) > kMaxStackAlignment &&
+        reinterpret_cast<uintptr_t>(stack_top) % kMaxStackAlignment == 0);
+
+    child_pid = clone(&ExecDeathTestChildMain, stack_top, SIGCHLD, &args);
+
+    GTEST_DEATH_TEST_CHECK_(munmap(stack, stack_size) != -1);
+  }
+#   else
+  const bool use_fork = true;
+#   endif  // GTEST_HAS_CLONE
+
+  if (use_fork && (child_pid = fork()) == 0) {
+      ExecDeathTestChildMain(&args);
+      _exit(0);
+  }
+#  endif  // GTEST_OS_QNX
+#  if GTEST_OS_LINUX
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(
+      sigaction(SIGPROF, &saved_sigprof_action, nullptr));
+#  endif  // GTEST_OS_LINUX
+
+  GTEST_DEATH_TEST_CHECK_(child_pid != -1);
+  return child_pid;
+}
+
+// The AssumeRole process for a fork-and-exec death test.  It re-executes the
+// main program from the beginning, setting the --gtest_filter
+// and --gtest_internal_run_death_test flags to cause only the current
+// death test to be re-run.
+DeathTest::TestRole ExecDeathTest::AssumeRole() {
+  const UnitTestImpl* const impl = GetUnitTestImpl();
+  const InternalRunDeathTestFlag* const flag =
+      impl->internal_run_death_test_flag();
+  const TestInfo* const info = impl->current_test_info();
+  const int death_test_index = info->result()->death_test_count();
+
+  if (flag != nullptr) {
+    set_write_fd(flag->write_fd());
+    return EXECUTE_TEST;
+  }
+
+  int pipe_fd[2];
+  GTEST_DEATH_TEST_CHECK_(pipe(pipe_fd) != -1);
+  // Clear the close-on-exec flag on the write end of the pipe, lest
+  // it be closed when the child process does an exec:
+  GTEST_DEATH_TEST_CHECK_(fcntl(pipe_fd[1], F_SETFD, 0) != -1);
+
+  const std::string filter_flag = std::string("--") + GTEST_FLAG_PREFIX_ +
+                                  kFilterFlag + "=" + info->test_suite_name() +
+                                  "." + info->name();
+  const std::string internal_flag =
+      std::string("--") + GTEST_FLAG_PREFIX_ + kInternalRunDeathTestFlag + "="
+      + file_ + "|" + StreamableToString(line_) + "|"
+      + StreamableToString(death_test_index) + "|"
+      + StreamableToString(pipe_fd[1]);
+  Arguments args;
+  args.AddArguments(GetArgvsForDeathTestChildProcess());
+  args.AddArgument(filter_flag.c_str());
+  args.AddArgument(internal_flag.c_str());
+
+  DeathTest::set_last_death_test_message("");
+
+  CaptureStderr();
+  // See the comment in NoExecDeathTest::AssumeRole for why the next line
+  // is necessary.
+  FlushInfoLog();
+
+  const pid_t child_pid = ExecDeathTestSpawnChild(args.Argv(), pipe_fd[0]);
+  GTEST_DEATH_TEST_CHECK_SYSCALL_(close(pipe_fd[1]));
+  set_child_pid(child_pid);
+  set_read_fd(pipe_fd[0]);
+  set_spawned(true);
+  return OVERSEE_TEST;
+}
+
+# endif  // !GTEST_OS_WINDOWS
+
+// Creates a concrete DeathTest-derived class that depends on the
+// --gtest_death_test_style flag, and sets the pointer pointed to
+// by the "test" argument to its address.  If the test should be
+// skipped, sets that pointer to NULL.  Returns true, unless the
+// flag is set to an invalid value.
+bool DefaultDeathTestFactory::Create(const char* statement,
+                                     Matcher<const std::string&> matcher,
+                                     const char* file, int line,
+                                     DeathTest** test) {
+  UnitTestImpl* const impl = GetUnitTestImpl();
+  const InternalRunDeathTestFlag* const flag =
+      impl->internal_run_death_test_flag();
+  const int death_test_index = impl->current_test_info()
+      ->increment_death_test_count();
+
+  if (flag != nullptr) {
+    if (death_test_index > flag->index()) {
+      DeathTest::set_last_death_test_message(
+          "Death test count (" + StreamableToString(death_test_index)
+          + ") somehow exceeded expected maximum ("
+          + StreamableToString(flag->index()) + ")");
+      return false;
+    }
+
+    if (!(flag->file() == file && flag->line() == line &&
+          flag->index() == death_test_index)) {
+      *test = nullptr;
+      return true;
+    }
+  }
+
+# if GTEST_OS_WINDOWS
+
+  if (GTEST_FLAG(death_test_style) == "threadsafe" ||
+      GTEST_FLAG(death_test_style) == "fast") {
+    *test = new WindowsDeathTest(statement, std::move(matcher), file, line);
+  }
+
+# elif GTEST_OS_FUCHSIA
+
+  if (GTEST_FLAG(death_test_style) == "threadsafe" ||
+      GTEST_FLAG(death_test_style) == "fast") {
+    *test = new FuchsiaDeathTest(statement, std::move(matcher), file, line);
+  }
+
+# else
+
+  if (GTEST_FLAG(death_test_style) == "threadsafe") {
+    *test = new ExecDeathTest(statement, std::move(matcher), file, line);
+  } else if (GTEST_FLAG(death_test_style) == "fast") {
+    *test = new NoExecDeathTest(statement, std::move(matcher));
+  }
+
+# endif  // GTEST_OS_WINDOWS
+
+  else {  // NOLINT - this is more readable than unbalanced brackets inside #if.
+    DeathTest::set_last_death_test_message(
+        "Unknown death test style \"" + GTEST_FLAG(death_test_style)
+        + "\" encountered");
+    return false;
+  }
+
+  return true;
+}
+
+# if GTEST_OS_WINDOWS
+// Recreates the pipe and event handles from the provided parameters,
+// signals the event, and returns a file descriptor wrapped around the pipe
+// handle. This function is called in the child process only.
+static int GetStatusFileDescriptor(unsigned int parent_process_id,
+                            size_t write_handle_as_size_t,
+                            size_t event_handle_as_size_t) {
+  AutoHandle parent_process_handle(::OpenProcess(PROCESS_DUP_HANDLE,
+                                                   FALSE,  // Non-inheritable.
+                                                   parent_process_id));
+  if (parent_process_handle.Get() == INVALID_HANDLE_VALUE) {
+    DeathTestAbort("Unable to open parent process " +
+                   StreamableToString(parent_process_id));
+  }
+
+  GTEST_CHECK_(sizeof(HANDLE) <= sizeof(size_t));
+
+  const HANDLE write_handle =
+      reinterpret_cast<HANDLE>(write_handle_as_size_t);
+  HANDLE dup_write_handle;
+
+  // The newly initialized handle is accessible only in the parent
+  // process. To obtain one accessible within the child, we need to use
+  // DuplicateHandle.
+  if (!::DuplicateHandle(parent_process_handle.Get(), write_handle,
+                         ::GetCurrentProcess(), &dup_write_handle,
+                         0x0,    // Requested privileges ignored since
+                                 // DUPLICATE_SAME_ACCESS is used.
+                         FALSE,  // Request non-inheritable handler.
+                         DUPLICATE_SAME_ACCESS)) {
+    DeathTestAbort("Unable to duplicate the pipe handle " +
+                   StreamableToString(write_handle_as_size_t) +
+                   " from the parent process " +
+                   StreamableToString(parent_process_id));
+  }
+
+  const HANDLE event_handle = reinterpret_cast<HANDLE>(event_handle_as_size_t);
+  HANDLE dup_event_handle;
+
+  if (!::DuplicateHandle(parent_process_handle.Get(), event_handle,
+                         ::GetCurrentProcess(), &dup_event_handle,
+                         0x0,
+                         FALSE,
+                         DUPLICATE_SAME_ACCESS)) {
+    DeathTestAbort("Unable to duplicate the event handle " +
+                   StreamableToString(event_handle_as_size_t) +
+                   " from the parent process " +
+                   StreamableToString(parent_process_id));
+  }
+
+  const int write_fd =
+      ::_open_osfhandle(reinterpret_cast<intptr_t>(dup_write_handle), O_APPEND);
+  if (write_fd == -1) {
+    DeathTestAbort("Unable to convert pipe handle " +
+                   StreamableToString(write_handle_as_size_t) +
+                   " to a file descriptor");
+  }
+
+  // Signals the parent that the write end of the pipe has been acquired
+  // so the parent can release its own write end.
+  ::SetEvent(dup_event_handle);
+
+  return write_fd;
+}
+# endif  // GTEST_OS_WINDOWS
+
+// Returns a newly created InternalRunDeathTestFlag object with fields
+// initialized from the GTEST_FLAG(internal_run_death_test) flag if
+// the flag is specified; otherwise returns NULL.
+InternalRunDeathTestFlag* ParseInternalRunDeathTestFlag() {
+  if (GTEST_FLAG(internal_run_death_test) == "") return nullptr;
+
+  // GTEST_HAS_DEATH_TEST implies that we have ::std::string, so we
+  // can use it here.
+  int line = -1;
+  int index = -1;
+  ::std::vector< ::std::string> fields;
+  SplitString(GTEST_FLAG(internal_run_death_test).c_str(), '|', &fields);
+  int write_fd = -1;
+
+# if GTEST_OS_WINDOWS
+
+  unsigned int parent_process_id = 0;
+  size_t write_handle_as_size_t = 0;
+  size_t event_handle_as_size_t = 0;
+
+  if (fields.size() != 6
+      || !ParseNaturalNumber(fields[1], &line)
+      || !ParseNaturalNumber(fields[2], &index)
+      || !ParseNaturalNumber(fields[3], &parent_process_id)
+      || !ParseNaturalNumber(fields[4], &write_handle_as_size_t)
+      || !ParseNaturalNumber(fields[5], &event_handle_as_size_t)) {
+    DeathTestAbort("Bad --gtest_internal_run_death_test flag: " +
+                   GTEST_FLAG(internal_run_death_test));
+  }
+  write_fd = GetStatusFileDescriptor(parent_process_id,
+                                     write_handle_as_size_t,
+                                     event_handle_as_size_t);
+
+# elif GTEST_OS_FUCHSIA
+
+  if (fields.size() != 3
+      || !ParseNaturalNumber(fields[1], &line)
+      || !ParseNaturalNumber(fields[2], &index)) {
+    DeathTestAbort("Bad --gtest_internal_run_death_test flag: "
+        + GTEST_FLAG(internal_run_death_test));
+  }
+
+# else
+
+  if (fields.size() != 4
+      || !ParseNaturalNumber(fields[1], &line)
+      || !ParseNaturalNumber(fields[2], &index)
+      || !ParseNaturalNumber(fields[3], &write_fd)) {
+    DeathTestAbort("Bad --gtest_internal_run_death_test flag: "
+        + GTEST_FLAG(internal_run_death_test));
+  }
+
+# endif  // GTEST_OS_WINDOWS
+
+  return new InternalRunDeathTestFlag(fields[0], line, index, write_fd);
+}
+
+}  // namespace internal
+
+#endif  // GTEST_HAS_DEATH_TEST
+
+}  // namespace testing
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+#include <stdlib.h>
+
+#if GTEST_OS_WINDOWS_MOBILE
+# include <windows.h>
+#elif GTEST_OS_WINDOWS
+# include <direct.h>
+# include <io.h>
+#else
+# include <limits.h>
+# include <climits>  // Some Linux distributions define PATH_MAX here.
+#endif  // GTEST_OS_WINDOWS_MOBILE
+
+
+#if GTEST_OS_WINDOWS
+# define GTEST_PATH_MAX_ _MAX_PATH
+#elif defined(PATH_MAX)
+# define GTEST_PATH_MAX_ PATH_MAX
+#elif defined(_XOPEN_PATH_MAX)
+# define GTEST_PATH_MAX_ _XOPEN_PATH_MAX
+#else
+# define GTEST_PATH_MAX_ _POSIX_PATH_MAX
+#endif  // GTEST_OS_WINDOWS
+
+namespace testing {
+namespace internal {
+
+#if GTEST_OS_WINDOWS
+// On Windows, '\\' is the standard path separator, but many tools and the
+// Windows API also accept '/' as an alternate path separator. Unless otherwise
+// noted, a file path can contain either kind of path separators, or a mixture
+// of them.
+const char kPathSeparator = '\\';
+const char kAlternatePathSeparator = '/';
+const char kAlternatePathSeparatorString[] = "/";
+# if GTEST_OS_WINDOWS_MOBILE
+// Windows CE doesn't have a current directory. You should not use
+// the current directory in tests on Windows CE, but this at least
+// provides a reasonable fallback.
+const char kCurrentDirectoryString[] = "\\";
+// Windows CE doesn't define INVALID_FILE_ATTRIBUTES
+const DWORD kInvalidFileAttributes = 0xffffffff;
+# else
+const char kCurrentDirectoryString[] = ".\\";
+# endif  // GTEST_OS_WINDOWS_MOBILE
+#else
+const char kPathSeparator = '/';
+const char kCurrentDirectoryString[] = "./";
+#endif  // GTEST_OS_WINDOWS
+
+// Returns whether the given character is a valid path separator.
+static bool IsPathSeparator(char c) {
+#if GTEST_HAS_ALT_PATH_SEP_
+  return (c == kPathSeparator) || (c == kAlternatePathSeparator);
+#else
+  return c == kPathSeparator;
+#endif
+}
+
+// Returns the current working directory, or "" if unsuccessful.
+FilePath FilePath::GetCurrentDir() {
+#if GTEST_OS_WINDOWS_MOBILE || GTEST_OS_WINDOWS_PHONE ||         \
+    GTEST_OS_WINDOWS_RT || GTEST_OS_ESP8266 || GTEST_OS_ESP32 || \
+    GTEST_OS_XTENSA
+  // These platforms do not have a current directory, so we just return
+  // something reasonable.
+  return FilePath(kCurrentDirectoryString);
+#elif GTEST_OS_WINDOWS
+  char cwd[GTEST_PATH_MAX_ + 1] = { '\0' };
+  return FilePath(_getcwd(cwd, sizeof(cwd)) == nullptr ? "" : cwd);
+#else
+  char cwd[GTEST_PATH_MAX_ + 1] = { '\0' };
+  char* result = getcwd(cwd, sizeof(cwd));
+# if GTEST_OS_NACL
+  // getcwd will likely fail in NaCl due to the sandbox, so return something
+  // reasonable. The user may have provided a shim implementation for getcwd,
+  // however, so fallback only when failure is detected.
+  return FilePath(result == nullptr ? kCurrentDirectoryString : cwd);
+# endif  // GTEST_OS_NACL
+  return FilePath(result == nullptr ? "" : cwd);
+#endif  // GTEST_OS_WINDOWS_MOBILE
+}
+
+// Returns a copy of the FilePath with the case-insensitive extension removed.
+// Example: FilePath("dir/file.exe").RemoveExtension("EXE") returns
+// FilePath("dir/file"). If a case-insensitive extension is not
+// found, returns a copy of the original FilePath.
+FilePath FilePath::RemoveExtension(const char* extension) const {
+  const std::string dot_extension = std::string(".") + extension;
+  if (String::EndsWithCaseInsensitive(pathname_, dot_extension)) {
+    return FilePath(pathname_.substr(
+        0, pathname_.length() - dot_extension.length()));
+  }
+  return *this;
+}
+
+// Returns a pointer to the last occurrence of a valid path separator in
+// the FilePath. On Windows, for example, both '/' and '\' are valid path
+// separators. Returns NULL if no path separator was found.
+const char* FilePath::FindLastPathSeparator() const {
+  const char* const last_sep = strrchr(c_str(), kPathSeparator);
+#if GTEST_HAS_ALT_PATH_SEP_
+  const char* const last_alt_sep = strrchr(c_str(), kAlternatePathSeparator);
+  // Comparing two pointers of which only one is NULL is undefined.
+  if (last_alt_sep != nullptr &&
+      (last_sep == nullptr || last_alt_sep > last_sep)) {
+    return last_alt_sep;
+  }
+#endif
+  return last_sep;
+}
+
+// Returns a copy of the FilePath with the directory part removed.
+// Example: FilePath("path/to/file").RemoveDirectoryName() returns
+// FilePath("file"). If there is no directory part ("just_a_file"), it returns
+// the FilePath unmodified. If there is no file part ("just_a_dir/") it
+// returns an empty FilePath ("").
+// On Windows platform, '\' is the path separator, otherwise it is '/'.
+FilePath FilePath::RemoveDirectoryName() const {
+  const char* const last_sep = FindLastPathSeparator();
+  return last_sep ? FilePath(last_sep + 1) : *this;
+}
+
+// RemoveFileName returns the directory path with the filename removed.
+// Example: FilePath("path/to/file").RemoveFileName() returns "path/to/".
+// If the FilePath is "a_file" or "/a_file", RemoveFileName returns
+// FilePath("./") or, on Windows, FilePath(".\\"). If the filepath does
+// not have a file, like "just/a/dir/", it returns the FilePath unmodified.
+// On Windows platform, '\' is the path separator, otherwise it is '/'.
+FilePath FilePath::RemoveFileName() const {
+  const char* const last_sep = FindLastPathSeparator();
+  std::string dir;
+  if (last_sep) {
+    dir = std::string(c_str(), static_cast<size_t>(last_sep + 1 - c_str()));
+  } else {
+    dir = kCurrentDirectoryString;
+  }
+  return FilePath(dir);
+}
+
+// Helper functions for naming files in a directory for xml output.
+
+// Given directory = "dir", base_name = "test", number = 0,
+// extension = "xml", returns "dir/test.xml". If number is greater
+// than zero (e.g., 12), returns "dir/test_12.xml".
+// On Windows platform, uses \ as the separator rather than /.
+FilePath FilePath::MakeFileName(const FilePath& directory,
+                                const FilePath& base_name,
+                                int number,
+                                const char* extension) {
+  std::string file;
+  if (number == 0) {
+    file = base_name.string() + "." + extension;
+  } else {
+    file = base_name.string() + "_" + StreamableToString(number)
+        + "." + extension;
+  }
+  return ConcatPaths(directory, FilePath(file));
+}
+
+// Given directory = "dir", relative_path = "test.xml", returns "dir/test.xml".
+// On Windows, uses \ as the separator rather than /.
+FilePath FilePath::ConcatPaths(const FilePath& directory,
+                               const FilePath& relative_path) {
+  if (directory.IsEmpty())
+    return relative_path;
+  const FilePath dir(directory.RemoveTrailingPathSeparator());
+  return FilePath(dir.string() + kPathSeparator + relative_path.string());
+}
+
+// Returns true if pathname describes something findable in the file-system,
+// either a file, directory, or whatever.
+bool FilePath::FileOrDirectoryExists() const {
+#if GTEST_OS_WINDOWS_MOBILE
+  LPCWSTR unicode = String::AnsiToUtf16(pathname_.c_str());
+  const DWORD attributes = GetFileAttributes(unicode);
+  delete [] unicode;
+  return attributes != kInvalidFileAttributes;
+#else
+  posix::StatStruct file_stat;
+  return posix::Stat(pathname_.c_str(), &file_stat) == 0;
+#endif  // GTEST_OS_WINDOWS_MOBILE
+}
+
+// Returns true if pathname describes a directory in the file-system
+// that exists.
+bool FilePath::DirectoryExists() const {
+  bool result = false;
+#if GTEST_OS_WINDOWS
+  // Don't strip off trailing separator if path is a root directory on
+  // Windows (like "C:\\").
+  const FilePath& path(IsRootDirectory() ? *this :
+                                           RemoveTrailingPathSeparator());
+#else
+  const FilePath& path(*this);
+#endif
+
+#if GTEST_OS_WINDOWS_MOBILE
+  LPCWSTR unicode = String::AnsiToUtf16(path.c_str());
+  const DWORD attributes = GetFileAttributes(unicode);
+  delete [] unicode;
+  if ((attributes != kInvalidFileAttributes) &&
+      (attributes & FILE_ATTRIBUTE_DIRECTORY)) {
+    result = true;
+  }
+#else
+  posix::StatStruct file_stat;
+  result = posix::Stat(path.c_str(), &file_stat) == 0 &&
+      posix::IsDir(file_stat);
+#endif  // GTEST_OS_WINDOWS_MOBILE
+
+  return result;
+}
+
+// Returns true if pathname describes a root directory. (Windows has one
+// root directory per disk drive.)
+bool FilePath::IsRootDirectory() const {
+#if GTEST_OS_WINDOWS
+  return pathname_.length() == 3 && IsAbsolutePath();
+#else
+  return pathname_.length() == 1 && IsPathSeparator(pathname_.c_str()[0]);
+#endif
+}
+
+// Returns true if pathname describes an absolute path.
+bool FilePath::IsAbsolutePath() const {
+  const char* const name = pathname_.c_str();
+#if GTEST_OS_WINDOWS
+  return pathname_.length() >= 3 &&
+     ((name[0] >= 'a' && name[0] <= 'z') ||
+      (name[0] >= 'A' && name[0] <= 'Z')) &&
+     name[1] == ':' &&
+     IsPathSeparator(name[2]);
+#else
+  return IsPathSeparator(name[0]);
+#endif
+}
+
+// Returns a pathname for a file that does not currently exist. The pathname
+// will be directory/base_name.extension or
+// directory/base_name_<number>.extension if directory/base_name.extension
+// already exists. The number will be incremented until a pathname is found
+// that does not already exist.
+// Examples: 'dir/foo_test.xml' or 'dir/foo_test_1.xml'.
+// There could be a race condition if two or more processes are calling this
+// function at the same time -- they could both pick the same filename.
+FilePath FilePath::GenerateUniqueFileName(const FilePath& directory,
+                                          const FilePath& base_name,
+                                          const char* extension) {
+  FilePath full_pathname;
+  int number = 0;
+  do {
+    full_pathname.Set(MakeFileName(directory, base_name, number++, extension));
+  } while (full_pathname.FileOrDirectoryExists());
+  return full_pathname;
+}
+
+// Returns true if FilePath ends with a path separator, which indicates that
+// it is intended to represent a directory. Returns false otherwise.
+// This does NOT check that a directory (or file) actually exists.
+bool FilePath::IsDirectory() const {
+  return !pathname_.empty() &&
+         IsPathSeparator(pathname_.c_str()[pathname_.length() - 1]);
+}
+
+// Create directories so that path exists. Returns true if successful or if
+// the directories already exist; returns false if unable to create directories
+// for any reason.
+bool FilePath::CreateDirectoriesRecursively() const {
+  if (!this->IsDirectory()) {
+    return false;
+  }
+
+  if (pathname_.length() == 0 || this->DirectoryExists()) {
+    return true;
+  }
+
+  const FilePath parent(this->RemoveTrailingPathSeparator().RemoveFileName());
+  return parent.CreateDirectoriesRecursively() && this->CreateFolder();
+}
+
+// Create the directory so that path exists. Returns true if successful or
+// if the directory already exists; returns false if unable to create the
+// directory for any reason, including if the parent directory does not
+// exist. Not named "CreateDirectory" because that's a macro on Windows.
+bool FilePath::CreateFolder() const {
+#if GTEST_OS_WINDOWS_MOBILE
+  FilePath removed_sep(this->RemoveTrailingPathSeparator());
+  LPCWSTR unicode = String::AnsiToUtf16(removed_sep.c_str());
+  int result = CreateDirectory(unicode, nullptr) ? 0 : -1;
+  delete [] unicode;
+#elif GTEST_OS_WINDOWS
+  int result = _mkdir(pathname_.c_str());
+#elif GTEST_OS_ESP8266 || GTEST_OS_XTENSA
+  // do nothing
+  int result = 0;
+#else
+  int result = mkdir(pathname_.c_str(), 0777);
+#endif  // GTEST_OS_WINDOWS_MOBILE
+
+  if (result == -1) {
+    return this->DirectoryExists();  // An error is OK if the directory exists.
+  }
+  return true;  // No error.
+}
+
+// If input name has a trailing separator character, remove it and return the
+// name, otherwise return the name string unmodified.
+// On Windows platform, uses \ as the separator, other platforms use /.
+FilePath FilePath::RemoveTrailingPathSeparator() const {
+  return IsDirectory()
+      ? FilePath(pathname_.substr(0, pathname_.length() - 1))
+      : *this;
+}
+
+// Removes any redundant separators that might be in the pathname.
+// For example, "bar///foo" becomes "bar/foo". Does not eliminate other
+// redundancies that might be in a pathname involving "." or "..".
+void FilePath::Normalize() {
+  auto out = pathname_.begin();
+
+  for (const char character : pathname_) {
+    if (!IsPathSeparator(character)) {
+      *(out++) = character;
+    } else if (out == pathname_.begin() || *std::prev(out) != kPathSeparator) {
+      *(out++) = kPathSeparator;
+    } else {
+      continue;
+    }
+  }
+
+  pathname_.erase(out, pathname_.end());
+}
+
+}  // namespace internal
+}  // namespace testing
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// The Google C++ Testing and Mocking Framework (Google Test)
+//
+// This file implements just enough of the matcher interface to allow
+// EXPECT_DEATH and friends to accept a matcher argument.
+
+
+#include <string>
+
+namespace testing {
+
+// Constructs a matcher that matches a const std::string& whose value is
+// equal to s.
+Matcher<const std::string&>::Matcher(const std::string& s) { *this = Eq(s); }
+
+// Constructs a matcher that matches a const std::string& whose value is
+// equal to s.
+Matcher<const std::string&>::Matcher(const char* s) {
+  *this = Eq(std::string(s));
+}
+
+// Constructs a matcher that matches a std::string whose value is equal to
+// s.
+Matcher<std::string>::Matcher(const std::string& s) { *this = Eq(s); }
+
+// Constructs a matcher that matches a std::string whose value is equal to
+// s.
+Matcher<std::string>::Matcher(const char* s) { *this = Eq(std::string(s)); }
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+// Constructs a matcher that matches a const StringView& whose value is
+// equal to s.
+Matcher<const internal::StringView&>::Matcher(const std::string& s) {
+  *this = Eq(s);
+}
+
+// Constructs a matcher that matches a const StringView& whose value is
+// equal to s.
+Matcher<const internal::StringView&>::Matcher(const char* s) {
+  *this = Eq(std::string(s));
+}
+
+// Constructs a matcher that matches a const StringView& whose value is
+// equal to s.
+Matcher<const internal::StringView&>::Matcher(internal::StringView s) {
+  *this = Eq(std::string(s));
+}
+
+// Constructs a matcher that matches a StringView whose value is equal to
+// s.
+Matcher<internal::StringView>::Matcher(const std::string& s) { *this = Eq(s); }
+
+// Constructs a matcher that matches a StringView whose value is equal to
+// s.
+Matcher<internal::StringView>::Matcher(const char* s) {
+  *this = Eq(std::string(s));
+}
+
+// Constructs a matcher that matches a StringView whose value is equal to
+// s.
+Matcher<internal::StringView>::Matcher(internal::StringView s) {
+  *this = Eq(std::string(s));
+}
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+}  // namespace testing
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <cstdint>
+#include <fstream>
+#include <memory>
+
+#if GTEST_OS_WINDOWS
+# include <windows.h>
+# include <io.h>
+# include <sys/stat.h>
+# include <map>  // Used in ThreadLocal.
+# ifdef _MSC_VER
+#  include <crtdbg.h>
+# endif  // _MSC_VER
+#else
+# include <unistd.h>
+#endif  // GTEST_OS_WINDOWS
+
+#if GTEST_OS_MAC
+# include <mach/mach_init.h>
+# include <mach/task.h>
+# include <mach/vm_map.h>
+#endif  // GTEST_OS_MAC
+
+#if GTEST_OS_DRAGONFLY || GTEST_OS_FREEBSD || GTEST_OS_GNU_KFREEBSD || \
+    GTEST_OS_NETBSD || GTEST_OS_OPENBSD
+# include <sys/sysctl.h>
+# if GTEST_OS_DRAGONFLY || GTEST_OS_FREEBSD || GTEST_OS_GNU_KFREEBSD
+#  include <sys/user.h>
+# endif
+#endif
+
+#if GTEST_OS_QNX
+# include <devctl.h>
+# include <fcntl.h>
+# include <sys/procfs.h>
+#endif  // GTEST_OS_QNX
+
+#if GTEST_OS_AIX
+# include <procinfo.h>
+# include <sys/types.h>
+#endif  // GTEST_OS_AIX
+
+#if GTEST_OS_FUCHSIA
+# include <zircon/process.h>
+# include <zircon/syscalls.h>
+#endif  // GTEST_OS_FUCHSIA
+
+
+namespace testing {
+namespace internal {
+
+#if defined(_MSC_VER) || defined(__BORLANDC__)
+// MSVC and C++Builder do not provide a definition of STDERR_FILENO.
+const int kStdOutFileno = 1;
+const int kStdErrFileno = 2;
+#else
+const int kStdOutFileno = STDOUT_FILENO;
+const int kStdErrFileno = STDERR_FILENO;
+#endif  // _MSC_VER
+
+#if GTEST_OS_LINUX
+
+namespace {
+template <typename T>
+T ReadProcFileField(const std::string& filename, int field) {
+  std::string dummy;
+  std::ifstream file(filename.c_str());
+  while (field-- > 0) {
+    file >> dummy;
+  }
+  T output = 0;
+  file >> output;
+  return output;
+}
+}  // namespace
+
+// Returns the number of active threads, or 0 when there is an error.
+size_t GetThreadCount() {
+  const std::string filename =
+      (Message() << "/proc/" << getpid() << "/stat").GetString();
+  return ReadProcFileField<size_t>(filename, 19);
+}
+
+#elif GTEST_OS_MAC
+
+size_t GetThreadCount() {
+  const task_t task = mach_task_self();
+  mach_msg_type_number_t thread_count;
+  thread_act_array_t thread_list;
+  const kern_return_t status = task_threads(task, &thread_list, &thread_count);
+  if (status == KERN_SUCCESS) {
+    // task_threads allocates resources in thread_list and we need to free them
+    // to avoid leaks.
+    vm_deallocate(task,
+                  reinterpret_cast<vm_address_t>(thread_list),
+                  sizeof(thread_t) * thread_count);
+    return static_cast<size_t>(thread_count);
+  } else {
+    return 0;
+  }
+}
+
+#elif GTEST_OS_DRAGONFLY || GTEST_OS_FREEBSD || GTEST_OS_GNU_KFREEBSD || \
+      GTEST_OS_NETBSD
+
+#if GTEST_OS_NETBSD
+#undef KERN_PROC
+#define KERN_PROC KERN_PROC2
+#define kinfo_proc kinfo_proc2
+#endif
+
+#if GTEST_OS_DRAGONFLY
+#define KP_NLWP(kp) (kp.kp_nthreads)
+#elif GTEST_OS_FREEBSD || GTEST_OS_GNU_KFREEBSD
+#define KP_NLWP(kp) (kp.ki_numthreads)
+#elif GTEST_OS_NETBSD
+#define KP_NLWP(kp) (kp.p_nlwps)
+#endif
+
+// Returns the number of threads running in the process, or 0 to indicate that
+// we cannot detect it.
+size_t GetThreadCount() {
+  int mib[] = {
+    CTL_KERN,
+    KERN_PROC,
+    KERN_PROC_PID,
+    getpid(),
+#if GTEST_OS_NETBSD
+    sizeof(struct kinfo_proc),
+    1,
+#endif
+  };
+  u_int miblen = sizeof(mib) / sizeof(mib[0]);
+  struct kinfo_proc info;
+  size_t size = sizeof(info);
+  if (sysctl(mib, miblen, &info, &size, NULL, 0)) {
+    return 0;
+  }
+  return static_cast<size_t>(KP_NLWP(info));
+}
+#elif GTEST_OS_OPENBSD
+
+// Returns the number of threads running in the process, or 0 to indicate that
+// we cannot detect it.
+size_t GetThreadCount() {
+  int mib[] = {
+    CTL_KERN,
+    KERN_PROC,
+    KERN_PROC_PID | KERN_PROC_SHOW_THREADS,
+    getpid(),
+    sizeof(struct kinfo_proc),
+    0,
+  };
+  u_int miblen = sizeof(mib) / sizeof(mib[0]);
+
+  // get number of structs
+  size_t size;
+  if (sysctl(mib, miblen, NULL, &size, NULL, 0)) {
+    return 0;
+  }
+
+  mib[5] = static_cast<int>(size / static_cast<size_t>(mib[4]));
+
+  // populate array of structs
+  struct kinfo_proc info[mib[5]];
+  if (sysctl(mib, miblen, &info, &size, NULL, 0)) {
+    return 0;
+  }
+
+  // exclude empty members
+  size_t nthreads = 0;
+  for (size_t i = 0; i < size / static_cast<size_t>(mib[4]); i++) {
+    if (info[i].p_tid != -1)
+      nthreads++;
+  }
+  return nthreads;
+}
+
+#elif GTEST_OS_QNX
+
+// Returns the number of threads running in the process, or 0 to indicate that
+// we cannot detect it.
+size_t GetThreadCount() {
+  const int fd = open("/proc/self/as", O_RDONLY);
+  if (fd < 0) {
+    return 0;
+  }
+  procfs_info process_info;
+  const int status =
+      devctl(fd, DCMD_PROC_INFO, &process_info, sizeof(process_info), nullptr);
+  close(fd);
+  if (status == EOK) {
+    return static_cast<size_t>(process_info.num_threads);
+  } else {
+    return 0;
+  }
+}
+
+#elif GTEST_OS_AIX
+
+size_t GetThreadCount() {
+  struct procentry64 entry;
+  pid_t pid = getpid();
+  int status = getprocs64(&entry, sizeof(entry), nullptr, 0, &pid, 1);
+  if (status == 1) {
+    return entry.pi_thcount;
+  } else {
+    return 0;
+  }
+}
+
+#elif GTEST_OS_FUCHSIA
+
+size_t GetThreadCount() {
+  int dummy_buffer;
+  size_t avail;
+  zx_status_t status = zx_object_get_info(
+      zx_process_self(),
+      ZX_INFO_PROCESS_THREADS,
+      &dummy_buffer,
+      0,
+      nullptr,
+      &avail);
+  if (status == ZX_OK) {
+    return avail;
+  } else {
+    return 0;
+  }
+}
+
+#else
+
+size_t GetThreadCount() {
+  // There's no portable way to detect the number of threads, so we just
+  // return 0 to indicate that we cannot detect it.
+  return 0;
+}
+
+#endif  // GTEST_OS_LINUX
+
+#if GTEST_IS_THREADSAFE && GTEST_OS_WINDOWS
+
+void SleepMilliseconds(int n) {
+  ::Sleep(static_cast<DWORD>(n));
+}
+
+AutoHandle::AutoHandle()
+    : handle_(INVALID_HANDLE_VALUE) {}
+
+AutoHandle::AutoHandle(Handle handle)
+    : handle_(handle) {}
+
+AutoHandle::~AutoHandle() {
+  Reset();
+}
+
+AutoHandle::Handle AutoHandle::Get() const {
+  return handle_;
+}
+
+void AutoHandle::Reset() {
+  Reset(INVALID_HANDLE_VALUE);
+}
+
+void AutoHandle::Reset(HANDLE handle) {
+  // Resetting with the same handle we already own is invalid.
+  if (handle_ != handle) {
+    if (IsCloseable()) {
+      ::CloseHandle(handle_);
+    }
+    handle_ = handle;
+  } else {
+    GTEST_CHECK_(!IsCloseable())
+        << "Resetting a valid handle to itself is likely a programmer error "
+            "and thus not allowed.";
+  }
+}
+
+bool AutoHandle::IsCloseable() const {
+  // Different Windows APIs may use either of these values to represent an
+  // invalid handle.
+  return handle_ != nullptr && handle_ != INVALID_HANDLE_VALUE;
+}
+
+Notification::Notification()
+    : event_(::CreateEvent(nullptr,     // Default security attributes.
+                           TRUE,        // Do not reset automatically.
+                           FALSE,       // Initially unset.
+                           nullptr)) {  // Anonymous event.
+  GTEST_CHECK_(event_.Get() != nullptr);
+}
+
+void Notification::Notify() {
+  GTEST_CHECK_(::SetEvent(event_.Get()) != FALSE);
+}
+
+void Notification::WaitForNotification() {
+  GTEST_CHECK_(
+      ::WaitForSingleObject(event_.Get(), INFINITE) == WAIT_OBJECT_0);
+}
+
+Mutex::Mutex()
+    : owner_thread_id_(0),
+      type_(kDynamic),
+      critical_section_init_phase_(0),
+      critical_section_(new CRITICAL_SECTION) {
+  ::InitializeCriticalSection(critical_section_);
+}
+
+Mutex::~Mutex() {
+  // Static mutexes are leaked intentionally. It is not thread-safe to try
+  // to clean them up.
+  if (type_ == kDynamic) {
+    ::DeleteCriticalSection(critical_section_);
+    delete critical_section_;
+    critical_section_ = nullptr;
+  }
+}
+
+void Mutex::Lock() {
+  ThreadSafeLazyInit();
+  ::EnterCriticalSection(critical_section_);
+  owner_thread_id_ = ::GetCurrentThreadId();
+}
+
+void Mutex::Unlock() {
+  ThreadSafeLazyInit();
+  // We don't protect writing to owner_thread_id_ here, as it's the
+  // caller's responsibility to ensure that the current thread holds the
+  // mutex when this is called.
+  owner_thread_id_ = 0;
+  ::LeaveCriticalSection(critical_section_);
+}
+
+// Does nothing if the current thread holds the mutex. Otherwise, crashes
+// with high probability.
+void Mutex::AssertHeld() {
+  ThreadSafeLazyInit();
+  GTEST_CHECK_(owner_thread_id_ == ::GetCurrentThreadId())
+      << "The current thread is not holding the mutex @" << this;
+}
+
+namespace {
+
+#ifdef _MSC_VER
+// Use the RAII idiom to flag mem allocs that are intentionally never
+// deallocated. The motivation is to silence the false positive mem leaks
+// that are reported by the debug version of MS's CRT which can only detect
+// if an alloc is missing a matching deallocation.
+// Example:
+//    MemoryIsNotDeallocated memory_is_not_deallocated;
+//    critical_section_ = new CRITICAL_SECTION;
+//
+class MemoryIsNotDeallocated
+{
+ public:
+  MemoryIsNotDeallocated() : old_crtdbg_flag_(0) {
+    old_crtdbg_flag_ = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
+    // Set heap allocation block type to _IGNORE_BLOCK so that MS debug CRT
+    // doesn't report mem leak if there's no matching deallocation.
+    _CrtSetDbgFlag(old_crtdbg_flag_ & ~_CRTDBG_ALLOC_MEM_DF);
+  }
+
+  ~MemoryIsNotDeallocated() {
+    // Restore the original _CRTDBG_ALLOC_MEM_DF flag
+    _CrtSetDbgFlag(old_crtdbg_flag_);
+  }
+
+ private:
+  int old_crtdbg_flag_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(MemoryIsNotDeallocated);
+};
+#endif  // _MSC_VER
+
+}  // namespace
+
+// Initializes owner_thread_id_ and critical_section_ in static mutexes.
+void Mutex::ThreadSafeLazyInit() {
+  // Dynamic mutexes are initialized in the constructor.
+  if (type_ == kStatic) {
+    switch (
+        ::InterlockedCompareExchange(&critical_section_init_phase_, 1L, 0L)) {
+      case 0:
+        // If critical_section_init_phase_ was 0 before the exchange, we
+        // are the first to test it and need to perform the initialization.
+        owner_thread_id_ = 0;
+        {
+          // Use RAII to flag that following mem alloc is never deallocated.
+#ifdef _MSC_VER
+          MemoryIsNotDeallocated memory_is_not_deallocated;
+#endif  // _MSC_VER
+          critical_section_ = new CRITICAL_SECTION;
+        }
+        ::InitializeCriticalSection(critical_section_);
+        // Updates the critical_section_init_phase_ to 2 to signal
+        // initialization complete.
+        GTEST_CHECK_(::InterlockedCompareExchange(
+                          &critical_section_init_phase_, 2L, 1L) ==
+                      1L);
+        break;
+      case 1:
+        // Somebody else is already initializing the mutex; spin until they
+        // are done.
+        while (::InterlockedCompareExchange(&critical_section_init_phase_,
+                                            2L,
+                                            2L) != 2L) {
+          // Possibly yields the rest of the thread's time slice to other
+          // threads.
+          ::Sleep(0);
+        }
+        break;
+
+      case 2:
+        break;  // The mutex is already initialized and ready for use.
+
+      default:
+        GTEST_CHECK_(false)
+            << "Unexpected value of critical_section_init_phase_ "
+            << "while initializing a static mutex.";
+    }
+  }
+}
+
+namespace {
+
+class ThreadWithParamSupport : public ThreadWithParamBase {
+ public:
+  static HANDLE CreateThread(Runnable* runnable,
+                             Notification* thread_can_start) {
+    ThreadMainParam* param = new ThreadMainParam(runnable, thread_can_start);
+    DWORD thread_id;
+    HANDLE thread_handle = ::CreateThread(
+        nullptr,  // Default security.
+        0,        // Default stack size.
+        &ThreadWithParamSupport::ThreadMain,
+        param,        // Parameter to ThreadMainStatic
+        0x0,          // Default creation flags.
+        &thread_id);  // Need a valid pointer for the call to work under Win98.
+    GTEST_CHECK_(thread_handle != nullptr)
+        << "CreateThread failed with error " << ::GetLastError() << ".";
+    if (thread_handle == nullptr) {
+      delete param;
+    }
+    return thread_handle;
+  }
+
+ private:
+  struct ThreadMainParam {
+    ThreadMainParam(Runnable* runnable, Notification* thread_can_start)
+        : runnable_(runnable),
+          thread_can_start_(thread_can_start) {
+    }
+    std::unique_ptr<Runnable> runnable_;
+    // Does not own.
+    Notification* thread_can_start_;
+  };
+
+  static DWORD WINAPI ThreadMain(void* ptr) {
+    // Transfers ownership.
+    std::unique_ptr<ThreadMainParam> param(static_cast<ThreadMainParam*>(ptr));
+    if (param->thread_can_start_ != nullptr)
+      param->thread_can_start_->WaitForNotification();
+    param->runnable_->Run();
+    return 0;
+  }
+
+  // Prohibit instantiation.
+  ThreadWithParamSupport();
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadWithParamSupport);
+};
+
+}  // namespace
+
+ThreadWithParamBase::ThreadWithParamBase(Runnable *runnable,
+                                         Notification* thread_can_start)
+      : thread_(ThreadWithParamSupport::CreateThread(runnable,
+                                                     thread_can_start)) {
+}
+
+ThreadWithParamBase::~ThreadWithParamBase() {
+  Join();
+}
+
+void ThreadWithParamBase::Join() {
+  GTEST_CHECK_(::WaitForSingleObject(thread_.Get(), INFINITE) == WAIT_OBJECT_0)
+      << "Failed to join the thread with error " << ::GetLastError() << ".";
+}
+
+// Maps a thread to a set of ThreadIdToThreadLocals that have values
+// instantiated on that thread and notifies them when the thread exits.  A
+// ThreadLocal instance is expected to persist until all threads it has
+// values on have terminated.
+class ThreadLocalRegistryImpl {
+ public:
+  // Registers thread_local_instance as having value on the current thread.
+  // Returns a value that can be used to identify the thread from other threads.
+  static ThreadLocalValueHolderBase* GetValueOnCurrentThread(
+      const ThreadLocalBase* thread_local_instance) {
+#ifdef _MSC_VER
+    MemoryIsNotDeallocated memory_is_not_deallocated;
+#endif  // _MSC_VER
+    DWORD current_thread = ::GetCurrentThreadId();
+    MutexLock lock(&mutex_);
+    ThreadIdToThreadLocals* const thread_to_thread_locals =
+        GetThreadLocalsMapLocked();
+    ThreadIdToThreadLocals::iterator thread_local_pos =
+        thread_to_thread_locals->find(current_thread);
+    if (thread_local_pos == thread_to_thread_locals->end()) {
+      thread_local_pos = thread_to_thread_locals->insert(
+          std::make_pair(current_thread, ThreadLocalValues())).first;
+      StartWatcherThreadFor(current_thread);
+    }
+    ThreadLocalValues& thread_local_values = thread_local_pos->second;
+    ThreadLocalValues::iterator value_pos =
+        thread_local_values.find(thread_local_instance);
+    if (value_pos == thread_local_values.end()) {
+      value_pos =
+          thread_local_values
+              .insert(std::make_pair(
+                  thread_local_instance,
+                  std::shared_ptr<ThreadLocalValueHolderBase>(
+                      thread_local_instance->NewValueForCurrentThread())))
+              .first;
+    }
+    return value_pos->second.get();
+  }
+
+  static void OnThreadLocalDestroyed(
+      const ThreadLocalBase* thread_local_instance) {
+    std::vector<std::shared_ptr<ThreadLocalValueHolderBase> > value_holders;
+    // Clean up the ThreadLocalValues data structure while holding the lock, but
+    // defer the destruction of the ThreadLocalValueHolderBases.
+    {
+      MutexLock lock(&mutex_);
+      ThreadIdToThreadLocals* const thread_to_thread_locals =
+          GetThreadLocalsMapLocked();
+      for (ThreadIdToThreadLocals::iterator it =
+          thread_to_thread_locals->begin();
+          it != thread_to_thread_locals->end();
+          ++it) {
+        ThreadLocalValues& thread_local_values = it->second;
+        ThreadLocalValues::iterator value_pos =
+            thread_local_values.find(thread_local_instance);
+        if (value_pos != thread_local_values.end()) {
+          value_holders.push_back(value_pos->second);
+          thread_local_values.erase(value_pos);
+          // This 'if' can only be successful at most once, so theoretically we
+          // could break out of the loop here, but we don't bother doing so.
+        }
+      }
+    }
+    // Outside the lock, let the destructor for 'value_holders' deallocate the
+    // ThreadLocalValueHolderBases.
+  }
+
+  static void OnThreadExit(DWORD thread_id) {
+    GTEST_CHECK_(thread_id != 0) << ::GetLastError();
+    std::vector<std::shared_ptr<ThreadLocalValueHolderBase> > value_holders;
+    // Clean up the ThreadIdToThreadLocals data structure while holding the
+    // lock, but defer the destruction of the ThreadLocalValueHolderBases.
+    {
+      MutexLock lock(&mutex_);
+      ThreadIdToThreadLocals* const thread_to_thread_locals =
+          GetThreadLocalsMapLocked();
+      ThreadIdToThreadLocals::iterator thread_local_pos =
+          thread_to_thread_locals->find(thread_id);
+      if (thread_local_pos != thread_to_thread_locals->end()) {
+        ThreadLocalValues& thread_local_values = thread_local_pos->second;
+        for (ThreadLocalValues::iterator value_pos =
+            thread_local_values.begin();
+            value_pos != thread_local_values.end();
+            ++value_pos) {
+          value_holders.push_back(value_pos->second);
+        }
+        thread_to_thread_locals->erase(thread_local_pos);
+      }
+    }
+    // Outside the lock, let the destructor for 'value_holders' deallocate the
+    // ThreadLocalValueHolderBases.
+  }
+
+ private:
+  // In a particular thread, maps a ThreadLocal object to its value.
+  typedef std::map<const ThreadLocalBase*,
+                   std::shared_ptr<ThreadLocalValueHolderBase> >
+      ThreadLocalValues;
+  // Stores all ThreadIdToThreadLocals having values in a thread, indexed by
+  // thread's ID.
+  typedef std::map<DWORD, ThreadLocalValues> ThreadIdToThreadLocals;
+
+  // Holds the thread id and thread handle that we pass from
+  // StartWatcherThreadFor to WatcherThreadFunc.
+  typedef std::pair<DWORD, HANDLE> ThreadIdAndHandle;
+
+  static void StartWatcherThreadFor(DWORD thread_id) {
+    // The returned handle will be kept in thread_map and closed by
+    // watcher_thread in WatcherThreadFunc.
+    HANDLE thread = ::OpenThread(SYNCHRONIZE | THREAD_QUERY_INFORMATION,
+                                 FALSE,
+                                 thread_id);
+    GTEST_CHECK_(thread != nullptr);
+    // We need to pass a valid thread ID pointer into CreateThread for it
+    // to work correctly under Win98.
+    DWORD watcher_thread_id;
+    HANDLE watcher_thread = ::CreateThread(
+        nullptr,  // Default security.
+        0,        // Default stack size
+        &ThreadLocalRegistryImpl::WatcherThreadFunc,
+        reinterpret_cast<LPVOID>(new ThreadIdAndHandle(thread_id, thread)),
+        CREATE_SUSPENDED, &watcher_thread_id);
+    GTEST_CHECK_(watcher_thread != nullptr);
+    // Give the watcher thread the same priority as ours to avoid being
+    // blocked by it.
+    ::SetThreadPriority(watcher_thread,
+                        ::GetThreadPriority(::GetCurrentThread()));
+    ::ResumeThread(watcher_thread);
+    ::CloseHandle(watcher_thread);
+  }
+
+  // Monitors exit from a given thread and notifies those
+  // ThreadIdToThreadLocals about thread termination.
+  static DWORD WINAPI WatcherThreadFunc(LPVOID param) {
+    const ThreadIdAndHandle* tah =
+        reinterpret_cast<const ThreadIdAndHandle*>(param);
+    GTEST_CHECK_(
+        ::WaitForSingleObject(tah->second, INFINITE) == WAIT_OBJECT_0);
+    OnThreadExit(tah->first);
+    ::CloseHandle(tah->second);
+    delete tah;
+    return 0;
+  }
+
+  // Returns map of thread local instances.
+  static ThreadIdToThreadLocals* GetThreadLocalsMapLocked() {
+    mutex_.AssertHeld();
+#ifdef _MSC_VER
+    MemoryIsNotDeallocated memory_is_not_deallocated;
+#endif  // _MSC_VER
+    static ThreadIdToThreadLocals* map = new ThreadIdToThreadLocals();
+    return map;
+  }
+
+  // Protects access to GetThreadLocalsMapLocked() and its return value.
+  static Mutex mutex_;
+  // Protects access to GetThreadMapLocked() and its return value.
+  static Mutex thread_map_mutex_;
+};
+
+Mutex ThreadLocalRegistryImpl::mutex_(Mutex::kStaticMutex);
+Mutex ThreadLocalRegistryImpl::thread_map_mutex_(Mutex::kStaticMutex);
+
+ThreadLocalValueHolderBase* ThreadLocalRegistry::GetValueOnCurrentThread(
+      const ThreadLocalBase* thread_local_instance) {
+  return ThreadLocalRegistryImpl::GetValueOnCurrentThread(
+      thread_local_instance);
+}
+
+void ThreadLocalRegistry::OnThreadLocalDestroyed(
+      const ThreadLocalBase* thread_local_instance) {
+  ThreadLocalRegistryImpl::OnThreadLocalDestroyed(thread_local_instance);
+}
+
+#endif  // GTEST_IS_THREADSAFE && GTEST_OS_WINDOWS
+
+#if GTEST_USES_POSIX_RE
+
+// Implements RE.  Currently only needed for death tests.
+
+RE::~RE() {
+  if (is_valid_) {
+    // regfree'ing an invalid regex might crash because the content
+    // of the regex is undefined. Since the regex's are essentially
+    // the same, one cannot be valid (or invalid) without the other
+    // being so too.
+    regfree(&partial_regex_);
+    regfree(&full_regex_);
+  }
+  free(const_cast<char*>(pattern_));
+}
+
+// Returns true if and only if regular expression re matches the entire str.
+bool RE::FullMatch(const char* str, const RE& re) {
+  if (!re.is_valid_) return false;
+
+  regmatch_t match;
+  return regexec(&re.full_regex_, str, 1, &match, 0) == 0;
+}
+
+// Returns true if and only if regular expression re matches a substring of
+// str (including str itself).
+bool RE::PartialMatch(const char* str, const RE& re) {
+  if (!re.is_valid_) return false;
+
+  regmatch_t match;
+  return regexec(&re.partial_regex_, str, 1, &match, 0) == 0;
+}
+
+// Initializes an RE from its string representation.
+void RE::Init(const char* regex) {
+  pattern_ = posix::StrDup(regex);
+
+  // Reserves enough bytes to hold the regular expression used for a
+  // full match.
+  const size_t full_regex_len = strlen(regex) + 10;
+  char* const full_pattern = new char[full_regex_len];
+
+  snprintf(full_pattern, full_regex_len, "^(%s)$", regex);
+  is_valid_ = regcomp(&full_regex_, full_pattern, REG_EXTENDED) == 0;
+  // We want to call regcomp(&partial_regex_, ...) even if the
+  // previous expression returns false.  Otherwise partial_regex_ may
+  // not be properly initialized can may cause trouble when it's
+  // freed.
+  //
+  // Some implementation of POSIX regex (e.g. on at least some
+  // versions of Cygwin) doesn't accept the empty string as a valid
+  // regex.  We change it to an equivalent form "()" to be safe.
+  if (is_valid_) {
+    const char* const partial_regex = (*regex == '\0') ? "()" : regex;
+    is_valid_ = regcomp(&partial_regex_, partial_regex, REG_EXTENDED) == 0;
+  }
+  EXPECT_TRUE(is_valid_)
+      << "Regular expression \"" << regex
+      << "\" is not a valid POSIX Extended regular expression.";
+
+  delete[] full_pattern;
+}
+
+#elif GTEST_USES_SIMPLE_RE
+
+// Returns true if and only if ch appears anywhere in str (excluding the
+// terminating '\0' character).
+bool IsInSet(char ch, const char* str) {
+  return ch != '\0' && strchr(str, ch) != nullptr;
+}
+
+// Returns true if and only if ch belongs to the given classification.
+// Unlike similar functions in <ctype.h>, these aren't affected by the
+// current locale.
+bool IsAsciiDigit(char ch) { return '0' <= ch && ch <= '9'; }
+bool IsAsciiPunct(char ch) {
+  return IsInSet(ch, "^-!\"#$%&'()*+,./:;<=>?@[\\]_`{|}~");
+}
+bool IsRepeat(char ch) { return IsInSet(ch, "?*+"); }
+bool IsAsciiWhiteSpace(char ch) { return IsInSet(ch, " \f\n\r\t\v"); }
+bool IsAsciiWordChar(char ch) {
+  return ('a' <= ch && ch <= 'z') || ('A' <= ch && ch <= 'Z') ||
+      ('0' <= ch && ch <= '9') || ch == '_';
+}
+
+// Returns true if and only if "\\c" is a supported escape sequence.
+bool IsValidEscape(char c) {
+  return (IsAsciiPunct(c) || IsInSet(c, "dDfnrsStvwW"));
+}
+
+// Returns true if and only if the given atom (specified by escaped and
+// pattern) matches ch.  The result is undefined if the atom is invalid.
+bool AtomMatchesChar(bool escaped, char pattern_char, char ch) {
+  if (escaped) {  // "\\p" where p is pattern_char.
+    switch (pattern_char) {
+      case 'd': return IsAsciiDigit(ch);
+      case 'D': return !IsAsciiDigit(ch);
+      case 'f': return ch == '\f';
+      case 'n': return ch == '\n';
+      case 'r': return ch == '\r';
+      case 's': return IsAsciiWhiteSpace(ch);
+      case 'S': return !IsAsciiWhiteSpace(ch);
+      case 't': return ch == '\t';
+      case 'v': return ch == '\v';
+      case 'w': return IsAsciiWordChar(ch);
+      case 'W': return !IsAsciiWordChar(ch);
+    }
+    return IsAsciiPunct(pattern_char) && pattern_char == ch;
+  }
+
+  return (pattern_char == '.' && ch != '\n') || pattern_char == ch;
+}
+
+// Helper function used by ValidateRegex() to format error messages.
+static std::string FormatRegexSyntaxError(const char* regex, int index) {
+  return (Message() << "Syntax error at index " << index
+          << " in simple regular expression \"" << regex << "\": ").GetString();
+}
+
+// Generates non-fatal failures and returns false if regex is invalid;
+// otherwise returns true.
+bool ValidateRegex(const char* regex) {
+  if (regex == nullptr) {
+    ADD_FAILURE() << "NULL is not a valid simple regular expression.";
+    return false;
+  }
+
+  bool is_valid = true;
+
+  // True if and only if ?, *, or + can follow the previous atom.
+  bool prev_repeatable = false;
+  for (int i = 0; regex[i]; i++) {
+    if (regex[i] == '\\') {  // An escape sequence
+      i++;
+      if (regex[i] == '\0') {
+        ADD_FAILURE() << FormatRegexSyntaxError(regex, i - 1)
+                      << "'\\' cannot appear at the end.";
+        return false;
+      }
+
+      if (!IsValidEscape(regex[i])) {
+        ADD_FAILURE() << FormatRegexSyntaxError(regex, i - 1)
+                      << "invalid escape sequence \"\\" << regex[i] << "\".";
+        is_valid = false;
+      }
+      prev_repeatable = true;
+    } else {  // Not an escape sequence.
+      const char ch = regex[i];
+
+      if (ch == '^' && i > 0) {
+        ADD_FAILURE() << FormatRegexSyntaxError(regex, i)
+                      << "'^' can only appear at the beginning.";
+        is_valid = false;
+      } else if (ch == '$' && regex[i + 1] != '\0') {
+        ADD_FAILURE() << FormatRegexSyntaxError(regex, i)
+                      << "'$' can only appear at the end.";
+        is_valid = false;
+      } else if (IsInSet(ch, "()[]{}|")) {
+        ADD_FAILURE() << FormatRegexSyntaxError(regex, i)
+                      << "'" << ch << "' is unsupported.";
+        is_valid = false;
+      } else if (IsRepeat(ch) && !prev_repeatable) {
+        ADD_FAILURE() << FormatRegexSyntaxError(regex, i)
+                      << "'" << ch << "' can only follow a repeatable token.";
+        is_valid = false;
+      }
+
+      prev_repeatable = !IsInSet(ch, "^$?*+");
+    }
+  }
+
+  return is_valid;
+}
+
+// Matches a repeated regex atom followed by a valid simple regular
+// expression.  The regex atom is defined as c if escaped is false,
+// or \c otherwise.  repeat is the repetition meta character (?, *,
+// or +).  The behavior is undefined if str contains too many
+// characters to be indexable by size_t, in which case the test will
+// probably time out anyway.  We are fine with this limitation as
+// std::string has it too.
+bool MatchRepetitionAndRegexAtHead(
+    bool escaped, char c, char repeat, const char* regex,
+    const char* str) {
+  const size_t min_count = (repeat == '+') ? 1 : 0;
+  const size_t max_count = (repeat == '?') ? 1 :
+      static_cast<size_t>(-1) - 1;
+  // We cannot call numeric_limits::max() as it conflicts with the
+  // max() macro on Windows.
+
+  for (size_t i = 0; i <= max_count; ++i) {
+    // We know that the atom matches each of the first i characters in str.
+    if (i >= min_count && MatchRegexAtHead(regex, str + i)) {
+      // We have enough matches at the head, and the tail matches too.
+      // Since we only care about *whether* the pattern matches str
+      // (as opposed to *how* it matches), there is no need to find a
+      // greedy match.
+      return true;
+    }
+    if (str[i] == '\0' || !AtomMatchesChar(escaped, c, str[i]))
+      return false;
+  }
+  return false;
+}
+
+// Returns true if and only if regex matches a prefix of str. regex must
+// be a valid simple regular expression and not start with "^", or the
+// result is undefined.
+bool MatchRegexAtHead(const char* regex, const char* str) {
+  if (*regex == '\0')  // An empty regex matches a prefix of anything.
+    return true;
+
+  // "$" only matches the end of a string.  Note that regex being
+  // valid guarantees that there's nothing after "$" in it.
+  if (*regex == '$')
+    return *str == '\0';
+
+  // Is the first thing in regex an escape sequence?
+  const bool escaped = *regex == '\\';
+  if (escaped)
+    ++regex;
+  if (IsRepeat(regex[1])) {
+    // MatchRepetitionAndRegexAtHead() calls MatchRegexAtHead(), so
+    // here's an indirect recursion.  It terminates as the regex gets
+    // shorter in each recursion.
+    return MatchRepetitionAndRegexAtHead(
+        escaped, regex[0], regex[1], regex + 2, str);
+  } else {
+    // regex isn't empty, isn't "$", and doesn't start with a
+    // repetition.  We match the first atom of regex with the first
+    // character of str and recurse.
+    return (*str != '\0') && AtomMatchesChar(escaped, *regex, *str) &&
+        MatchRegexAtHead(regex + 1, str + 1);
+  }
+}
+
+// Returns true if and only if regex matches any substring of str.  regex must
+// be a valid simple regular expression, or the result is undefined.
+//
+// The algorithm is recursive, but the recursion depth doesn't exceed
+// the regex length, so we won't need to worry about running out of
+// stack space normally.  In rare cases the time complexity can be
+// exponential with respect to the regex length + the string length,
+// but usually it's must faster (often close to linear).
+bool MatchRegexAnywhere(const char* regex, const char* str) {
+  if (regex == nullptr || str == nullptr) return false;
+
+  if (*regex == '^')
+    return MatchRegexAtHead(regex + 1, str);
+
+  // A successful match can be anywhere in str.
+  do {
+    if (MatchRegexAtHead(regex, str))
+      return true;
+  } while (*str++ != '\0');
+  return false;
+}
+
+// Implements the RE class.
+
+RE::~RE() {
+  free(const_cast<char*>(pattern_));
+  free(const_cast<char*>(full_pattern_));
+}
+
+// Returns true if and only if regular expression re matches the entire str.
+bool RE::FullMatch(const char* str, const RE& re) {
+  return re.is_valid_ && MatchRegexAnywhere(re.full_pattern_, str);
+}
+
+// Returns true if and only if regular expression re matches a substring of
+// str (including str itself).
+bool RE::PartialMatch(const char* str, const RE& re) {
+  return re.is_valid_ && MatchRegexAnywhere(re.pattern_, str);
+}
+
+// Initializes an RE from its string representation.
+void RE::Init(const char* regex) {
+  pattern_ = full_pattern_ = nullptr;
+  if (regex != nullptr) {
+    pattern_ = posix::StrDup(regex);
+  }
+
+  is_valid_ = ValidateRegex(regex);
+  if (!is_valid_) {
+    // No need to calculate the full pattern when the regex is invalid.
+    return;
+  }
+
+  const size_t len = strlen(regex);
+  // Reserves enough bytes to hold the regular expression used for a
+  // full match: we need space to prepend a '^', append a '$', and
+  // terminate the string with '\0'.
+  char* buffer = static_cast<char*>(malloc(len + 3));
+  full_pattern_ = buffer;
+
+  if (*regex != '^')
+    *buffer++ = '^';  // Makes sure full_pattern_ starts with '^'.
+
+  // We don't use snprintf or strncpy, as they trigger a warning when
+  // compiled with VC++ 8.0.
+  memcpy(buffer, regex, len);
+  buffer += len;
+
+  if (len == 0 || regex[len - 1] != '$')
+    *buffer++ = '$';  // Makes sure full_pattern_ ends with '$'.
+
+  *buffer = '\0';
+}
+
+#endif  // GTEST_USES_POSIX_RE
+
+const char kUnknownFile[] = "unknown file";
+
+// Formats a source file path and a line number as they would appear
+// in an error message from the compiler used to compile this code.
+GTEST_API_ ::std::string FormatFileLocation(const char* file, int line) {
+  const std::string file_name(file == nullptr ? kUnknownFile : file);
+
+  if (line < 0) {
+    return file_name + ":";
+  }
+#ifdef _MSC_VER
+  return file_name + "(" + StreamableToString(line) + "):";
+#else
+  return file_name + ":" + StreamableToString(line) + ":";
+#endif  // _MSC_VER
+}
+
+// Formats a file location for compiler-independent XML output.
+// Although this function is not platform dependent, we put it next to
+// FormatFileLocation in order to contrast the two functions.
+// Note that FormatCompilerIndependentFileLocation() does NOT append colon
+// to the file location it produces, unlike FormatFileLocation().
+GTEST_API_ ::std::string FormatCompilerIndependentFileLocation(
+    const char* file, int line) {
+  const std::string file_name(file == nullptr ? kUnknownFile : file);
+
+  if (line < 0)
+    return file_name;
+  else
+    return file_name + ":" + StreamableToString(line);
+}
+
+GTestLog::GTestLog(GTestLogSeverity severity, const char* file, int line)
+    : severity_(severity) {
+  const char* const marker =
+      severity == GTEST_INFO ?    "[  INFO ]" :
+      severity == GTEST_WARNING ? "[WARNING]" :
+      severity == GTEST_ERROR ?   "[ ERROR ]" : "[ FATAL ]";
+  GetStream() << ::std::endl << marker << " "
+              << FormatFileLocation(file, line).c_str() << ": ";
+}
+
+// Flushes the buffers and, if severity is GTEST_FATAL, aborts the program.
+GTestLog::~GTestLog() {
+  GetStream() << ::std::endl;
+  if (severity_ == GTEST_FATAL) {
+    fflush(stderr);
+    posix::Abort();
+  }
+}
+
+// Disable Microsoft deprecation warnings for POSIX functions called from
+// this class (creat, dup, dup2, and close)
+GTEST_DISABLE_MSC_DEPRECATED_PUSH_()
+
+#if GTEST_HAS_STREAM_REDIRECTION
+
+// Object that captures an output stream (stdout/stderr).
+class CapturedStream {
+ public:
+  // The ctor redirects the stream to a temporary file.
+  explicit CapturedStream(int fd) : fd_(fd), uncaptured_fd_(dup(fd)) {
+# if GTEST_OS_WINDOWS
+    char temp_dir_path[MAX_PATH + 1] = { '\0' };  // NOLINT
+    char temp_file_path[MAX_PATH + 1] = { '\0' };  // NOLINT
+
+    ::GetTempPathA(sizeof(temp_dir_path), temp_dir_path);
+    const UINT success = ::GetTempFileNameA(temp_dir_path,
+                                            "gtest_redir",
+                                            0,  // Generate unique file name.
+                                            temp_file_path);
+    GTEST_CHECK_(success != 0)
+        << "Unable to create a temporary file in " << temp_dir_path;
+    const int captured_fd = creat(temp_file_path, _S_IREAD | _S_IWRITE);
+    GTEST_CHECK_(captured_fd != -1) << "Unable to open temporary file "
+                                    << temp_file_path;
+    filename_ = temp_file_path;
+# else
+    // There's no guarantee that a test has write access to the current
+    // directory, so we create the temporary file in the /tmp directory
+    // instead. We use /tmp on most systems, and /sdcard on Android.
+    // That's because Android doesn't have /tmp.
+#  if GTEST_OS_LINUX_ANDROID
+    // Note: Android applications are expected to call the framework's
+    // Context.getExternalStorageDirectory() method through JNI to get
+    // the location of the world-writable SD Card directory. However,
+    // this requires a Context handle, which cannot be retrieved
+    // globally from native code. Doing so also precludes running the
+    // code as part of a regular standalone executable, which doesn't
+    // run in a Dalvik process (e.g. when running it through 'adb shell').
+    //
+    // The location /data/local/tmp is directly accessible from native code.
+    // '/sdcard' and other variants cannot be relied on, as they are not
+    // guaranteed to be mounted, or may have a delay in mounting.
+    char name_template[] = "/data/local/tmp/gtest_captured_stream.XXXXXX";
+#  else
+    char name_template[] = "/tmp/captured_stream.XXXXXX";
+#  endif  // GTEST_OS_LINUX_ANDROID
+    const int captured_fd = mkstemp(name_template);
+    if (captured_fd == -1) {
+      GTEST_LOG_(WARNING)
+          << "Failed to create tmp file " << name_template
+          << " for test; does the test have access to the /tmp directory?";
+    }
+    filename_ = name_template;
+# endif  // GTEST_OS_WINDOWS
+    fflush(nullptr);
+    dup2(captured_fd, fd_);
+    close(captured_fd);
+  }
+
+  ~CapturedStream() {
+    remove(filename_.c_str());
+  }
+
+  std::string GetCapturedString() {
+    if (uncaptured_fd_ != -1) {
+      // Restores the original stream.
+      fflush(nullptr);
+      dup2(uncaptured_fd_, fd_);
+      close(uncaptured_fd_);
+      uncaptured_fd_ = -1;
+    }
+
+    FILE* const file = posix::FOpen(filename_.c_str(), "r");
+    if (file == nullptr) {
+      GTEST_LOG_(FATAL) << "Failed to open tmp file " << filename_
+                        << " for capturing stream.";
+    }
+    const std::string content = ReadEntireFile(file);
+    posix::FClose(file);
+    return content;
+  }
+
+ private:
+  const int fd_;  // A stream to capture.
+  int uncaptured_fd_;
+  // Name of the temporary file holding the stderr output.
+  ::std::string filename_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(CapturedStream);
+};
+
+GTEST_DISABLE_MSC_DEPRECATED_POP_()
+
+static CapturedStream* g_captured_stderr = nullptr;
+static CapturedStream* g_captured_stdout = nullptr;
+
+// Starts capturing an output stream (stdout/stderr).
+static void CaptureStream(int fd, const char* stream_name,
+                          CapturedStream** stream) {
+  if (*stream != nullptr) {
+    GTEST_LOG_(FATAL) << "Only one " << stream_name
+                      << " capturer can exist at a time.";
+  }
+  *stream = new CapturedStream(fd);
+}
+
+// Stops capturing the output stream and returns the captured string.
+static std::string GetCapturedStream(CapturedStream** captured_stream) {
+  const std::string content = (*captured_stream)->GetCapturedString();
+
+  delete *captured_stream;
+  *captured_stream = nullptr;
+
+  return content;
+}
+
+// Starts capturing stdout.
+void CaptureStdout() {
+  CaptureStream(kStdOutFileno, "stdout", &g_captured_stdout);
+}
+
+// Starts capturing stderr.
+void CaptureStderr() {
+  CaptureStream(kStdErrFileno, "stderr", &g_captured_stderr);
+}
+
+// Stops capturing stdout and returns the captured string.
+std::string GetCapturedStdout() {
+  return GetCapturedStream(&g_captured_stdout);
+}
+
+// Stops capturing stderr and returns the captured string.
+std::string GetCapturedStderr() {
+  return GetCapturedStream(&g_captured_stderr);
+}
+
+#endif  // GTEST_HAS_STREAM_REDIRECTION
+
+
+
+
+
+size_t GetFileSize(FILE* file) {
+  fseek(file, 0, SEEK_END);
+  return static_cast<size_t>(ftell(file));
+}
+
+std::string ReadEntireFile(FILE* file) {
+  const size_t file_size = GetFileSize(file);
+  char* const buffer = new char[file_size];
+
+  size_t bytes_last_read = 0;  // # of bytes read in the last fread()
+  size_t bytes_read = 0;       // # of bytes read so far
+
+  fseek(file, 0, SEEK_SET);
+
+  // Keeps reading the file until we cannot read further or the
+  // pre-determined file size is reached.
+  do {
+    bytes_last_read = fread(buffer+bytes_read, 1, file_size-bytes_read, file);
+    bytes_read += bytes_last_read;
+  } while (bytes_last_read > 0 && bytes_read < file_size);
+
+  const std::string content(buffer, bytes_read);
+  delete[] buffer;
+
+  return content;
+}
+
+#if GTEST_HAS_DEATH_TEST
+static const std::vector<std::string>* g_injected_test_argvs =
+    nullptr;  // Owned.
+
+std::vector<std::string> GetInjectableArgvs() {
+  if (g_injected_test_argvs != nullptr) {
+    return *g_injected_test_argvs;
+  }
+  return GetArgvs();
+}
+
+void SetInjectableArgvs(const std::vector<std::string>* new_argvs) {
+  if (g_injected_test_argvs != new_argvs) delete g_injected_test_argvs;
+  g_injected_test_argvs = new_argvs;
+}
+
+void SetInjectableArgvs(const std::vector<std::string>& new_argvs) {
+  SetInjectableArgvs(
+      new std::vector<std::string>(new_argvs.begin(), new_argvs.end()));
+}
+
+void ClearInjectableArgvs() {
+  delete g_injected_test_argvs;
+  g_injected_test_argvs = nullptr;
+}
+#endif  // GTEST_HAS_DEATH_TEST
+
+#if GTEST_OS_WINDOWS_MOBILE
+namespace posix {
+void Abort() {
+  DebugBreak();
+  TerminateProcess(GetCurrentProcess(), 1);
+}
+}  // namespace posix
+#endif  // GTEST_OS_WINDOWS_MOBILE
+
+// Returns the name of the environment variable corresponding to the
+// given flag.  For example, FlagToEnvVar("foo") will return
+// "GTEST_FOO" in the open-source version.
+static std::string FlagToEnvVar(const char* flag) {
+  const std::string full_flag =
+      (Message() << GTEST_FLAG_PREFIX_ << flag).GetString();
+
+  Message env_var;
+  for (size_t i = 0; i != full_flag.length(); i++) {
+    env_var << ToUpper(full_flag.c_str()[i]);
+  }
+
+  return env_var.GetString();
+}
+
+// Parses 'str' for a 32-bit signed integer.  If successful, writes
+// the result to *value and returns true; otherwise leaves *value
+// unchanged and returns false.
+bool ParseInt32(const Message& src_text, const char* str, int32_t* value) {
+  // Parses the environment variable as a decimal integer.
+  char* end = nullptr;
+  const long long_value = strtol(str, &end, 10);  // NOLINT
+
+  // Has strtol() consumed all characters in the string?
+  if (*end != '\0') {
+    // No - an invalid character was encountered.
+    Message msg;
+    msg << "WARNING: " << src_text
+        << " is expected to be a 32-bit integer, but actually"
+        << " has value \"" << str << "\".\n";
+    printf("%s", msg.GetString().c_str());
+    fflush(stdout);
+    return false;
+  }
+
+  // Is the parsed value in the range of an int32_t?
+  const auto result = static_cast<int32_t>(long_value);
+  if (long_value == LONG_MAX || long_value == LONG_MIN ||
+      // The parsed value overflows as a long.  (strtol() returns
+      // LONG_MAX or LONG_MIN when the input overflows.)
+      result != long_value
+      // The parsed value overflows as an int32_t.
+      ) {
+    Message msg;
+    msg << "WARNING: " << src_text
+        << " is expected to be a 32-bit integer, but actually"
+        << " has value " << str << ", which overflows.\n";
+    printf("%s", msg.GetString().c_str());
+    fflush(stdout);
+    return false;
+  }
+
+  *value = result;
+  return true;
+}
+
+// Reads and returns the Boolean environment variable corresponding to
+// the given flag; if it's not set, returns default_value.
+//
+// The value is considered true if and only if it's not "0".
+bool BoolFromGTestEnv(const char* flag, bool default_value) {
+#if defined(GTEST_GET_BOOL_FROM_ENV_)
+  return GTEST_GET_BOOL_FROM_ENV_(flag, default_value);
+#else
+  const std::string env_var = FlagToEnvVar(flag);
+  const char* const string_value = posix::GetEnv(env_var.c_str());
+  return string_value == nullptr ? default_value
+                                 : strcmp(string_value, "0") != 0;
+#endif  // defined(GTEST_GET_BOOL_FROM_ENV_)
+}
+
+// Reads and returns a 32-bit integer stored in the environment
+// variable corresponding to the given flag; if it isn't set or
+// doesn't represent a valid 32-bit integer, returns default_value.
+int32_t Int32FromGTestEnv(const char* flag, int32_t default_value) {
+#if defined(GTEST_GET_INT32_FROM_ENV_)
+  return GTEST_GET_INT32_FROM_ENV_(flag, default_value);
+#else
+  const std::string env_var = FlagToEnvVar(flag);
+  const char* const string_value = posix::GetEnv(env_var.c_str());
+  if (string_value == nullptr) {
+    // The environment variable is not set.
+    return default_value;
+  }
+
+  int32_t result = default_value;
+  if (!ParseInt32(Message() << "Environment variable " << env_var,
+                  string_value, &result)) {
+    printf("The default value %s is used.\n",
+           (Message() << default_value).GetString().c_str());
+    fflush(stdout);
+    return default_value;
+  }
+
+  return result;
+#endif  // defined(GTEST_GET_INT32_FROM_ENV_)
+}
+
+// As a special case for the 'output' flag, if GTEST_OUTPUT is not
+// set, we look for XML_OUTPUT_FILE, which is set by the Bazel build
+// system.  The value of XML_OUTPUT_FILE is a filename without the
+// "xml:" prefix of GTEST_OUTPUT.
+// Note that this is meant to be called at the call site so it does
+// not check that the flag is 'output'
+// In essence this checks an env variable called XML_OUTPUT_FILE
+// and if it is set we prepend "xml:" to its value, if it not set we return ""
+std::string OutputFlagAlsoCheckEnvVar(){
+  std::string default_value_for_output_flag = "";
+  const char* xml_output_file_env = posix::GetEnv("XML_OUTPUT_FILE");
+  if (nullptr != xml_output_file_env) {
+    default_value_for_output_flag = std::string("xml:") + xml_output_file_env;
+  }
+  return default_value_for_output_flag;
+}
+
+// Reads and returns the string environment variable corresponding to
+// the given flag; if it's not set, returns default_value.
+const char* StringFromGTestEnv(const char* flag, const char* default_value) {
+#if defined(GTEST_GET_STRING_FROM_ENV_)
+  return GTEST_GET_STRING_FROM_ENV_(flag, default_value);
+#else
+  const std::string env_var = FlagToEnvVar(flag);
+  const char* const value = posix::GetEnv(env_var.c_str());
+  return value == nullptr ? default_value : value;
+#endif  // defined(GTEST_GET_STRING_FROM_ENV_)
+}
+
+}  // namespace internal
+}  // namespace testing
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Test - The Google C++ Testing and Mocking Framework
+//
+// This file implements a universal value printer that can print a
+// value of any type T:
+//
+//   void ::testing::internal::UniversalPrinter<T>::Print(value, ostream_ptr);
+//
+// It uses the << operator when possible, and prints the bytes in the
+// object otherwise.  A user can override its behavior for a class
+// type Foo by defining either operator<<(::std::ostream&, const Foo&)
+// or void PrintTo(const Foo&, ::std::ostream*) in the namespace that
+// defines Foo.
+
+
+#include <stdio.h>
+
+#include <cctype>
+#include <cstdint>
+#include <cwchar>
+#include <ostream>  // NOLINT
+#include <string>
+#include <type_traits>
+
+
+namespace testing {
+
+namespace {
+
+using ::std::ostream;
+
+// Prints a segment of bytes in the given object.
+GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
+GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
+GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_
+GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
+void PrintByteSegmentInObjectTo(const unsigned char* obj_bytes, size_t start,
+                                size_t count, ostream* os) {
+  char text[5] = "";
+  for (size_t i = 0; i != count; i++) {
+    const size_t j = start + i;
+    if (i != 0) {
+      // Organizes the bytes into groups of 2 for easy parsing by
+      // human.
+      if ((j % 2) == 0)
+        *os << ' ';
+      else
+        *os << '-';
+    }
+    GTEST_SNPRINTF_(text, sizeof(text), "%02X", obj_bytes[j]);
+    *os << text;
+  }
+}
+
+// Prints the bytes in the given value to the given ostream.
+void PrintBytesInObjectToImpl(const unsigned char* obj_bytes, size_t count,
+                              ostream* os) {
+  // Tells the user how big the object is.
+  *os << count << "-byte object <";
+
+  const size_t kThreshold = 132;
+  const size_t kChunkSize = 64;
+  // If the object size is bigger than kThreshold, we'll have to omit
+  // some details by printing only the first and the last kChunkSize
+  // bytes.
+  if (count < kThreshold) {
+    PrintByteSegmentInObjectTo(obj_bytes, 0, count, os);
+  } else {
+    PrintByteSegmentInObjectTo(obj_bytes, 0, kChunkSize, os);
+    *os << " ... ";
+    // Rounds up to 2-byte boundary.
+    const size_t resume_pos = (count - kChunkSize + 1)/2*2;
+    PrintByteSegmentInObjectTo(obj_bytes, resume_pos, count - resume_pos, os);
+  }
+  *os << ">";
+}
+
+// Helpers for widening a character to char32_t. Since the standard does not
+// specify if char / wchar_t is signed or unsigned, it is important to first
+// convert it to the unsigned type of the same width before widening it to
+// char32_t.
+template <typename CharType>
+char32_t ToChar32(CharType in) {
+  return static_cast<char32_t>(
+      static_cast<typename std::make_unsigned<CharType>::type>(in));
+}
+
+}  // namespace
+
+namespace internal {
+
+// Delegates to PrintBytesInObjectToImpl() to print the bytes in the
+// given object.  The delegation simplifies the implementation, which
+// uses the << operator and thus is easier done outside of the
+// ::testing::internal namespace, which contains a << operator that
+// sometimes conflicts with the one in STL.
+void PrintBytesInObjectTo(const unsigned char* obj_bytes, size_t count,
+                          ostream* os) {
+  PrintBytesInObjectToImpl(obj_bytes, count, os);
+}
+
+// Depending on the value of a char (or wchar_t), we print it in one
+// of three formats:
+//   - as is if it's a printable ASCII (e.g. 'a', '2', ' '),
+//   - as a hexadecimal escape sequence (e.g. '\x7F'), or
+//   - as a special escape sequence (e.g. '\r', '\n').
+enum CharFormat {
+  kAsIs,
+  kHexEscape,
+  kSpecialEscape
+};
+
+// Returns true if c is a printable ASCII character.  We test the
+// value of c directly instead of calling isprint(), which is buggy on
+// Windows Mobile.
+inline bool IsPrintableAscii(char32_t c) { return 0x20 <= c && c <= 0x7E; }
+
+// Prints c (of type char, char8_t, char16_t, char32_t, or wchar_t) as a
+// character literal without the quotes, escaping it when necessary; returns how
+// c was formatted.
+template <typename Char>
+static CharFormat PrintAsCharLiteralTo(Char c, ostream* os) {
+  const char32_t u_c = ToChar32(c);
+  switch (u_c) {
+    case L'\0':
+      *os << "\\0";
+      break;
+    case L'\'':
+      *os << "\\'";
+      break;
+    case L'\\':
+      *os << "\\\\";
+      break;
+    case L'\a':
+      *os << "\\a";
+      break;
+    case L'\b':
+      *os << "\\b";
+      break;
+    case L'\f':
+      *os << "\\f";
+      break;
+    case L'\n':
+      *os << "\\n";
+      break;
+    case L'\r':
+      *os << "\\r";
+      break;
+    case L'\t':
+      *os << "\\t";
+      break;
+    case L'\v':
+      *os << "\\v";
+      break;
+    default:
+      if (IsPrintableAscii(u_c)) {
+        *os << static_cast<char>(c);
+        return kAsIs;
+      } else {
+        ostream::fmtflags flags = os->flags();
+        *os << "\\x" << std::hex << std::uppercase << static_cast<int>(u_c);
+        os->flags(flags);
+        return kHexEscape;
+      }
+  }
+  return kSpecialEscape;
+}
+
+// Prints a char32_t c as if it's part of a string literal, escaping it when
+// necessary; returns how c was formatted.
+static CharFormat PrintAsStringLiteralTo(char32_t c, ostream* os) {
+  switch (c) {
+    case L'\'':
+      *os << "'";
+      return kAsIs;
+    case L'"':
+      *os << "\\\"";
+      return kSpecialEscape;
+    default:
+      return PrintAsCharLiteralTo(c, os);
+  }
+}
+
+static const char* GetCharWidthPrefix(char) {
+  return "";
+}
+
+static const char* GetCharWidthPrefix(signed char) {
+  return "";
+}
+
+static const char* GetCharWidthPrefix(unsigned char) {
+  return "";
+}
+
+#ifdef __cpp_char8_t
+static const char* GetCharWidthPrefix(char8_t) {
+  return "u8";
+}
+#endif
+
+static const char* GetCharWidthPrefix(char16_t) {
+  return "u";
+}
+
+static const char* GetCharWidthPrefix(char32_t) {
+  return "U";
+}
+
+static const char* GetCharWidthPrefix(wchar_t) {
+  return "L";
+}
+
+// Prints a char c as if it's part of a string literal, escaping it when
+// necessary; returns how c was formatted.
+static CharFormat PrintAsStringLiteralTo(char c, ostream* os) {
+  return PrintAsStringLiteralTo(ToChar32(c), os);
+}
+
+#ifdef __cpp_char8_t
+static CharFormat PrintAsStringLiteralTo(char8_t c, ostream* os) {
+  return PrintAsStringLiteralTo(ToChar32(c), os);
+}
+#endif
+
+static CharFormat PrintAsStringLiteralTo(char16_t c, ostream* os) {
+  return PrintAsStringLiteralTo(ToChar32(c), os);
+}
+
+static CharFormat PrintAsStringLiteralTo(wchar_t c, ostream* os) {
+  return PrintAsStringLiteralTo(ToChar32(c), os);
+}
+
+// Prints a character c (of type char, char8_t, char16_t, char32_t, or wchar_t)
+// and its code. '\0' is printed as "'\\0'", other unprintable characters are
+// also properly escaped using the standard C++ escape sequence.
+template <typename Char>
+void PrintCharAndCodeTo(Char c, ostream* os) {
+  // First, print c as a literal in the most readable form we can find.
+  *os << GetCharWidthPrefix(c) << "'";
+  const CharFormat format = PrintAsCharLiteralTo(c, os);
+  *os << "'";
+
+  // To aid user debugging, we also print c's code in decimal, unless
+  // it's 0 (in which case c was printed as '\\0', making the code
+  // obvious).
+  if (c == 0)
+    return;
+  *os << " (" << static_cast<int>(c);
+
+  // For more convenience, we print c's code again in hexadecimal,
+  // unless c was already printed in the form '\x##' or the code is in
+  // [1, 9].
+  if (format == kHexEscape || (1 <= c && c <= 9)) {
+    // Do nothing.
+  } else {
+    *os << ", 0x" << String::FormatHexInt(static_cast<int>(c));
+  }
+  *os << ")";
+}
+
+void PrintTo(unsigned char c, ::std::ostream* os) { PrintCharAndCodeTo(c, os); }
+void PrintTo(signed char c, ::std::ostream* os) { PrintCharAndCodeTo(c, os); }
+
+// Prints a wchar_t as a symbol if it is printable or as its internal
+// code otherwise and also as its code.  L'\0' is printed as "L'\\0'".
+void PrintTo(wchar_t wc, ostream* os) { PrintCharAndCodeTo(wc, os); }
+
+// TODO(dcheng): Consider making this delegate to PrintCharAndCodeTo() as well.
+void PrintTo(char32_t c, ::std::ostream* os) {
+  *os << std::hex << "U+" << std::uppercase << std::setfill('0') << std::setw(4)
+      << static_cast<uint32_t>(c);
+}
+
+// Prints the given array of characters to the ostream.  CharType must be either
+// char, char8_t, char16_t, char32_t, or wchar_t.
+// The array starts at begin, the length is len, it may include '\0' characters
+// and may not be NUL-terminated.
+template <typename CharType>
+GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
+GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
+GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_
+GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
+static CharFormat PrintCharsAsStringTo(
+    const CharType* begin, size_t len, ostream* os) {
+  const char* const quote_prefix = GetCharWidthPrefix(*begin);
+  *os << quote_prefix << "\"";
+  bool is_previous_hex = false;
+  CharFormat print_format = kAsIs;
+  for (size_t index = 0; index < len; ++index) {
+    const CharType cur = begin[index];
+    if (is_previous_hex && IsXDigit(cur)) {
+      // Previous character is of '\x..' form and this character can be
+      // interpreted as another hexadecimal digit in its number. Break string to
+      // disambiguate.
+      *os << "\" " << quote_prefix << "\"";
+    }
+    is_previous_hex = PrintAsStringLiteralTo(cur, os) == kHexEscape;
+    // Remember if any characters required hex escaping.
+    if (is_previous_hex) {
+      print_format = kHexEscape;
+    }
+  }
+  *os << "\"";
+  return print_format;
+}
+
+// Prints a (const) char/wchar_t array of 'len' elements, starting at address
+// 'begin'.  CharType must be either char or wchar_t.
+template <typename CharType>
+GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
+GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
+GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_
+GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
+static void UniversalPrintCharArray(
+    const CharType* begin, size_t len, ostream* os) {
+  // The code
+  //   const char kFoo[] = "foo";
+  // generates an array of 4, not 3, elements, with the last one being '\0'.
+  //
+  // Therefore when printing a char array, we don't print the last element if
+  // it's '\0', such that the output matches the string literal as it's
+  // written in the source code.
+  if (len > 0 && begin[len - 1] == '\0') {
+    PrintCharsAsStringTo(begin, len - 1, os);
+    return;
+  }
+
+  // If, however, the last element in the array is not '\0', e.g.
+  //    const char kFoo[] = { 'f', 'o', 'o' };
+  // we must print the entire array.  We also print a message to indicate
+  // that the array is not NUL-terminated.
+  PrintCharsAsStringTo(begin, len, os);
+  *os << " (no terminating NUL)";
+}
+
+// Prints a (const) char array of 'len' elements, starting at address 'begin'.
+void UniversalPrintArray(const char* begin, size_t len, ostream* os) {
+  UniversalPrintCharArray(begin, len, os);
+}
+
+#ifdef __cpp_char8_t
+// Prints a (const) char8_t array of 'len' elements, starting at address
+// 'begin'.
+void UniversalPrintArray(const char8_t* begin, size_t len, ostream* os) {
+  UniversalPrintCharArray(begin, len, os);
+}
+#endif
+
+// Prints a (const) char16_t array of 'len' elements, starting at address
+// 'begin'.
+void UniversalPrintArray(const char16_t* begin, size_t len, ostream* os) {
+  UniversalPrintCharArray(begin, len, os);
+}
+
+// Prints a (const) char32_t array of 'len' elements, starting at address
+// 'begin'.
+void UniversalPrintArray(const char32_t* begin, size_t len, ostream* os) {
+  UniversalPrintCharArray(begin, len, os);
+}
+
+// Prints a (const) wchar_t array of 'len' elements, starting at address
+// 'begin'.
+void UniversalPrintArray(const wchar_t* begin, size_t len, ostream* os) {
+  UniversalPrintCharArray(begin, len, os);
+}
+
+namespace {
+
+// Prints a null-terminated C-style string to the ostream.
+template <typename Char>
+void PrintCStringTo(const Char* s, ostream* os) {
+  if (s == nullptr) {
+    *os << "NULL";
+  } else {
+    *os << ImplicitCast_<const void*>(s) << " pointing to ";
+    PrintCharsAsStringTo(s, std::char_traits<Char>::length(s), os);
+  }
+}
+
+}  // anonymous namespace
+
+void PrintTo(const char* s, ostream* os) { PrintCStringTo(s, os); }
+
+#ifdef __cpp_char8_t
+void PrintTo(const char8_t* s, ostream* os) { PrintCStringTo(s, os); }
+#endif
+
+void PrintTo(const char16_t* s, ostream* os) { PrintCStringTo(s, os); }
+
+void PrintTo(const char32_t* s, ostream* os) { PrintCStringTo(s, os); }
+
+// MSVC compiler can be configured to define whar_t as a typedef
+// of unsigned short. Defining an overload for const wchar_t* in that case
+// would cause pointers to unsigned shorts be printed as wide strings,
+// possibly accessing more memory than intended and causing invalid
+// memory accesses. MSVC defines _NATIVE_WCHAR_T_DEFINED symbol when
+// wchar_t is implemented as a native type.
+#if !defined(_MSC_VER) || defined(_NATIVE_WCHAR_T_DEFINED)
+// Prints the given wide C string to the ostream.
+void PrintTo(const wchar_t* s, ostream* os) { PrintCStringTo(s, os); }
+#endif  // wchar_t is native
+
+namespace {
+
+bool ContainsUnprintableControlCodes(const char* str, size_t length) {
+  const unsigned char *s = reinterpret_cast<const unsigned char *>(str);
+
+  for (size_t i = 0; i < length; i++) {
+    unsigned char ch = *s++;
+    if (std::iscntrl(ch)) {
+        switch (ch) {
+        case '\t':
+        case '\n':
+        case '\r':
+          break;
+        default:
+          return true;
+        }
+      }
+  }
+  return false;
+}
+
+bool IsUTF8TrailByte(unsigned char t) { return 0x80 <= t && t<= 0xbf; }
+
+bool IsValidUTF8(const char* str, size_t length) {
+  const unsigned char *s = reinterpret_cast<const unsigned char *>(str);
+
+  for (size_t i = 0; i < length;) {
+    unsigned char lead = s[i++];
+
+    if (lead <= 0x7f) {
+      continue;  // single-byte character (ASCII) 0..7F
+    }
+    if (lead < 0xc2) {
+      return false;  // trail byte or non-shortest form
+    } else if (lead <= 0xdf && (i + 1) <= length && IsUTF8TrailByte(s[i])) {
+      ++i;  // 2-byte character
+    } else if (0xe0 <= lead && lead <= 0xef && (i + 2) <= length &&
+               IsUTF8TrailByte(s[i]) &&
+               IsUTF8TrailByte(s[i + 1]) &&
+               // check for non-shortest form and surrogate
+               (lead != 0xe0 || s[i] >= 0xa0) &&
+               (lead != 0xed || s[i] < 0xa0)) {
+      i += 2;  // 3-byte character
+    } else if (0xf0 <= lead && lead <= 0xf4 && (i + 3) <= length &&
+               IsUTF8TrailByte(s[i]) &&
+               IsUTF8TrailByte(s[i + 1]) &&
+               IsUTF8TrailByte(s[i + 2]) &&
+               // check for non-shortest form
+               (lead != 0xf0 || s[i] >= 0x90) &&
+               (lead != 0xf4 || s[i] < 0x90)) {
+      i += 3;  // 4-byte character
+    } else {
+      return false;
+    }
+  }
+  return true;
+}
+
+void ConditionalPrintAsText(const char* str, size_t length, ostream* os) {
+  if (!ContainsUnprintableControlCodes(str, length) &&
+      IsValidUTF8(str, length)) {
+    *os << "\n    As Text: \"" << str << "\"";
+  }
+}
+
+}  // anonymous namespace
+
+void PrintStringTo(const ::std::string& s, ostream* os) {
+  if (PrintCharsAsStringTo(s.data(), s.size(), os) == kHexEscape) {
+    if (GTEST_FLAG(print_utf8)) {
+      ConditionalPrintAsText(s.data(), s.size(), os);
+    }
+  }
+}
+
+#ifdef __cpp_char8_t
+void PrintU8StringTo(const ::std::u8string& s, ostream* os) {
+  PrintCharsAsStringTo(s.data(), s.size(), os);
+}
+#endif
+
+void PrintU16StringTo(const ::std::u16string& s, ostream* os) {
+  PrintCharsAsStringTo(s.data(), s.size(), os);
+}
+
+void PrintU32StringTo(const ::std::u32string& s, ostream* os) {
+  PrintCharsAsStringTo(s.data(), s.size(), os);
+}
+
+#if GTEST_HAS_STD_WSTRING
+void PrintWideStringTo(const ::std::wstring& s, ostream* os) {
+  PrintCharsAsStringTo(s.data(), s.size(), os);
+}
+#endif  // GTEST_HAS_STD_WSTRING
+
+}  // namespace internal
+
+}  // namespace testing
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// The Google C++ Testing and Mocking Framework (Google Test)
+
+
+
+namespace testing {
+
+using internal::GetUnitTestImpl;
+
+// Gets the summary of the failure message by omitting the stack trace
+// in it.
+std::string TestPartResult::ExtractSummary(const char* message) {
+  const char* const stack_trace = strstr(message, internal::kStackTraceMarker);
+  return stack_trace == nullptr ? message : std::string(message, stack_trace);
+}
+
+// Prints a TestPartResult object.
+std::ostream& operator<<(std::ostream& os, const TestPartResult& result) {
+  return os << internal::FormatFileLocation(result.file_name(),
+                                            result.line_number())
+            << " "
+            << (result.type() == TestPartResult::kSuccess
+                    ? "Success"
+                    : result.type() == TestPartResult::kSkip
+                          ? "Skipped"
+                          : result.type() == TestPartResult::kFatalFailure
+                                ? "Fatal failure"
+                                : "Non-fatal failure")
+            << ":\n"
+            << result.message() << std::endl;
+}
+
+// Appends a TestPartResult to the array.
+void TestPartResultArray::Append(const TestPartResult& result) {
+  array_.push_back(result);
+}
+
+// Returns the TestPartResult at the given index (0-based).
+const TestPartResult& TestPartResultArray::GetTestPartResult(int index) const {
+  if (index < 0 || index >= size()) {
+    printf("\nInvalid index (%d) into TestPartResultArray.\n", index);
+    internal::posix::Abort();
+  }
+
+  return array_[static_cast<size_t>(index)];
+}
+
+// Returns the number of TestPartResult objects in the array.
+int TestPartResultArray::size() const {
+  return static_cast<int>(array_.size());
+}
+
+namespace internal {
+
+HasNewFatalFailureHelper::HasNewFatalFailureHelper()
+    : has_new_fatal_failure_(false),
+      original_reporter_(GetUnitTestImpl()->
+                         GetTestPartResultReporterForCurrentThread()) {
+  GetUnitTestImpl()->SetTestPartResultReporterForCurrentThread(this);
+}
+
+HasNewFatalFailureHelper::~HasNewFatalFailureHelper() {
+  GetUnitTestImpl()->SetTestPartResultReporterForCurrentThread(
+      original_reporter_);
+}
+
+void HasNewFatalFailureHelper::ReportTestPartResult(
+    const TestPartResult& result) {
+  if (result.fatally_failed())
+    has_new_fatal_failure_ = true;
+  original_reporter_->ReportTestPartResult(result);
+}
+
+}  // namespace internal
+
+}  // namespace testing
+// Copyright 2008 Google Inc.
+// All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+
+
+namespace testing {
+namespace internal {
+
+// Skips to the first non-space char in str. Returns an empty string if str
+// contains only whitespace characters.
+static const char* SkipSpaces(const char* str) {
+  while (IsSpace(*str))
+    str++;
+  return str;
+}
+
+static std::vector<std::string> SplitIntoTestNames(const char* src) {
+  std::vector<std::string> name_vec;
+  src = SkipSpaces(src);
+  for (; src != nullptr; src = SkipComma(src)) {
+    name_vec.push_back(StripTrailingSpaces(GetPrefixUntilComma(src)));
+  }
+  return name_vec;
+}
+
+// Verifies that registered_tests match the test names in
+// registered_tests_; returns registered_tests if successful, or
+// aborts the program otherwise.
+const char* TypedTestSuitePState::VerifyRegisteredTestNames(
+    const char* test_suite_name, const char* file, int line,
+    const char* registered_tests) {
+  RegisterTypeParameterizedTestSuite(test_suite_name, CodeLocation(file, line));
+
+  typedef RegisteredTestsMap::const_iterator RegisteredTestIter;
+  registered_ = true;
+
+  std::vector<std::string> name_vec = SplitIntoTestNames(registered_tests);
+
+  Message errors;
+
+  std::set<std::string> tests;
+  for (std::vector<std::string>::const_iterator name_it = name_vec.begin();
+       name_it != name_vec.end(); ++name_it) {
+    const std::string& name = *name_it;
+    if (tests.count(name) != 0) {
+      errors << "Test " << name << " is listed more than once.\n";
+      continue;
+    }
+
+    if (registered_tests_.count(name) != 0) {
+      tests.insert(name);
+    } else {
+      errors << "No test named " << name
+             << " can be found in this test suite.\n";
+    }
+  }
+
+  for (RegisteredTestIter it = registered_tests_.begin();
+       it != registered_tests_.end();
+       ++it) {
+    if (tests.count(it->first) == 0) {
+      errors << "You forgot to list test " << it->first << ".\n";
+    }
+  }
+
+  const std::string& errors_str = errors.GetString();
+  if (errors_str != "") {
+    fprintf(stderr, "%s %s", FormatFileLocation(file, line).c_str(),
+            errors_str.c_str());
+    fflush(stderr);
+    posix::Abort();
+  }
+
+  return registered_tests;
+}
+
+}  // namespace internal
+}  // namespace testing
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// Google C++ Mocking Framework (Google Mock)
+//
+// This file #includes all Google Mock implementation .cc files.  The
+// purpose is to allow a user to build Google Mock by compiling this
+// file alone.
+
+// This line ensures that gmock.h can be compiled on its own, even
+// when it's fused.
+#include "gmock/gmock.h"
+
+// The following lines pull in the real gmock *.cc files.
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file implements cardinalities.
+
+
+#include <limits.h>
+#include <ostream>  // NOLINT
+#include <sstream>
+#include <string>
+
+namespace testing {
+
+namespace {
+
+// Implements the Between(m, n) cardinality.
+class BetweenCardinalityImpl : public CardinalityInterface {
+ public:
+  BetweenCardinalityImpl(int min, int max)
+      : min_(min >= 0 ? min : 0),
+        max_(max >= min_ ? max : min_) {
+    std::stringstream ss;
+    if (min < 0) {
+      ss << "The invocation lower bound must be >= 0, "
+         << "but is actually " << min << ".";
+      internal::Expect(false, __FILE__, __LINE__, ss.str());
+    } else if (max < 0) {
+      ss << "The invocation upper bound must be >= 0, "
+         << "but is actually " << max << ".";
+      internal::Expect(false, __FILE__, __LINE__, ss.str());
+    } else if (min > max) {
+      ss << "The invocation upper bound (" << max
+         << ") must be >= the invocation lower bound (" << min
+         << ").";
+      internal::Expect(false, __FILE__, __LINE__, ss.str());
+    }
+  }
+
+  // Conservative estimate on the lower/upper bound of the number of
+  // calls allowed.
+  int ConservativeLowerBound() const override { return min_; }
+  int ConservativeUpperBound() const override { return max_; }
+
+  bool IsSatisfiedByCallCount(int call_count) const override {
+    return min_ <= call_count && call_count <= max_;
+  }
+
+  bool IsSaturatedByCallCount(int call_count) const override {
+    return call_count >= max_;
+  }
+
+  void DescribeTo(::std::ostream* os) const override;
+
+ private:
+  const int min_;
+  const int max_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(BetweenCardinalityImpl);
+};
+
+// Formats "n times" in a human-friendly way.
+inline std::string FormatTimes(int n) {
+  if (n == 1) {
+    return "once";
+  } else if (n == 2) {
+    return "twice";
+  } else {
+    std::stringstream ss;
+    ss << n << " times";
+    return ss.str();
+  }
+}
+
+// Describes the Between(m, n) cardinality in human-friendly text.
+void BetweenCardinalityImpl::DescribeTo(::std::ostream* os) const {
+  if (min_ == 0) {
+    if (max_ == 0) {
+      *os << "never called";
+    } else if (max_ == INT_MAX) {
+      *os << "called any number of times";
+    } else {
+      *os << "called at most " << FormatTimes(max_);
+    }
+  } else if (min_ == max_) {
+    *os << "called " << FormatTimes(min_);
+  } else if (max_ == INT_MAX) {
+    *os << "called at least " << FormatTimes(min_);
+  } else {
+    // 0 < min_ < max_ < INT_MAX
+    *os << "called between " << min_ << " and " << max_ << " times";
+  }
+}
+
+}  // Unnamed namespace
+
+// Describes the given call count to an ostream.
+void Cardinality::DescribeActualCallCountTo(int actual_call_count,
+                                            ::std::ostream* os) {
+  if (actual_call_count > 0) {
+    *os << "called " << FormatTimes(actual_call_count);
+  } else {
+    *os << "never called";
+  }
+}
+
+// Creates a cardinality that allows at least n calls.
+GTEST_API_ Cardinality AtLeast(int n) { return Between(n, INT_MAX); }
+
+// Creates a cardinality that allows at most n calls.
+GTEST_API_ Cardinality AtMost(int n) { return Between(0, n); }
+
+// Creates a cardinality that allows any number of calls.
+GTEST_API_ Cardinality AnyNumber() { return AtLeast(0); }
+
+// Creates a cardinality that allows between min and max calls.
+GTEST_API_ Cardinality Between(int min, int max) {
+  return Cardinality(new BetweenCardinalityImpl(min, max));
+}
+
+// Creates a cardinality that allows exactly n calls.
+GTEST_API_ Cardinality Exactly(int n) { return Between(n, n); }
+
+}  // namespace testing
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file defines some utilities useful for implementing Google
+// Mock.  They are subject to change without notice, so please DO NOT
+// USE THEM IN USER CODE.
+
+
+#include <ctype.h>
+#include <ostream>  // NOLINT
+#include <string>
+
+namespace testing {
+namespace internal {
+
+// Joins a vector of strings as if they are fields of a tuple; returns
+// the joined string.
+GTEST_API_ std::string JoinAsTuple(const Strings& fields) {
+  switch (fields.size()) {
+    case 0:
+      return "";
+    case 1:
+      return fields[0];
+    default:
+      std::string result = "(" + fields[0];
+      for (size_t i = 1; i < fields.size(); i++) {
+        result += ", ";
+        result += fields[i];
+      }
+      result += ")";
+      return result;
+  }
+}
+
+// Converts an identifier name to a space-separated list of lower-case
+// words.  Each maximum substring of the form [A-Za-z][a-z]*|\d+ is
+// treated as one word.  For example, both "FooBar123" and
+// "foo_bar_123" are converted to "foo bar 123".
+GTEST_API_ std::string ConvertIdentifierNameToWords(const char* id_name) {
+  std::string result;
+  char prev_char = '\0';
+  for (const char* p = id_name; *p != '\0'; prev_char = *(p++)) {
+    // We don't care about the current locale as the input is
+    // guaranteed to be a valid C++ identifier name.
+    const bool starts_new_word = IsUpper(*p) ||
+        (!IsAlpha(prev_char) && IsLower(*p)) ||
+        (!IsDigit(prev_char) && IsDigit(*p));
+
+    if (IsAlNum(*p)) {
+      if (starts_new_word && result != "")
+        result += ' ';
+      result += ToLower(*p);
+    }
+  }
+  return result;
+}
+
+// This class reports Google Mock failures as Google Test failures.  A
+// user can define another class in a similar fashion if they intend to
+// use Google Mock with a testing framework other than Google Test.
+class GoogleTestFailureReporter : public FailureReporterInterface {
+ public:
+  void ReportFailure(FailureType type, const char* file, int line,
+                     const std::string& message) override {
+    AssertHelper(type == kFatal ?
+                 TestPartResult::kFatalFailure :
+                 TestPartResult::kNonFatalFailure,
+                 file,
+                 line,
+                 message.c_str()) = Message();
+    if (type == kFatal) {
+      posix::Abort();
+    }
+  }
+};
+
+// Returns the global failure reporter.  Will create a
+// GoogleTestFailureReporter and return it the first time called.
+GTEST_API_ FailureReporterInterface* GetFailureReporter() {
+  // Points to the global failure reporter used by Google Mock.  gcc
+  // guarantees that the following use of failure_reporter is
+  // thread-safe.  We may need to add additional synchronization to
+  // protect failure_reporter if we port Google Mock to other
+  // compilers.
+  static FailureReporterInterface* const failure_reporter =
+      new GoogleTestFailureReporter();
+  return failure_reporter;
+}
+
+// Protects global resources (stdout in particular) used by Log().
+static GTEST_DEFINE_STATIC_MUTEX_(g_log_mutex);
+
+// Returns true if and only if a log with the given severity is visible
+// according to the --gmock_verbose flag.
+GTEST_API_ bool LogIsVisible(LogSeverity severity) {
+  if (GMOCK_FLAG(verbose) == kInfoVerbosity) {
+    // Always show the log if --gmock_verbose=info.
+    return true;
+  } else if (GMOCK_FLAG(verbose) == kErrorVerbosity) {
+    // Always hide it if --gmock_verbose=error.
+    return false;
+  } else {
+    // If --gmock_verbose is neither "info" nor "error", we treat it
+    // as "warning" (its default value).
+    return severity == kWarning;
+  }
+}
+
+// Prints the given message to stdout if and only if 'severity' >= the level
+// specified by the --gmock_verbose flag.  If stack_frames_to_skip >=
+// 0, also prints the stack trace excluding the top
+// stack_frames_to_skip frames.  In opt mode, any positive
+// stack_frames_to_skip is treated as 0, since we don't know which
+// function calls will be inlined by the compiler and need to be
+// conservative.
+GTEST_API_ void Log(LogSeverity severity, const std::string& message,
+                    int stack_frames_to_skip) {
+  if (!LogIsVisible(severity))
+    return;
+
+  // Ensures that logs from different threads don't interleave.
+  MutexLock l(&g_log_mutex);
+
+  if (severity == kWarning) {
+    // Prints a GMOCK WARNING marker to make the warnings easily searchable.
+    std::cout << "\nGMOCK WARNING:";
+  }
+  // Pre-pends a new-line to message if it doesn't start with one.
+  if (message.empty() || message[0] != '\n') {
+    std::cout << "\n";
+  }
+  std::cout << message;
+  if (stack_frames_to_skip >= 0) {
+#ifdef NDEBUG
+    // In opt mode, we have to be conservative and skip no stack frame.
+    const int actual_to_skip = 0;
+#else
+    // In dbg mode, we can do what the caller tell us to do (plus one
+    // for skipping this function's stack frame).
+    const int actual_to_skip = stack_frames_to_skip + 1;
+#endif  // NDEBUG
+
+    // Appends a new-line to message if it doesn't end with one.
+    if (!message.empty() && *message.rbegin() != '\n') {
+      std::cout << "\n";
+    }
+    std::cout << "Stack trace:\n"
+         << ::testing::internal::GetCurrentOsStackTraceExceptTop(
+             ::testing::UnitTest::GetInstance(), actual_to_skip);
+  }
+  std::cout << ::std::flush;
+}
+
+GTEST_API_ WithoutMatchers GetWithoutMatchers() { return WithoutMatchers(); }
+
+GTEST_API_ void IllegalDoDefault(const char* file, int line) {
+  internal::Assert(
+      false, file, line,
+      "You are using DoDefault() inside a composite action like "
+      "DoAll() or WithArgs().  This is not supported for technical "
+      "reasons.  Please instead spell out the default action, or "
+      "assign the default action to an Action variable and use "
+      "the variable in various places.");
+}
+
+}  // namespace internal
+}  // namespace testing
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file implements Matcher<const string&>, Matcher<string>, and
+// utilities for defining matchers.
+
+
+#include <string.h>
+#include <iostream>
+#include <sstream>
+#include <string>
+
+namespace testing {
+namespace internal {
+
+// Returns the description for a matcher defined using the MATCHER*()
+// macro where the user-supplied description string is "", if
+// 'negation' is false; otherwise returns the description of the
+// negation of the matcher.  'param_values' contains a list of strings
+// that are the print-out of the matcher's parameters.
+GTEST_API_ std::string FormatMatcherDescription(bool negation,
+                                                const char* matcher_name,
+                                                const Strings& param_values) {
+  std::string result = ConvertIdentifierNameToWords(matcher_name);
+  if (param_values.size() >= 1) result += " " + JoinAsTuple(param_values);
+  return negation ? "not (" + result + ")" : result;
+}
+
+// FindMaxBipartiteMatching and its helper class.
+//
+// Uses the well-known Ford-Fulkerson max flow method to find a maximum
+// bipartite matching. Flow is considered to be from left to right.
+// There is an implicit source node that is connected to all of the left
+// nodes, and an implicit sink node that is connected to all of the
+// right nodes. All edges have unit capacity.
+//
+// Neither the flow graph nor the residual flow graph are represented
+// explicitly. Instead, they are implied by the information in 'graph' and
+// a vector<int> called 'left_' whose elements are initialized to the
+// value kUnused. This represents the initial state of the algorithm,
+// where the flow graph is empty, and the residual flow graph has the
+// following edges:
+//   - An edge from source to each left_ node
+//   - An edge from each right_ node to sink
+//   - An edge from each left_ node to each right_ node, if the
+//     corresponding edge exists in 'graph'.
+//
+// When the TryAugment() method adds a flow, it sets left_[l] = r for some
+// nodes l and r. This induces the following changes:
+//   - The edges (source, l), (l, r), and (r, sink) are added to the
+//     flow graph.
+//   - The same three edges are removed from the residual flow graph.
+//   - The reverse edges (l, source), (r, l), and (sink, r) are added
+//     to the residual flow graph, which is a directional graph
+//     representing unused flow capacity.
+//
+// When the method augments a flow (moving left_[l] from some r1 to some
+// other r2), this can be thought of as "undoing" the above steps with
+// respect to r1 and "redoing" them with respect to r2.
+//
+// It bears repeating that the flow graph and residual flow graph are
+// never represented explicitly, but can be derived by looking at the
+// information in 'graph' and in left_.
+//
+// As an optimization, there is a second vector<int> called right_ which
+// does not provide any new information. Instead, it enables more
+// efficient queries about edges entering or leaving the right-side nodes
+// of the flow or residual flow graphs. The following invariants are
+// maintained:
+//
+// left[l] == kUnused or right[left[l]] == l
+// right[r] == kUnused or left[right[r]] == r
+//
+// . [ source ]                                        .
+// .   |||                                             .
+// .   |||                                             .
+// .   ||\--> left[0]=1  ---\    right[0]=-1 ----\     .
+// .   ||                   |                    |     .
+// .   |\---> left[1]=-1    \--> right[1]=0  ---\|     .
+// .   |                                        ||     .
+// .   \----> left[2]=2  ------> right[2]=2  --\||     .
+// .                                           |||     .
+// .         elements           matchers       vvv     .
+// .                                         [ sink ]  .
+//
+// See Also:
+//   [1] Cormen, et al (2001). "Section 26.2: The Ford-Fulkerson method".
+//       "Introduction to Algorithms (Second ed.)", pp. 651-664.
+//   [2] "Ford-Fulkerson algorithm", Wikipedia,
+//       'http://en.wikipedia.org/wiki/Ford%E2%80%93Fulkerson_algorithm'
+class MaxBipartiteMatchState {
+ public:
+  explicit MaxBipartiteMatchState(const MatchMatrix& graph)
+      : graph_(&graph),
+        left_(graph_->LhsSize(), kUnused),
+        right_(graph_->RhsSize(), kUnused) {}
+
+  // Returns the edges of a maximal match, each in the form {left, right}.
+  ElementMatcherPairs Compute() {
+    // 'seen' is used for path finding { 0: unseen, 1: seen }.
+    ::std::vector<char> seen;
+    // Searches the residual flow graph for a path from each left node to
+    // the sink in the residual flow graph, and if one is found, add flow
+    // to the graph. It's okay to search through the left nodes once. The
+    // edge from the implicit source node to each previously-visited left
+    // node will have flow if that left node has any path to the sink
+    // whatsoever. Subsequent augmentations can only add flow to the
+    // network, and cannot take away that previous flow unit from the source.
+    // Since the source-to-left edge can only carry one flow unit (or,
+    // each element can be matched to only one matcher), there is no need
+    // to visit the left nodes more than once looking for augmented paths.
+    // The flow is known to be possible or impossible by looking at the
+    // node once.
+    for (size_t ilhs = 0; ilhs < graph_->LhsSize(); ++ilhs) {
+      // Reset the path-marking vector and try to find a path from
+      // source to sink starting at the left_[ilhs] node.
+      GTEST_CHECK_(left_[ilhs] == kUnused)
+          << "ilhs: " << ilhs << ", left_[ilhs]: " << left_[ilhs];
+      // 'seen' initialized to 'graph_->RhsSize()' copies of 0.
+      seen.assign(graph_->RhsSize(), 0);
+      TryAugment(ilhs, &seen);
+    }
+    ElementMatcherPairs result;
+    for (size_t ilhs = 0; ilhs < left_.size(); ++ilhs) {
+      size_t irhs = left_[ilhs];
+      if (irhs == kUnused) continue;
+      result.push_back(ElementMatcherPair(ilhs, irhs));
+    }
+    return result;
+  }
+
+ private:
+  static const size_t kUnused = static_cast<size_t>(-1);
+
+  // Perform a depth-first search from left node ilhs to the sink.  If a
+  // path is found, flow is added to the network by linking the left and
+  // right vector elements corresponding each segment of the path.
+  // Returns true if a path to sink was found, which means that a unit of
+  // flow was added to the network. The 'seen' vector elements correspond
+  // to right nodes and are marked to eliminate cycles from the search.
+  //
+  // Left nodes will only be explored at most once because they
+  // are accessible from at most one right node in the residual flow
+  // graph.
+  //
+  // Note that left_[ilhs] is the only element of left_ that TryAugment will
+  // potentially transition from kUnused to another value. Any other
+  // left_ element holding kUnused before TryAugment will be holding it
+  // when TryAugment returns.
+  //
+  bool TryAugment(size_t ilhs, ::std::vector<char>* seen) {
+    for (size_t irhs = 0; irhs < graph_->RhsSize(); ++irhs) {
+      if ((*seen)[irhs]) continue;
+      if (!graph_->HasEdge(ilhs, irhs)) continue;
+      // There's an available edge from ilhs to irhs.
+      (*seen)[irhs] = 1;
+      // Next a search is performed to determine whether
+      // this edge is a dead end or leads to the sink.
+      //
+      // right_[irhs] == kUnused means that there is residual flow from
+      // right node irhs to the sink, so we can use that to finish this
+      // flow path and return success.
+      //
+      // Otherwise there is residual flow to some ilhs. We push flow
+      // along that path and call ourselves recursively to see if this
+      // ultimately leads to sink.
+      if (right_[irhs] == kUnused || TryAugment(right_[irhs], seen)) {
+        // Add flow from left_[ilhs] to right_[irhs].
+        left_[ilhs] = irhs;
+        right_[irhs] = ilhs;
+        return true;
+      }
+    }
+    return false;
+  }
+
+  const MatchMatrix* graph_;  // not owned
+  // Each element of the left_ vector represents a left hand side node
+  // (i.e. an element) and each element of right_ is a right hand side
+  // node (i.e. a matcher). The values in the left_ vector indicate
+  // outflow from that node to a node on the right_ side. The values
+  // in the right_ indicate inflow, and specify which left_ node is
+  // feeding that right_ node, if any. For example, left_[3] == 1 means
+  // there's a flow from element #3 to matcher #1. Such a flow would also
+  // be redundantly represented in the right_ vector as right_[1] == 3.
+  // Elements of left_ and right_ are either kUnused or mutually
+  // referent. Mutually referent means that left_[right_[i]] = i and
+  // right_[left_[i]] = i.
+  ::std::vector<size_t> left_;
+  ::std::vector<size_t> right_;
+};
+
+const size_t MaxBipartiteMatchState::kUnused;
+
+GTEST_API_ ElementMatcherPairs FindMaxBipartiteMatching(const MatchMatrix& g) {
+  return MaxBipartiteMatchState(g).Compute();
+}
+
+static void LogElementMatcherPairVec(const ElementMatcherPairs& pairs,
+                                     ::std::ostream* stream) {
+  typedef ElementMatcherPairs::const_iterator Iter;
+  ::std::ostream& os = *stream;
+  os << "{";
+  const char* sep = "";
+  for (Iter it = pairs.begin(); it != pairs.end(); ++it) {
+    os << sep << "\n  ("
+       << "element #" << it->first << ", "
+       << "matcher #" << it->second << ")";
+    sep = ",";
+  }
+  os << "\n}";
+}
+
+bool MatchMatrix::NextGraph() {
+  for (size_t ilhs = 0; ilhs < LhsSize(); ++ilhs) {
+    for (size_t irhs = 0; irhs < RhsSize(); ++irhs) {
+      char& b = matched_[SpaceIndex(ilhs, irhs)];
+      if (!b) {
+        b = 1;
+        return true;
+      }
+      b = 0;
+    }
+  }
+  return false;
+}
+
+void MatchMatrix::Randomize() {
+  for (size_t ilhs = 0; ilhs < LhsSize(); ++ilhs) {
+    for (size_t irhs = 0; irhs < RhsSize(); ++irhs) {
+      char& b = matched_[SpaceIndex(ilhs, irhs)];
+      b = static_cast<char>(rand() & 1);  // NOLINT
+    }
+  }
+}
+
+std::string MatchMatrix::DebugString() const {
+  ::std::stringstream ss;
+  const char* sep = "";
+  for (size_t i = 0; i < LhsSize(); ++i) {
+    ss << sep;
+    for (size_t j = 0; j < RhsSize(); ++j) {
+      ss << HasEdge(i, j);
+    }
+    sep = ";";
+  }
+  return ss.str();
+}
+
+void UnorderedElementsAreMatcherImplBase::DescribeToImpl(
+    ::std::ostream* os) const {
+  switch (match_flags()) {
+    case UnorderedMatcherRequire::ExactMatch:
+      if (matcher_describers_.empty()) {
+        *os << "is empty";
+        return;
+      }
+      if (matcher_describers_.size() == 1) {
+        *os << "has " << Elements(1) << " and that element ";
+        matcher_describers_[0]->DescribeTo(os);
+        return;
+      }
+      *os << "has " << Elements(matcher_describers_.size())
+          << " and there exists some permutation of elements such that:\n";
+      break;
+    case UnorderedMatcherRequire::Superset:
+      *os << "a surjection from elements to requirements exists such that:\n";
+      break;
+    case UnorderedMatcherRequire::Subset:
+      *os << "an injection from elements to requirements exists such that:\n";
+      break;
+  }
+
+  const char* sep = "";
+  for (size_t i = 0; i != matcher_describers_.size(); ++i) {
+    *os << sep;
+    if (match_flags() == UnorderedMatcherRequire::ExactMatch) {
+      *os << " - element #" << i << " ";
+    } else {
+      *os << " - an element ";
+    }
+    matcher_describers_[i]->DescribeTo(os);
+    if (match_flags() == UnorderedMatcherRequire::ExactMatch) {
+      sep = ", and\n";
+    } else {
+      sep = "\n";
+    }
+  }
+}
+
+void UnorderedElementsAreMatcherImplBase::DescribeNegationToImpl(
+    ::std::ostream* os) const {
+  switch (match_flags()) {
+    case UnorderedMatcherRequire::ExactMatch:
+      if (matcher_describers_.empty()) {
+        *os << "isn't empty";
+        return;
+      }
+      if (matcher_describers_.size() == 1) {
+        *os << "doesn't have " << Elements(1) << ", or has " << Elements(1)
+            << " that ";
+        matcher_describers_[0]->DescribeNegationTo(os);
+        return;
+      }
+      *os << "doesn't have " << Elements(matcher_describers_.size())
+          << ", or there exists no permutation of elements such that:\n";
+      break;
+    case UnorderedMatcherRequire::Superset:
+      *os << "no surjection from elements to requirements exists such that:\n";
+      break;
+    case UnorderedMatcherRequire::Subset:
+      *os << "no injection from elements to requirements exists such that:\n";
+      break;
+  }
+  const char* sep = "";
+  for (size_t i = 0; i != matcher_describers_.size(); ++i) {
+    *os << sep;
+    if (match_flags() == UnorderedMatcherRequire::ExactMatch) {
+      *os << " - element #" << i << " ";
+    } else {
+      *os << " - an element ";
+    }
+    matcher_describers_[i]->DescribeTo(os);
+    if (match_flags() == UnorderedMatcherRequire::ExactMatch) {
+      sep = ", and\n";
+    } else {
+      sep = "\n";
+    }
+  }
+}
+
+// Checks that all matchers match at least one element, and that all
+// elements match at least one matcher. This enables faster matching
+// and better error reporting.
+// Returns false, writing an explanation to 'listener', if and only
+// if the success criteria are not met.
+bool UnorderedElementsAreMatcherImplBase::VerifyMatchMatrix(
+    const ::std::vector<std::string>& element_printouts,
+    const MatchMatrix& matrix, MatchResultListener* listener) const {
+  bool result = true;
+  ::std::vector<char> element_matched(matrix.LhsSize(), 0);
+  ::std::vector<char> matcher_matched(matrix.RhsSize(), 0);
+
+  for (size_t ilhs = 0; ilhs < matrix.LhsSize(); ilhs++) {
+    for (size_t irhs = 0; irhs < matrix.RhsSize(); irhs++) {
+      char matched = matrix.HasEdge(ilhs, irhs);
+      element_matched[ilhs] |= matched;
+      matcher_matched[irhs] |= matched;
+    }
+  }
+
+  if (match_flags() & UnorderedMatcherRequire::Superset) {
+    const char* sep =
+        "where the following matchers don't match any elements:\n";
+    for (size_t mi = 0; mi < matcher_matched.size(); ++mi) {
+      if (matcher_matched[mi]) continue;
+      result = false;
+      if (listener->IsInterested()) {
+        *listener << sep << "matcher #" << mi << ": ";
+        matcher_describers_[mi]->DescribeTo(listener->stream());
+        sep = ",\n";
+      }
+    }
+  }
+
+  if (match_flags() & UnorderedMatcherRequire::Subset) {
+    const char* sep =
+        "where the following elements don't match any matchers:\n";
+    const char* outer_sep = "";
+    if (!result) {
+      outer_sep = "\nand ";
+    }
+    for (size_t ei = 0; ei < element_matched.size(); ++ei) {
+      if (element_matched[ei]) continue;
+      result = false;
+      if (listener->IsInterested()) {
+        *listener << outer_sep << sep << "element #" << ei << ": "
+                  << element_printouts[ei];
+        sep = ",\n";
+        outer_sep = "";
+      }
+    }
+  }
+  return result;
+}
+
+bool UnorderedElementsAreMatcherImplBase::FindPairing(
+    const MatchMatrix& matrix, MatchResultListener* listener) const {
+  ElementMatcherPairs matches = FindMaxBipartiteMatching(matrix);
+
+  size_t max_flow = matches.size();
+  if ((match_flags() & UnorderedMatcherRequire::Superset) &&
+      max_flow < matrix.RhsSize()) {
+    if (listener->IsInterested()) {
+      *listener << "where no permutation of the elements can satisfy all "
+                   "matchers, and the closest match is "
+                << max_flow << " of " << matrix.RhsSize()
+                << " matchers with the pairings:\n";
+      LogElementMatcherPairVec(matches, listener->stream());
+    }
+    return false;
+  }
+  if ((match_flags() & UnorderedMatcherRequire::Subset) &&
+      max_flow < matrix.LhsSize()) {
+    if (listener->IsInterested()) {
+      *listener
+          << "where not all elements can be matched, and the closest match is "
+          << max_flow << " of " << matrix.RhsSize()
+          << " matchers with the pairings:\n";
+      LogElementMatcherPairVec(matches, listener->stream());
+    }
+    return false;
+  }
+
+  if (matches.size() > 1) {
+    if (listener->IsInterested()) {
+      const char* sep = "where:\n";
+      for (size_t mi = 0; mi < matches.size(); ++mi) {
+        *listener << sep << " - element #" << matches[mi].first
+                  << " is matched by matcher #" << matches[mi].second;
+        sep = ",\n";
+      }
+    }
+  }
+  return true;
+}
+
+}  // namespace internal
+}  // namespace testing
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file implements the spec builder syntax (ON_CALL and
+// EXPECT_CALL).
+
+
+#include <stdlib.h>
+
+#include <iostream>  // NOLINT
+#include <map>
+#include <memory>
+#include <set>
+#include <string>
+#include <vector>
+
+
+#if GTEST_OS_CYGWIN || GTEST_OS_LINUX || GTEST_OS_MAC
+# include <unistd.h>  // NOLINT
+#endif
+
+// Silence C4800 (C4800: 'int *const ': forcing value
+// to bool 'true' or 'false') for MSVC 15
+#ifdef _MSC_VER
+#if _MSC_VER == 1900
+#  pragma warning(push)
+#  pragma warning(disable:4800)
+#endif
+#endif
+
+namespace testing {
+namespace internal {
+
+// Protects the mock object registry (in class Mock), all function
+// mockers, and all expectations.
+GTEST_API_ GTEST_DEFINE_STATIC_MUTEX_(g_gmock_mutex);
+
+// Logs a message including file and line number information.
+GTEST_API_ void LogWithLocation(testing::internal::LogSeverity severity,
+                                const char* file, int line,
+                                const std::string& message) {
+  ::std::ostringstream s;
+  s << internal::FormatFileLocation(file, line) << " " << message
+    << ::std::endl;
+  Log(severity, s.str(), 0);
+}
+
+// Constructs an ExpectationBase object.
+ExpectationBase::ExpectationBase(const char* a_file, int a_line,
+                                 const std::string& a_source_text)
+    : file_(a_file),
+      line_(a_line),
+      source_text_(a_source_text),
+      cardinality_specified_(false),
+      cardinality_(Exactly(1)),
+      call_count_(0),
+      retired_(false),
+      extra_matcher_specified_(false),
+      repeated_action_specified_(false),
+      retires_on_saturation_(false),
+      last_clause_(kNone),
+      action_count_checked_(false) {}
+
+// Destructs an ExpectationBase object.
+ExpectationBase::~ExpectationBase() {}
+
+// Explicitly specifies the cardinality of this expectation.  Used by
+// the subclasses to implement the .Times() clause.
+void ExpectationBase::SpecifyCardinality(const Cardinality& a_cardinality) {
+  cardinality_specified_ = true;
+  cardinality_ = a_cardinality;
+}
+
+// Retires all pre-requisites of this expectation.
+void ExpectationBase::RetireAllPreRequisites()
+    GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+  if (is_retired()) {
+    // We can take this short-cut as we never retire an expectation
+    // until we have retired all its pre-requisites.
+    return;
+  }
+
+  ::std::vector<ExpectationBase*> expectations(1, this);
+  while (!expectations.empty()) {
+    ExpectationBase* exp = expectations.back();
+    expectations.pop_back();
+
+    for (ExpectationSet::const_iterator it =
+             exp->immediate_prerequisites_.begin();
+         it != exp->immediate_prerequisites_.end(); ++it) {
+      ExpectationBase* next = it->expectation_base().get();
+      if (!next->is_retired()) {
+        next->Retire();
+        expectations.push_back(next);
+      }
+    }
+  }
+}
+
+// Returns true if and only if all pre-requisites of this expectation
+// have been satisfied.
+bool ExpectationBase::AllPrerequisitesAreSatisfied() const
+    GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+  g_gmock_mutex.AssertHeld();
+  ::std::vector<const ExpectationBase*> expectations(1, this);
+  while (!expectations.empty()) {
+    const ExpectationBase* exp = expectations.back();
+    expectations.pop_back();
+
+    for (ExpectationSet::const_iterator it =
+             exp->immediate_prerequisites_.begin();
+         it != exp->immediate_prerequisites_.end(); ++it) {
+      const ExpectationBase* next = it->expectation_base().get();
+      if (!next->IsSatisfied()) return false;
+      expectations.push_back(next);
+    }
+  }
+  return true;
+}
+
+// Adds unsatisfied pre-requisites of this expectation to 'result'.
+void ExpectationBase::FindUnsatisfiedPrerequisites(ExpectationSet* result) const
+    GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+  g_gmock_mutex.AssertHeld();
+  ::std::vector<const ExpectationBase*> expectations(1, this);
+  while (!expectations.empty()) {
+    const ExpectationBase* exp = expectations.back();
+    expectations.pop_back();
+
+    for (ExpectationSet::const_iterator it =
+             exp->immediate_prerequisites_.begin();
+         it != exp->immediate_prerequisites_.end(); ++it) {
+      const ExpectationBase* next = it->expectation_base().get();
+
+      if (next->IsSatisfied()) {
+        // If *it is satisfied and has a call count of 0, some of its
+        // pre-requisites may not be satisfied yet.
+        if (next->call_count_ == 0) {
+          expectations.push_back(next);
+        }
+      } else {
+        // Now that we know next is unsatisfied, we are not so interested
+        // in whether its pre-requisites are satisfied.  Therefore we
+        // don't iterate into it here.
+        *result += *it;
+      }
+    }
+  }
+}
+
+// Describes how many times a function call matching this
+// expectation has occurred.
+void ExpectationBase::DescribeCallCountTo(::std::ostream* os) const
+    GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+  g_gmock_mutex.AssertHeld();
+
+  // Describes how many times the function is expected to be called.
+  *os << "         Expected: to be ";
+  cardinality().DescribeTo(os);
+  *os << "\n           Actual: ";
+  Cardinality::DescribeActualCallCountTo(call_count(), os);
+
+  // Describes the state of the expectation (e.g. is it satisfied?
+  // is it active?).
+  *os << " - " << (IsOverSaturated() ? "over-saturated" :
+                   IsSaturated() ? "saturated" :
+                   IsSatisfied() ? "satisfied" : "unsatisfied")
+      << " and "
+      << (is_retired() ? "retired" : "active");
+}
+
+// Checks the action count (i.e. the number of WillOnce() and
+// WillRepeatedly() clauses) against the cardinality if this hasn't
+// been done before.  Prints a warning if there are too many or too
+// few actions.
+void ExpectationBase::CheckActionCountIfNotDone() const
+    GTEST_LOCK_EXCLUDED_(mutex_) {
+  bool should_check = false;
+  {
+    MutexLock l(&mutex_);
+    if (!action_count_checked_) {
+      action_count_checked_ = true;
+      should_check = true;
+    }
+  }
+
+  if (should_check) {
+    if (!cardinality_specified_) {
+      // The cardinality was inferred - no need to check the action
+      // count against it.
+      return;
+    }
+
+    // The cardinality was explicitly specified.
+    const int action_count = static_cast<int>(untyped_actions_.size());
+    const int upper_bound = cardinality().ConservativeUpperBound();
+    const int lower_bound = cardinality().ConservativeLowerBound();
+    bool too_many;  // True if there are too many actions, or false
+    // if there are too few.
+    if (action_count > upper_bound ||
+        (action_count == upper_bound && repeated_action_specified_)) {
+      too_many = true;
+    } else if (0 < action_count && action_count < lower_bound &&
+               !repeated_action_specified_) {
+      too_many = false;
+    } else {
+      return;
+    }
+
+    ::std::stringstream ss;
+    DescribeLocationTo(&ss);
+    ss << "Too " << (too_many ? "many" : "few")
+       << " actions specified in " << source_text() << "...\n"
+       << "Expected to be ";
+    cardinality().DescribeTo(&ss);
+    ss << ", but has " << (too_many ? "" : "only ")
+       << action_count << " WillOnce()"
+       << (action_count == 1 ? "" : "s");
+    if (repeated_action_specified_) {
+      ss << " and a WillRepeatedly()";
+    }
+    ss << ".";
+    Log(kWarning, ss.str(), -1);  // -1 means "don't print stack trace".
+  }
+}
+
+// Implements the .Times() clause.
+void ExpectationBase::UntypedTimes(const Cardinality& a_cardinality) {
+  if (last_clause_ == kTimes) {
+    ExpectSpecProperty(false,
+                       ".Times() cannot appear "
+                       "more than once in an EXPECT_CALL().");
+  } else {
+    ExpectSpecProperty(last_clause_ < kTimes,
+                       ".Times() cannot appear after "
+                       ".InSequence(), .WillOnce(), .WillRepeatedly(), "
+                       "or .RetiresOnSaturation().");
+  }
+  last_clause_ = kTimes;
+
+  SpecifyCardinality(a_cardinality);
+}
+
+// Points to the implicit sequence introduced by a living InSequence
+// object (if any) in the current thread or NULL.
+GTEST_API_ ThreadLocal<Sequence*> g_gmock_implicit_sequence;
+
+// Reports an uninteresting call (whose description is in msg) in the
+// manner specified by 'reaction'.
+void ReportUninterestingCall(CallReaction reaction, const std::string& msg) {
+  // Include a stack trace only if --gmock_verbose=info is specified.
+  const int stack_frames_to_skip =
+      GMOCK_FLAG(verbose) == kInfoVerbosity ? 3 : -1;
+  switch (reaction) {
+    case kAllow:
+      Log(kInfo, msg, stack_frames_to_skip);
+      break;
+    case kWarn:
+      Log(kWarning,
+          msg +
+              "\nNOTE: You can safely ignore the above warning unless this "
+              "call should not happen.  Do not suppress it by blindly adding "
+              "an EXPECT_CALL() if you don't mean to enforce the call.  "
+              "See "
+              "https://github.com/google/googletest/blob/master/docs/"
+              "gmock_cook_book.md#"
+              "knowing-when-to-expect for details.\n",
+          stack_frames_to_skip);
+      break;
+    default:  // FAIL
+      Expect(false, nullptr, -1, msg);
+  }
+}
+
+UntypedFunctionMockerBase::UntypedFunctionMockerBase()
+    : mock_obj_(nullptr), name_("") {}
+
+UntypedFunctionMockerBase::~UntypedFunctionMockerBase() {}
+
+// Sets the mock object this mock method belongs to, and registers
+// this information in the global mock registry.  Will be called
+// whenever an EXPECT_CALL() or ON_CALL() is executed on this mock
+// method.
+void UntypedFunctionMockerBase::RegisterOwner(const void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+  {
+    MutexLock l(&g_gmock_mutex);
+    mock_obj_ = mock_obj;
+  }
+  Mock::Register(mock_obj, this);
+}
+
+// Sets the mock object this mock method belongs to, and sets the name
+// of the mock function.  Will be called upon each invocation of this
+// mock function.
+void UntypedFunctionMockerBase::SetOwnerAndName(const void* mock_obj,
+                                                const char* name)
+    GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+  // We protect name_ under g_gmock_mutex in case this mock function
+  // is called from two threads concurrently.
+  MutexLock l(&g_gmock_mutex);
+  mock_obj_ = mock_obj;
+  name_ = name;
+}
+
+// Returns the name of the function being mocked.  Must be called
+// after RegisterOwner() or SetOwnerAndName() has been called.
+const void* UntypedFunctionMockerBase::MockObject() const
+    GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+  const void* mock_obj;
+  {
+    // We protect mock_obj_ under g_gmock_mutex in case this mock
+    // function is called from two threads concurrently.
+    MutexLock l(&g_gmock_mutex);
+    Assert(mock_obj_ != nullptr, __FILE__, __LINE__,
+           "MockObject() must not be called before RegisterOwner() or "
+           "SetOwnerAndName() has been called.");
+    mock_obj = mock_obj_;
+  }
+  return mock_obj;
+}
+
+// Returns the name of this mock method.  Must be called after
+// SetOwnerAndName() has been called.
+const char* UntypedFunctionMockerBase::Name() const
+    GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+  const char* name;
+  {
+    // We protect name_ under g_gmock_mutex in case this mock
+    // function is called from two threads concurrently.
+    MutexLock l(&g_gmock_mutex);
+    Assert(name_ != nullptr, __FILE__, __LINE__,
+           "Name() must not be called before SetOwnerAndName() has "
+           "been called.");
+    name = name_;
+  }
+  return name;
+}
+
+// Calculates the result of invoking this mock function with the given
+// arguments, prints it, and returns it.  The caller is responsible
+// for deleting the result.
+UntypedActionResultHolderBase* UntypedFunctionMockerBase::UntypedInvokeWith(
+    void* const untyped_args) GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+  // See the definition of untyped_expectations_ for why access to it
+  // is unprotected here.
+  if (untyped_expectations_.size() == 0) {
+    // No expectation is set on this mock method - we have an
+    // uninteresting call.
+
+    // We must get Google Mock's reaction on uninteresting calls
+    // made on this mock object BEFORE performing the action,
+    // because the action may DELETE the mock object and make the
+    // following expression meaningless.
+    const CallReaction reaction =
+        Mock::GetReactionOnUninterestingCalls(MockObject());
+
+    // True if and only if we need to print this call's arguments and return
+    // value.  This definition must be kept in sync with
+    // the behavior of ReportUninterestingCall().
+    const bool need_to_report_uninteresting_call =
+        // If the user allows this uninteresting call, we print it
+        // only when they want informational messages.
+        reaction == kAllow ? LogIsVisible(kInfo) :
+                           // If the user wants this to be a warning, we print
+                           // it only when they want to see warnings.
+            reaction == kWarn
+                ? LogIsVisible(kWarning)
+                :
+                // Otherwise, the user wants this to be an error, and we
+                // should always print detailed information in the error.
+                true;
+
+    if (!need_to_report_uninteresting_call) {
+      // Perform the action without printing the call information.
+      return this->UntypedPerformDefaultAction(
+          untyped_args, "Function call: " + std::string(Name()));
+    }
+
+    // Warns about the uninteresting call.
+    ::std::stringstream ss;
+    this->UntypedDescribeUninterestingCall(untyped_args, &ss);
+
+    // Calculates the function result.
+    UntypedActionResultHolderBase* const result =
+        this->UntypedPerformDefaultAction(untyped_args, ss.str());
+
+    // Prints the function result.
+    if (result != nullptr) result->PrintAsActionResult(&ss);
+
+    ReportUninterestingCall(reaction, ss.str());
+    return result;
+  }
+
+  bool is_excessive = false;
+  ::std::stringstream ss;
+  ::std::stringstream why;
+  ::std::stringstream loc;
+  const void* untyped_action = nullptr;
+
+  // The UntypedFindMatchingExpectation() function acquires and
+  // releases g_gmock_mutex.
+
+  const ExpectationBase* const untyped_expectation =
+      this->UntypedFindMatchingExpectation(untyped_args, &untyped_action,
+                                           &is_excessive, &ss, &why);
+  const bool found = untyped_expectation != nullptr;
+
+  // True if and only if we need to print the call's arguments
+  // and return value.
+  // This definition must be kept in sync with the uses of Expect()
+  // and Log() in this function.
+  const bool need_to_report_call =
+      !found || is_excessive || LogIsVisible(kInfo);
+  if (!need_to_report_call) {
+    // Perform the action without printing the call information.
+    return untyped_action == nullptr
+               ? this->UntypedPerformDefaultAction(untyped_args, "")
+               : this->UntypedPerformAction(untyped_action, untyped_args);
+  }
+
+  ss << "    Function call: " << Name();
+  this->UntypedPrintArgs(untyped_args, &ss);
+
+  // In case the action deletes a piece of the expectation, we
+  // generate the message beforehand.
+  if (found && !is_excessive) {
+    untyped_expectation->DescribeLocationTo(&loc);
+  }
+
+  UntypedActionResultHolderBase* result = nullptr;
+
+  auto perform_action = [&] {
+    return untyped_action == nullptr
+               ? this->UntypedPerformDefaultAction(untyped_args, ss.str())
+               : this->UntypedPerformAction(untyped_action, untyped_args);
+  };
+  auto handle_failures = [&] {
+    ss << "\n" << why.str();
+
+    if (!found) {
+      // No expectation matches this call - reports a failure.
+      Expect(false, nullptr, -1, ss.str());
+    } else if (is_excessive) {
+      // We had an upper-bound violation and the failure message is in ss.
+      Expect(false, untyped_expectation->file(), untyped_expectation->line(),
+             ss.str());
+    } else {
+      // We had an expected call and the matching expectation is
+      // described in ss.
+      Log(kInfo, loc.str() + ss.str(), 2);
+    }
+  };
+#if GTEST_HAS_EXCEPTIONS
+  try {
+    result = perform_action();
+  } catch (...) {
+    handle_failures();
+    throw;
+  }
+#else
+  result = perform_action();
+#endif
+
+  if (result != nullptr) result->PrintAsActionResult(&ss);
+  handle_failures();
+  return result;
+}
+
+// Returns an Expectation object that references and co-owns exp,
+// which must be an expectation on this mock function.
+Expectation UntypedFunctionMockerBase::GetHandleOf(ExpectationBase* exp) {
+  // See the definition of untyped_expectations_ for why access to it
+  // is unprotected here.
+  for (UntypedExpectations::const_iterator it =
+           untyped_expectations_.begin();
+       it != untyped_expectations_.end(); ++it) {
+    if (it->get() == exp) {
+      return Expectation(*it);
+    }
+  }
+
+  Assert(false, __FILE__, __LINE__, "Cannot find expectation.");
+  return Expectation();
+  // The above statement is just to make the code compile, and will
+  // never be executed.
+}
+
+// Verifies that all expectations on this mock function have been
+// satisfied.  Reports one or more Google Test non-fatal failures
+// and returns false if not.
+bool UntypedFunctionMockerBase::VerifyAndClearExpectationsLocked()
+    GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+  g_gmock_mutex.AssertHeld();
+  bool expectations_met = true;
+  for (UntypedExpectations::const_iterator it =
+           untyped_expectations_.begin();
+       it != untyped_expectations_.end(); ++it) {
+    ExpectationBase* const untyped_expectation = it->get();
+    if (untyped_expectation->IsOverSaturated()) {
+      // There was an upper-bound violation.  Since the error was
+      // already reported when it occurred, there is no need to do
+      // anything here.
+      expectations_met = false;
+    } else if (!untyped_expectation->IsSatisfied()) {
+      expectations_met = false;
+      ::std::stringstream ss;
+      ss  << "Actual function call count doesn't match "
+          << untyped_expectation->source_text() << "...\n";
+      // No need to show the source file location of the expectation
+      // in the description, as the Expect() call that follows already
+      // takes care of it.
+      untyped_expectation->MaybeDescribeExtraMatcherTo(&ss);
+      untyped_expectation->DescribeCallCountTo(&ss);
+      Expect(false, untyped_expectation->file(),
+             untyped_expectation->line(), ss.str());
+    }
+  }
+
+  // Deleting our expectations may trigger other mock objects to be deleted, for
+  // example if an action contains a reference counted smart pointer to that
+  // mock object, and that is the last reference. So if we delete our
+  // expectations within the context of the global mutex we may deadlock when
+  // this method is called again. Instead, make a copy of the set of
+  // expectations to delete, clear our set within the mutex, and then clear the
+  // copied set outside of it.
+  UntypedExpectations expectations_to_delete;
+  untyped_expectations_.swap(expectations_to_delete);
+
+  g_gmock_mutex.Unlock();
+  expectations_to_delete.clear();
+  g_gmock_mutex.Lock();
+
+  return expectations_met;
+}
+
+CallReaction intToCallReaction(int mock_behavior) {
+  if (mock_behavior >= kAllow && mock_behavior <= kFail) {
+    return static_cast<internal::CallReaction>(mock_behavior);
+  }
+  return kWarn;
+}
+
+}  // namespace internal
+
+// Class Mock.
+
+namespace {
+
+typedef std::set<internal::UntypedFunctionMockerBase*> FunctionMockers;
+
+// The current state of a mock object.  Such information is needed for
+// detecting leaked mock objects and explicitly verifying a mock's
+// expectations.
+struct MockObjectState {
+  MockObjectState()
+      : first_used_file(nullptr), first_used_line(-1), leakable(false) {}
+
+  // Where in the source file an ON_CALL or EXPECT_CALL is first
+  // invoked on this mock object.
+  const char* first_used_file;
+  int first_used_line;
+  ::std::string first_used_test_suite;
+  ::std::string first_used_test;
+  bool leakable;  // true if and only if it's OK to leak the object.
+  FunctionMockers function_mockers;  // All registered methods of the object.
+};
+
+// A global registry holding the state of all mock objects that are
+// alive.  A mock object is added to this registry the first time
+// Mock::AllowLeak(), ON_CALL(), or EXPECT_CALL() is called on it.  It
+// is removed from the registry in the mock object's destructor.
+class MockObjectRegistry {
+ public:
+  // Maps a mock object (identified by its address) to its state.
+  typedef std::map<const void*, MockObjectState> StateMap;
+
+  // This destructor will be called when a program exits, after all
+  // tests in it have been run.  By then, there should be no mock
+  // object alive.  Therefore we report any living object as test
+  // failure, unless the user explicitly asked us to ignore it.
+  ~MockObjectRegistry() {
+    if (!GMOCK_FLAG(catch_leaked_mocks))
+      return;
+
+    int leaked_count = 0;
+    for (StateMap::const_iterator it = states_.begin(); it != states_.end();
+         ++it) {
+      if (it->second.leakable)  // The user said it's fine to leak this object.
+        continue;
+
+      // FIXME: Print the type of the leaked object.
+      // This can help the user identify the leaked object.
+      std::cout << "\n";
+      const MockObjectState& state = it->second;
+      std::cout << internal::FormatFileLocation(state.first_used_file,
+                                                state.first_used_line);
+      std::cout << " ERROR: this mock object";
+      if (state.first_used_test != "") {
+        std::cout << " (used in test " << state.first_used_test_suite << "."
+                  << state.first_used_test << ")";
+      }
+      std::cout << " should be deleted but never is. Its address is @"
+           << it->first << ".";
+      leaked_count++;
+    }
+    if (leaked_count > 0) {
+      std::cout << "\nERROR: " << leaked_count << " leaked mock "
+                << (leaked_count == 1 ? "object" : "objects")
+                << " found at program exit. Expectations on a mock object are "
+                   "verified when the object is destructed. Leaking a mock "
+                   "means that its expectations aren't verified, which is "
+                   "usually a test bug. If you really intend to leak a mock, "
+                   "you can suppress this error using "
+                   "testing::Mock::AllowLeak(mock_object), or you may use a "
+                   "fake or stub instead of a mock.\n";
+      std::cout.flush();
+      ::std::cerr.flush();
+      // RUN_ALL_TESTS() has already returned when this destructor is
+      // called.  Therefore we cannot use the normal Google Test
+      // failure reporting mechanism.
+      _exit(1);  // We cannot call exit() as it is not reentrant and
+                 // may already have been called.
+    }
+  }
+
+  StateMap& states() { return states_; }
+
+ private:
+  StateMap states_;
+};
+
+// Protected by g_gmock_mutex.
+MockObjectRegistry g_mock_object_registry;
+
+// Maps a mock object to the reaction Google Mock should have when an
+// uninteresting method is called.  Protected by g_gmock_mutex.
+std::map<const void*, internal::CallReaction> g_uninteresting_call_reaction;
+
+// Sets the reaction Google Mock should have when an uninteresting
+// method of the given mock object is called.
+void SetReactionOnUninterestingCalls(const void* mock_obj,
+                                     internal::CallReaction reaction)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  internal::MutexLock l(&internal::g_gmock_mutex);
+  g_uninteresting_call_reaction[mock_obj] = reaction;
+}
+
+}  // namespace
+
+// Tells Google Mock to allow uninteresting calls on the given mock
+// object.
+void Mock::AllowUninterestingCalls(const void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  SetReactionOnUninterestingCalls(mock_obj, internal::kAllow);
+}
+
+// Tells Google Mock to warn the user about uninteresting calls on the
+// given mock object.
+void Mock::WarnUninterestingCalls(const void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  SetReactionOnUninterestingCalls(mock_obj, internal::kWarn);
+}
+
+// Tells Google Mock to fail uninteresting calls on the given mock
+// object.
+void Mock::FailUninterestingCalls(const void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  SetReactionOnUninterestingCalls(mock_obj, internal::kFail);
+}
+
+// Tells Google Mock the given mock object is being destroyed and its
+// entry in the call-reaction table should be removed.
+void Mock::UnregisterCallReaction(const void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  internal::MutexLock l(&internal::g_gmock_mutex);
+  g_uninteresting_call_reaction.erase(mock_obj);
+}
+
+// Returns the reaction Google Mock will have on uninteresting calls
+// made on the given mock object.
+internal::CallReaction Mock::GetReactionOnUninterestingCalls(
+    const void* mock_obj)
+        GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  internal::MutexLock l(&internal::g_gmock_mutex);
+  return (g_uninteresting_call_reaction.count(mock_obj) == 0) ?
+      internal::intToCallReaction(GMOCK_FLAG(default_mock_behavior)) :
+      g_uninteresting_call_reaction[mock_obj];
+}
+
+// Tells Google Mock to ignore mock_obj when checking for leaked mock
+// objects.
+void Mock::AllowLeak(const void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  internal::MutexLock l(&internal::g_gmock_mutex);
+  g_mock_object_registry.states()[mock_obj].leakable = true;
+}
+
+// Verifies and clears all expectations on the given mock object.  If
+// the expectations aren't satisfied, generates one or more Google
+// Test non-fatal failures and returns false.
+bool Mock::VerifyAndClearExpectations(void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  internal::MutexLock l(&internal::g_gmock_mutex);
+  return VerifyAndClearExpectationsLocked(mock_obj);
+}
+
+// Verifies all expectations on the given mock object and clears its
+// default actions and expectations.  Returns true if and only if the
+// verification was successful.
+bool Mock::VerifyAndClear(void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  internal::MutexLock l(&internal::g_gmock_mutex);
+  ClearDefaultActionsLocked(mock_obj);
+  return VerifyAndClearExpectationsLocked(mock_obj);
+}
+
+// Verifies and clears all expectations on the given mock object.  If
+// the expectations aren't satisfied, generates one or more Google
+// Test non-fatal failures and returns false.
+bool Mock::VerifyAndClearExpectationsLocked(void* mock_obj)
+    GTEST_EXCLUSIVE_LOCK_REQUIRED_(internal::g_gmock_mutex) {
+  internal::g_gmock_mutex.AssertHeld();
+  if (g_mock_object_registry.states().count(mock_obj) == 0) {
+    // No EXPECT_CALL() was set on the given mock object.
+    return true;
+  }
+
+  // Verifies and clears the expectations on each mock method in the
+  // given mock object.
+  bool expectations_met = true;
+  FunctionMockers& mockers =
+      g_mock_object_registry.states()[mock_obj].function_mockers;
+  for (FunctionMockers::const_iterator it = mockers.begin();
+       it != mockers.end(); ++it) {
+    if (!(*it)->VerifyAndClearExpectationsLocked()) {
+      expectations_met = false;
+    }
+  }
+
+  // We don't clear the content of mockers, as they may still be
+  // needed by ClearDefaultActionsLocked().
+  return expectations_met;
+}
+
+bool Mock::IsNaggy(void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  return Mock::GetReactionOnUninterestingCalls(mock_obj) == internal::kWarn;
+}
+bool Mock::IsNice(void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  return Mock::GetReactionOnUninterestingCalls(mock_obj) == internal::kAllow;
+}
+bool Mock::IsStrict(void* mock_obj)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  return Mock::GetReactionOnUninterestingCalls(mock_obj) == internal::kFail;
+}
+
+// Registers a mock object and a mock method it owns.
+void Mock::Register(const void* mock_obj,
+                    internal::UntypedFunctionMockerBase* mocker)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  internal::MutexLock l(&internal::g_gmock_mutex);
+  g_mock_object_registry.states()[mock_obj].function_mockers.insert(mocker);
+}
+
+// Tells Google Mock where in the source code mock_obj is used in an
+// ON_CALL or EXPECT_CALL.  In case mock_obj is leaked, this
+// information helps the user identify which object it is.
+void Mock::RegisterUseByOnCallOrExpectCall(const void* mock_obj,
+                                           const char* file, int line)
+    GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex) {
+  internal::MutexLock l(&internal::g_gmock_mutex);
+  MockObjectState& state = g_mock_object_registry.states()[mock_obj];
+  if (state.first_used_file == nullptr) {
+    state.first_used_file = file;
+    state.first_used_line = line;
+    const TestInfo* const test_info =
+        UnitTest::GetInstance()->current_test_info();
+    if (test_info != nullptr) {
+      state.first_used_test_suite = test_info->test_suite_name();
+      state.first_used_test = test_info->name();
+    }
+  }
+}
+
+// Unregisters a mock method; removes the owning mock object from the
+// registry when the last mock method associated with it has been
+// unregistered.  This is called only in the destructor of
+// FunctionMockerBase.
+void Mock::UnregisterLocked(internal::UntypedFunctionMockerBase* mocker)
+    GTEST_EXCLUSIVE_LOCK_REQUIRED_(internal::g_gmock_mutex) {
+  internal::g_gmock_mutex.AssertHeld();
+  for (MockObjectRegistry::StateMap::iterator it =
+           g_mock_object_registry.states().begin();
+       it != g_mock_object_registry.states().end(); ++it) {
+    FunctionMockers& mockers = it->second.function_mockers;
+    if (mockers.erase(mocker) > 0) {
+      // mocker was in mockers and has been just removed.
+      if (mockers.empty()) {
+        g_mock_object_registry.states().erase(it);
+      }
+      return;
+    }
+  }
+}
+
+// Clears all ON_CALL()s set on the given mock object.
+void Mock::ClearDefaultActionsLocked(void* mock_obj)
+    GTEST_EXCLUSIVE_LOCK_REQUIRED_(internal::g_gmock_mutex) {
+  internal::g_gmock_mutex.AssertHeld();
+
+  if (g_mock_object_registry.states().count(mock_obj) == 0) {
+    // No ON_CALL() was set on the given mock object.
+    return;
+  }
+
+  // Clears the default actions for each mock method in the given mock
+  // object.
+  FunctionMockers& mockers =
+      g_mock_object_registry.states()[mock_obj].function_mockers;
+  for (FunctionMockers::const_iterator it = mockers.begin();
+       it != mockers.end(); ++it) {
+    (*it)->ClearDefaultActionsLocked();
+  }
+
+  // We don't clear the content of mockers, as they may still be
+  // needed by VerifyAndClearExpectationsLocked().
+}
+
+Expectation::Expectation() {}
+
+Expectation::Expectation(
+    const std::shared_ptr<internal::ExpectationBase>& an_expectation_base)
+    : expectation_base_(an_expectation_base) {}
+
+Expectation::~Expectation() {}
+
+// Adds an expectation to a sequence.
+void Sequence::AddExpectation(const Expectation& expectation) const {
+  if (*last_expectation_ != expectation) {
+    if (last_expectation_->expectation_base() != nullptr) {
+      expectation.expectation_base()->immediate_prerequisites_
+          += *last_expectation_;
+    }
+    *last_expectation_ = expectation;
+  }
+}
+
+// Creates the implicit sequence if there isn't one.
+InSequence::InSequence() {
+  if (internal::g_gmock_implicit_sequence.get() == nullptr) {
+    internal::g_gmock_implicit_sequence.set(new Sequence);
+    sequence_created_ = true;
+  } else {
+    sequence_created_ = false;
+  }
+}
+
+// Deletes the implicit sequence if it was created by the constructor
+// of this object.
+InSequence::~InSequence() {
+  if (sequence_created_) {
+    delete internal::g_gmock_implicit_sequence.get();
+    internal::g_gmock_implicit_sequence.set(nullptr);
+  }
+}
+
+}  // namespace testing
+
+#ifdef _MSC_VER
+#if _MSC_VER == 1900
+#  pragma warning(pop)
+#endif
+#endif
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+
+namespace testing {
+
+GMOCK_DEFINE_bool_(catch_leaked_mocks, true,
+                   "true if and only if Google Mock should report leaked "
+                   "mock objects as failures.");
+
+GMOCK_DEFINE_string_(verbose, internal::kWarningVerbosity,
+                     "Controls how verbose Google Mock's output is."
+                     "  Valid values:\n"
+                     "  info    - prints all messages.\n"
+                     "  warning - prints warnings and errors.\n"
+                     "  error   - prints errors only.");
+
+GMOCK_DEFINE_int32_(default_mock_behavior, 1,
+                    "Controls the default behavior of mocks."
+                    "  Valid values:\n"
+                    "  0 - by default, mocks act as NiceMocks.\n"
+                    "  1 - by default, mocks act as NaggyMocks.\n"
+                    "  2 - by default, mocks act as StrictMocks.");
+
+namespace internal {
+
+// Parses a string as a command line flag.  The string should have the
+// format "--gmock_flag=value".  When def_optional is true, the
+// "=value" part can be omitted.
+//
+// Returns the value of the flag, or NULL if the parsing failed.
+static const char* ParseGoogleMockFlagValue(const char* str,
+                                            const char* flag,
+                                            bool def_optional) {
+  // str and flag must not be NULL.
+  if (str == nullptr || flag == nullptr) return nullptr;
+
+  // The flag must start with "--gmock_".
+  const std::string flag_str = std::string("--gmock_") + flag;
+  const size_t flag_len = flag_str.length();
+  if (strncmp(str, flag_str.c_str(), flag_len) != 0) return nullptr;
+
+  // Skips the flag name.
+  const char* flag_end = str + flag_len;
+
+  // When def_optional is true, it's OK to not have a "=value" part.
+  if (def_optional && (flag_end[0] == '\0')) {
+    return flag_end;
+  }
+
+  // If def_optional is true and there are more characters after the
+  // flag name, or if def_optional is false, there must be a '=' after
+  // the flag name.
+  if (flag_end[0] != '=') return nullptr;
+
+  // Returns the string after "=".
+  return flag_end + 1;
+}
+
+// Parses a string for a Google Mock bool flag, in the form of
+// "--gmock_flag=value".
+//
+// On success, stores the value of the flag in *value, and returns
+// true.  On failure, returns false without changing *value.
+static bool ParseGoogleMockBoolFlag(const char* str, const char* flag,
+                                    bool* value) {
+  // Gets the value of the flag as a string.
+  const char* const value_str = ParseGoogleMockFlagValue(str, flag, true);
+
+  // Aborts if the parsing failed.
+  if (value_str == nullptr) return false;
+
+  // Converts the string value to a bool.
+  *value = !(*value_str == '0' || *value_str == 'f' || *value_str == 'F');
+  return true;
+}
+
+// Parses a string for a Google Mock string flag, in the form of
+// "--gmock_flag=value".
+//
+// On success, stores the value of the flag in *value, and returns
+// true.  On failure, returns false without changing *value.
+template <typename String>
+static bool ParseGoogleMockStringFlag(const char* str, const char* flag,
+                                      String* value) {
+  // Gets the value of the flag as a string.
+  const char* const value_str = ParseGoogleMockFlagValue(str, flag, false);
+
+  // Aborts if the parsing failed.
+  if (value_str == nullptr) return false;
+
+  // Sets *value to the value of the flag.
+  *value = value_str;
+  return true;
+}
+
+static bool ParseGoogleMockIntFlag(const char* str, const char* flag,
+                                   int32_t* value) {
+  // Gets the value of the flag as a string.
+  const char* const value_str = ParseGoogleMockFlagValue(str, flag, true);
+
+  // Aborts if the parsing failed.
+  if (value_str == nullptr) return false;
+
+  // Sets *value to the value of the flag.
+  return ParseInt32(Message() << "The value of flag --" << flag,
+                    value_str, value);
+}
+
+// The internal implementation of InitGoogleMock().
+//
+// The type parameter CharType can be instantiated to either char or
+// wchar_t.
+template <typename CharType>
+void InitGoogleMockImpl(int* argc, CharType** argv) {
+  // Makes sure Google Test is initialized.  InitGoogleTest() is
+  // idempotent, so it's fine if the user has already called it.
+  InitGoogleTest(argc, argv);
+  if (*argc <= 0) return;
+
+  for (int i = 1; i != *argc; i++) {
+    const std::string arg_string = StreamableToString(argv[i]);
+    const char* const arg = arg_string.c_str();
+
+    // Do we see a Google Mock flag?
+    if (ParseGoogleMockBoolFlag(arg, "catch_leaked_mocks",
+                                &GMOCK_FLAG(catch_leaked_mocks)) ||
+        ParseGoogleMockStringFlag(arg, "verbose", &GMOCK_FLAG(verbose)) ||
+        ParseGoogleMockIntFlag(arg, "default_mock_behavior",
+                               &GMOCK_FLAG(default_mock_behavior))) {
+      // Yes.  Shift the remainder of the argv list left by one.  Note
+      // that argv has (*argc + 1) elements, the last one always being
+      // NULL.  The following loop moves the trailing NULL element as
+      // well.
+      for (int j = i; j != *argc; j++) {
+        argv[j] = argv[j + 1];
+      }
+
+      // Decrements the argument count.
+      (*argc)--;
+
+      // We also need to decrement the iterator as we just removed
+      // an element.
+      i--;
+    }
+  }
+}
+
+}  // namespace internal
+
+// Initializes Google Mock.  This must be called before running the
+// tests.  In particular, it parses a command line for the flags that
+// Google Mock recognizes.  Whenever a Google Mock flag is seen, it is
+// removed from argv, and *argc is decremented.
+//
+// No value is returned.  Instead, the Google Mock flag variables are
+// updated.
+//
+// Since Google Test is needed for Google Mock to work, this function
+// also initializes Google Test and parses its flags, if that hasn't
+// been done.
+GTEST_API_ void InitGoogleMock(int* argc, char** argv) {
+  internal::InitGoogleMockImpl(argc, argv);
+}
+
+// This overloaded version can be used in Windows programs compiled in
+// UNICODE mode.
+GTEST_API_ void InitGoogleMock(int* argc, wchar_t** argv) {
+  internal::InitGoogleMockImpl(argc, argv);
+}
+
+// This overloaded version can be used on Arduino/embedded platforms where
+// there is no argc/argv.
+GTEST_API_ void InitGoogleMock() {
+  // Since Arduino doesn't have a command line, fake out the argc/argv arguments
+  int argc = 1;
+  const auto arg0 = "dummy";
+  char* argv0 = const_cast<char*>(arg0);
+  char** argv = &argv0;
+
+  internal::InitGoogleMockImpl(&argc, argv);
+}
+
+}  // namespace testing
diff --git a/src/fmt/test/gtest/gmock/gmock.h b/src/fmt/test/gtest/gmock/gmock.h
new file mode 100644
index 000000000..d121f7df2
--- /dev/null
+++ b/src/fmt/test/gtest/gmock/gmock.h
@@ -0,0 +1,11645 @@
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This is the main header file a user should include.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_H_
+
+// This file implements the following syntax:
+//
+//   ON_CALL(mock_object, Method(...))
+//     .With(...) ?
+//     .WillByDefault(...);
+//
+// where With() is optional and WillByDefault() must appear exactly
+// once.
+//
+//   EXPECT_CALL(mock_object, Method(...))
+//     .With(...) ?
+//     .Times(...) ?
+//     .InSequence(...) *
+//     .WillOnce(...) *
+//     .WillRepeatedly(...) ?
+//     .RetiresOnSaturation() ? ;
+//
+// where all clauses are optional and WillOnce() can be repeated.
+
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// The ACTION* family of macros can be used in a namespace scope to
+// define custom actions easily.  The syntax:
+//
+//   ACTION(name) { statements; }
+//
+// will define an action with the given name that executes the
+// statements.  The value returned by the statements will be used as
+// the return value of the action.  Inside the statements, you can
+// refer to the K-th (0-based) argument of the mock function by
+// 'argK', and refer to its type by 'argK_type'.  For example:
+//
+//   ACTION(IncrementArg1) {
+//     arg1_type temp = arg1;
+//     return ++(*temp);
+//   }
+//
+// allows you to write
+//
+//   ...WillOnce(IncrementArg1());
+//
+// You can also refer to the entire argument tuple and its type by
+// 'args' and 'args_type', and refer to the mock function type and its
+// return type by 'function_type' and 'return_type'.
+//
+// Note that you don't need to specify the types of the mock function
+// arguments.  However rest assured that your code is still type-safe:
+// you'll get a compiler error if *arg1 doesn't support the ++
+// operator, or if the type of ++(*arg1) isn't compatible with the
+// mock function's return type, for example.
+//
+// Sometimes you'll want to parameterize the action.   For that you can use
+// another macro:
+//
+//   ACTION_P(name, param_name) { statements; }
+//
+// For example:
+//
+//   ACTION_P(Add, n) { return arg0 + n; }
+//
+// will allow you to write:
+//
+//   ...WillOnce(Add(5));
+//
+// Note that you don't need to provide the type of the parameter
+// either.  If you need to reference the type of a parameter named
+// 'foo', you can write 'foo_type'.  For example, in the body of
+// ACTION_P(Add, n) above, you can write 'n_type' to refer to the type
+// of 'n'.
+//
+// We also provide ACTION_P2, ACTION_P3, ..., up to ACTION_P10 to support
+// multi-parameter actions.
+//
+// For the purpose of typing, you can view
+//
+//   ACTION_Pk(Foo, p1, ..., pk) { ... }
+//
+// as shorthand for
+//
+//   template <typename p1_type, ..., typename pk_type>
+//   FooActionPk<p1_type, ..., pk_type> Foo(p1_type p1, ..., pk_type pk) { ... }
+//
+// In particular, you can provide the template type arguments
+// explicitly when invoking Foo(), as in Foo<long, bool>(5, false);
+// although usually you can rely on the compiler to infer the types
+// for you automatically.  You can assign the result of expression
+// Foo(p1, ..., pk) to a variable of type FooActionPk<p1_type, ...,
+// pk_type>.  This can be useful when composing actions.
+//
+// You can also overload actions with different numbers of parameters:
+//
+//   ACTION_P(Plus, a) { ... }
+//   ACTION_P2(Plus, a, b) { ... }
+//
+// While it's tempting to always use the ACTION* macros when defining
+// a new action, you should also consider implementing ActionInterface
+// or using MakePolymorphicAction() instead, especially if you need to
+// use the action a lot.  While these approaches require more work,
+// they give you more control on the types of the mock function
+// arguments and the action parameters, which in general leads to
+// better compiler error messages that pay off in the long run.  They
+// also allow overloading actions based on parameter types (as opposed
+// to just based on the number of parameters).
+//
+// CAVEAT:
+//
+// ACTION*() can only be used in a namespace scope as templates cannot be
+// declared inside of a local class.
+// Users can, however, define any local functors (e.g. a lambda) that
+// can be used as actions.
+//
+// MORE INFORMATION:
+//
+// To learn more about using these macros, please search for 'ACTION' on
+// https://github.com/google/googletest/blob/master/docs/gmock_cook_book.md
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
+
+#ifndef _WIN32_WCE
+# include <errno.h>
+#endif
+
+#include <algorithm>
+#include <functional>
+#include <memory>
+#include <string>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file defines some utilities useful for implementing Google
+// Mock.  They are subject to change without notice, so please DO NOT
+// USE THEM IN USER CODE.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_INTERNAL_UTILS_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_INTERNAL_UTILS_H_
+
+#include <stdio.h>
+#include <ostream>  // NOLINT
+#include <string>
+#include <type_traits>
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// Low-level types and utilities for porting Google Mock to various
+// platforms.  All macros ending with _ and symbols defined in an
+// internal namespace are subject to change without notice.  Code
+// outside Google Mock MUST NOT USE THEM DIRECTLY.  Macros that don't
+// end with _ are part of Google Mock's public API and can be used by
+// code outside Google Mock.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_PORT_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_PORT_H_
+
+#include <assert.h>
+#include <stdlib.h>
+#include <cstdint>
+#include <iostream>
+
+// Most of the utilities needed for porting Google Mock are also
+// required for Google Test and are defined in gtest-port.h.
+//
+// Note to maintainers: to reduce code duplication, prefer adding
+// portability utilities to Google Test's gtest-port.h instead of
+// here, as Google Mock depends on Google Test.  Only add a utility
+// here if it's truly specific to Google Mock.
+
+#include "gtest/gtest.h"
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Injection point for custom user configurations. See README for details
+//
+// ** Custom implementation starts here **
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_CUSTOM_GMOCK_PORT_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_CUSTOM_GMOCK_PORT_H_
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_CUSTOM_GMOCK_PORT_H_
+
+// For MS Visual C++, check the compiler version. At least VS 2015 is
+// required to compile Google Mock.
+#if defined(_MSC_VER) && _MSC_VER < 1900
+# error "At least Visual C++ 2015 (14.0) is required to compile Google Mock."
+#endif
+
+// Macro for referencing flags.  This is public as we want the user to
+// use this syntax to reference Google Mock flags.
+#define GMOCK_FLAG(name) FLAGS_gmock_##name
+
+#if !defined(GMOCK_DECLARE_bool_)
+
+// Macros for declaring flags.
+# define GMOCK_DECLARE_bool_(name) extern GTEST_API_ bool GMOCK_FLAG(name)
+# define GMOCK_DECLARE_int32_(name) extern GTEST_API_ int32_t GMOCK_FLAG(name)
+# define GMOCK_DECLARE_string_(name) \
+    extern GTEST_API_ ::std::string GMOCK_FLAG(name)
+
+// Macros for defining flags.
+# define GMOCK_DEFINE_bool_(name, default_val, doc) \
+    GTEST_API_ bool GMOCK_FLAG(name) = (default_val)
+# define GMOCK_DEFINE_int32_(name, default_val, doc) \
+    GTEST_API_ int32_t GMOCK_FLAG(name) = (default_val)
+# define GMOCK_DEFINE_string_(name, default_val, doc) \
+    GTEST_API_ ::std::string GMOCK_FLAG(name) = (default_val)
+
+#endif  // !defined(GMOCK_DECLARE_bool_)
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_PORT_H_
+
+namespace testing {
+
+template <typename>
+class Matcher;
+
+namespace internal {
+
+// Silence MSVC C4100 (unreferenced formal parameter) and
+// C4805('==': unsafe mix of type 'const int' and type 'const bool')
+#ifdef _MSC_VER
+# pragma warning(push)
+# pragma warning(disable:4100)
+# pragma warning(disable:4805)
+#endif
+
+// Joins a vector of strings as if they are fields of a tuple; returns
+// the joined string.
+GTEST_API_ std::string JoinAsTuple(const Strings& fields);
+
+// Converts an identifier name to a space-separated list of lower-case
+// words.  Each maximum substring of the form [A-Za-z][a-z]*|\d+ is
+// treated as one word.  For example, both "FooBar123" and
+// "foo_bar_123" are converted to "foo bar 123".
+GTEST_API_ std::string ConvertIdentifierNameToWords(const char* id_name);
+
+// GetRawPointer(p) returns the raw pointer underlying p when p is a
+// smart pointer, or returns p itself when p is already a raw pointer.
+// The following default implementation is for the smart pointer case.
+template <typename Pointer>
+inline const typename Pointer::element_type* GetRawPointer(const Pointer& p) {
+  return p.get();
+}
+// This overloaded version is for the raw pointer case.
+template <typename Element>
+inline Element* GetRawPointer(Element* p) { return p; }
+
+// MSVC treats wchar_t as a native type usually, but treats it as the
+// same as unsigned short when the compiler option /Zc:wchar_t- is
+// specified.  It defines _NATIVE_WCHAR_T_DEFINED symbol when wchar_t
+// is a native type.
+#if defined(_MSC_VER) && !defined(_NATIVE_WCHAR_T_DEFINED)
+// wchar_t is a typedef.
+#else
+# define GMOCK_WCHAR_T_IS_NATIVE_ 1
+#endif
+
+// In what follows, we use the term "kind" to indicate whether a type
+// is bool, an integer type (excluding bool), a floating-point type,
+// or none of them.  This categorization is useful for determining
+// when a matcher argument type can be safely converted to another
+// type in the implementation of SafeMatcherCast.
+enum TypeKind {
+  kBool, kInteger, kFloatingPoint, kOther
+};
+
+// KindOf<T>::value is the kind of type T.
+template <typename T> struct KindOf {
+  enum { value = kOther };  // The default kind.
+};
+
+// This macro declares that the kind of 'type' is 'kind'.
+#define GMOCK_DECLARE_KIND_(type, kind) \
+  template <> struct KindOf<type> { enum { value = kind }; }
+
+GMOCK_DECLARE_KIND_(bool, kBool);
+
+// All standard integer types.
+GMOCK_DECLARE_KIND_(char, kInteger);
+GMOCK_DECLARE_KIND_(signed char, kInteger);
+GMOCK_DECLARE_KIND_(unsigned char, kInteger);
+GMOCK_DECLARE_KIND_(short, kInteger);  // NOLINT
+GMOCK_DECLARE_KIND_(unsigned short, kInteger);  // NOLINT
+GMOCK_DECLARE_KIND_(int, kInteger);
+GMOCK_DECLARE_KIND_(unsigned int, kInteger);
+GMOCK_DECLARE_KIND_(long, kInteger);  // NOLINT
+GMOCK_DECLARE_KIND_(unsigned long, kInteger);  // NOLINT
+GMOCK_DECLARE_KIND_(long long, kInteger);  // NOLINT
+GMOCK_DECLARE_KIND_(unsigned long long, kInteger);  // NOLINT
+
+#if GMOCK_WCHAR_T_IS_NATIVE_
+GMOCK_DECLARE_KIND_(wchar_t, kInteger);
+#endif
+
+// All standard floating-point types.
+GMOCK_DECLARE_KIND_(float, kFloatingPoint);
+GMOCK_DECLARE_KIND_(double, kFloatingPoint);
+GMOCK_DECLARE_KIND_(long double, kFloatingPoint);
+
+#undef GMOCK_DECLARE_KIND_
+
+// Evaluates to the kind of 'type'.
+#define GMOCK_KIND_OF_(type) \
+  static_cast< ::testing::internal::TypeKind>( \
+      ::testing::internal::KindOf<type>::value)
+
+// LosslessArithmeticConvertibleImpl<kFromKind, From, kToKind, To>::value
+// is true if and only if arithmetic type From can be losslessly converted to
+// arithmetic type To.
+//
+// It's the user's responsibility to ensure that both From and To are
+// raw (i.e. has no CV modifier, is not a pointer, and is not a
+// reference) built-in arithmetic types, kFromKind is the kind of
+// From, and kToKind is the kind of To; the value is
+// implementation-defined when the above pre-condition is violated.
+template <TypeKind kFromKind, typename From, TypeKind kToKind, typename To>
+using LosslessArithmeticConvertibleImpl = std::integral_constant<
+    bool,
+    // clang-format off
+      // Converting from bool is always lossless
+      (kFromKind == kBool) ? true
+      // Converting between any other type kinds will be lossy if the type
+      // kinds are not the same.
+    : (kFromKind != kToKind) ? false
+    : (kFromKind == kInteger &&
+       // Converting between integers of different widths is allowed so long
+       // as the conversion does not go from signed to unsigned.
+      (((sizeof(From) < sizeof(To)) &&
+        !(std::is_signed<From>::value && !std::is_signed<To>::value)) ||
+       // Converting between integers of the same width only requires the
+       // two types to have the same signedness.
+       ((sizeof(From) == sizeof(To)) &&
+        (std::is_signed<From>::value == std::is_signed<To>::value)))
+       ) ? true
+      // Floating point conversions are lossless if and only if `To` is at least
+      // as wide as `From`.
+    : (kFromKind == kFloatingPoint && (sizeof(From) <= sizeof(To))) ? true
+    : false
+    // clang-format on
+    >;
+
+// LosslessArithmeticConvertible<From, To>::value is true if and only if
+// arithmetic type From can be losslessly converted to arithmetic type To.
+//
+// It's the user's responsibility to ensure that both From and To are
+// raw (i.e. has no CV modifier, is not a pointer, and is not a
+// reference) built-in arithmetic types; the value is
+// implementation-defined when the above pre-condition is violated.
+template <typename From, typename To>
+using LosslessArithmeticConvertible =
+    LosslessArithmeticConvertibleImpl<GMOCK_KIND_OF_(From), From,
+                                      GMOCK_KIND_OF_(To), To>;
+
+// This interface knows how to report a Google Mock failure (either
+// non-fatal or fatal).
+class FailureReporterInterface {
+ public:
+  // The type of a failure (either non-fatal or fatal).
+  enum FailureType {
+    kNonfatal, kFatal
+  };
+
+  virtual ~FailureReporterInterface() {}
+
+  // Reports a failure that occurred at the given source file location.
+  virtual void ReportFailure(FailureType type, const char* file, int line,
+                             const std::string& message) = 0;
+};
+
+// Returns the failure reporter used by Google Mock.
+GTEST_API_ FailureReporterInterface* GetFailureReporter();
+
+// Asserts that condition is true; aborts the process with the given
+// message if condition is false.  We cannot use LOG(FATAL) or CHECK()
+// as Google Mock might be used to mock the log sink itself.  We
+// inline this function to prevent it from showing up in the stack
+// trace.
+inline void Assert(bool condition, const char* file, int line,
+                   const std::string& msg) {
+  if (!condition) {
+    GetFailureReporter()->ReportFailure(FailureReporterInterface::kFatal,
+                                        file, line, msg);
+  }
+}
+inline void Assert(bool condition, const char* file, int line) {
+  Assert(condition, file, line, "Assertion failed.");
+}
+
+// Verifies that condition is true; generates a non-fatal failure if
+// condition is false.
+inline void Expect(bool condition, const char* file, int line,
+                   const std::string& msg) {
+  if (!condition) {
+    GetFailureReporter()->ReportFailure(FailureReporterInterface::kNonfatal,
+                                        file, line, msg);
+  }
+}
+inline void Expect(bool condition, const char* file, int line) {
+  Expect(condition, file, line, "Expectation failed.");
+}
+
+// Severity level of a log.
+enum LogSeverity {
+  kInfo = 0,
+  kWarning = 1
+};
+
+// Valid values for the --gmock_verbose flag.
+
+// All logs (informational and warnings) are printed.
+const char kInfoVerbosity[] = "info";
+// Only warnings are printed.
+const char kWarningVerbosity[] = "warning";
+// No logs are printed.
+const char kErrorVerbosity[] = "error";
+
+// Returns true if and only if a log with the given severity is visible
+// according to the --gmock_verbose flag.
+GTEST_API_ bool LogIsVisible(LogSeverity severity);
+
+// Prints the given message to stdout if and only if 'severity' >= the level
+// specified by the --gmock_verbose flag.  If stack_frames_to_skip >=
+// 0, also prints the stack trace excluding the top
+// stack_frames_to_skip frames.  In opt mode, any positive
+// stack_frames_to_skip is treated as 0, since we don't know which
+// function calls will be inlined by the compiler and need to be
+// conservative.
+GTEST_API_ void Log(LogSeverity severity, const std::string& message,
+                    int stack_frames_to_skip);
+
+// A marker class that is used to resolve parameterless expectations to the
+// correct overload. This must not be instantiable, to prevent client code from
+// accidentally resolving to the overload; for example:
+//
+//    ON_CALL(mock, Method({}, nullptr))...
+//
+class WithoutMatchers {
+ private:
+  WithoutMatchers() {}
+  friend GTEST_API_ WithoutMatchers GetWithoutMatchers();
+};
+
+// Internal use only: access the singleton instance of WithoutMatchers.
+GTEST_API_ WithoutMatchers GetWithoutMatchers();
+
+// Disable MSVC warnings for infinite recursion, since in this case the
+// the recursion is unreachable.
+#ifdef _MSC_VER
+# pragma warning(push)
+# pragma warning(disable:4717)
+#endif
+
+// Invalid<T>() is usable as an expression of type T, but will terminate
+// the program with an assertion failure if actually run.  This is useful
+// when a value of type T is needed for compilation, but the statement
+// will not really be executed (or we don't care if the statement
+// crashes).
+template <typename T>
+inline T Invalid() {
+  Assert(false, "", -1, "Internal error: attempt to return invalid value");
+  // This statement is unreachable, and would never terminate even if it
+  // could be reached. It is provided only to placate compiler warnings
+  // about missing return statements.
+  return Invalid<T>();
+}
+
+#ifdef _MSC_VER
+# pragma warning(pop)
+#endif
+
+// Given a raw type (i.e. having no top-level reference or const
+// modifier) RawContainer that's either an STL-style container or a
+// native array, class StlContainerView<RawContainer> has the
+// following members:
+//
+//   - type is a type that provides an STL-style container view to
+//     (i.e. implements the STL container concept for) RawContainer;
+//   - const_reference is a type that provides a reference to a const
+//     RawContainer;
+//   - ConstReference(raw_container) returns a const reference to an STL-style
+//     container view to raw_container, which is a RawContainer.
+//   - Copy(raw_container) returns an STL-style container view of a
+//     copy of raw_container, which is a RawContainer.
+//
+// This generic version is used when RawContainer itself is already an
+// STL-style container.
+template <class RawContainer>
+class StlContainerView {
+ public:
+  typedef RawContainer type;
+  typedef const type& const_reference;
+
+  static const_reference ConstReference(const RawContainer& container) {
+    static_assert(!std::is_const<RawContainer>::value,
+                  "RawContainer type must not be const");
+    return container;
+  }
+  static type Copy(const RawContainer& container) { return container; }
+};
+
+// This specialization is used when RawContainer is a native array type.
+template <typename Element, size_t N>
+class StlContainerView<Element[N]> {
+ public:
+  typedef typename std::remove_const<Element>::type RawElement;
+  typedef internal::NativeArray<RawElement> type;
+  // NativeArray<T> can represent a native array either by value or by
+  // reference (selected by a constructor argument), so 'const type'
+  // can be used to reference a const native array.  We cannot
+  // 'typedef const type& const_reference' here, as that would mean
+  // ConstReference() has to return a reference to a local variable.
+  typedef const type const_reference;
+
+  static const_reference ConstReference(const Element (&array)[N]) {
+    static_assert(std::is_same<Element, RawElement>::value,
+                  "Element type must not be const");
+    return type(array, N, RelationToSourceReference());
+  }
+  static type Copy(const Element (&array)[N]) {
+    return type(array, N, RelationToSourceCopy());
+  }
+};
+
+// This specialization is used when RawContainer is a native array
+// represented as a (pointer, size) tuple.
+template <typename ElementPointer, typename Size>
+class StlContainerView< ::std::tuple<ElementPointer, Size> > {
+ public:
+  typedef typename std::remove_const<
+      typename std::pointer_traits<ElementPointer>::element_type>::type
+      RawElement;
+  typedef internal::NativeArray<RawElement> type;
+  typedef const type const_reference;
+
+  static const_reference ConstReference(
+      const ::std::tuple<ElementPointer, Size>& array) {
+    return type(std::get<0>(array), std::get<1>(array),
+                RelationToSourceReference());
+  }
+  static type Copy(const ::std::tuple<ElementPointer, Size>& array) {
+    return type(std::get<0>(array), std::get<1>(array), RelationToSourceCopy());
+  }
+};
+
+// The following specialization prevents the user from instantiating
+// StlContainer with a reference type.
+template <typename T> class StlContainerView<T&>;
+
+// A type transform to remove constness from the first part of a pair.
+// Pairs like that are used as the value_type of associative containers,
+// and this transform produces a similar but assignable pair.
+template <typename T>
+struct RemoveConstFromKey {
+  typedef T type;
+};
+
+// Partially specialized to remove constness from std::pair<const K, V>.
+template <typename K, typename V>
+struct RemoveConstFromKey<std::pair<const K, V> > {
+  typedef std::pair<K, V> type;
+};
+
+// Emit an assertion failure due to incorrect DoDefault() usage. Out-of-lined to
+// reduce code size.
+GTEST_API_ void IllegalDoDefault(const char* file, int line);
+
+template <typename F, typename Tuple, size_t... Idx>
+auto ApplyImpl(F&& f, Tuple&& args, IndexSequence<Idx...>) -> decltype(
+    std::forward<F>(f)(std::get<Idx>(std::forward<Tuple>(args))...)) {
+  return std::forward<F>(f)(std::get<Idx>(std::forward<Tuple>(args))...);
+}
+
+// Apply the function to a tuple of arguments.
+template <typename F, typename Tuple>
+auto Apply(F&& f, Tuple&& args) -> decltype(
+    ApplyImpl(std::forward<F>(f), std::forward<Tuple>(args),
+              MakeIndexSequence<std::tuple_size<
+                  typename std::remove_reference<Tuple>::type>::value>())) {
+  return ApplyImpl(std::forward<F>(f), std::forward<Tuple>(args),
+                   MakeIndexSequence<std::tuple_size<
+                       typename std::remove_reference<Tuple>::type>::value>());
+}
+
+// Template struct Function<F>, where F must be a function type, contains
+// the following typedefs:
+//
+//   Result:               the function's return type.
+//   Arg<N>:               the type of the N-th argument, where N starts with 0.
+//   ArgumentTuple:        the tuple type consisting of all parameters of F.
+//   ArgumentMatcherTuple: the tuple type consisting of Matchers for all
+//                         parameters of F.
+//   MakeResultVoid:       the function type obtained by substituting void
+//                         for the return type of F.
+//   MakeResultIgnoredValue:
+//                         the function type obtained by substituting Something
+//                         for the return type of F.
+template <typename T>
+struct Function;
+
+template <typename R, typename... Args>
+struct Function<R(Args...)> {
+  using Result = R;
+  static constexpr size_t ArgumentCount = sizeof...(Args);
+  template <size_t I>
+  using Arg = ElemFromList<I, Args...>;
+  using ArgumentTuple = std::tuple<Args...>;
+  using ArgumentMatcherTuple = std::tuple<Matcher<Args>...>;
+  using MakeResultVoid = void(Args...);
+  using MakeResultIgnoredValue = IgnoredValue(Args...);
+};
+
+template <typename R, typename... Args>
+constexpr size_t Function<R(Args...)>::ArgumentCount;
+
+#ifdef _MSC_VER
+# pragma warning(pop)
+#endif
+
+}  // namespace internal
+}  // namespace testing
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_INTERNAL_UTILS_H_
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_PP_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_PP_H_
+
+// Expands and concatenates the arguments. Constructed macros reevaluate.
+#define GMOCK_PP_CAT(_1, _2) GMOCK_PP_INTERNAL_CAT(_1, _2)
+
+// Expands and stringifies the only argument.
+#define GMOCK_PP_STRINGIZE(...) GMOCK_PP_INTERNAL_STRINGIZE(__VA_ARGS__)
+
+// Returns empty. Given a variadic number of arguments.
+#define GMOCK_PP_EMPTY(...)
+
+// Returns a comma. Given a variadic number of arguments.
+#define GMOCK_PP_COMMA(...) ,
+
+// Returns the only argument.
+#define GMOCK_PP_IDENTITY(_1) _1
+
+// Evaluates to the number of arguments after expansion.
+//
+//   #define PAIR x, y
+//
+//   GMOCK_PP_NARG() => 1
+//   GMOCK_PP_NARG(x) => 1
+//   GMOCK_PP_NARG(x, y) => 2
+//   GMOCK_PP_NARG(PAIR) => 2
+//
+// Requires: the number of arguments after expansion is at most 15.
+#define GMOCK_PP_NARG(...) \
+  GMOCK_PP_INTERNAL_16TH(  \
+      (__VA_ARGS__, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0))
+
+// Returns 1 if the expansion of arguments has an unprotected comma. Otherwise
+// returns 0. Requires no more than 15 unprotected commas.
+#define GMOCK_PP_HAS_COMMA(...) \
+  GMOCK_PP_INTERNAL_16TH(       \
+      (__VA_ARGS__, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0))
+
+// Returns the first argument.
+#define GMOCK_PP_HEAD(...) GMOCK_PP_INTERNAL_HEAD((__VA_ARGS__, unusedArg))
+
+// Returns the tail. A variadic list of all arguments minus the first. Requires
+// at least one argument.
+#define GMOCK_PP_TAIL(...) GMOCK_PP_INTERNAL_TAIL((__VA_ARGS__))
+
+// Calls CAT(_Macro, NARG(__VA_ARGS__))(__VA_ARGS__)
+#define GMOCK_PP_VARIADIC_CALL(_Macro, ...) \
+  GMOCK_PP_IDENTITY(                        \
+      GMOCK_PP_CAT(_Macro, GMOCK_PP_NARG(__VA_ARGS__))(__VA_ARGS__))
+
+// If the arguments after expansion have no tokens, evaluates to `1`. Otherwise
+// evaluates to `0`.
+//
+// Requires: * the number of arguments after expansion is at most 15.
+//           * If the argument is a macro, it must be able to be called with one
+//             argument.
+//
+// Implementation details:
+//
+// There is one case when it generates a compile error: if the argument is macro
+// that cannot be called with one argument.
+//
+//   #define M(a, b)  // it doesn't matter what it expands to
+//
+//   // Expected: expands to `0`.
+//   // Actual: compile error.
+//   GMOCK_PP_IS_EMPTY(M)
+//
+// There are 4 cases tested:
+//
+// * __VA_ARGS__ possible expansion has no unparen'd commas. Expected 0.
+// * __VA_ARGS__ possible expansion is not enclosed in parenthesis. Expected 0.
+// * __VA_ARGS__ possible expansion is not a macro that ()-evaluates to a comma.
+//   Expected 0
+// * __VA_ARGS__ is empty, or has unparen'd commas, or is enclosed in
+//   parenthesis, or is a macro that ()-evaluates to comma. Expected 1.
+//
+// We trigger detection on '0001', i.e. on empty.
+#define GMOCK_PP_IS_EMPTY(...)                                               \
+  GMOCK_PP_INTERNAL_IS_EMPTY(GMOCK_PP_HAS_COMMA(__VA_ARGS__),                \
+                             GMOCK_PP_HAS_COMMA(GMOCK_PP_COMMA __VA_ARGS__), \
+                             GMOCK_PP_HAS_COMMA(__VA_ARGS__()),              \
+                             GMOCK_PP_HAS_COMMA(GMOCK_PP_COMMA __VA_ARGS__()))
+
+// Evaluates to _Then if _Cond is 1 and _Else if _Cond is 0.
+#define GMOCK_PP_IF(_Cond, _Then, _Else) \
+  GMOCK_PP_CAT(GMOCK_PP_INTERNAL_IF_, _Cond)(_Then, _Else)
+
+// Similar to GMOCK_PP_IF but takes _Then and _Else in parentheses.
+//
+// GMOCK_PP_GENERIC_IF(1, (a, b, c), (d, e, f)) => a, b, c
+// GMOCK_PP_GENERIC_IF(0, (a, b, c), (d, e, f)) => d, e, f
+//
+#define GMOCK_PP_GENERIC_IF(_Cond, _Then, _Else) \
+  GMOCK_PP_REMOVE_PARENS(GMOCK_PP_IF(_Cond, _Then, _Else))
+
+// Evaluates to the number of arguments after expansion. Identifies 'empty' as
+// 0.
+//
+//   #define PAIR x, y
+//
+//   GMOCK_PP_NARG0() => 0
+//   GMOCK_PP_NARG0(x) => 1
+//   GMOCK_PP_NARG0(x, y) => 2
+//   GMOCK_PP_NARG0(PAIR) => 2
+//
+// Requires: * the number of arguments after expansion is at most 15.
+//           * If the argument is a macro, it must be able to be called with one
+//             argument.
+#define GMOCK_PP_NARG0(...) \
+  GMOCK_PP_IF(GMOCK_PP_IS_EMPTY(__VA_ARGS__), 0, GMOCK_PP_NARG(__VA_ARGS__))
+
+// Expands to 1 if the first argument starts with something in parentheses,
+// otherwise to 0.
+#define GMOCK_PP_IS_BEGIN_PARENS(...)                              \
+  GMOCK_PP_HEAD(GMOCK_PP_CAT(GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_R_, \
+                             GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_C __VA_ARGS__))
+
+// Expands to 1 is there is only one argument and it is enclosed in parentheses.
+#define GMOCK_PP_IS_ENCLOSED_PARENS(...)             \
+  GMOCK_PP_IF(GMOCK_PP_IS_BEGIN_PARENS(__VA_ARGS__), \
+              GMOCK_PP_IS_EMPTY(GMOCK_PP_EMPTY __VA_ARGS__), 0)
+
+// Remove the parens, requires GMOCK_PP_IS_ENCLOSED_PARENS(args) => 1.
+#define GMOCK_PP_REMOVE_PARENS(...) GMOCK_PP_INTERNAL_REMOVE_PARENS __VA_ARGS__
+
+// Expands to _Macro(0, _Data, e1) _Macro(1, _Data, e2) ... _Macro(K -1, _Data,
+// eK) as many of GMOCK_INTERNAL_NARG0 _Tuple.
+// Requires: * |_Macro| can be called with 3 arguments.
+//           * |_Tuple| expansion has no more than 15 elements.
+#define GMOCK_PP_FOR_EACH(_Macro, _Data, _Tuple)                        \
+  GMOCK_PP_CAT(GMOCK_PP_INTERNAL_FOR_EACH_IMPL_, GMOCK_PP_NARG0 _Tuple) \
+  (0, _Macro, _Data, _Tuple)
+
+// Expands to _Macro(0, _Data, ) _Macro(1, _Data, ) ... _Macro(K - 1, _Data, )
+// Empty if _K = 0.
+// Requires: * |_Macro| can be called with 3 arguments.
+//           * |_K| literal between 0 and 15
+#define GMOCK_PP_REPEAT(_Macro, _Data, _N)           \
+  GMOCK_PP_CAT(GMOCK_PP_INTERNAL_FOR_EACH_IMPL_, _N) \
+  (0, _Macro, _Data, GMOCK_PP_INTENRAL_EMPTY_TUPLE)
+
+// Increments the argument, requires the argument to be between 0 and 15.
+#define GMOCK_PP_INC(_i) GMOCK_PP_CAT(GMOCK_PP_INTERNAL_INC_, _i)
+
+// Returns comma if _i != 0. Requires _i to be between 0 and 15.
+#define GMOCK_PP_COMMA_IF(_i) GMOCK_PP_CAT(GMOCK_PP_INTERNAL_COMMA_IF_, _i)
+
+// Internal details follow. Do not use any of these symbols outside of this
+// file or we will break your code.
+#define GMOCK_PP_INTENRAL_EMPTY_TUPLE (, , , , , , , , , , , , , , , )
+#define GMOCK_PP_INTERNAL_CAT(_1, _2) _1##_2
+#define GMOCK_PP_INTERNAL_STRINGIZE(...) #__VA_ARGS__
+#define GMOCK_PP_INTERNAL_CAT_5(_1, _2, _3, _4, _5) _1##_2##_3##_4##_5
+#define GMOCK_PP_INTERNAL_IS_EMPTY(_1, _2, _3, _4)                             \
+  GMOCK_PP_HAS_COMMA(GMOCK_PP_INTERNAL_CAT_5(GMOCK_PP_INTERNAL_IS_EMPTY_CASE_, \
+                                             _1, _2, _3, _4))
+#define GMOCK_PP_INTERNAL_IS_EMPTY_CASE_0001 ,
+#define GMOCK_PP_INTERNAL_IF_1(_Then, _Else) _Then
+#define GMOCK_PP_INTERNAL_IF_0(_Then, _Else) _Else
+
+// Because of MSVC treating a token with a comma in it as a single token when
+// passed to another macro, we need to force it to evaluate it as multiple
+// tokens. We do that by using a "IDENTITY(MACRO PARENTHESIZED_ARGS)" macro. We
+// define one per possible macro that relies on this behavior. Note "_Args" must
+// be parenthesized.
+#define GMOCK_PP_INTERNAL_INTERNAL_16TH(_1, _2, _3, _4, _5, _6, _7, _8, _9, \
+                                        _10, _11, _12, _13, _14, _15, _16,  \
+                                        ...)                                \
+  _16
+#define GMOCK_PP_INTERNAL_16TH(_Args) \
+  GMOCK_PP_IDENTITY(GMOCK_PP_INTERNAL_INTERNAL_16TH _Args)
+#define GMOCK_PP_INTERNAL_INTERNAL_HEAD(_1, ...) _1
+#define GMOCK_PP_INTERNAL_HEAD(_Args) \
+  GMOCK_PP_IDENTITY(GMOCK_PP_INTERNAL_INTERNAL_HEAD _Args)
+#define GMOCK_PP_INTERNAL_INTERNAL_TAIL(_1, ...) __VA_ARGS__
+#define GMOCK_PP_INTERNAL_TAIL(_Args) \
+  GMOCK_PP_IDENTITY(GMOCK_PP_INTERNAL_INTERNAL_TAIL _Args)
+
+#define GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_C(...) 1 _
+#define GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_R_1 1,
+#define GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_R_GMOCK_PP_INTERNAL_IBP_IS_VARIADIC_C \
+  0,
+#define GMOCK_PP_INTERNAL_REMOVE_PARENS(...) __VA_ARGS__
+#define GMOCK_PP_INTERNAL_INC_0 1
+#define GMOCK_PP_INTERNAL_INC_1 2
+#define GMOCK_PP_INTERNAL_INC_2 3
+#define GMOCK_PP_INTERNAL_INC_3 4
+#define GMOCK_PP_INTERNAL_INC_4 5
+#define GMOCK_PP_INTERNAL_INC_5 6
+#define GMOCK_PP_INTERNAL_INC_6 7
+#define GMOCK_PP_INTERNAL_INC_7 8
+#define GMOCK_PP_INTERNAL_INC_8 9
+#define GMOCK_PP_INTERNAL_INC_9 10
+#define GMOCK_PP_INTERNAL_INC_10 11
+#define GMOCK_PP_INTERNAL_INC_11 12
+#define GMOCK_PP_INTERNAL_INC_12 13
+#define GMOCK_PP_INTERNAL_INC_13 14
+#define GMOCK_PP_INTERNAL_INC_14 15
+#define GMOCK_PP_INTERNAL_INC_15 16
+#define GMOCK_PP_INTERNAL_COMMA_IF_0
+#define GMOCK_PP_INTERNAL_COMMA_IF_1 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_2 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_3 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_4 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_5 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_6 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_7 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_8 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_9 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_10 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_11 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_12 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_13 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_14 ,
+#define GMOCK_PP_INTERNAL_COMMA_IF_15 ,
+#define GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, _element) \
+  _Macro(_i, _Data, _element)
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_0(_i, _Macro, _Data, _Tuple)
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_1(_i, _Macro, _Data, _Tuple) \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple)
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_2(_i, _Macro, _Data, _Tuple)    \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_1(GMOCK_PP_INC(_i), _Macro, _Data,    \
+                                    (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_3(_i, _Macro, _Data, _Tuple)    \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_2(GMOCK_PP_INC(_i), _Macro, _Data,    \
+                                    (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_4(_i, _Macro, _Data, _Tuple)    \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_3(GMOCK_PP_INC(_i), _Macro, _Data,    \
+                                    (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_5(_i, _Macro, _Data, _Tuple)    \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_4(GMOCK_PP_INC(_i), _Macro, _Data,    \
+                                    (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_6(_i, _Macro, _Data, _Tuple)    \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_5(GMOCK_PP_INC(_i), _Macro, _Data,    \
+                                    (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_7(_i, _Macro, _Data, _Tuple)    \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_6(GMOCK_PP_INC(_i), _Macro, _Data,    \
+                                    (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_8(_i, _Macro, _Data, _Tuple)    \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_7(GMOCK_PP_INC(_i), _Macro, _Data,    \
+                                    (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_9(_i, _Macro, _Data, _Tuple)    \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_8(GMOCK_PP_INC(_i), _Macro, _Data,    \
+                                    (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_10(_i, _Macro, _Data, _Tuple)   \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_9(GMOCK_PP_INC(_i), _Macro, _Data,    \
+                                    (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_11(_i, _Macro, _Data, _Tuple)   \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_10(GMOCK_PP_INC(_i), _Macro, _Data,   \
+                                     (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_12(_i, _Macro, _Data, _Tuple)   \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_11(GMOCK_PP_INC(_i), _Macro, _Data,   \
+                                     (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_13(_i, _Macro, _Data, _Tuple)   \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_12(GMOCK_PP_INC(_i), _Macro, _Data,   \
+                                     (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_14(_i, _Macro, _Data, _Tuple)   \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_13(GMOCK_PP_INC(_i), _Macro, _Data,   \
+                                     (GMOCK_PP_TAIL _Tuple))
+#define GMOCK_PP_INTERNAL_FOR_EACH_IMPL_15(_i, _Macro, _Data, _Tuple)   \
+  GMOCK_PP_INTERNAL_CALL_MACRO(_Macro, _i, _Data, GMOCK_PP_HEAD _Tuple) \
+  GMOCK_PP_INTERNAL_FOR_EACH_IMPL_14(GMOCK_PP_INC(_i), _Macro, _Data,   \
+                                     (GMOCK_PP_TAIL _Tuple))
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_PP_H_
+
+#ifdef _MSC_VER
+# pragma warning(push)
+# pragma warning(disable:4100)
+#endif
+
+namespace testing {
+
+// To implement an action Foo, define:
+//   1. a class FooAction that implements the ActionInterface interface, and
+//   2. a factory function that creates an Action object from a
+//      const FooAction*.
+//
+// The two-level delegation design follows that of Matcher, providing
+// consistency for extension developers.  It also eases ownership
+// management as Action objects can now be copied like plain values.
+
+namespace internal {
+
+// BuiltInDefaultValueGetter<T, true>::Get() returns a
+// default-constructed T value.  BuiltInDefaultValueGetter<T,
+// false>::Get() crashes with an error.
+//
+// This primary template is used when kDefaultConstructible is true.
+template <typename T, bool kDefaultConstructible>
+struct BuiltInDefaultValueGetter {
+  static T Get() { return T(); }
+};
+template <typename T>
+struct BuiltInDefaultValueGetter<T, false> {
+  static T Get() {
+    Assert(false, __FILE__, __LINE__,
+           "Default action undefined for the function return type.");
+    return internal::Invalid<T>();
+    // The above statement will never be reached, but is required in
+    // order for this function to compile.
+  }
+};
+
+// BuiltInDefaultValue<T>::Get() returns the "built-in" default value
+// for type T, which is NULL when T is a raw pointer type, 0 when T is
+// a numeric type, false when T is bool, or "" when T is string or
+// std::string.  In addition, in C++11 and above, it turns a
+// default-constructed T value if T is default constructible.  For any
+// other type T, the built-in default T value is undefined, and the
+// function will abort the process.
+template <typename T>
+class BuiltInDefaultValue {
+ public:
+  // This function returns true if and only if type T has a built-in default
+  // value.
+  static bool Exists() {
+    return ::std::is_default_constructible<T>::value;
+  }
+
+  static T Get() {
+    return BuiltInDefaultValueGetter<
+        T, ::std::is_default_constructible<T>::value>::Get();
+  }
+};
+
+// This partial specialization says that we use the same built-in
+// default value for T and const T.
+template <typename T>
+class BuiltInDefaultValue<const T> {
+ public:
+  static bool Exists() { return BuiltInDefaultValue<T>::Exists(); }
+  static T Get() { return BuiltInDefaultValue<T>::Get(); }
+};
+
+// This partial specialization defines the default values for pointer
+// types.
+template <typename T>
+class BuiltInDefaultValue<T*> {
+ public:
+  static bool Exists() { return true; }
+  static T* Get() { return nullptr; }
+};
+
+// The following specializations define the default values for
+// specific types we care about.
+#define GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(type, value) \
+  template <> \
+  class BuiltInDefaultValue<type> { \
+   public: \
+    static bool Exists() { return true; } \
+    static type Get() { return value; } \
+  }
+
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(void, );  // NOLINT
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(::std::string, "");
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(bool, false);
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned char, '\0');
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed char, '\0');
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(char, '\0');
+
+// There's no need for a default action for signed wchar_t, as that
+// type is the same as wchar_t for gcc, and invalid for MSVC.
+//
+// There's also no need for a default action for unsigned wchar_t, as
+// that type is the same as unsigned int for gcc, and invalid for
+// MSVC.
+#if GMOCK_WCHAR_T_IS_NATIVE_
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(wchar_t, 0U);  // NOLINT
+#endif
+
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned short, 0U);  // NOLINT
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed short, 0);     // NOLINT
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned int, 0U);
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed int, 0);
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long, 0UL);  // NOLINT
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long, 0L);     // NOLINT
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long long, 0);  // NOLINT
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long long, 0);  // NOLINT
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(float, 0);
+GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(double, 0);
+
+#undef GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_
+
+// Simple two-arg form of std::disjunction.
+template <typename P, typename Q>
+using disjunction = typename ::std::conditional<P::value, P, Q>::type;
+
+}  // namespace internal
+
+// When an unexpected function call is encountered, Google Mock will
+// let it return a default value if the user has specified one for its
+// return type, or if the return type has a built-in default value;
+// otherwise Google Mock won't know what value to return and will have
+// to abort the process.
+//
+// The DefaultValue<T> class allows a user to specify the
+// default value for a type T that is both copyable and publicly
+// destructible (i.e. anything that can be used as a function return
+// type).  The usage is:
+//
+//   // Sets the default value for type T to be foo.
+//   DefaultValue<T>::Set(foo);
+template <typename T>
+class DefaultValue {
+ public:
+  // Sets the default value for type T; requires T to be
+  // copy-constructable and have a public destructor.
+  static void Set(T x) {
+    delete producer_;
+    producer_ = new FixedValueProducer(x);
+  }
+
+  // Provides a factory function to be called to generate the default value.
+  // This method can be used even if T is only move-constructible, but it is not
+  // limited to that case.
+  typedef T (*FactoryFunction)();
+  static void SetFactory(FactoryFunction factory) {
+    delete producer_;
+    producer_ = new FactoryValueProducer(factory);
+  }
+
+  // Unsets the default value for type T.
+  static void Clear() {
+    delete producer_;
+    producer_ = nullptr;
+  }
+
+  // Returns true if and only if the user has set the default value for type T.
+  static bool IsSet() { return producer_ != nullptr; }
+
+  // Returns true if T has a default return value set by the user or there
+  // exists a built-in default value.
+  static bool Exists() {
+    return IsSet() || internal::BuiltInDefaultValue<T>::Exists();
+  }
+
+  // Returns the default value for type T if the user has set one;
+  // otherwise returns the built-in default value. Requires that Exists()
+  // is true, which ensures that the return value is well-defined.
+  static T Get() {
+    return producer_ == nullptr ? internal::BuiltInDefaultValue<T>::Get()
+                                : producer_->Produce();
+  }
+
+ private:
+  class ValueProducer {
+   public:
+    virtual ~ValueProducer() {}
+    virtual T Produce() = 0;
+  };
+
+  class FixedValueProducer : public ValueProducer {
+   public:
+    explicit FixedValueProducer(T value) : value_(value) {}
+    T Produce() override { return value_; }
+
+   private:
+    const T value_;
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(FixedValueProducer);
+  };
+
+  class FactoryValueProducer : public ValueProducer {
+   public:
+    explicit FactoryValueProducer(FactoryFunction factory)
+        : factory_(factory) {}
+    T Produce() override { return factory_(); }
+
+   private:
+    const FactoryFunction factory_;
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(FactoryValueProducer);
+  };
+
+  static ValueProducer* producer_;
+};
+
+// This partial specialization allows a user to set default values for
+// reference types.
+template <typename T>
+class DefaultValue<T&> {
+ public:
+  // Sets the default value for type T&.
+  static void Set(T& x) {  // NOLINT
+    address_ = &x;
+  }
+
+  // Unsets the default value for type T&.
+  static void Clear() { address_ = nullptr; }
+
+  // Returns true if and only if the user has set the default value for type T&.
+  static bool IsSet() { return address_ != nullptr; }
+
+  // Returns true if T has a default return value set by the user or there
+  // exists a built-in default value.
+  static bool Exists() {
+    return IsSet() || internal::BuiltInDefaultValue<T&>::Exists();
+  }
+
+  // Returns the default value for type T& if the user has set one;
+  // otherwise returns the built-in default value if there is one;
+  // otherwise aborts the process.
+  static T& Get() {
+    return address_ == nullptr ? internal::BuiltInDefaultValue<T&>::Get()
+                               : *address_;
+  }
+
+ private:
+  static T* address_;
+};
+
+// This specialization allows DefaultValue<void>::Get() to
+// compile.
+template <>
+class DefaultValue<void> {
+ public:
+  static bool Exists() { return true; }
+  static void Get() {}
+};
+
+// Points to the user-set default value for type T.
+template <typename T>
+typename DefaultValue<T>::ValueProducer* DefaultValue<T>::producer_ = nullptr;
+
+// Points to the user-set default value for type T&.
+template <typename T>
+T* DefaultValue<T&>::address_ = nullptr;
+
+// Implement this interface to define an action for function type F.
+template <typename F>
+class ActionInterface {
+ public:
+  typedef typename internal::Function<F>::Result Result;
+  typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
+
+  ActionInterface() {}
+  virtual ~ActionInterface() {}
+
+  // Performs the action.  This method is not const, as in general an
+  // action can have side effects and be stateful.  For example, a
+  // get-the-next-element-from-the-collection action will need to
+  // remember the current element.
+  virtual Result Perform(const ArgumentTuple& args) = 0;
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ActionInterface);
+};
+
+// An Action<F> is a copyable and IMMUTABLE (except by assignment)
+// object that represents an action to be taken when a mock function
+// of type F is called.  The implementation of Action<T> is just a
+// std::shared_ptr to const ActionInterface<T>. Don't inherit from Action!
+// You can view an object implementing ActionInterface<F> as a
+// concrete action (including its current state), and an Action<F>
+// object as a handle to it.
+template <typename F>
+class Action {
+  // Adapter class to allow constructing Action from a legacy ActionInterface.
+  // New code should create Actions from functors instead.
+  struct ActionAdapter {
+    // Adapter must be copyable to satisfy std::function requirements.
+    ::std::shared_ptr<ActionInterface<F>> impl_;
+
+    template <typename... Args>
+    typename internal::Function<F>::Result operator()(Args&&... args) {
+      return impl_->Perform(
+          ::std::forward_as_tuple(::std::forward<Args>(args)...));
+    }
+  };
+
+  template <typename G>
+  using IsCompatibleFunctor = std::is_constructible<std::function<F>, G>;
+
+ public:
+  typedef typename internal::Function<F>::Result Result;
+  typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
+
+  // Constructs a null Action.  Needed for storing Action objects in
+  // STL containers.
+  Action() {}
+
+  // Construct an Action from a specified callable.
+  // This cannot take std::function directly, because then Action would not be
+  // directly constructible from lambda (it would require two conversions).
+  template <
+      typename G,
+      typename = typename std::enable_if<internal::disjunction<
+          IsCompatibleFunctor<G>, std::is_constructible<std::function<Result()>,
+                                                        G>>::value>::type>
+  Action(G&& fun) {  // NOLINT
+    Init(::std::forward<G>(fun), IsCompatibleFunctor<G>());
+  }
+
+  // Constructs an Action from its implementation.
+  explicit Action(ActionInterface<F>* impl)
+      : fun_(ActionAdapter{::std::shared_ptr<ActionInterface<F>>(impl)}) {}
+
+  // This constructor allows us to turn an Action<Func> object into an
+  // Action<F>, as long as F's arguments can be implicitly converted
+  // to Func's and Func's return type can be implicitly converted to F's.
+  template <typename Func>
+  explicit Action(const Action<Func>& action) : fun_(action.fun_) {}
+
+  // Returns true if and only if this is the DoDefault() action.
+  bool IsDoDefault() const { return fun_ == nullptr; }
+
+  // Performs the action.  Note that this method is const even though
+  // the corresponding method in ActionInterface is not.  The reason
+  // is that a const Action<F> means that it cannot be re-bound to
+  // another concrete action, not that the concrete action it binds to
+  // cannot change state.  (Think of the difference between a const
+  // pointer and a pointer to const.)
+  Result Perform(ArgumentTuple args) const {
+    if (IsDoDefault()) {
+      internal::IllegalDoDefault(__FILE__, __LINE__);
+    }
+    return internal::Apply(fun_, ::std::move(args));
+  }
+
+ private:
+  template <typename G>
+  friend class Action;
+
+  template <typename G>
+  void Init(G&& g, ::std::true_type) {
+    fun_ = ::std::forward<G>(g);
+  }
+
+  template <typename G>
+  void Init(G&& g, ::std::false_type) {
+    fun_ = IgnoreArgs<typename ::std::decay<G>::type>{::std::forward<G>(g)};
+  }
+
+  template <typename FunctionImpl>
+  struct IgnoreArgs {
+    template <typename... Args>
+    Result operator()(const Args&...) const {
+      return function_impl();
+    }
+
+    FunctionImpl function_impl;
+  };
+
+  // fun_ is an empty function if and only if this is the DoDefault() action.
+  ::std::function<F> fun_;
+};
+
+// The PolymorphicAction class template makes it easy to implement a
+// polymorphic action (i.e. an action that can be used in mock
+// functions of than one type, e.g. Return()).
+//
+// To define a polymorphic action, a user first provides a COPYABLE
+// implementation class that has a Perform() method template:
+//
+//   class FooAction {
+//    public:
+//     template <typename Result, typename ArgumentTuple>
+//     Result Perform(const ArgumentTuple& args) const {
+//       // Processes the arguments and returns a result, using
+//       // std::get<N>(args) to get the N-th (0-based) argument in the tuple.
+//     }
+//     ...
+//   };
+//
+// Then the user creates the polymorphic action using
+// MakePolymorphicAction(object) where object has type FooAction.  See
+// the definition of Return(void) and SetArgumentPointee<N>(value) for
+// complete examples.
+template <typename Impl>
+class PolymorphicAction {
+ public:
+  explicit PolymorphicAction(const Impl& impl) : impl_(impl) {}
+
+  template <typename F>
+  operator Action<F>() const {
+    return Action<F>(new MonomorphicImpl<F>(impl_));
+  }
+
+ private:
+  template <typename F>
+  class MonomorphicImpl : public ActionInterface<F> {
+   public:
+    typedef typename internal::Function<F>::Result Result;
+    typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
+
+    explicit MonomorphicImpl(const Impl& impl) : impl_(impl) {}
+
+    Result Perform(const ArgumentTuple& args) override {
+      return impl_.template Perform<Result>(args);
+    }
+
+   private:
+    Impl impl_;
+  };
+
+  Impl impl_;
+};
+
+// Creates an Action from its implementation and returns it.  The
+// created Action object owns the implementation.
+template <typename F>
+Action<F> MakeAction(ActionInterface<F>* impl) {
+  return Action<F>(impl);
+}
+
+// Creates a polymorphic action from its implementation.  This is
+// easier to use than the PolymorphicAction<Impl> constructor as it
+// doesn't require you to explicitly write the template argument, e.g.
+//
+//   MakePolymorphicAction(foo);
+// vs
+//   PolymorphicAction<TypeOfFoo>(foo);
+template <typename Impl>
+inline PolymorphicAction<Impl> MakePolymorphicAction(const Impl& impl) {
+  return PolymorphicAction<Impl>(impl);
+}
+
+namespace internal {
+
+// Helper struct to specialize ReturnAction to execute a move instead of a copy
+// on return. Useful for move-only types, but could be used on any type.
+template <typename T>
+struct ByMoveWrapper {
+  explicit ByMoveWrapper(T value) : payload(std::move(value)) {}
+  T payload;
+};
+
+// Implements the polymorphic Return(x) action, which can be used in
+// any function that returns the type of x, regardless of the argument
+// types.
+//
+// Note: The value passed into Return must be converted into
+// Function<F>::Result when this action is cast to Action<F> rather than
+// when that action is performed. This is important in scenarios like
+//
+// MOCK_METHOD1(Method, T(U));
+// ...
+// {
+//   Foo foo;
+//   X x(&foo);
+//   EXPECT_CALL(mock, Method(_)).WillOnce(Return(x));
+// }
+//
+// In the example above the variable x holds reference to foo which leaves
+// scope and gets destroyed.  If copying X just copies a reference to foo,
+// that copy will be left with a hanging reference.  If conversion to T
+// makes a copy of foo, the above code is safe. To support that scenario, we
+// need to make sure that the type conversion happens inside the EXPECT_CALL
+// statement, and conversion of the result of Return to Action<T(U)> is a
+// good place for that.
+//
+// The real life example of the above scenario happens when an invocation
+// of gtl::Container() is passed into Return.
+//
+template <typename R>
+class ReturnAction {
+ public:
+  // Constructs a ReturnAction object from the value to be returned.
+  // 'value' is passed by value instead of by const reference in order
+  // to allow Return("string literal") to compile.
+  explicit ReturnAction(R value) : value_(new R(std::move(value))) {}
+
+  // This template type conversion operator allows Return(x) to be
+  // used in ANY function that returns x's type.
+  template <typename F>
+  operator Action<F>() const {  // NOLINT
+    // Assert statement belongs here because this is the best place to verify
+    // conditions on F. It produces the clearest error messages
+    // in most compilers.
+    // Impl really belongs in this scope as a local class but can't
+    // because MSVC produces duplicate symbols in different translation units
+    // in this case. Until MS fixes that bug we put Impl into the class scope
+    // and put the typedef both here (for use in assert statement) and
+    // in the Impl class. But both definitions must be the same.
+    typedef typename Function<F>::Result Result;
+    GTEST_COMPILE_ASSERT_(
+        !std::is_reference<Result>::value,
+        use_ReturnRef_instead_of_Return_to_return_a_reference);
+    static_assert(!std::is_void<Result>::value,
+                  "Can't use Return() on an action expected to return `void`.");
+    return Action<F>(new Impl<R, F>(value_));
+  }
+
+ private:
+  // Implements the Return(x) action for a particular function type F.
+  template <typename R_, typename F>
+  class Impl : public ActionInterface<F> {
+   public:
+    typedef typename Function<F>::Result Result;
+    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
+
+    // The implicit cast is necessary when Result has more than one
+    // single-argument constructor (e.g. Result is std::vector<int>) and R
+    // has a type conversion operator template.  In that case, value_(value)
+    // won't compile as the compiler doesn't known which constructor of
+    // Result to call.  ImplicitCast_ forces the compiler to convert R to
+    // Result without considering explicit constructors, thus resolving the
+    // ambiguity. value_ is then initialized using its copy constructor.
+    explicit Impl(const std::shared_ptr<R>& value)
+        : value_before_cast_(*value),
+          value_(ImplicitCast_<Result>(value_before_cast_)) {}
+
+    Result Perform(const ArgumentTuple&) override { return value_; }
+
+   private:
+    GTEST_COMPILE_ASSERT_(!std::is_reference<Result>::value,
+                          Result_cannot_be_a_reference_type);
+    // We save the value before casting just in case it is being cast to a
+    // wrapper type.
+    R value_before_cast_;
+    Result value_;
+
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(Impl);
+  };
+
+  // Partially specialize for ByMoveWrapper. This version of ReturnAction will
+  // move its contents instead.
+  template <typename R_, typename F>
+  class Impl<ByMoveWrapper<R_>, F> : public ActionInterface<F> {
+   public:
+    typedef typename Function<F>::Result Result;
+    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
+
+    explicit Impl(const std::shared_ptr<R>& wrapper)
+        : performed_(false), wrapper_(wrapper) {}
+
+    Result Perform(const ArgumentTuple&) override {
+      GTEST_CHECK_(!performed_)
+          << "A ByMove() action should only be performed once.";
+      performed_ = true;
+      return std::move(wrapper_->payload);
+    }
+
+   private:
+    bool performed_;
+    const std::shared_ptr<R> wrapper_;
+  };
+
+  const std::shared_ptr<R> value_;
+};
+
+// Implements the ReturnNull() action.
+class ReturnNullAction {
+ public:
+  // Allows ReturnNull() to be used in any pointer-returning function. In C++11
+  // this is enforced by returning nullptr, and in non-C++11 by asserting a
+  // pointer type on compile time.
+  template <typename Result, typename ArgumentTuple>
+  static Result Perform(const ArgumentTuple&) {
+    return nullptr;
+  }
+};
+
+// Implements the Return() action.
+class ReturnVoidAction {
+ public:
+  // Allows Return() to be used in any void-returning function.
+  template <typename Result, typename ArgumentTuple>
+  static void Perform(const ArgumentTuple&) {
+    static_assert(std::is_void<Result>::value, "Result should be void.");
+  }
+};
+
+// Implements the polymorphic ReturnRef(x) action, which can be used
+// in any function that returns a reference to the type of x,
+// regardless of the argument types.
+template <typename T>
+class ReturnRefAction {
+ public:
+  // Constructs a ReturnRefAction object from the reference to be returned.
+  explicit ReturnRefAction(T& ref) : ref_(ref) {}  // NOLINT
+
+  // This template type conversion operator allows ReturnRef(x) to be
+  // used in ANY function that returns a reference to x's type.
+  template <typename F>
+  operator Action<F>() const {
+    typedef typename Function<F>::Result Result;
+    // Asserts that the function return type is a reference.  This
+    // catches the user error of using ReturnRef(x) when Return(x)
+    // should be used, and generates some helpful error message.
+    GTEST_COMPILE_ASSERT_(std::is_reference<Result>::value,
+                          use_Return_instead_of_ReturnRef_to_return_a_value);
+    return Action<F>(new Impl<F>(ref_));
+  }
+
+ private:
+  // Implements the ReturnRef(x) action for a particular function type F.
+  template <typename F>
+  class Impl : public ActionInterface<F> {
+   public:
+    typedef typename Function<F>::Result Result;
+    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
+
+    explicit Impl(T& ref) : ref_(ref) {}  // NOLINT
+
+    Result Perform(const ArgumentTuple&) override { return ref_; }
+
+   private:
+    T& ref_;
+  };
+
+  T& ref_;
+};
+
+// Implements the polymorphic ReturnRefOfCopy(x) action, which can be
+// used in any function that returns a reference to the type of x,
+// regardless of the argument types.
+template <typename T>
+class ReturnRefOfCopyAction {
+ public:
+  // Constructs a ReturnRefOfCopyAction object from the reference to
+  // be returned.
+  explicit ReturnRefOfCopyAction(const T& value) : value_(value) {}  // NOLINT
+
+  // This template type conversion operator allows ReturnRefOfCopy(x) to be
+  // used in ANY function that returns a reference to x's type.
+  template <typename F>
+  operator Action<F>() const {
+    typedef typename Function<F>::Result Result;
+    // Asserts that the function return type is a reference.  This
+    // catches the user error of using ReturnRefOfCopy(x) when Return(x)
+    // should be used, and generates some helpful error message.
+    GTEST_COMPILE_ASSERT_(
+        std::is_reference<Result>::value,
+        use_Return_instead_of_ReturnRefOfCopy_to_return_a_value);
+    return Action<F>(new Impl<F>(value_));
+  }
+
+ private:
+  // Implements the ReturnRefOfCopy(x) action for a particular function type F.
+  template <typename F>
+  class Impl : public ActionInterface<F> {
+   public:
+    typedef typename Function<F>::Result Result;
+    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
+
+    explicit Impl(const T& value) : value_(value) {}  // NOLINT
+
+    Result Perform(const ArgumentTuple&) override { return value_; }
+
+   private:
+    T value_;
+  };
+
+  const T value_;
+};
+
+// Implements the polymorphic ReturnRoundRobin(v) action, which can be
+// used in any function that returns the element_type of v.
+template <typename T>
+class ReturnRoundRobinAction {
+ public:
+  explicit ReturnRoundRobinAction(std::vector<T> values) {
+    GTEST_CHECK_(!values.empty())
+        << "ReturnRoundRobin requires at least one element.";
+    state_->values = std::move(values);
+  }
+
+  template <typename... Args>
+  T operator()(Args&&...) const {
+     return state_->Next();
+  }
+
+ private:
+  struct State {
+    T Next() {
+      T ret_val = values[i++];
+      if (i == values.size()) i = 0;
+      return ret_val;
+    }
+
+    std::vector<T> values;
+    size_t i = 0;
+  };
+  std::shared_ptr<State> state_ = std::make_shared<State>();
+};
+
+// Implements the polymorphic DoDefault() action.
+class DoDefaultAction {
+ public:
+  // This template type conversion operator allows DoDefault() to be
+  // used in any function.
+  template <typename F>
+  operator Action<F>() const { return Action<F>(); }  // NOLINT
+};
+
+// Implements the Assign action to set a given pointer referent to a
+// particular value.
+template <typename T1, typename T2>
+class AssignAction {
+ public:
+  AssignAction(T1* ptr, T2 value) : ptr_(ptr), value_(value) {}
+
+  template <typename Result, typename ArgumentTuple>
+  void Perform(const ArgumentTuple& /* args */) const {
+    *ptr_ = value_;
+  }
+
+ private:
+  T1* const ptr_;
+  const T2 value_;
+};
+
+#if !GTEST_OS_WINDOWS_MOBILE
+
+// Implements the SetErrnoAndReturn action to simulate return from
+// various system calls and libc functions.
+template <typename T>
+class SetErrnoAndReturnAction {
+ public:
+  SetErrnoAndReturnAction(int errno_value, T result)
+      : errno_(errno_value),
+        result_(result) {}
+  template <typename Result, typename ArgumentTuple>
+  Result Perform(const ArgumentTuple& /* args */) const {
+    errno = errno_;
+    return result_;
+  }
+
+ private:
+  const int errno_;
+  const T result_;
+};
+
+#endif  // !GTEST_OS_WINDOWS_MOBILE
+
+// Implements the SetArgumentPointee<N>(x) action for any function
+// whose N-th argument (0-based) is a pointer to x's type.
+template <size_t N, typename A, typename = void>
+struct SetArgumentPointeeAction {
+  A value;
+
+  template <typename... Args>
+  void operator()(const Args&... args) const {
+    *::std::get<N>(std::tie(args...)) = value;
+  }
+};
+
+// Implements the Invoke(object_ptr, &Class::Method) action.
+template <class Class, typename MethodPtr>
+struct InvokeMethodAction {
+  Class* const obj_ptr;
+  const MethodPtr method_ptr;
+
+  template <typename... Args>
+  auto operator()(Args&&... args) const
+      -> decltype((obj_ptr->*method_ptr)(std::forward<Args>(args)...)) {
+    return (obj_ptr->*method_ptr)(std::forward<Args>(args)...);
+  }
+};
+
+// Implements the InvokeWithoutArgs(f) action.  The template argument
+// FunctionImpl is the implementation type of f, which can be either a
+// function pointer or a functor.  InvokeWithoutArgs(f) can be used as an
+// Action<F> as long as f's type is compatible with F.
+template <typename FunctionImpl>
+struct InvokeWithoutArgsAction {
+  FunctionImpl function_impl;
+
+  // Allows InvokeWithoutArgs(f) to be used as any action whose type is
+  // compatible with f.
+  template <typename... Args>
+  auto operator()(const Args&...) -> decltype(function_impl()) {
+    return function_impl();
+  }
+};
+
+// Implements the InvokeWithoutArgs(object_ptr, &Class::Method) action.
+template <class Class, typename MethodPtr>
+struct InvokeMethodWithoutArgsAction {
+  Class* const obj_ptr;
+  const MethodPtr method_ptr;
+
+  using ReturnType =
+      decltype((std::declval<Class*>()->*std::declval<MethodPtr>())());
+
+  template <typename... Args>
+  ReturnType operator()(const Args&...) const {
+    return (obj_ptr->*method_ptr)();
+  }
+};
+
+// Implements the IgnoreResult(action) action.
+template <typename A>
+class IgnoreResultAction {
+ public:
+  explicit IgnoreResultAction(const A& action) : action_(action) {}
+
+  template <typename F>
+  operator Action<F>() const {
+    // Assert statement belongs here because this is the best place to verify
+    // conditions on F. It produces the clearest error messages
+    // in most compilers.
+    // Impl really belongs in this scope as a local class but can't
+    // because MSVC produces duplicate symbols in different translation units
+    // in this case. Until MS fixes that bug we put Impl into the class scope
+    // and put the typedef both here (for use in assert statement) and
+    // in the Impl class. But both definitions must be the same.
+    typedef typename internal::Function<F>::Result Result;
+
+    // Asserts at compile time that F returns void.
+    static_assert(std::is_void<Result>::value, "Result type should be void.");
+
+    return Action<F>(new Impl<F>(action_));
+  }
+
+ private:
+  template <typename F>
+  class Impl : public ActionInterface<F> {
+   public:
+    typedef typename internal::Function<F>::Result Result;
+    typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
+
+    explicit Impl(const A& action) : action_(action) {}
+
+    void Perform(const ArgumentTuple& args) override {
+      // Performs the action and ignores its result.
+      action_.Perform(args);
+    }
+
+   private:
+    // Type OriginalFunction is the same as F except that its return
+    // type is IgnoredValue.
+    typedef typename internal::Function<F>::MakeResultIgnoredValue
+        OriginalFunction;
+
+    const Action<OriginalFunction> action_;
+  };
+
+  const A action_;
+};
+
+template <typename InnerAction, size_t... I>
+struct WithArgsAction {
+  InnerAction action;
+
+  // The inner action could be anything convertible to Action<X>.
+  // We use the conversion operator to detect the signature of the inner Action.
+  template <typename R, typename... Args>
+  operator Action<R(Args...)>() const {  // NOLINT
+    using TupleType = std::tuple<Args...>;
+    Action<R(typename std::tuple_element<I, TupleType>::type...)>
+        converted(action);
+
+    return [converted](Args... args) -> R {
+      return converted.Perform(std::forward_as_tuple(
+        std::get<I>(std::forward_as_tuple(std::forward<Args>(args)...))...));
+    };
+  }
+};
+
+template <typename... Actions>
+struct DoAllAction {
+ private:
+  template <typename T>
+  using NonFinalType =
+      typename std::conditional<std::is_scalar<T>::value, T, const T&>::type;
+
+  template <typename ActionT, size_t... I>
+  std::vector<ActionT> Convert(IndexSequence<I...>) const {
+    return {ActionT(std::get<I>(actions))...};
+  }
+
+ public:
+  std::tuple<Actions...> actions;
+
+  template <typename R, typename... Args>
+  operator Action<R(Args...)>() const {  // NOLINT
+    struct Op {
+      std::vector<Action<void(NonFinalType<Args>...)>> converted;
+      Action<R(Args...)> last;
+      R operator()(Args... args) const {
+        auto tuple_args = std::forward_as_tuple(std::forward<Args>(args)...);
+        for (auto& a : converted) {
+          a.Perform(tuple_args);
+        }
+        return last.Perform(std::move(tuple_args));
+      }
+    };
+    return Op{Convert<Action<void(NonFinalType<Args>...)>>(
+                  MakeIndexSequence<sizeof...(Actions) - 1>()),
+              std::get<sizeof...(Actions) - 1>(actions)};
+  }
+};
+
+template <typename T, typename... Params>
+struct ReturnNewAction {
+  T* operator()() const {
+    return internal::Apply(
+        [](const Params&... unpacked_params) {
+          return new T(unpacked_params...);
+        },
+        params);
+  }
+  std::tuple<Params...> params;
+};
+
+template <size_t k>
+struct ReturnArgAction {
+  template <typename... Args>
+  auto operator()(const Args&... args) const ->
+      typename std::tuple_element<k, std::tuple<Args...>>::type {
+    return std::get<k>(std::tie(args...));
+  }
+};
+
+template <size_t k, typename Ptr>
+struct SaveArgAction {
+  Ptr pointer;
+
+  template <typename... Args>
+  void operator()(const Args&... args) const {
+    *pointer = std::get<k>(std::tie(args...));
+  }
+};
+
+template <size_t k, typename Ptr>
+struct SaveArgPointeeAction {
+  Ptr pointer;
+
+  template <typename... Args>
+  void operator()(const Args&... args) const {
+    *pointer = *std::get<k>(std::tie(args...));
+  }
+};
+
+template <size_t k, typename T>
+struct SetArgRefereeAction {
+  T value;
+
+  template <typename... Args>
+  void operator()(Args&&... args) const {
+    using argk_type =
+        typename ::std::tuple_element<k, std::tuple<Args...>>::type;
+    static_assert(std::is_lvalue_reference<argk_type>::value,
+                  "Argument must be a reference type.");
+    std::get<k>(std::tie(args...)) = value;
+  }
+};
+
+template <size_t k, typename I1, typename I2>
+struct SetArrayArgumentAction {
+  I1 first;
+  I2 last;
+
+  template <typename... Args>
+  void operator()(const Args&... args) const {
+    auto value = std::get<k>(std::tie(args...));
+    for (auto it = first; it != last; ++it, (void)++value) {
+      *value = *it;
+    }
+  }
+};
+
+template <size_t k>
+struct DeleteArgAction {
+  template <typename... Args>
+  void operator()(const Args&... args) const {
+    delete std::get<k>(std::tie(args...));
+  }
+};
+
+template <typename Ptr>
+struct ReturnPointeeAction {
+  Ptr pointer;
+  template <typename... Args>
+  auto operator()(const Args&...) const -> decltype(*pointer) {
+    return *pointer;
+  }
+};
+
+#if GTEST_HAS_EXCEPTIONS
+template <typename T>
+struct ThrowAction {
+  T exception;
+  // We use a conversion operator to adapt to any return type.
+  template <typename R, typename... Args>
+  operator Action<R(Args...)>() const {  // NOLINT
+    T copy = exception;
+    return [copy](Args...) -> R { throw copy; };
+  }
+};
+#endif  // GTEST_HAS_EXCEPTIONS
+
+}  // namespace internal
+
+// An Unused object can be implicitly constructed from ANY value.
+// This is handy when defining actions that ignore some or all of the
+// mock function arguments.  For example, given
+//
+//   MOCK_METHOD3(Foo, double(const string& label, double x, double y));
+//   MOCK_METHOD3(Bar, double(int index, double x, double y));
+//
+// instead of
+//
+//   double DistanceToOriginWithLabel(const string& label, double x, double y) {
+//     return sqrt(x*x + y*y);
+//   }
+//   double DistanceToOriginWithIndex(int index, double x, double y) {
+//     return sqrt(x*x + y*y);
+//   }
+//   ...
+//   EXPECT_CALL(mock, Foo("abc", _, _))
+//       .WillOnce(Invoke(DistanceToOriginWithLabel));
+//   EXPECT_CALL(mock, Bar(5, _, _))
+//       .WillOnce(Invoke(DistanceToOriginWithIndex));
+//
+// you could write
+//
+//   // We can declare any uninteresting argument as Unused.
+//   double DistanceToOrigin(Unused, double x, double y) {
+//     return sqrt(x*x + y*y);
+//   }
+//   ...
+//   EXPECT_CALL(mock, Foo("abc", _, _)).WillOnce(Invoke(DistanceToOrigin));
+//   EXPECT_CALL(mock, Bar(5, _, _)).WillOnce(Invoke(DistanceToOrigin));
+typedef internal::IgnoredValue Unused;
+
+// Creates an action that does actions a1, a2, ..., sequentially in
+// each invocation. All but the last action will have a readonly view of the
+// arguments.
+template <typename... Action>
+internal::DoAllAction<typename std::decay<Action>::type...> DoAll(
+    Action&&... action) {
+  return {std::forward_as_tuple(std::forward<Action>(action)...)};
+}
+
+// WithArg<k>(an_action) creates an action that passes the k-th
+// (0-based) argument of the mock function to an_action and performs
+// it.  It adapts an action accepting one argument to one that accepts
+// multiple arguments.  For convenience, we also provide
+// WithArgs<k>(an_action) (defined below) as a synonym.
+template <size_t k, typename InnerAction>
+internal::WithArgsAction<typename std::decay<InnerAction>::type, k>
+WithArg(InnerAction&& action) {
+  return {std::forward<InnerAction>(action)};
+}
+
+// WithArgs<N1, N2, ..., Nk>(an_action) creates an action that passes
+// the selected arguments of the mock function to an_action and
+// performs it.  It serves as an adaptor between actions with
+// different argument lists.
+template <size_t k, size_t... ks, typename InnerAction>
+internal::WithArgsAction<typename std::decay<InnerAction>::type, k, ks...>
+WithArgs(InnerAction&& action) {
+  return {std::forward<InnerAction>(action)};
+}
+
+// WithoutArgs(inner_action) can be used in a mock function with a
+// non-empty argument list to perform inner_action, which takes no
+// argument.  In other words, it adapts an action accepting no
+// argument to one that accepts (and ignores) arguments.
+template <typename InnerAction>
+internal::WithArgsAction<typename std::decay<InnerAction>::type>
+WithoutArgs(InnerAction&& action) {
+  return {std::forward<InnerAction>(action)};
+}
+
+// Creates an action that returns 'value'.  'value' is passed by value
+// instead of const reference - otherwise Return("string literal")
+// will trigger a compiler error about using array as initializer.
+template <typename R>
+internal::ReturnAction<R> Return(R value) {
+  return internal::ReturnAction<R>(std::move(value));
+}
+
+// Creates an action that returns NULL.
+inline PolymorphicAction<internal::ReturnNullAction> ReturnNull() {
+  return MakePolymorphicAction(internal::ReturnNullAction());
+}
+
+// Creates an action that returns from a void function.
+inline PolymorphicAction<internal::ReturnVoidAction> Return() {
+  return MakePolymorphicAction(internal::ReturnVoidAction());
+}
+
+// Creates an action that returns the reference to a variable.
+template <typename R>
+inline internal::ReturnRefAction<R> ReturnRef(R& x) {  // NOLINT
+  return internal::ReturnRefAction<R>(x);
+}
+
+// Prevent using ReturnRef on reference to temporary.
+template <typename R, R* = nullptr>
+internal::ReturnRefAction<R> ReturnRef(R&&) = delete;
+
+// Creates an action that returns the reference to a copy of the
+// argument.  The copy is created when the action is constructed and
+// lives as long as the action.
+template <typename R>
+inline internal::ReturnRefOfCopyAction<R> ReturnRefOfCopy(const R& x) {
+  return internal::ReturnRefOfCopyAction<R>(x);
+}
+
+// Modifies the parent action (a Return() action) to perform a move of the
+// argument instead of a copy.
+// Return(ByMove()) actions can only be executed once and will assert this
+// invariant.
+template <typename R>
+internal::ByMoveWrapper<R> ByMove(R x) {
+  return internal::ByMoveWrapper<R>(std::move(x));
+}
+
+// Creates an action that returns an element of `vals`. Calling this action will
+// repeatedly return the next value from `vals` until it reaches the end and
+// will restart from the beginning.
+template <typename T>
+internal::ReturnRoundRobinAction<T> ReturnRoundRobin(std::vector<T> vals) {
+  return internal::ReturnRoundRobinAction<T>(std::move(vals));
+}
+
+// Creates an action that returns an element of `vals`. Calling this action will
+// repeatedly return the next value from `vals` until it reaches the end and
+// will restart from the beginning.
+template <typename T>
+internal::ReturnRoundRobinAction<T> ReturnRoundRobin(
+    std::initializer_list<T> vals) {
+  return internal::ReturnRoundRobinAction<T>(std::vector<T>(vals));
+}
+
+// Creates an action that does the default action for the give mock function.
+inline internal::DoDefaultAction DoDefault() {
+  return internal::DoDefaultAction();
+}
+
+// Creates an action that sets the variable pointed by the N-th
+// (0-based) function argument to 'value'.
+template <size_t N, typename T>
+internal::SetArgumentPointeeAction<N, T> SetArgPointee(T value) {
+  return {std::move(value)};
+}
+
+// The following version is DEPRECATED.
+template <size_t N, typename T>
+internal::SetArgumentPointeeAction<N, T> SetArgumentPointee(T value) {
+  return {std::move(value)};
+}
+
+// Creates an action that sets a pointer referent to a given value.
+template <typename T1, typename T2>
+PolymorphicAction<internal::AssignAction<T1, T2> > Assign(T1* ptr, T2 val) {
+  return MakePolymorphicAction(internal::AssignAction<T1, T2>(ptr, val));
+}
+
+#if !GTEST_OS_WINDOWS_MOBILE
+
+// Creates an action that sets errno and returns the appropriate error.
+template <typename T>
+PolymorphicAction<internal::SetErrnoAndReturnAction<T> >
+SetErrnoAndReturn(int errval, T result) {
+  return MakePolymorphicAction(
+      internal::SetErrnoAndReturnAction<T>(errval, result));
+}
+
+#endif  // !GTEST_OS_WINDOWS_MOBILE
+
+// Various overloads for Invoke().
+
+// Legacy function.
+// Actions can now be implicitly constructed from callables. No need to create
+// wrapper objects.
+// This function exists for backwards compatibility.
+template <typename FunctionImpl>
+typename std::decay<FunctionImpl>::type Invoke(FunctionImpl&& function_impl) {
+  return std::forward<FunctionImpl>(function_impl);
+}
+
+// Creates an action that invokes the given method on the given object
+// with the mock function's arguments.
+template <class Class, typename MethodPtr>
+internal::InvokeMethodAction<Class, MethodPtr> Invoke(Class* obj_ptr,
+                                                      MethodPtr method_ptr) {
+  return {obj_ptr, method_ptr};
+}
+
+// Creates an action that invokes 'function_impl' with no argument.
+template <typename FunctionImpl>
+internal::InvokeWithoutArgsAction<typename std::decay<FunctionImpl>::type>
+InvokeWithoutArgs(FunctionImpl function_impl) {
+  return {std::move(function_impl)};
+}
+
+// Creates an action that invokes the given method on the given object
+// with no argument.
+template <class Class, typename MethodPtr>
+internal::InvokeMethodWithoutArgsAction<Class, MethodPtr> InvokeWithoutArgs(
+    Class* obj_ptr, MethodPtr method_ptr) {
+  return {obj_ptr, method_ptr};
+}
+
+// Creates an action that performs an_action and throws away its
+// result.  In other words, it changes the return type of an_action to
+// void.  an_action MUST NOT return void, or the code won't compile.
+template <typename A>
+inline internal::IgnoreResultAction<A> IgnoreResult(const A& an_action) {
+  return internal::IgnoreResultAction<A>(an_action);
+}
+
+// Creates a reference wrapper for the given L-value.  If necessary,
+// you can explicitly specify the type of the reference.  For example,
+// suppose 'derived' is an object of type Derived, ByRef(derived)
+// would wrap a Derived&.  If you want to wrap a const Base& instead,
+// where Base is a base class of Derived, just write:
+//
+//   ByRef<const Base>(derived)
+//
+// N.B. ByRef is redundant with std::ref, std::cref and std::reference_wrapper.
+// However, it may still be used for consistency with ByMove().
+template <typename T>
+inline ::std::reference_wrapper<T> ByRef(T& l_value) {  // NOLINT
+  return ::std::reference_wrapper<T>(l_value);
+}
+
+// The ReturnNew<T>(a1, a2, ..., a_k) action returns a pointer to a new
+// instance of type T, constructed on the heap with constructor arguments
+// a1, a2, ..., and a_k. The caller assumes ownership of the returned value.
+template <typename T, typename... Params>
+internal::ReturnNewAction<T, typename std::decay<Params>::type...> ReturnNew(
+    Params&&... params) {
+  return {std::forward_as_tuple(std::forward<Params>(params)...)};
+}
+
+// Action ReturnArg<k>() returns the k-th argument of the mock function.
+template <size_t k>
+internal::ReturnArgAction<k> ReturnArg() {
+  return {};
+}
+
+// Action SaveArg<k>(pointer) saves the k-th (0-based) argument of the
+// mock function to *pointer.
+template <size_t k, typename Ptr>
+internal::SaveArgAction<k, Ptr> SaveArg(Ptr pointer) {
+  return {pointer};
+}
+
+// Action SaveArgPointee<k>(pointer) saves the value pointed to
+// by the k-th (0-based) argument of the mock function to *pointer.
+template <size_t k, typename Ptr>
+internal::SaveArgPointeeAction<k, Ptr> SaveArgPointee(Ptr pointer) {
+  return {pointer};
+}
+
+// Action SetArgReferee<k>(value) assigns 'value' to the variable
+// referenced by the k-th (0-based) argument of the mock function.
+template <size_t k, typename T>
+internal::SetArgRefereeAction<k, typename std::decay<T>::type> SetArgReferee(
+    T&& value) {
+  return {std::forward<T>(value)};
+}
+
+// Action SetArrayArgument<k>(first, last) copies the elements in
+// source range [first, last) to the array pointed to by the k-th
+// (0-based) argument, which can be either a pointer or an
+// iterator. The action does not take ownership of the elements in the
+// source range.
+template <size_t k, typename I1, typename I2>
+internal::SetArrayArgumentAction<k, I1, I2> SetArrayArgument(I1 first,
+                                                             I2 last) {
+  return {first, last};
+}
+
+// Action DeleteArg<k>() deletes the k-th (0-based) argument of the mock
+// function.
+template <size_t k>
+internal::DeleteArgAction<k> DeleteArg() {
+  return {};
+}
+
+// This action returns the value pointed to by 'pointer'.
+template <typename Ptr>
+internal::ReturnPointeeAction<Ptr> ReturnPointee(Ptr pointer) {
+  return {pointer};
+}
+
+// Action Throw(exception) can be used in a mock function of any type
+// to throw the given exception.  Any copyable value can be thrown.
+#if GTEST_HAS_EXCEPTIONS
+template <typename T>
+internal::ThrowAction<typename std::decay<T>::type> Throw(T&& exception) {
+  return {std::forward<T>(exception)};
+}
+#endif  // GTEST_HAS_EXCEPTIONS
+
+namespace internal {
+
+// A macro from the ACTION* family (defined later in gmock-generated-actions.h)
+// defines an action that can be used in a mock function.  Typically,
+// these actions only care about a subset of the arguments of the mock
+// function.  For example, if such an action only uses the second
+// argument, it can be used in any mock function that takes >= 2
+// arguments where the type of the second argument is compatible.
+//
+// Therefore, the action implementation must be prepared to take more
+// arguments than it needs.  The ExcessiveArg type is used to
+// represent those excessive arguments.  In order to keep the compiler
+// error messages tractable, we define it in the testing namespace
+// instead of testing::internal.  However, this is an INTERNAL TYPE
+// and subject to change without notice, so a user MUST NOT USE THIS
+// TYPE DIRECTLY.
+struct ExcessiveArg {};
+
+// Builds an implementation of an Action<> for some particular signature, using
+// a class defined by an ACTION* macro.
+template <typename F, typename Impl> struct ActionImpl;
+
+template <typename Impl>
+struct ImplBase {
+  struct Holder {
+    // Allows each copy of the Action<> to get to the Impl.
+    explicit operator const Impl&() const { return *ptr; }
+    std::shared_ptr<Impl> ptr;
+  };
+  using type = typename std::conditional<std::is_constructible<Impl>::value,
+                                         Impl, Holder>::type;
+};
+
+template <typename R, typename... Args, typename Impl>
+struct ActionImpl<R(Args...), Impl> : ImplBase<Impl>::type {
+  using Base = typename ImplBase<Impl>::type;
+  using function_type = R(Args...);
+  using args_type = std::tuple<Args...>;
+
+  ActionImpl() = default;  // Only defined if appropriate for Base.
+  explicit ActionImpl(std::shared_ptr<Impl> impl) : Base{std::move(impl)} { }
+
+  R operator()(Args&&... arg) const {
+    static constexpr size_t kMaxArgs =
+        sizeof...(Args) <= 10 ? sizeof...(Args) : 10;
+    return Apply(MakeIndexSequence<kMaxArgs>{},
+                 MakeIndexSequence<10 - kMaxArgs>{},
+                 args_type{std::forward<Args>(arg)...});
+  }
+
+  template <std::size_t... arg_id, std::size_t... excess_id>
+  R Apply(IndexSequence<arg_id...>, IndexSequence<excess_id...>,
+          const args_type& args) const {
+    // Impl need not be specific to the signature of action being implemented;
+    // only the implementing function body needs to have all of the specific
+    // types instantiated.  Up to 10 of the args that are provided by the
+    // args_type get passed, followed by a dummy of unspecified type for the
+    // remainder up to 10 explicit args.
+    static constexpr ExcessiveArg kExcessArg{};
+    return static_cast<const Impl&>(*this).template gmock_PerformImpl<
+        /*function_type=*/function_type, /*return_type=*/R,
+        /*args_type=*/args_type,
+        /*argN_type=*/typename std::tuple_element<arg_id, args_type>::type...>(
+        /*args=*/args, std::get<arg_id>(args)...,
+        ((void)excess_id, kExcessArg)...);
+  }
+};
+
+// Stores a default-constructed Impl as part of the Action<>'s
+// std::function<>. The Impl should be trivial to copy.
+template <typename F, typename Impl>
+::testing::Action<F> MakeAction() {
+  return ::testing::Action<F>(ActionImpl<F, Impl>());
+}
+
+// Stores just the one given instance of Impl.
+template <typename F, typename Impl>
+::testing::Action<F> MakeAction(std::shared_ptr<Impl> impl) {
+  return ::testing::Action<F>(ActionImpl<F, Impl>(std::move(impl)));
+}
+
+#define GMOCK_INTERNAL_ARG_UNUSED(i, data, el) \
+  , const arg##i##_type& arg##i GTEST_ATTRIBUTE_UNUSED_
+#define GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_           \
+  const args_type& args GTEST_ATTRIBUTE_UNUSED_ GMOCK_PP_REPEAT( \
+      GMOCK_INTERNAL_ARG_UNUSED, , 10)
+
+#define GMOCK_INTERNAL_ARG(i, data, el) , const arg##i##_type& arg##i
+#define GMOCK_ACTION_ARG_TYPES_AND_NAMES_ \
+  const args_type& args GMOCK_PP_REPEAT(GMOCK_INTERNAL_ARG, , 10)
+
+#define GMOCK_INTERNAL_TEMPLATE_ARG(i, data, el) , typename arg##i##_type
+#define GMOCK_ACTION_TEMPLATE_ARGS_NAMES_ \
+  GMOCK_PP_TAIL(GMOCK_PP_REPEAT(GMOCK_INTERNAL_TEMPLATE_ARG, , 10))
+
+#define GMOCK_INTERNAL_TYPENAME_PARAM(i, data, param) , typename param##_type
+#define GMOCK_ACTION_TYPENAME_PARAMS_(params) \
+  GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPENAME_PARAM, , params))
+
+#define GMOCK_INTERNAL_TYPE_PARAM(i, data, param) , param##_type
+#define GMOCK_ACTION_TYPE_PARAMS_(params) \
+  GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPE_PARAM, , params))
+
+#define GMOCK_INTERNAL_TYPE_GVALUE_PARAM(i, data, param) \
+  , param##_type gmock_p##i
+#define GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params) \
+  GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPE_GVALUE_PARAM, , params))
+
+#define GMOCK_INTERNAL_GVALUE_PARAM(i, data, param) \
+  , std::forward<param##_type>(gmock_p##i)
+#define GMOCK_ACTION_GVALUE_PARAMS_(params) \
+  GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_GVALUE_PARAM, , params))
+
+#define GMOCK_INTERNAL_INIT_PARAM(i, data, param) \
+  , param(::std::forward<param##_type>(gmock_p##i))
+#define GMOCK_ACTION_INIT_PARAMS_(params) \
+  GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_INIT_PARAM, , params))
+
+#define GMOCK_INTERNAL_FIELD_PARAM(i, data, param) param##_type param;
+#define GMOCK_ACTION_FIELD_PARAMS_(params) \
+  GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_FIELD_PARAM, , params)
+
+#define GMOCK_INTERNAL_ACTION(name, full_name, params)                        \
+  template <GMOCK_ACTION_TYPENAME_PARAMS_(params)>                            \
+  class full_name {                                                           \
+   public:                                                                    \
+    explicit full_name(GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params))              \
+        : impl_(std::make_shared<gmock_Impl>(                                 \
+                GMOCK_ACTION_GVALUE_PARAMS_(params))) { }                     \
+    full_name(const full_name&) = default;                                    \
+    full_name(full_name&&) noexcept = default;                                \
+    template <typename F>                                                     \
+    operator ::testing::Action<F>() const {                                   \
+      return ::testing::internal::MakeAction<F>(impl_);                       \
+    }                                                                         \
+   private:                                                                   \
+    class gmock_Impl {                                                        \
+     public:                                                                  \
+      explicit gmock_Impl(GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params))           \
+          : GMOCK_ACTION_INIT_PARAMS_(params) {}                              \
+      template <typename function_type, typename return_type,                 \
+                typename args_type, GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>        \
+      return_type gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_) const; \
+      GMOCK_ACTION_FIELD_PARAMS_(params)                                      \
+    };                                                                        \
+    std::shared_ptr<const gmock_Impl> impl_;                                  \
+  };                                                                          \
+  template <GMOCK_ACTION_TYPENAME_PARAMS_(params)>                            \
+  inline full_name<GMOCK_ACTION_TYPE_PARAMS_(params)> name(                   \
+      GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)) {                             \
+    return full_name<GMOCK_ACTION_TYPE_PARAMS_(params)>(                      \
+        GMOCK_ACTION_GVALUE_PARAMS_(params));                                 \
+  }                                                                           \
+  template <GMOCK_ACTION_TYPENAME_PARAMS_(params)>                            \
+  template <typename function_type, typename return_type, typename args_type, \
+            GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>                                \
+  return_type full_name<GMOCK_ACTION_TYPE_PARAMS_(params)>::gmock_Impl::      \
+  gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_) const
+
+}  // namespace internal
+
+// Similar to GMOCK_INTERNAL_ACTION, but no bound parameters are stored.
+#define ACTION(name)                                                          \
+  class name##Action {                                                        \
+   public:                                                                    \
+   explicit name##Action() noexcept {}                                        \
+   name##Action(const name##Action&) noexcept {}                              \
+    template <typename F>                                                     \
+    operator ::testing::Action<F>() const {                                   \
+      return ::testing::internal::MakeAction<F, gmock_Impl>();                \
+    }                                                                         \
+   private:                                                                   \
+    class gmock_Impl {                                                        \
+     public:                                                                  \
+      template <typename function_type, typename return_type,                 \
+                typename args_type, GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>        \
+      return_type gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_) const; \
+    };                                                                        \
+  };                                                                          \
+  inline name##Action name() GTEST_MUST_USE_RESULT_;                          \
+  inline name##Action name() { return name##Action(); }                       \
+  template <typename function_type, typename return_type, typename args_type, \
+            GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>                                \
+  return_type name##Action::gmock_Impl::gmock_PerformImpl(                    \
+      GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_) const
+
+#define ACTION_P(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP, (__VA_ARGS__))
+
+#define ACTION_P2(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP2, (__VA_ARGS__))
+
+#define ACTION_P3(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP3, (__VA_ARGS__))
+
+#define ACTION_P4(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP4, (__VA_ARGS__))
+
+#define ACTION_P5(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP5, (__VA_ARGS__))
+
+#define ACTION_P6(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP6, (__VA_ARGS__))
+
+#define ACTION_P7(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP7, (__VA_ARGS__))
+
+#define ACTION_P8(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP8, (__VA_ARGS__))
+
+#define ACTION_P9(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP9, (__VA_ARGS__))
+
+#define ACTION_P10(name, ...) \
+  GMOCK_INTERNAL_ACTION(name, name##ActionP10, (__VA_ARGS__))
+
+}  // namespace testing
+
+#ifdef _MSC_VER
+# pragma warning(pop)
+#endif
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file implements some commonly used cardinalities.  More
+// cardinalities can be defined by the user implementing the
+// CardinalityInterface interface if necessary.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_CARDINALITIES_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_CARDINALITIES_H_
+
+#include <limits.h>
+#include <memory>
+#include <ostream>  // NOLINT
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+namespace testing {
+
+// To implement a cardinality Foo, define:
+//   1. a class FooCardinality that implements the
+//      CardinalityInterface interface, and
+//   2. a factory function that creates a Cardinality object from a
+//      const FooCardinality*.
+//
+// The two-level delegation design follows that of Matcher, providing
+// consistency for extension developers.  It also eases ownership
+// management as Cardinality objects can now be copied like plain values.
+
+// The implementation of a cardinality.
+class CardinalityInterface {
+ public:
+  virtual ~CardinalityInterface() {}
+
+  // Conservative estimate on the lower/upper bound of the number of
+  // calls allowed.
+  virtual int ConservativeLowerBound() const { return 0; }
+  virtual int ConservativeUpperBound() const { return INT_MAX; }
+
+  // Returns true if and only if call_count calls will satisfy this
+  // cardinality.
+  virtual bool IsSatisfiedByCallCount(int call_count) const = 0;
+
+  // Returns true if and only if call_count calls will saturate this
+  // cardinality.
+  virtual bool IsSaturatedByCallCount(int call_count) const = 0;
+
+  // Describes self to an ostream.
+  virtual void DescribeTo(::std::ostream* os) const = 0;
+};
+
+// A Cardinality is a copyable and IMMUTABLE (except by assignment)
+// object that specifies how many times a mock function is expected to
+// be called.  The implementation of Cardinality is just a std::shared_ptr
+// to const CardinalityInterface. Don't inherit from Cardinality!
+class GTEST_API_ Cardinality {
+ public:
+  // Constructs a null cardinality.  Needed for storing Cardinality
+  // objects in STL containers.
+  Cardinality() {}
+
+  // Constructs a Cardinality from its implementation.
+  explicit Cardinality(const CardinalityInterface* impl) : impl_(impl) {}
+
+  // Conservative estimate on the lower/upper bound of the number of
+  // calls allowed.
+  int ConservativeLowerBound() const { return impl_->ConservativeLowerBound(); }
+  int ConservativeUpperBound() const { return impl_->ConservativeUpperBound(); }
+
+  // Returns true if and only if call_count calls will satisfy this
+  // cardinality.
+  bool IsSatisfiedByCallCount(int call_count) const {
+    return impl_->IsSatisfiedByCallCount(call_count);
+  }
+
+  // Returns true if and only if call_count calls will saturate this
+  // cardinality.
+  bool IsSaturatedByCallCount(int call_count) const {
+    return impl_->IsSaturatedByCallCount(call_count);
+  }
+
+  // Returns true if and only if call_count calls will over-saturate this
+  // cardinality, i.e. exceed the maximum number of allowed calls.
+  bool IsOverSaturatedByCallCount(int call_count) const {
+    return impl_->IsSaturatedByCallCount(call_count) &&
+        !impl_->IsSatisfiedByCallCount(call_count);
+  }
+
+  // Describes self to an ostream
+  void DescribeTo(::std::ostream* os) const { impl_->DescribeTo(os); }
+
+  // Describes the given actual call count to an ostream.
+  static void DescribeActualCallCountTo(int actual_call_count,
+                                        ::std::ostream* os);
+
+ private:
+  std::shared_ptr<const CardinalityInterface> impl_;
+};
+
+// Creates a cardinality that allows at least n calls.
+GTEST_API_ Cardinality AtLeast(int n);
+
+// Creates a cardinality that allows at most n calls.
+GTEST_API_ Cardinality AtMost(int n);
+
+// Creates a cardinality that allows any number of calls.
+GTEST_API_ Cardinality AnyNumber();
+
+// Creates a cardinality that allows between min and max calls.
+GTEST_API_ Cardinality Between(int min, int max);
+
+// Creates a cardinality that allows exactly n calls.
+GTEST_API_ Cardinality Exactly(int n);
+
+// Creates a cardinality from its implementation.
+inline Cardinality MakeCardinality(const CardinalityInterface* c) {
+  return Cardinality(c);
+}
+
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_CARDINALITIES_H_
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file implements MOCK_METHOD.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_FUNCTION_MOCKER_H_  // NOLINT
+#define GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_FUNCTION_MOCKER_H_  // NOLINT
+
+#include <type_traits>  // IWYU pragma: keep
+#include <utility>      // IWYU pragma: keep
+
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file implements the ON_CALL() and EXPECT_CALL() macros.
+//
+// A user can use the ON_CALL() macro to specify the default action of
+// a mock method.  The syntax is:
+//
+//   ON_CALL(mock_object, Method(argument-matchers))
+//       .With(multi-argument-matcher)
+//       .WillByDefault(action);
+//
+//  where the .With() clause is optional.
+//
+// A user can use the EXPECT_CALL() macro to specify an expectation on
+// a mock method.  The syntax is:
+//
+//   EXPECT_CALL(mock_object, Method(argument-matchers))
+//       .With(multi-argument-matchers)
+//       .Times(cardinality)
+//       .InSequence(sequences)
+//       .After(expectations)
+//       .WillOnce(action)
+//       .WillRepeatedly(action)
+//       .RetiresOnSaturation();
+//
+// where all clauses are optional, and .InSequence()/.After()/
+// .WillOnce() can appear any number of times.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_SPEC_BUILDERS_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_SPEC_BUILDERS_H_
+
+#include <functional>
+#include <map>
+#include <memory>
+#include <set>
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// The MATCHER* family of macros can be used in a namespace scope to
+// define custom matchers easily.
+//
+// Basic Usage
+// ===========
+//
+// The syntax
+//
+//   MATCHER(name, description_string) { statements; }
+//
+// defines a matcher with the given name that executes the statements,
+// which must return a bool to indicate if the match succeeds.  Inside
+// the statements, you can refer to the value being matched by 'arg',
+// and refer to its type by 'arg_type'.
+//
+// The description string documents what the matcher does, and is used
+// to generate the failure message when the match fails.  Since a
+// MATCHER() is usually defined in a header file shared by multiple
+// C++ source files, we require the description to be a C-string
+// literal to avoid possible side effects.  It can be empty, in which
+// case we'll use the sequence of words in the matcher name as the
+// description.
+//
+// For example:
+//
+//   MATCHER(IsEven, "") { return (arg % 2) == 0; }
+//
+// allows you to write
+//
+//   // Expects mock_foo.Bar(n) to be called where n is even.
+//   EXPECT_CALL(mock_foo, Bar(IsEven()));
+//
+// or,
+//
+//   // Verifies that the value of some_expression is even.
+//   EXPECT_THAT(some_expression, IsEven());
+//
+// If the above assertion fails, it will print something like:
+//
+//   Value of: some_expression
+//   Expected: is even
+//     Actual: 7
+//
+// where the description "is even" is automatically calculated from the
+// matcher name IsEven.
+//
+// Argument Type
+// =============
+//
+// Note that the type of the value being matched (arg_type) is
+// determined by the context in which you use the matcher and is
+// supplied to you by the compiler, so you don't need to worry about
+// declaring it (nor can you).  This allows the matcher to be
+// polymorphic.  For example, IsEven() can be used to match any type
+// where the value of "(arg % 2) == 0" can be implicitly converted to
+// a bool.  In the "Bar(IsEven())" example above, if method Bar()
+// takes an int, 'arg_type' will be int; if it takes an unsigned long,
+// 'arg_type' will be unsigned long; and so on.
+//
+// Parameterizing Matchers
+// =======================
+//
+// Sometimes you'll want to parameterize the matcher.  For that you
+// can use another macro:
+//
+//   MATCHER_P(name, param_name, description_string) { statements; }
+//
+// For example:
+//
+//   MATCHER_P(HasAbsoluteValue, value, "") { return abs(arg) == value; }
+//
+// will allow you to write:
+//
+//   EXPECT_THAT(Blah("a"), HasAbsoluteValue(n));
+//
+// which may lead to this message (assuming n is 10):
+//
+//   Value of: Blah("a")
+//   Expected: has absolute value 10
+//     Actual: -9
+//
+// Note that both the matcher description and its parameter are
+// printed, making the message human-friendly.
+//
+// In the matcher definition body, you can write 'foo_type' to
+// reference the type of a parameter named 'foo'.  For example, in the
+// body of MATCHER_P(HasAbsoluteValue, value) above, you can write
+// 'value_type' to refer to the type of 'value'.
+//
+// We also provide MATCHER_P2, MATCHER_P3, ..., up to MATCHER_P$n to
+// support multi-parameter matchers.
+//
+// Describing Parameterized Matchers
+// =================================
+//
+// The last argument to MATCHER*() is a string-typed expression.  The
+// expression can reference all of the matcher's parameters and a
+// special bool-typed variable named 'negation'.  When 'negation' is
+// false, the expression should evaluate to the matcher's description;
+// otherwise it should evaluate to the description of the negation of
+// the matcher.  For example,
+//
+//   using testing::PrintToString;
+//
+//   MATCHER_P2(InClosedRange, low, hi,
+//       std::string(negation ? "is not" : "is") + " in range [" +
+//       PrintToString(low) + ", " + PrintToString(hi) + "]") {
+//     return low <= arg && arg <= hi;
+//   }
+//   ...
+//   EXPECT_THAT(3, InClosedRange(4, 6));
+//   EXPECT_THAT(3, Not(InClosedRange(2, 4)));
+//
+// would generate two failures that contain the text:
+//
+//   Expected: is in range [4, 6]
+//   ...
+//   Expected: is not in range [2, 4]
+//
+// If you specify "" as the description, the failure message will
+// contain the sequence of words in the matcher name followed by the
+// parameter values printed as a tuple.  For example,
+//
+//   MATCHER_P2(InClosedRange, low, hi, "") { ... }
+//   ...
+//   EXPECT_THAT(3, InClosedRange(4, 6));
+//   EXPECT_THAT(3, Not(InClosedRange(2, 4)));
+//
+// would generate two failures that contain the text:
+//
+//   Expected: in closed range (4, 6)
+//   ...
+//   Expected: not (in closed range (2, 4))
+//
+// Types of Matcher Parameters
+// ===========================
+//
+// For the purpose of typing, you can view
+//
+//   MATCHER_Pk(Foo, p1, ..., pk, description_string) { ... }
+//
+// as shorthand for
+//
+//   template <typename p1_type, ..., typename pk_type>
+//   FooMatcherPk<p1_type, ..., pk_type>
+//   Foo(p1_type p1, ..., pk_type pk) { ... }
+//
+// When you write Foo(v1, ..., vk), the compiler infers the types of
+// the parameters v1, ..., and vk for you.  If you are not happy with
+// the result of the type inference, you can specify the types by
+// explicitly instantiating the template, as in Foo<long, bool>(5,
+// false).  As said earlier, you don't get to (or need to) specify
+// 'arg_type' as that's determined by the context in which the matcher
+// is used.  You can assign the result of expression Foo(p1, ..., pk)
+// to a variable of type FooMatcherPk<p1_type, ..., pk_type>.  This
+// can be useful when composing matchers.
+//
+// While you can instantiate a matcher template with reference types,
+// passing the parameters by pointer usually makes your code more
+// readable.  If, however, you still want to pass a parameter by
+// reference, be aware that in the failure message generated by the
+// matcher you will see the value of the referenced object but not its
+// address.
+//
+// Explaining Match Results
+// ========================
+//
+// Sometimes the matcher description alone isn't enough to explain why
+// the match has failed or succeeded.  For example, when expecting a
+// long string, it can be very helpful to also print the diff between
+// the expected string and the actual one.  To achieve that, you can
+// optionally stream additional information to a special variable
+// named result_listener, whose type is a pointer to class
+// MatchResultListener:
+//
+//   MATCHER_P(EqualsLongString, str, "") {
+//     if (arg == str) return true;
+//
+//     *result_listener << "the difference: "
+///                     << DiffStrings(str, arg);
+//     return false;
+//   }
+//
+// Overloading Matchers
+// ====================
+//
+// You can overload matchers with different numbers of parameters:
+//
+//   MATCHER_P(Blah, a, description_string1) { ... }
+//   MATCHER_P2(Blah, a, b, description_string2) { ... }
+//
+// Caveats
+// =======
+//
+// When defining a new matcher, you should also consider implementing
+// MatcherInterface or using MakePolymorphicMatcher().  These
+// approaches require more work than the MATCHER* macros, but also
+// give you more control on the types of the value being matched and
+// the matcher parameters, which may leads to better compiler error
+// messages when the matcher is used wrong.  They also allow
+// overloading matchers based on parameter types (as opposed to just
+// based on the number of parameters).
+//
+// MATCHER*() can only be used in a namespace scope as templates cannot be
+// declared inside of a local class.
+//
+// More Information
+// ================
+//
+// To learn more about using these macros, please search for 'MATCHER'
+// on
+// https://github.com/google/googletest/blob/master/docs/gmock_cook_book.md
+//
+// This file also implements some commonly used argument matchers.  More
+// matchers can be defined by the user implementing the
+// MatcherInterface<T> interface if necessary.
+//
+// See googletest/include/gtest/gtest-matchers.h for the definition of class
+// Matcher, class MatcherInterface, and others.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_MATCHERS_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_MATCHERS_H_
+
+#include <algorithm>
+#include <cmath>
+#include <initializer_list>
+#include <iterator>
+#include <limits>
+#include <memory>
+#include <ostream>  // NOLINT
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+
+// MSVC warning C5046 is new as of VS2017 version 15.8.
+#if defined(_MSC_VER) && _MSC_VER >= 1915
+#define GMOCK_MAYBE_5046_ 5046
+#else
+#define GMOCK_MAYBE_5046_
+#endif
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(
+    4251 GMOCK_MAYBE_5046_ /* class A needs to have dll-interface to be used by
+                              clients of class B */
+    /* Symbol involving type with internal linkage not defined */)
+
+namespace testing {
+
+// To implement a matcher Foo for type T, define:
+//   1. a class FooMatcherImpl that implements the
+//      MatcherInterface<T> interface, and
+//   2. a factory function that creates a Matcher<T> object from a
+//      FooMatcherImpl*.
+//
+// The two-level delegation design makes it possible to allow a user
+// to write "v" instead of "Eq(v)" where a Matcher is expected, which
+// is impossible if we pass matchers by pointers.  It also eases
+// ownership management as Matcher objects can now be copied like
+// plain values.
+
+// A match result listener that stores the explanation in a string.
+class StringMatchResultListener : public MatchResultListener {
+ public:
+  StringMatchResultListener() : MatchResultListener(&ss_) {}
+
+  // Returns the explanation accumulated so far.
+  std::string str() const { return ss_.str(); }
+
+  // Clears the explanation accumulated so far.
+  void Clear() { ss_.str(""); }
+
+ private:
+  ::std::stringstream ss_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(StringMatchResultListener);
+};
+
+// Anything inside the 'internal' namespace IS INTERNAL IMPLEMENTATION
+// and MUST NOT BE USED IN USER CODE!!!
+namespace internal {
+
+// The MatcherCastImpl class template is a helper for implementing
+// MatcherCast().  We need this helper in order to partially
+// specialize the implementation of MatcherCast() (C++ allows
+// class/struct templates to be partially specialized, but not
+// function templates.).
+
+// This general version is used when MatcherCast()'s argument is a
+// polymorphic matcher (i.e. something that can be converted to a
+// Matcher but is not one yet; for example, Eq(value)) or a value (for
+// example, "hello").
+template <typename T, typename M>
+class MatcherCastImpl {
+ public:
+  static Matcher<T> Cast(const M& polymorphic_matcher_or_value) {
+    // M can be a polymorphic matcher, in which case we want to use
+    // its conversion operator to create Matcher<T>.  Or it can be a value
+    // that should be passed to the Matcher<T>'s constructor.
+    //
+    // We can't call Matcher<T>(polymorphic_matcher_or_value) when M is a
+    // polymorphic matcher because it'll be ambiguous if T has an implicit
+    // constructor from M (this usually happens when T has an implicit
+    // constructor from any type).
+    //
+    // It won't work to unconditionally implicit_cast
+    // polymorphic_matcher_or_value to Matcher<T> because it won't trigger
+    // a user-defined conversion from M to T if one exists (assuming M is
+    // a value).
+    return CastImpl(polymorphic_matcher_or_value,
+                    std::is_convertible<M, Matcher<T>>{},
+                    std::is_convertible<M, T>{});
+  }
+
+ private:
+  template <bool Ignore>
+  static Matcher<T> CastImpl(const M& polymorphic_matcher_or_value,
+                             std::true_type /* convertible_to_matcher */,
+                             std::integral_constant<bool, Ignore>) {
+    // M is implicitly convertible to Matcher<T>, which means that either
+    // M is a polymorphic matcher or Matcher<T> has an implicit constructor
+    // from M.  In both cases using the implicit conversion will produce a
+    // matcher.
+    //
+    // Even if T has an implicit constructor from M, it won't be called because
+    // creating Matcher<T> would require a chain of two user-defined conversions
+    // (first to create T from M and then to create Matcher<T> from T).
+    return polymorphic_matcher_or_value;
+  }
+
+  // M can't be implicitly converted to Matcher<T>, so M isn't a polymorphic
+  // matcher. It's a value of a type implicitly convertible to T. Use direct
+  // initialization to create a matcher.
+  static Matcher<T> CastImpl(const M& value,
+                             std::false_type /* convertible_to_matcher */,
+                             std::true_type /* convertible_to_T */) {
+    return Matcher<T>(ImplicitCast_<T>(value));
+  }
+
+  // M can't be implicitly converted to either Matcher<T> or T. Attempt to use
+  // polymorphic matcher Eq(value) in this case.
+  //
+  // Note that we first attempt to perform an implicit cast on the value and
+  // only fall back to the polymorphic Eq() matcher afterwards because the
+  // latter calls bool operator==(const Lhs& lhs, const Rhs& rhs) in the end
+  // which might be undefined even when Rhs is implicitly convertible to Lhs
+  // (e.g. std::pair<const int, int> vs. std::pair<int, int>).
+  //
+  // We don't define this method inline as we need the declaration of Eq().
+  static Matcher<T> CastImpl(const M& value,
+                             std::false_type /* convertible_to_matcher */,
+                             std::false_type /* convertible_to_T */);
+};
+
+// This more specialized version is used when MatcherCast()'s argument
+// is already a Matcher.  This only compiles when type T can be
+// statically converted to type U.
+template <typename T, typename U>
+class MatcherCastImpl<T, Matcher<U> > {
+ public:
+  static Matcher<T> Cast(const Matcher<U>& source_matcher) {
+    return Matcher<T>(new Impl(source_matcher));
+  }
+
+ private:
+  class Impl : public MatcherInterface<T> {
+   public:
+    explicit Impl(const Matcher<U>& source_matcher)
+        : source_matcher_(source_matcher) {}
+
+    // We delegate the matching logic to the source matcher.
+    bool MatchAndExplain(T x, MatchResultListener* listener) const override {
+      using FromType = typename std::remove_cv<typename std::remove_pointer<
+          typename std::remove_reference<T>::type>::type>::type;
+      using ToType = typename std::remove_cv<typename std::remove_pointer<
+          typename std::remove_reference<U>::type>::type>::type;
+      // Do not allow implicitly converting base*/& to derived*/&.
+      static_assert(
+          // Do not trigger if only one of them is a pointer. That implies a
+          // regular conversion and not a down_cast.
+          (std::is_pointer<typename std::remove_reference<T>::type>::value !=
+           std::is_pointer<typename std::remove_reference<U>::type>::value) ||
+              std::is_same<FromType, ToType>::value ||
+              !std::is_base_of<FromType, ToType>::value,
+          "Can't implicitly convert from <base> to <derived>");
+
+      // Do the cast to `U` explicitly if necessary.
+      // Otherwise, let implicit conversions do the trick.
+      using CastType =
+          typename std::conditional<std::is_convertible<T&, const U&>::value,
+                                    T&, U>::type;
+
+      return source_matcher_.MatchAndExplain(static_cast<CastType>(x),
+                                             listener);
+    }
+
+    void DescribeTo(::std::ostream* os) const override {
+      source_matcher_.DescribeTo(os);
+    }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      source_matcher_.DescribeNegationTo(os);
+    }
+
+   private:
+    const Matcher<U> source_matcher_;
+  };
+};
+
+// This even more specialized version is used for efficiently casting
+// a matcher to its own type.
+template <typename T>
+class MatcherCastImpl<T, Matcher<T> > {
+ public:
+  static Matcher<T> Cast(const Matcher<T>& matcher) { return matcher; }
+};
+
+// Template specialization for parameterless Matcher.
+template <typename Derived>
+class MatcherBaseImpl {
+ public:
+  MatcherBaseImpl() = default;
+
+  template <typename T>
+  operator ::testing::Matcher<T>() const {  // NOLINT(runtime/explicit)
+    return ::testing::Matcher<T>(new
+                                 typename Derived::template gmock_Impl<T>());
+  }
+};
+
+// Template specialization for Matcher with parameters.
+template <template <typename...> class Derived, typename... Ts>
+class MatcherBaseImpl<Derived<Ts...>> {
+ public:
+  // Mark the constructor explicit for single argument T to avoid implicit
+  // conversions.
+  template <typename E = std::enable_if<sizeof...(Ts) == 1>,
+            typename E::type* = nullptr>
+  explicit MatcherBaseImpl(Ts... params)
+      : params_(std::forward<Ts>(params)...) {}
+  template <typename E = std::enable_if<sizeof...(Ts) != 1>,
+            typename = typename E::type>
+  MatcherBaseImpl(Ts... params)  // NOLINT
+      : params_(std::forward<Ts>(params)...) {}
+
+  template <typename F>
+  operator ::testing::Matcher<F>() const {  // NOLINT(runtime/explicit)
+    return Apply<F>(MakeIndexSequence<sizeof...(Ts)>{});
+  }
+
+ private:
+  template <typename F, std::size_t... tuple_ids>
+  ::testing::Matcher<F> Apply(IndexSequence<tuple_ids...>) const {
+    return ::testing::Matcher<F>(
+        new typename Derived<Ts...>::template gmock_Impl<F>(
+            std::get<tuple_ids>(params_)...));
+  }
+
+  const std::tuple<Ts...> params_;
+};
+
+}  // namespace internal
+
+// In order to be safe and clear, casting between different matcher
+// types is done explicitly via MatcherCast<T>(m), which takes a
+// matcher m and returns a Matcher<T>.  It compiles only when T can be
+// statically converted to the argument type of m.
+template <typename T, typename M>
+inline Matcher<T> MatcherCast(const M& matcher) {
+  return internal::MatcherCastImpl<T, M>::Cast(matcher);
+}
+
+// This overload handles polymorphic matchers and values only since
+// monomorphic matchers are handled by the next one.
+template <typename T, typename M>
+inline Matcher<T> SafeMatcherCast(const M& polymorphic_matcher_or_value) {
+  return MatcherCast<T>(polymorphic_matcher_or_value);
+}
+
+// This overload handles monomorphic matchers.
+//
+// In general, if type T can be implicitly converted to type U, we can
+// safely convert a Matcher<U> to a Matcher<T> (i.e. Matcher is
+// contravariant): just keep a copy of the original Matcher<U>, convert the
+// argument from type T to U, and then pass it to the underlying Matcher<U>.
+// The only exception is when U is a reference and T is not, as the
+// underlying Matcher<U> may be interested in the argument's address, which
+// is not preserved in the conversion from T to U.
+template <typename T, typename U>
+inline Matcher<T> SafeMatcherCast(const Matcher<U>& matcher) {
+  // Enforce that T can be implicitly converted to U.
+  static_assert(std::is_convertible<const T&, const U&>::value,
+                "T must be implicitly convertible to U");
+  // Enforce that we are not converting a non-reference type T to a reference
+  // type U.
+  GTEST_COMPILE_ASSERT_(
+      std::is_reference<T>::value || !std::is_reference<U>::value,
+      cannot_convert_non_reference_arg_to_reference);
+  // In case both T and U are arithmetic types, enforce that the
+  // conversion is not lossy.
+  typedef GTEST_REMOVE_REFERENCE_AND_CONST_(T) RawT;
+  typedef GTEST_REMOVE_REFERENCE_AND_CONST_(U) RawU;
+  constexpr bool kTIsOther = GMOCK_KIND_OF_(RawT) == internal::kOther;
+  constexpr bool kUIsOther = GMOCK_KIND_OF_(RawU) == internal::kOther;
+  GTEST_COMPILE_ASSERT_(
+      kTIsOther || kUIsOther ||
+      (internal::LosslessArithmeticConvertible<RawT, RawU>::value),
+      conversion_of_arithmetic_types_must_be_lossless);
+  return MatcherCast<T>(matcher);
+}
+
+// A<T>() returns a matcher that matches any value of type T.
+template <typename T>
+Matcher<T> A();
+
+// Anything inside the 'internal' namespace IS INTERNAL IMPLEMENTATION
+// and MUST NOT BE USED IN USER CODE!!!
+namespace internal {
+
+// If the explanation is not empty, prints it to the ostream.
+inline void PrintIfNotEmpty(const std::string& explanation,
+                            ::std::ostream* os) {
+  if (explanation != "" && os != nullptr) {
+    *os << ", " << explanation;
+  }
+}
+
+// Returns true if the given type name is easy to read by a human.
+// This is used to decide whether printing the type of a value might
+// be helpful.
+inline bool IsReadableTypeName(const std::string& type_name) {
+  // We consider a type name readable if it's short or doesn't contain
+  // a template or function type.
+  return (type_name.length() <= 20 ||
+          type_name.find_first_of("<(") == std::string::npos);
+}
+
+// Matches the value against the given matcher, prints the value and explains
+// the match result to the listener. Returns the match result.
+// 'listener' must not be NULL.
+// Value cannot be passed by const reference, because some matchers take a
+// non-const argument.
+template <typename Value, typename T>
+bool MatchPrintAndExplain(Value& value, const Matcher<T>& matcher,
+                          MatchResultListener* listener) {
+  if (!listener->IsInterested()) {
+    // If the listener is not interested, we do not need to construct the
+    // inner explanation.
+    return matcher.Matches(value);
+  }
+
+  StringMatchResultListener inner_listener;
+  const bool match = matcher.MatchAndExplain(value, &inner_listener);
+
+  UniversalPrint(value, listener->stream());
+#if GTEST_HAS_RTTI
+  const std::string& type_name = GetTypeName<Value>();
+  if (IsReadableTypeName(type_name))
+    *listener->stream() << " (of type " << type_name << ")";
+#endif
+  PrintIfNotEmpty(inner_listener.str(), listener->stream());
+
+  return match;
+}
+
+// An internal helper class for doing compile-time loop on a tuple's
+// fields.
+template <size_t N>
+class TuplePrefix {
+ public:
+  // TuplePrefix<N>::Matches(matcher_tuple, value_tuple) returns true
+  // if and only if the first N fields of matcher_tuple matches
+  // the first N fields of value_tuple, respectively.
+  template <typename MatcherTuple, typename ValueTuple>
+  static bool Matches(const MatcherTuple& matcher_tuple,
+                      const ValueTuple& value_tuple) {
+    return TuplePrefix<N - 1>::Matches(matcher_tuple, value_tuple) &&
+           std::get<N - 1>(matcher_tuple).Matches(std::get<N - 1>(value_tuple));
+  }
+
+  // TuplePrefix<N>::ExplainMatchFailuresTo(matchers, values, os)
+  // describes failures in matching the first N fields of matchers
+  // against the first N fields of values.  If there is no failure,
+  // nothing will be streamed to os.
+  template <typename MatcherTuple, typename ValueTuple>
+  static void ExplainMatchFailuresTo(const MatcherTuple& matchers,
+                                     const ValueTuple& values,
+                                     ::std::ostream* os) {
+    // First, describes failures in the first N - 1 fields.
+    TuplePrefix<N - 1>::ExplainMatchFailuresTo(matchers, values, os);
+
+    // Then describes the failure (if any) in the (N - 1)-th (0-based)
+    // field.
+    typename std::tuple_element<N - 1, MatcherTuple>::type matcher =
+        std::get<N - 1>(matchers);
+    typedef typename std::tuple_element<N - 1, ValueTuple>::type Value;
+    const Value& value = std::get<N - 1>(values);
+    StringMatchResultListener listener;
+    if (!matcher.MatchAndExplain(value, &listener)) {
+      *os << "  Expected arg #" << N - 1 << ": ";
+      std::get<N - 1>(matchers).DescribeTo(os);
+      *os << "\n           Actual: ";
+      // We remove the reference in type Value to prevent the
+      // universal printer from printing the address of value, which
+      // isn't interesting to the user most of the time.  The
+      // matcher's MatchAndExplain() method handles the case when
+      // the address is interesting.
+      internal::UniversalPrint(value, os);
+      PrintIfNotEmpty(listener.str(), os);
+      *os << "\n";
+    }
+  }
+};
+
+// The base case.
+template <>
+class TuplePrefix<0> {
+ public:
+  template <typename MatcherTuple, typename ValueTuple>
+  static bool Matches(const MatcherTuple& /* matcher_tuple */,
+                      const ValueTuple& /* value_tuple */) {
+    return true;
+  }
+
+  template <typename MatcherTuple, typename ValueTuple>
+  static void ExplainMatchFailuresTo(const MatcherTuple& /* matchers */,
+                                     const ValueTuple& /* values */,
+                                     ::std::ostream* /* os */) {}
+};
+
+// TupleMatches(matcher_tuple, value_tuple) returns true if and only if
+// all matchers in matcher_tuple match the corresponding fields in
+// value_tuple.  It is a compiler error if matcher_tuple and
+// value_tuple have different number of fields or incompatible field
+// types.
+template <typename MatcherTuple, typename ValueTuple>
+bool TupleMatches(const MatcherTuple& matcher_tuple,
+                  const ValueTuple& value_tuple) {
+  // Makes sure that matcher_tuple and value_tuple have the same
+  // number of fields.
+  GTEST_COMPILE_ASSERT_(std::tuple_size<MatcherTuple>::value ==
+                            std::tuple_size<ValueTuple>::value,
+                        matcher_and_value_have_different_numbers_of_fields);
+  return TuplePrefix<std::tuple_size<ValueTuple>::value>::Matches(matcher_tuple,
+                                                                  value_tuple);
+}
+
+// Describes failures in matching matchers against values.  If there
+// is no failure, nothing will be streamed to os.
+template <typename MatcherTuple, typename ValueTuple>
+void ExplainMatchFailureTupleTo(const MatcherTuple& matchers,
+                                const ValueTuple& values,
+                                ::std::ostream* os) {
+  TuplePrefix<std::tuple_size<MatcherTuple>::value>::ExplainMatchFailuresTo(
+      matchers, values, os);
+}
+
+// TransformTupleValues and its helper.
+//
+// TransformTupleValuesHelper hides the internal machinery that
+// TransformTupleValues uses to implement a tuple traversal.
+template <typename Tuple, typename Func, typename OutIter>
+class TransformTupleValuesHelper {
+ private:
+  typedef ::std::tuple_size<Tuple> TupleSize;
+
+ public:
+  // For each member of tuple 't', taken in order, evaluates '*out++ = f(t)'.
+  // Returns the final value of 'out' in case the caller needs it.
+  static OutIter Run(Func f, const Tuple& t, OutIter out) {
+    return IterateOverTuple<Tuple, TupleSize::value>()(f, t, out);
+  }
+
+ private:
+  template <typename Tup, size_t kRemainingSize>
+  struct IterateOverTuple {
+    OutIter operator() (Func f, const Tup& t, OutIter out) const {
+      *out++ = f(::std::get<TupleSize::value - kRemainingSize>(t));
+      return IterateOverTuple<Tup, kRemainingSize - 1>()(f, t, out);
+    }
+  };
+  template <typename Tup>
+  struct IterateOverTuple<Tup, 0> {
+    OutIter operator() (Func /* f */, const Tup& /* t */, OutIter out) const {
+      return out;
+    }
+  };
+};
+
+// Successively invokes 'f(element)' on each element of the tuple 't',
+// appending each result to the 'out' iterator. Returns the final value
+// of 'out'.
+template <typename Tuple, typename Func, typename OutIter>
+OutIter TransformTupleValues(Func f, const Tuple& t, OutIter out) {
+  return TransformTupleValuesHelper<Tuple, Func, OutIter>::Run(f, t, out);
+}
+
+// Implements _, a matcher that matches any value of any
+// type.  This is a polymorphic matcher, so we need a template type
+// conversion operator to make it appearing as a Matcher<T> for any
+// type T.
+class AnythingMatcher {
+ public:
+  using is_gtest_matcher = void;
+
+  template <typename T>
+  bool MatchAndExplain(const T& /* x */, std::ostream* /* listener */) const {
+    return true;
+  }
+  void DescribeTo(std::ostream* os) const { *os << "is anything"; }
+  void DescribeNegationTo(::std::ostream* os) const {
+    // This is mostly for completeness' sake, as it's not very useful
+    // to write Not(A<bool>()).  However we cannot completely rule out
+    // such a possibility, and it doesn't hurt to be prepared.
+    *os << "never matches";
+  }
+};
+
+// Implements the polymorphic IsNull() matcher, which matches any raw or smart
+// pointer that is NULL.
+class IsNullMatcher {
+ public:
+  template <typename Pointer>
+  bool MatchAndExplain(const Pointer& p,
+                       MatchResultListener* /* listener */) const {
+    return p == nullptr;
+  }
+
+  void DescribeTo(::std::ostream* os) const { *os << "is NULL"; }
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "isn't NULL";
+  }
+};
+
+// Implements the polymorphic NotNull() matcher, which matches any raw or smart
+// pointer that is not NULL.
+class NotNullMatcher {
+ public:
+  template <typename Pointer>
+  bool MatchAndExplain(const Pointer& p,
+                       MatchResultListener* /* listener */) const {
+    return p != nullptr;
+  }
+
+  void DescribeTo(::std::ostream* os) const { *os << "isn't NULL"; }
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "is NULL";
+  }
+};
+
+// Ref(variable) matches any argument that is a reference to
+// 'variable'.  This matcher is polymorphic as it can match any
+// super type of the type of 'variable'.
+//
+// The RefMatcher template class implements Ref(variable).  It can
+// only be instantiated with a reference type.  This prevents a user
+// from mistakenly using Ref(x) to match a non-reference function
+// argument.  For example, the following will righteously cause a
+// compiler error:
+//
+//   int n;
+//   Matcher<int> m1 = Ref(n);   // This won't compile.
+//   Matcher<int&> m2 = Ref(n);  // This will compile.
+template <typename T>
+class RefMatcher;
+
+template <typename T>
+class RefMatcher<T&> {
+  // Google Mock is a generic framework and thus needs to support
+  // mocking any function types, including those that take non-const
+  // reference arguments.  Therefore the template parameter T (and
+  // Super below) can be instantiated to either a const type or a
+  // non-const type.
+ public:
+  // RefMatcher() takes a T& instead of const T&, as we want the
+  // compiler to catch using Ref(const_value) as a matcher for a
+  // non-const reference.
+  explicit RefMatcher(T& x) : object_(x) {}  // NOLINT
+
+  template <typename Super>
+  operator Matcher<Super&>() const {
+    // By passing object_ (type T&) to Impl(), which expects a Super&,
+    // we make sure that Super is a super type of T.  In particular,
+    // this catches using Ref(const_value) as a matcher for a
+    // non-const reference, as you cannot implicitly convert a const
+    // reference to a non-const reference.
+    return MakeMatcher(new Impl<Super>(object_));
+  }
+
+ private:
+  template <typename Super>
+  class Impl : public MatcherInterface<Super&> {
+   public:
+    explicit Impl(Super& x) : object_(x) {}  // NOLINT
+
+    // MatchAndExplain() takes a Super& (as opposed to const Super&)
+    // in order to match the interface MatcherInterface<Super&>.
+    bool MatchAndExplain(Super& x,
+                         MatchResultListener* listener) const override {
+      *listener << "which is located @" << static_cast<const void*>(&x);
+      return &x == &object_;
+    }
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "references the variable ";
+      UniversalPrinter<Super&>::Print(object_, os);
+    }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "does not reference the variable ";
+      UniversalPrinter<Super&>::Print(object_, os);
+    }
+
+   private:
+    const Super& object_;
+  };
+
+  T& object_;
+};
+
+// Polymorphic helper functions for narrow and wide string matchers.
+inline bool CaseInsensitiveCStringEquals(const char* lhs, const char* rhs) {
+  return String::CaseInsensitiveCStringEquals(lhs, rhs);
+}
+
+inline bool CaseInsensitiveCStringEquals(const wchar_t* lhs,
+                                         const wchar_t* rhs) {
+  return String::CaseInsensitiveWideCStringEquals(lhs, rhs);
+}
+
+// String comparison for narrow or wide strings that can have embedded NUL
+// characters.
+template <typename StringType>
+bool CaseInsensitiveStringEquals(const StringType& s1,
+                                 const StringType& s2) {
+  // Are the heads equal?
+  if (!CaseInsensitiveCStringEquals(s1.c_str(), s2.c_str())) {
+    return false;
+  }
+
+  // Skip the equal heads.
+  const typename StringType::value_type nul = 0;
+  const size_t i1 = s1.find(nul), i2 = s2.find(nul);
+
+  // Are we at the end of either s1 or s2?
+  if (i1 == StringType::npos || i2 == StringType::npos) {
+    return i1 == i2;
+  }
+
+  // Are the tails equal?
+  return CaseInsensitiveStringEquals(s1.substr(i1 + 1), s2.substr(i2 + 1));
+}
+
+// String matchers.
+
+// Implements equality-based string matchers like StrEq, StrCaseNe, and etc.
+template <typename StringType>
+class StrEqualityMatcher {
+ public:
+  StrEqualityMatcher(StringType str, bool expect_eq, bool case_sensitive)
+      : string_(std::move(str)),
+        expect_eq_(expect_eq),
+        case_sensitive_(case_sensitive) {}
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  bool MatchAndExplain(const internal::StringView& s,
+                       MatchResultListener* listener) const {
+    // This should fail to compile if StringView is used with wide
+    // strings.
+    const StringType& str = std::string(s);
+    return MatchAndExplain(str, listener);
+  }
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+  // Accepts pointer types, particularly:
+  //   const char*
+  //   char*
+  //   const wchar_t*
+  //   wchar_t*
+  template <typename CharType>
+  bool MatchAndExplain(CharType* s, MatchResultListener* listener) const {
+    if (s == nullptr) {
+      return !expect_eq_;
+    }
+    return MatchAndExplain(StringType(s), listener);
+  }
+
+  // Matches anything that can convert to StringType.
+  //
+  // This is a template, not just a plain function with const StringType&,
+  // because StringView has some interfering non-explicit constructors.
+  template <typename MatcheeStringType>
+  bool MatchAndExplain(const MatcheeStringType& s,
+                       MatchResultListener* /* listener */) const {
+    const StringType s2(s);
+    const bool eq = case_sensitive_ ? s2 == string_ :
+        CaseInsensitiveStringEquals(s2, string_);
+    return expect_eq_ == eq;
+  }
+
+  void DescribeTo(::std::ostream* os) const {
+    DescribeToHelper(expect_eq_, os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const {
+    DescribeToHelper(!expect_eq_, os);
+  }
+
+ private:
+  void DescribeToHelper(bool expect_eq, ::std::ostream* os) const {
+    *os << (expect_eq ? "is " : "isn't ");
+    *os << "equal to ";
+    if (!case_sensitive_) {
+      *os << "(ignoring case) ";
+    }
+    UniversalPrint(string_, os);
+  }
+
+  const StringType string_;
+  const bool expect_eq_;
+  const bool case_sensitive_;
+};
+
+// Implements the polymorphic HasSubstr(substring) matcher, which
+// can be used as a Matcher<T> as long as T can be converted to a
+// string.
+template <typename StringType>
+class HasSubstrMatcher {
+ public:
+  explicit HasSubstrMatcher(const StringType& substring)
+      : substring_(substring) {}
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  bool MatchAndExplain(const internal::StringView& s,
+                       MatchResultListener* listener) const {
+    // This should fail to compile if StringView is used with wide
+    // strings.
+    const StringType& str = std::string(s);
+    return MatchAndExplain(str, listener);
+  }
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+  // Accepts pointer types, particularly:
+  //   const char*
+  //   char*
+  //   const wchar_t*
+  //   wchar_t*
+  template <typename CharType>
+  bool MatchAndExplain(CharType* s, MatchResultListener* listener) const {
+    return s != nullptr && MatchAndExplain(StringType(s), listener);
+  }
+
+  // Matches anything that can convert to StringType.
+  //
+  // This is a template, not just a plain function with const StringType&,
+  // because StringView has some interfering non-explicit constructors.
+  template <typename MatcheeStringType>
+  bool MatchAndExplain(const MatcheeStringType& s,
+                       MatchResultListener* /* listener */) const {
+    return StringType(s).find(substring_) != StringType::npos;
+  }
+
+  // Describes what this matcher matches.
+  void DescribeTo(::std::ostream* os) const {
+    *os << "has substring ";
+    UniversalPrint(substring_, os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "has no substring ";
+    UniversalPrint(substring_, os);
+  }
+
+ private:
+  const StringType substring_;
+};
+
+// Implements the polymorphic StartsWith(substring) matcher, which
+// can be used as a Matcher<T> as long as T can be converted to a
+// string.
+template <typename StringType>
+class StartsWithMatcher {
+ public:
+  explicit StartsWithMatcher(const StringType& prefix) : prefix_(prefix) {
+  }
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  bool MatchAndExplain(const internal::StringView& s,
+                       MatchResultListener* listener) const {
+    // This should fail to compile if StringView is used with wide
+    // strings.
+    const StringType& str = std::string(s);
+    return MatchAndExplain(str, listener);
+  }
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+  // Accepts pointer types, particularly:
+  //   const char*
+  //   char*
+  //   const wchar_t*
+  //   wchar_t*
+  template <typename CharType>
+  bool MatchAndExplain(CharType* s, MatchResultListener* listener) const {
+    return s != nullptr && MatchAndExplain(StringType(s), listener);
+  }
+
+  // Matches anything that can convert to StringType.
+  //
+  // This is a template, not just a plain function with const StringType&,
+  // because StringView has some interfering non-explicit constructors.
+  template <typename MatcheeStringType>
+  bool MatchAndExplain(const MatcheeStringType& s,
+                       MatchResultListener* /* listener */) const {
+    const StringType& s2(s);
+    return s2.length() >= prefix_.length() &&
+        s2.substr(0, prefix_.length()) == prefix_;
+  }
+
+  void DescribeTo(::std::ostream* os) const {
+    *os << "starts with ";
+    UniversalPrint(prefix_, os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "doesn't start with ";
+    UniversalPrint(prefix_, os);
+  }
+
+ private:
+  const StringType prefix_;
+};
+
+// Implements the polymorphic EndsWith(substring) matcher, which
+// can be used as a Matcher<T> as long as T can be converted to a
+// string.
+template <typename StringType>
+class EndsWithMatcher {
+ public:
+  explicit EndsWithMatcher(const StringType& suffix) : suffix_(suffix) {}
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  bool MatchAndExplain(const internal::StringView& s,
+                       MatchResultListener* listener) const {
+    // This should fail to compile if StringView is used with wide
+    // strings.
+    const StringType& str = std::string(s);
+    return MatchAndExplain(str, listener);
+  }
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+  // Accepts pointer types, particularly:
+  //   const char*
+  //   char*
+  //   const wchar_t*
+  //   wchar_t*
+  template <typename CharType>
+  bool MatchAndExplain(CharType* s, MatchResultListener* listener) const {
+    return s != nullptr && MatchAndExplain(StringType(s), listener);
+  }
+
+  // Matches anything that can convert to StringType.
+  //
+  // This is a template, not just a plain function with const StringType&,
+  // because StringView has some interfering non-explicit constructors.
+  template <typename MatcheeStringType>
+  bool MatchAndExplain(const MatcheeStringType& s,
+                       MatchResultListener* /* listener */) const {
+    const StringType& s2(s);
+    return s2.length() >= suffix_.length() &&
+        s2.substr(s2.length() - suffix_.length()) == suffix_;
+  }
+
+  void DescribeTo(::std::ostream* os) const {
+    *os << "ends with ";
+    UniversalPrint(suffix_, os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "doesn't end with ";
+    UniversalPrint(suffix_, os);
+  }
+
+ private:
+  const StringType suffix_;
+};
+
+// Implements a matcher that compares the two fields of a 2-tuple
+// using one of the ==, <=, <, etc, operators.  The two fields being
+// compared don't have to have the same type.
+//
+// The matcher defined here is polymorphic (for example, Eq() can be
+// used to match a std::tuple<int, short>, a std::tuple<const long&, double>,
+// etc).  Therefore we use a template type conversion operator in the
+// implementation.
+template <typename D, typename Op>
+class PairMatchBase {
+ public:
+  template <typename T1, typename T2>
+  operator Matcher<::std::tuple<T1, T2>>() const {
+    return Matcher<::std::tuple<T1, T2>>(new Impl<const ::std::tuple<T1, T2>&>);
+  }
+  template <typename T1, typename T2>
+  operator Matcher<const ::std::tuple<T1, T2>&>() const {
+    return MakeMatcher(new Impl<const ::std::tuple<T1, T2>&>);
+  }
+
+ private:
+  static ::std::ostream& GetDesc(::std::ostream& os) {  // NOLINT
+    return os << D::Desc();
+  }
+
+  template <typename Tuple>
+  class Impl : public MatcherInterface<Tuple> {
+   public:
+    bool MatchAndExplain(Tuple args,
+                         MatchResultListener* /* listener */) const override {
+      return Op()(::std::get<0>(args), ::std::get<1>(args));
+    }
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "are " << GetDesc;
+    }
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "aren't " << GetDesc;
+    }
+  };
+};
+
+class Eq2Matcher : public PairMatchBase<Eq2Matcher, AnyEq> {
+ public:
+  static const char* Desc() { return "an equal pair"; }
+};
+class Ne2Matcher : public PairMatchBase<Ne2Matcher, AnyNe> {
+ public:
+  static const char* Desc() { return "an unequal pair"; }
+};
+class Lt2Matcher : public PairMatchBase<Lt2Matcher, AnyLt> {
+ public:
+  static const char* Desc() { return "a pair where the first < the second"; }
+};
+class Gt2Matcher : public PairMatchBase<Gt2Matcher, AnyGt> {
+ public:
+  static const char* Desc() { return "a pair where the first > the second"; }
+};
+class Le2Matcher : public PairMatchBase<Le2Matcher, AnyLe> {
+ public:
+  static const char* Desc() { return "a pair where the first <= the second"; }
+};
+class Ge2Matcher : public PairMatchBase<Ge2Matcher, AnyGe> {
+ public:
+  static const char* Desc() { return "a pair where the first >= the second"; }
+};
+
+// Implements the Not(...) matcher for a particular argument type T.
+// We do not nest it inside the NotMatcher class template, as that
+// will prevent different instantiations of NotMatcher from sharing
+// the same NotMatcherImpl<T> class.
+template <typename T>
+class NotMatcherImpl : public MatcherInterface<const T&> {
+ public:
+  explicit NotMatcherImpl(const Matcher<T>& matcher)
+      : matcher_(matcher) {}
+
+  bool MatchAndExplain(const T& x,
+                       MatchResultListener* listener) const override {
+    return !matcher_.MatchAndExplain(x, listener);
+  }
+
+  void DescribeTo(::std::ostream* os) const override {
+    matcher_.DescribeNegationTo(os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const override {
+    matcher_.DescribeTo(os);
+  }
+
+ private:
+  const Matcher<T> matcher_;
+};
+
+// Implements the Not(m) matcher, which matches a value that doesn't
+// match matcher m.
+template <typename InnerMatcher>
+class NotMatcher {
+ public:
+  explicit NotMatcher(InnerMatcher matcher) : matcher_(matcher) {}
+
+  // This template type conversion operator allows Not(m) to be used
+  // to match any type m can match.
+  template <typename T>
+  operator Matcher<T>() const {
+    return Matcher<T>(new NotMatcherImpl<T>(SafeMatcherCast<T>(matcher_)));
+  }
+
+ private:
+  InnerMatcher matcher_;
+};
+
+// Implements the AllOf(m1, m2) matcher for a particular argument type
+// T. We do not nest it inside the BothOfMatcher class template, as
+// that will prevent different instantiations of BothOfMatcher from
+// sharing the same BothOfMatcherImpl<T> class.
+template <typename T>
+class AllOfMatcherImpl : public MatcherInterface<const T&> {
+ public:
+  explicit AllOfMatcherImpl(std::vector<Matcher<T> > matchers)
+      : matchers_(std::move(matchers)) {}
+
+  void DescribeTo(::std::ostream* os) const override {
+    *os << "(";
+    for (size_t i = 0; i < matchers_.size(); ++i) {
+      if (i != 0) *os << ") and (";
+      matchers_[i].DescribeTo(os);
+    }
+    *os << ")";
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const override {
+    *os << "(";
+    for (size_t i = 0; i < matchers_.size(); ++i) {
+      if (i != 0) *os << ") or (";
+      matchers_[i].DescribeNegationTo(os);
+    }
+    *os << ")";
+  }
+
+  bool MatchAndExplain(const T& x,
+                       MatchResultListener* listener) const override {
+    // If either matcher1_ or matcher2_ doesn't match x, we only need
+    // to explain why one of them fails.
+    std::string all_match_result;
+
+    for (size_t i = 0; i < matchers_.size(); ++i) {
+      StringMatchResultListener slistener;
+      if (matchers_[i].MatchAndExplain(x, &slistener)) {
+        if (all_match_result.empty()) {
+          all_match_result = slistener.str();
+        } else {
+          std::string result = slistener.str();
+          if (!result.empty()) {
+            all_match_result += ", and ";
+            all_match_result += result;
+          }
+        }
+      } else {
+        *listener << slistener.str();
+        return false;
+      }
+    }
+
+    // Otherwise we need to explain why *both* of them match.
+    *listener << all_match_result;
+    return true;
+  }
+
+ private:
+  const std::vector<Matcher<T> > matchers_;
+};
+
+// VariadicMatcher is used for the variadic implementation of
+// AllOf(m_1, m_2, ...) and AnyOf(m_1, m_2, ...).
+// CombiningMatcher<T> is used to recursively combine the provided matchers
+// (of type Args...).
+template <template <typename T> class CombiningMatcher, typename... Args>
+class VariadicMatcher {
+ public:
+  VariadicMatcher(const Args&... matchers)  // NOLINT
+      : matchers_(matchers...) {
+    static_assert(sizeof...(Args) > 0, "Must have at least one matcher.");
+  }
+
+  VariadicMatcher(const VariadicMatcher&) = default;
+  VariadicMatcher& operator=(const VariadicMatcher&) = delete;
+
+  // This template type conversion operator allows an
+  // VariadicMatcher<Matcher1, Matcher2...> object to match any type that
+  // all of the provided matchers (Matcher1, Matcher2, ...) can match.
+  template <typename T>
+  operator Matcher<T>() const {
+    std::vector<Matcher<T> > values;
+    CreateVariadicMatcher<T>(&values, std::integral_constant<size_t, 0>());
+    return Matcher<T>(new CombiningMatcher<T>(std::move(values)));
+  }
+
+ private:
+  template <typename T, size_t I>
+  void CreateVariadicMatcher(std::vector<Matcher<T> >* values,
+                             std::integral_constant<size_t, I>) const {
+    values->push_back(SafeMatcherCast<T>(std::get<I>(matchers_)));
+    CreateVariadicMatcher<T>(values, std::integral_constant<size_t, I + 1>());
+  }
+
+  template <typename T>
+  void CreateVariadicMatcher(
+      std::vector<Matcher<T> >*,
+      std::integral_constant<size_t, sizeof...(Args)>) const {}
+
+  std::tuple<Args...> matchers_;
+};
+
+template <typename... Args>
+using AllOfMatcher = VariadicMatcher<AllOfMatcherImpl, Args...>;
+
+// Implements the AnyOf(m1, m2) matcher for a particular argument type
+// T.  We do not nest it inside the AnyOfMatcher class template, as
+// that will prevent different instantiations of AnyOfMatcher from
+// sharing the same EitherOfMatcherImpl<T> class.
+template <typename T>
+class AnyOfMatcherImpl : public MatcherInterface<const T&> {
+ public:
+  explicit AnyOfMatcherImpl(std::vector<Matcher<T> > matchers)
+      : matchers_(std::move(matchers)) {}
+
+  void DescribeTo(::std::ostream* os) const override {
+    *os << "(";
+    for (size_t i = 0; i < matchers_.size(); ++i) {
+      if (i != 0) *os << ") or (";
+      matchers_[i].DescribeTo(os);
+    }
+    *os << ")";
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const override {
+    *os << "(";
+    for (size_t i = 0; i < matchers_.size(); ++i) {
+      if (i != 0) *os << ") and (";
+      matchers_[i].DescribeNegationTo(os);
+    }
+    *os << ")";
+  }
+
+  bool MatchAndExplain(const T& x,
+                       MatchResultListener* listener) const override {
+    std::string no_match_result;
+
+    // If either matcher1_ or matcher2_ matches x, we just need to
+    // explain why *one* of them matches.
+    for (size_t i = 0; i < matchers_.size(); ++i) {
+      StringMatchResultListener slistener;
+      if (matchers_[i].MatchAndExplain(x, &slistener)) {
+        *listener << slistener.str();
+        return true;
+      } else {
+        if (no_match_result.empty()) {
+          no_match_result = slistener.str();
+        } else {
+          std::string result = slistener.str();
+          if (!result.empty()) {
+            no_match_result += ", and ";
+            no_match_result += result;
+          }
+        }
+      }
+    }
+
+    // Otherwise we need to explain why *both* of them fail.
+    *listener << no_match_result;
+    return false;
+  }
+
+ private:
+  const std::vector<Matcher<T> > matchers_;
+};
+
+// AnyOfMatcher is used for the variadic implementation of AnyOf(m_1, m_2, ...).
+template <typename... Args>
+using AnyOfMatcher = VariadicMatcher<AnyOfMatcherImpl, Args...>;
+
+// Wrapper for implementation of Any/AllOfArray().
+template <template <class> class MatcherImpl, typename T>
+class SomeOfArrayMatcher {
+ public:
+  // Constructs the matcher from a sequence of element values or
+  // element matchers.
+  template <typename Iter>
+  SomeOfArrayMatcher(Iter first, Iter last) : matchers_(first, last) {}
+
+  template <typename U>
+  operator Matcher<U>() const {  // NOLINT
+    using RawU = typename std::decay<U>::type;
+    std::vector<Matcher<RawU>> matchers;
+    for (const auto& matcher : matchers_) {
+      matchers.push_back(MatcherCast<RawU>(matcher));
+    }
+    return Matcher<U>(new MatcherImpl<RawU>(std::move(matchers)));
+  }
+
+ private:
+  const ::std::vector<T> matchers_;
+};
+
+template <typename T>
+using AllOfArrayMatcher = SomeOfArrayMatcher<AllOfMatcherImpl, T>;
+
+template <typename T>
+using AnyOfArrayMatcher = SomeOfArrayMatcher<AnyOfMatcherImpl, T>;
+
+// Used for implementing Truly(pred), which turns a predicate into a
+// matcher.
+template <typename Predicate>
+class TrulyMatcher {
+ public:
+  explicit TrulyMatcher(Predicate pred) : predicate_(pred) {}
+
+  // This method template allows Truly(pred) to be used as a matcher
+  // for type T where T is the argument type of predicate 'pred'.  The
+  // argument is passed by reference as the predicate may be
+  // interested in the address of the argument.
+  template <typename T>
+  bool MatchAndExplain(T& x,  // NOLINT
+                       MatchResultListener* listener) const {
+    // Without the if-statement, MSVC sometimes warns about converting
+    // a value to bool (warning 4800).
+    //
+    // We cannot write 'return !!predicate_(x);' as that doesn't work
+    // when predicate_(x) returns a class convertible to bool but
+    // having no operator!().
+    if (predicate_(x))
+      return true;
+    *listener << "didn't satisfy the given predicate";
+    return false;
+  }
+
+  void DescribeTo(::std::ostream* os) const {
+    *os << "satisfies the given predicate";
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "doesn't satisfy the given predicate";
+  }
+
+ private:
+  Predicate predicate_;
+};
+
+// Used for implementing Matches(matcher), which turns a matcher into
+// a predicate.
+template <typename M>
+class MatcherAsPredicate {
+ public:
+  explicit MatcherAsPredicate(M matcher) : matcher_(matcher) {}
+
+  // This template operator() allows Matches(m) to be used as a
+  // predicate on type T where m is a matcher on type T.
+  //
+  // The argument x is passed by reference instead of by value, as
+  // some matcher may be interested in its address (e.g. as in
+  // Matches(Ref(n))(x)).
+  template <typename T>
+  bool operator()(const T& x) const {
+    // We let matcher_ commit to a particular type here instead of
+    // when the MatcherAsPredicate object was constructed.  This
+    // allows us to write Matches(m) where m is a polymorphic matcher
+    // (e.g. Eq(5)).
+    //
+    // If we write Matcher<T>(matcher_).Matches(x) here, it won't
+    // compile when matcher_ has type Matcher<const T&>; if we write
+    // Matcher<const T&>(matcher_).Matches(x) here, it won't compile
+    // when matcher_ has type Matcher<T>; if we just write
+    // matcher_.Matches(x), it won't compile when matcher_ is
+    // polymorphic, e.g. Eq(5).
+    //
+    // MatcherCast<const T&>() is necessary for making the code work
+    // in all of the above situations.
+    return MatcherCast<const T&>(matcher_).Matches(x);
+  }
+
+ private:
+  M matcher_;
+};
+
+// For implementing ASSERT_THAT() and EXPECT_THAT().  The template
+// argument M must be a type that can be converted to a matcher.
+template <typename M>
+class PredicateFormatterFromMatcher {
+ public:
+  explicit PredicateFormatterFromMatcher(M m) : matcher_(std::move(m)) {}
+
+  // This template () operator allows a PredicateFormatterFromMatcher
+  // object to act as a predicate-formatter suitable for using with
+  // Google Test's EXPECT_PRED_FORMAT1() macro.
+  template <typename T>
+  AssertionResult operator()(const char* value_text, const T& x) const {
+    // We convert matcher_ to a Matcher<const T&> *now* instead of
+    // when the PredicateFormatterFromMatcher object was constructed,
+    // as matcher_ may be polymorphic (e.g. NotNull()) and we won't
+    // know which type to instantiate it to until we actually see the
+    // type of x here.
+    //
+    // We write SafeMatcherCast<const T&>(matcher_) instead of
+    // Matcher<const T&>(matcher_), as the latter won't compile when
+    // matcher_ has type Matcher<T> (e.g. An<int>()).
+    // We don't write MatcherCast<const T&> either, as that allows
+    // potentially unsafe downcasting of the matcher argument.
+    const Matcher<const T&> matcher = SafeMatcherCast<const T&>(matcher_);
+
+    // The expected path here is that the matcher should match (i.e. that most
+    // tests pass) so optimize for this case.
+    if (matcher.Matches(x)) {
+      return AssertionSuccess();
+    }
+
+    ::std::stringstream ss;
+    ss << "Value of: " << value_text << "\n"
+       << "Expected: ";
+    matcher.DescribeTo(&ss);
+
+    // Rerun the matcher to "PrintAndExplain" the failure.
+    StringMatchResultListener listener;
+    if (MatchPrintAndExplain(x, matcher, &listener)) {
+      ss << "\n  The matcher failed on the initial attempt; but passed when "
+            "rerun to generate the explanation.";
+    }
+    ss << "\n  Actual: " << listener.str();
+    return AssertionFailure() << ss.str();
+  }
+
+ private:
+  const M matcher_;
+};
+
+// A helper function for converting a matcher to a predicate-formatter
+// without the user needing to explicitly write the type.  This is
+// used for implementing ASSERT_THAT() and EXPECT_THAT().
+// Implementation detail: 'matcher' is received by-value to force decaying.
+template <typename M>
+inline PredicateFormatterFromMatcher<M>
+MakePredicateFormatterFromMatcher(M matcher) {
+  return PredicateFormatterFromMatcher<M>(std::move(matcher));
+}
+
+// Implements the polymorphic IsNan() matcher, which matches any floating type
+// value that is Nan.
+class IsNanMatcher {
+ public:
+  template <typename FloatType>
+  bool MatchAndExplain(const FloatType& f,
+                       MatchResultListener* /* listener */) const {
+    return (::std::isnan)(f);
+  }
+
+  void DescribeTo(::std::ostream* os) const { *os << "is NaN"; }
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "isn't NaN";
+  }
+};
+
+// Implements the polymorphic floating point equality matcher, which matches
+// two float values using ULP-based approximation or, optionally, a
+// user-specified epsilon.  The template is meant to be instantiated with
+// FloatType being either float or double.
+template <typename FloatType>
+class FloatingEqMatcher {
+ public:
+  // Constructor for FloatingEqMatcher.
+  // The matcher's input will be compared with expected.  The matcher treats two
+  // NANs as equal if nan_eq_nan is true.  Otherwise, under IEEE standards,
+  // equality comparisons between NANs will always return false.  We specify a
+  // negative max_abs_error_ term to indicate that ULP-based approximation will
+  // be used for comparison.
+  FloatingEqMatcher(FloatType expected, bool nan_eq_nan) :
+    expected_(expected), nan_eq_nan_(nan_eq_nan), max_abs_error_(-1) {
+  }
+
+  // Constructor that supports a user-specified max_abs_error that will be used
+  // for comparison instead of ULP-based approximation.  The max absolute
+  // should be non-negative.
+  FloatingEqMatcher(FloatType expected, bool nan_eq_nan,
+                    FloatType max_abs_error)
+      : expected_(expected),
+        nan_eq_nan_(nan_eq_nan),
+        max_abs_error_(max_abs_error) {
+    GTEST_CHECK_(max_abs_error >= 0)
+        << ", where max_abs_error is" << max_abs_error;
+  }
+
+  // Implements floating point equality matcher as a Matcher<T>.
+  template <typename T>
+  class Impl : public MatcherInterface<T> {
+   public:
+    Impl(FloatType expected, bool nan_eq_nan, FloatType max_abs_error)
+        : expected_(expected),
+          nan_eq_nan_(nan_eq_nan),
+          max_abs_error_(max_abs_error) {}
+
+    bool MatchAndExplain(T value,
+                         MatchResultListener* listener) const override {
+      const FloatingPoint<FloatType> actual(value), expected(expected_);
+
+      // Compares NaNs first, if nan_eq_nan_ is true.
+      if (actual.is_nan() || expected.is_nan()) {
+        if (actual.is_nan() && expected.is_nan()) {
+          return nan_eq_nan_;
+        }
+        // One is nan; the other is not nan.
+        return false;
+      }
+      if (HasMaxAbsError()) {
+        // We perform an equality check so that inf will match inf, regardless
+        // of error bounds.  If the result of value - expected_ would result in
+        // overflow or if either value is inf, the default result is infinity,
+        // which should only match if max_abs_error_ is also infinity.
+        if (value == expected_) {
+          return true;
+        }
+
+        const FloatType diff = value - expected_;
+        if (::std::fabs(diff) <= max_abs_error_) {
+          return true;
+        }
+
+        if (listener->IsInterested()) {
+          *listener << "which is " << diff << " from " << expected_;
+        }
+        return false;
+      } else {
+        return actual.AlmostEquals(expected);
+      }
+    }
+
+    void DescribeTo(::std::ostream* os) const override {
+      // os->precision() returns the previously set precision, which we
+      // store to restore the ostream to its original configuration
+      // after outputting.
+      const ::std::streamsize old_precision = os->precision(
+          ::std::numeric_limits<FloatType>::digits10 + 2);
+      if (FloatingPoint<FloatType>(expected_).is_nan()) {
+        if (nan_eq_nan_) {
+          *os << "is NaN";
+        } else {
+          *os << "never matches";
+        }
+      } else {
+        *os << "is approximately " << expected_;
+        if (HasMaxAbsError()) {
+          *os << " (absolute error <= " << max_abs_error_ << ")";
+        }
+      }
+      os->precision(old_precision);
+    }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      // As before, get original precision.
+      const ::std::streamsize old_precision = os->precision(
+          ::std::numeric_limits<FloatType>::digits10 + 2);
+      if (FloatingPoint<FloatType>(expected_).is_nan()) {
+        if (nan_eq_nan_) {
+          *os << "isn't NaN";
+        } else {
+          *os << "is anything";
+        }
+      } else {
+        *os << "isn't approximately " << expected_;
+        if (HasMaxAbsError()) {
+          *os << " (absolute error > " << max_abs_error_ << ")";
+        }
+      }
+      // Restore original precision.
+      os->precision(old_precision);
+    }
+
+   private:
+    bool HasMaxAbsError() const {
+      return max_abs_error_ >= 0;
+    }
+
+    const FloatType expected_;
+    const bool nan_eq_nan_;
+    // max_abs_error will be used for value comparison when >= 0.
+    const FloatType max_abs_error_;
+  };
+
+  // The following 3 type conversion operators allow FloatEq(expected) and
+  // NanSensitiveFloatEq(expected) to be used as a Matcher<float>, a
+  // Matcher<const float&>, or a Matcher<float&>, but nothing else.
+  operator Matcher<FloatType>() const {
+    return MakeMatcher(
+        new Impl<FloatType>(expected_, nan_eq_nan_, max_abs_error_));
+  }
+
+  operator Matcher<const FloatType&>() const {
+    return MakeMatcher(
+        new Impl<const FloatType&>(expected_, nan_eq_nan_, max_abs_error_));
+  }
+
+  operator Matcher<FloatType&>() const {
+    return MakeMatcher(
+        new Impl<FloatType&>(expected_, nan_eq_nan_, max_abs_error_));
+  }
+
+ private:
+  const FloatType expected_;
+  const bool nan_eq_nan_;
+  // max_abs_error will be used for value comparison when >= 0.
+  const FloatType max_abs_error_;
+};
+
+// A 2-tuple ("binary") wrapper around FloatingEqMatcher:
+// FloatingEq2Matcher() matches (x, y) by matching FloatingEqMatcher(x, false)
+// against y, and FloatingEq2Matcher(e) matches FloatingEqMatcher(x, false, e)
+// against y. The former implements "Eq", the latter "Near". At present, there
+// is no version that compares NaNs as equal.
+template <typename FloatType>
+class FloatingEq2Matcher {
+ public:
+  FloatingEq2Matcher() { Init(-1, false); }
+
+  explicit FloatingEq2Matcher(bool nan_eq_nan) { Init(-1, nan_eq_nan); }
+
+  explicit FloatingEq2Matcher(FloatType max_abs_error) {
+    Init(max_abs_error, false);
+  }
+
+  FloatingEq2Matcher(FloatType max_abs_error, bool nan_eq_nan) {
+    Init(max_abs_error, nan_eq_nan);
+  }
+
+  template <typename T1, typename T2>
+  operator Matcher<::std::tuple<T1, T2>>() const {
+    return MakeMatcher(
+        new Impl<::std::tuple<T1, T2>>(max_abs_error_, nan_eq_nan_));
+  }
+  template <typename T1, typename T2>
+  operator Matcher<const ::std::tuple<T1, T2>&>() const {
+    return MakeMatcher(
+        new Impl<const ::std::tuple<T1, T2>&>(max_abs_error_, nan_eq_nan_));
+  }
+
+ private:
+  static ::std::ostream& GetDesc(::std::ostream& os) {  // NOLINT
+    return os << "an almost-equal pair";
+  }
+
+  template <typename Tuple>
+  class Impl : public MatcherInterface<Tuple> {
+   public:
+    Impl(FloatType max_abs_error, bool nan_eq_nan) :
+        max_abs_error_(max_abs_error),
+        nan_eq_nan_(nan_eq_nan) {}
+
+    bool MatchAndExplain(Tuple args,
+                         MatchResultListener* listener) const override {
+      if (max_abs_error_ == -1) {
+        FloatingEqMatcher<FloatType> fm(::std::get<0>(args), nan_eq_nan_);
+        return static_cast<Matcher<FloatType>>(fm).MatchAndExplain(
+            ::std::get<1>(args), listener);
+      } else {
+        FloatingEqMatcher<FloatType> fm(::std::get<0>(args), nan_eq_nan_,
+                                        max_abs_error_);
+        return static_cast<Matcher<FloatType>>(fm).MatchAndExplain(
+            ::std::get<1>(args), listener);
+      }
+    }
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "are " << GetDesc;
+    }
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "aren't " << GetDesc;
+    }
+
+   private:
+    FloatType max_abs_error_;
+    const bool nan_eq_nan_;
+  };
+
+  void Init(FloatType max_abs_error_val, bool nan_eq_nan_val) {
+    max_abs_error_ = max_abs_error_val;
+    nan_eq_nan_ = nan_eq_nan_val;
+  }
+  FloatType max_abs_error_;
+  bool nan_eq_nan_;
+};
+
+// Implements the Pointee(m) matcher for matching a pointer whose
+// pointee matches matcher m.  The pointer can be either raw or smart.
+template <typename InnerMatcher>
+class PointeeMatcher {
+ public:
+  explicit PointeeMatcher(const InnerMatcher& matcher) : matcher_(matcher) {}
+
+  // This type conversion operator template allows Pointee(m) to be
+  // used as a matcher for any pointer type whose pointee type is
+  // compatible with the inner matcher, where type Pointer can be
+  // either a raw pointer or a smart pointer.
+  //
+  // The reason we do this instead of relying on
+  // MakePolymorphicMatcher() is that the latter is not flexible
+  // enough for implementing the DescribeTo() method of Pointee().
+  template <typename Pointer>
+  operator Matcher<Pointer>() const {
+    return Matcher<Pointer>(new Impl<const Pointer&>(matcher_));
+  }
+
+ private:
+  // The monomorphic implementation that works for a particular pointer type.
+  template <typename Pointer>
+  class Impl : public MatcherInterface<Pointer> {
+   public:
+    using Pointee =
+        typename std::pointer_traits<GTEST_REMOVE_REFERENCE_AND_CONST_(
+            Pointer)>::element_type;
+
+    explicit Impl(const InnerMatcher& matcher)
+        : matcher_(MatcherCast<const Pointee&>(matcher)) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "points to a value that ";
+      matcher_.DescribeTo(os);
+    }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "does not point to a value that ";
+      matcher_.DescribeTo(os);
+    }
+
+    bool MatchAndExplain(Pointer pointer,
+                         MatchResultListener* listener) const override {
+      if (GetRawPointer(pointer) == nullptr) return false;
+
+      *listener << "which points to ";
+      return MatchPrintAndExplain(*pointer, matcher_, listener);
+    }
+
+   private:
+    const Matcher<const Pointee&> matcher_;
+  };
+
+  const InnerMatcher matcher_;
+};
+
+// Implements the Pointer(m) matcher
+// Implements the Pointer(m) matcher for matching a pointer that matches matcher
+// m.  The pointer can be either raw or smart, and will match `m` against the
+// raw pointer.
+template <typename InnerMatcher>
+class PointerMatcher {
+ public:
+  explicit PointerMatcher(const InnerMatcher& matcher) : matcher_(matcher) {}
+
+  // This type conversion operator template allows Pointer(m) to be
+  // used as a matcher for any pointer type whose pointer type is
+  // compatible with the inner matcher, where type PointerType can be
+  // either a raw pointer or a smart pointer.
+  //
+  // The reason we do this instead of relying on
+  // MakePolymorphicMatcher() is that the latter is not flexible
+  // enough for implementing the DescribeTo() method of Pointer().
+  template <typename PointerType>
+  operator Matcher<PointerType>() const {  // NOLINT
+    return Matcher<PointerType>(new Impl<const PointerType&>(matcher_));
+  }
+
+ private:
+  // The monomorphic implementation that works for a particular pointer type.
+  template <typename PointerType>
+  class Impl : public MatcherInterface<PointerType> {
+   public:
+    using Pointer =
+        const typename std::pointer_traits<GTEST_REMOVE_REFERENCE_AND_CONST_(
+            PointerType)>::element_type*;
+
+    explicit Impl(const InnerMatcher& matcher)
+        : matcher_(MatcherCast<Pointer>(matcher)) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "is a pointer that ";
+      matcher_.DescribeTo(os);
+    }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "is not a pointer that ";
+      matcher_.DescribeTo(os);
+    }
+
+    bool MatchAndExplain(PointerType pointer,
+                         MatchResultListener* listener) const override {
+      *listener << "which is a pointer that ";
+      Pointer p = GetRawPointer(pointer);
+      return MatchPrintAndExplain(p, matcher_, listener);
+    }
+
+   private:
+    Matcher<Pointer> matcher_;
+  };
+
+  const InnerMatcher matcher_;
+};
+
+#if GTEST_HAS_RTTI
+// Implements the WhenDynamicCastTo<T>(m) matcher that matches a pointer or
+// reference that matches inner_matcher when dynamic_cast<T> is applied.
+// The result of dynamic_cast<To> is forwarded to the inner matcher.
+// If To is a pointer and the cast fails, the inner matcher will receive NULL.
+// If To is a reference and the cast fails, this matcher returns false
+// immediately.
+template <typename To>
+class WhenDynamicCastToMatcherBase {
+ public:
+  explicit WhenDynamicCastToMatcherBase(const Matcher<To>& matcher)
+      : matcher_(matcher) {}
+
+  void DescribeTo(::std::ostream* os) const {
+    GetCastTypeDescription(os);
+    matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const {
+    GetCastTypeDescription(os);
+    matcher_.DescribeNegationTo(os);
+  }
+
+ protected:
+  const Matcher<To> matcher_;
+
+  static std::string GetToName() {
+    return GetTypeName<To>();
+  }
+
+ private:
+  static void GetCastTypeDescription(::std::ostream* os) {
+    *os << "when dynamic_cast to " << GetToName() << ", ";
+  }
+};
+
+// Primary template.
+// To is a pointer. Cast and forward the result.
+template <typename To>
+class WhenDynamicCastToMatcher : public WhenDynamicCastToMatcherBase<To> {
+ public:
+  explicit WhenDynamicCastToMatcher(const Matcher<To>& matcher)
+      : WhenDynamicCastToMatcherBase<To>(matcher) {}
+
+  template <typename From>
+  bool MatchAndExplain(From from, MatchResultListener* listener) const {
+    To to = dynamic_cast<To>(from);
+    return MatchPrintAndExplain(to, this->matcher_, listener);
+  }
+};
+
+// Specialize for references.
+// In this case we return false if the dynamic_cast fails.
+template <typename To>
+class WhenDynamicCastToMatcher<To&> : public WhenDynamicCastToMatcherBase<To&> {
+ public:
+  explicit WhenDynamicCastToMatcher(const Matcher<To&>& matcher)
+      : WhenDynamicCastToMatcherBase<To&>(matcher) {}
+
+  template <typename From>
+  bool MatchAndExplain(From& from, MatchResultListener* listener) const {
+    // We don't want an std::bad_cast here, so do the cast with pointers.
+    To* to = dynamic_cast<To*>(&from);
+    if (to == nullptr) {
+      *listener << "which cannot be dynamic_cast to " << this->GetToName();
+      return false;
+    }
+    return MatchPrintAndExplain(*to, this->matcher_, listener);
+  }
+};
+#endif  // GTEST_HAS_RTTI
+
+// Implements the Field() matcher for matching a field (i.e. member
+// variable) of an object.
+template <typename Class, typename FieldType>
+class FieldMatcher {
+ public:
+  FieldMatcher(FieldType Class::*field,
+               const Matcher<const FieldType&>& matcher)
+      : field_(field), matcher_(matcher), whose_field_("whose given field ") {}
+
+  FieldMatcher(const std::string& field_name, FieldType Class::*field,
+               const Matcher<const FieldType&>& matcher)
+      : field_(field),
+        matcher_(matcher),
+        whose_field_("whose field `" + field_name + "` ") {}
+
+  void DescribeTo(::std::ostream* os) const {
+    *os << "is an object " << whose_field_;
+    matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "is an object " << whose_field_;
+    matcher_.DescribeNegationTo(os);
+  }
+
+  template <typename T>
+  bool MatchAndExplain(const T& value, MatchResultListener* listener) const {
+    // FIXME: The dispatch on std::is_pointer was introduced as a workaround for
+    // a compiler bug, and can now be removed.
+    return MatchAndExplainImpl(
+        typename std::is_pointer<typename std::remove_const<T>::type>::type(),
+        value, listener);
+  }
+
+ private:
+  bool MatchAndExplainImpl(std::false_type /* is_not_pointer */,
+                           const Class& obj,
+                           MatchResultListener* listener) const {
+    *listener << whose_field_ << "is ";
+    return MatchPrintAndExplain(obj.*field_, matcher_, listener);
+  }
+
+  bool MatchAndExplainImpl(std::true_type /* is_pointer */, const Class* p,
+                           MatchResultListener* listener) const {
+    if (p == nullptr) return false;
+
+    *listener << "which points to an object ";
+    // Since *p has a field, it must be a class/struct/union type and
+    // thus cannot be a pointer.  Therefore we pass false_type() as
+    // the first argument.
+    return MatchAndExplainImpl(std::false_type(), *p, listener);
+  }
+
+  const FieldType Class::*field_;
+  const Matcher<const FieldType&> matcher_;
+
+  // Contains either "whose given field " if the name of the field is unknown
+  // or "whose field `name_of_field` " if the name is known.
+  const std::string whose_field_;
+};
+
+// Implements the Property() matcher for matching a property
+// (i.e. return value of a getter method) of an object.
+//
+// Property is a const-qualified member function of Class returning
+// PropertyType.
+template <typename Class, typename PropertyType, typename Property>
+class PropertyMatcher {
+ public:
+  typedef const PropertyType& RefToConstProperty;
+
+  PropertyMatcher(Property property, const Matcher<RefToConstProperty>& matcher)
+      : property_(property),
+        matcher_(matcher),
+        whose_property_("whose given property ") {}
+
+  PropertyMatcher(const std::string& property_name, Property property,
+                  const Matcher<RefToConstProperty>& matcher)
+      : property_(property),
+        matcher_(matcher),
+        whose_property_("whose property `" + property_name + "` ") {}
+
+  void DescribeTo(::std::ostream* os) const {
+    *os << "is an object " << whose_property_;
+    matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "is an object " << whose_property_;
+    matcher_.DescribeNegationTo(os);
+  }
+
+  template <typename T>
+  bool MatchAndExplain(const T&value, MatchResultListener* listener) const {
+    return MatchAndExplainImpl(
+        typename std::is_pointer<typename std::remove_const<T>::type>::type(),
+        value, listener);
+  }
+
+ private:
+  bool MatchAndExplainImpl(std::false_type /* is_not_pointer */,
+                           const Class& obj,
+                           MatchResultListener* listener) const {
+    *listener << whose_property_ << "is ";
+    // Cannot pass the return value (for example, int) to MatchPrintAndExplain,
+    // which takes a non-const reference as argument.
+    RefToConstProperty result = (obj.*property_)();
+    return MatchPrintAndExplain(result, matcher_, listener);
+  }
+
+  bool MatchAndExplainImpl(std::true_type /* is_pointer */, const Class* p,
+                           MatchResultListener* listener) const {
+    if (p == nullptr) return false;
+
+    *listener << "which points to an object ";
+    // Since *p has a property method, it must be a class/struct/union
+    // type and thus cannot be a pointer.  Therefore we pass
+    // false_type() as the first argument.
+    return MatchAndExplainImpl(std::false_type(), *p, listener);
+  }
+
+  Property property_;
+  const Matcher<RefToConstProperty> matcher_;
+
+  // Contains either "whose given property " if the name of the property is
+  // unknown or "whose property `name_of_property` " if the name is known.
+  const std::string whose_property_;
+};
+
+// Type traits specifying various features of different functors for ResultOf.
+// The default template specifies features for functor objects.
+template <typename Functor>
+struct CallableTraits {
+  typedef Functor StorageType;
+
+  static void CheckIsValid(Functor /* functor */) {}
+
+  template <typename T>
+  static auto Invoke(Functor f, const T& arg) -> decltype(f(arg)) {
+    return f(arg);
+  }
+};
+
+// Specialization for function pointers.
+template <typename ArgType, typename ResType>
+struct CallableTraits<ResType(*)(ArgType)> {
+  typedef ResType ResultType;
+  typedef ResType(*StorageType)(ArgType);
+
+  static void CheckIsValid(ResType(*f)(ArgType)) {
+    GTEST_CHECK_(f != nullptr)
+        << "NULL function pointer is passed into ResultOf().";
+  }
+  template <typename T>
+  static ResType Invoke(ResType(*f)(ArgType), T arg) {
+    return (*f)(arg);
+  }
+};
+
+// Implements the ResultOf() matcher for matching a return value of a
+// unary function of an object.
+template <typename Callable, typename InnerMatcher>
+class ResultOfMatcher {
+ public:
+  ResultOfMatcher(Callable callable, InnerMatcher matcher)
+      : callable_(std::move(callable)), matcher_(std::move(matcher)) {
+    CallableTraits<Callable>::CheckIsValid(callable_);
+  }
+
+  template <typename T>
+  operator Matcher<T>() const {
+    return Matcher<T>(new Impl<const T&>(callable_, matcher_));
+  }
+
+ private:
+  typedef typename CallableTraits<Callable>::StorageType CallableStorageType;
+
+  template <typename T>
+  class Impl : public MatcherInterface<T> {
+    using ResultType = decltype(CallableTraits<Callable>::template Invoke<T>(
+        std::declval<CallableStorageType>(), std::declval<T>()));
+
+   public:
+    template <typename M>
+    Impl(const CallableStorageType& callable, const M& matcher)
+        : callable_(callable), matcher_(MatcherCast<ResultType>(matcher)) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "is mapped by the given callable to a value that ";
+      matcher_.DescribeTo(os);
+    }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "is mapped by the given callable to a value that ";
+      matcher_.DescribeNegationTo(os);
+    }
+
+    bool MatchAndExplain(T obj, MatchResultListener* listener) const override {
+      *listener << "which is mapped by the given callable to ";
+      // Cannot pass the return value directly to MatchPrintAndExplain, which
+      // takes a non-const reference as argument.
+      // Also, specifying template argument explicitly is needed because T could
+      // be a non-const reference (e.g. Matcher<Uncopyable&>).
+      ResultType result =
+          CallableTraits<Callable>::template Invoke<T>(callable_, obj);
+      return MatchPrintAndExplain(result, matcher_, listener);
+    }
+
+   private:
+    // Functors often define operator() as non-const method even though
+    // they are actually stateless. But we need to use them even when
+    // 'this' is a const pointer. It's the user's responsibility not to
+    // use stateful callables with ResultOf(), which doesn't guarantee
+    // how many times the callable will be invoked.
+    mutable CallableStorageType callable_;
+    const Matcher<ResultType> matcher_;
+  };  // class Impl
+
+  const CallableStorageType callable_;
+  const InnerMatcher matcher_;
+};
+
+// Implements a matcher that checks the size of an STL-style container.
+template <typename SizeMatcher>
+class SizeIsMatcher {
+ public:
+  explicit SizeIsMatcher(const SizeMatcher& size_matcher)
+       : size_matcher_(size_matcher) {
+  }
+
+  template <typename Container>
+  operator Matcher<Container>() const {
+    return Matcher<Container>(new Impl<const Container&>(size_matcher_));
+  }
+
+  template <typename Container>
+  class Impl : public MatcherInterface<Container> {
+   public:
+    using SizeType = decltype(std::declval<Container>().size());
+    explicit Impl(const SizeMatcher& size_matcher)
+        : size_matcher_(MatcherCast<SizeType>(size_matcher)) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "size ";
+      size_matcher_.DescribeTo(os);
+    }
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "size ";
+      size_matcher_.DescribeNegationTo(os);
+    }
+
+    bool MatchAndExplain(Container container,
+                         MatchResultListener* listener) const override {
+      SizeType size = container.size();
+      StringMatchResultListener size_listener;
+      const bool result = size_matcher_.MatchAndExplain(size, &size_listener);
+      *listener
+          << "whose size " << size << (result ? " matches" : " doesn't match");
+      PrintIfNotEmpty(size_listener.str(), listener->stream());
+      return result;
+    }
+
+   private:
+    const Matcher<SizeType> size_matcher_;
+  };
+
+ private:
+  const SizeMatcher size_matcher_;
+};
+
+// Implements a matcher that checks the begin()..end() distance of an STL-style
+// container.
+template <typename DistanceMatcher>
+class BeginEndDistanceIsMatcher {
+ public:
+  explicit BeginEndDistanceIsMatcher(const DistanceMatcher& distance_matcher)
+      : distance_matcher_(distance_matcher) {}
+
+  template <typename Container>
+  operator Matcher<Container>() const {
+    return Matcher<Container>(new Impl<const Container&>(distance_matcher_));
+  }
+
+  template <typename Container>
+  class Impl : public MatcherInterface<Container> {
+   public:
+    typedef internal::StlContainerView<
+        GTEST_REMOVE_REFERENCE_AND_CONST_(Container)> ContainerView;
+    typedef typename std::iterator_traits<
+        typename ContainerView::type::const_iterator>::difference_type
+        DistanceType;
+    explicit Impl(const DistanceMatcher& distance_matcher)
+        : distance_matcher_(MatcherCast<DistanceType>(distance_matcher)) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "distance between begin() and end() ";
+      distance_matcher_.DescribeTo(os);
+    }
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "distance between begin() and end() ";
+      distance_matcher_.DescribeNegationTo(os);
+    }
+
+    bool MatchAndExplain(Container container,
+                         MatchResultListener* listener) const override {
+      using std::begin;
+      using std::end;
+      DistanceType distance = std::distance(begin(container), end(container));
+      StringMatchResultListener distance_listener;
+      const bool result =
+          distance_matcher_.MatchAndExplain(distance, &distance_listener);
+      *listener << "whose distance between begin() and end() " << distance
+                << (result ? " matches" : " doesn't match");
+      PrintIfNotEmpty(distance_listener.str(), listener->stream());
+      return result;
+    }
+
+   private:
+    const Matcher<DistanceType> distance_matcher_;
+  };
+
+ private:
+  const DistanceMatcher distance_matcher_;
+};
+
+// Implements an equality matcher for any STL-style container whose elements
+// support ==. This matcher is like Eq(), but its failure explanations provide
+// more detailed information that is useful when the container is used as a set.
+// The failure message reports elements that are in one of the operands but not
+// the other. The failure messages do not report duplicate or out-of-order
+// elements in the containers (which don't properly matter to sets, but can
+// occur if the containers are vectors or lists, for example).
+//
+// Uses the container's const_iterator, value_type, operator ==,
+// begin(), and end().
+template <typename Container>
+class ContainerEqMatcher {
+ public:
+  typedef internal::StlContainerView<Container> View;
+  typedef typename View::type StlContainer;
+  typedef typename View::const_reference StlContainerReference;
+
+  static_assert(!std::is_const<Container>::value,
+                "Container type must not be const");
+  static_assert(!std::is_reference<Container>::value,
+                "Container type must not be a reference");
+
+  // We make a copy of expected in case the elements in it are modified
+  // after this matcher is created.
+  explicit ContainerEqMatcher(const Container& expected)
+      : expected_(View::Copy(expected)) {}
+
+  void DescribeTo(::std::ostream* os) const {
+    *os << "equals ";
+    UniversalPrint(expected_, os);
+  }
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "does not equal ";
+    UniversalPrint(expected_, os);
+  }
+
+  template <typename LhsContainer>
+  bool MatchAndExplain(const LhsContainer& lhs,
+                       MatchResultListener* listener) const {
+    typedef internal::StlContainerView<
+        typename std::remove_const<LhsContainer>::type>
+        LhsView;
+    typedef typename LhsView::type LhsStlContainer;
+    StlContainerReference lhs_stl_container = LhsView::ConstReference(lhs);
+    if (lhs_stl_container == expected_)
+      return true;
+
+    ::std::ostream* const os = listener->stream();
+    if (os != nullptr) {
+      // Something is different. Check for extra values first.
+      bool printed_header = false;
+      for (typename LhsStlContainer::const_iterator it =
+               lhs_stl_container.begin();
+           it != lhs_stl_container.end(); ++it) {
+        if (internal::ArrayAwareFind(expected_.begin(), expected_.end(), *it) ==
+            expected_.end()) {
+          if (printed_header) {
+            *os << ", ";
+          } else {
+            *os << "which has these unexpected elements: ";
+            printed_header = true;
+          }
+          UniversalPrint(*it, os);
+        }
+      }
+
+      // Now check for missing values.
+      bool printed_header2 = false;
+      for (typename StlContainer::const_iterator it = expected_.begin();
+           it != expected_.end(); ++it) {
+        if (internal::ArrayAwareFind(
+                lhs_stl_container.begin(), lhs_stl_container.end(), *it) ==
+            lhs_stl_container.end()) {
+          if (printed_header2) {
+            *os << ", ";
+          } else {
+            *os << (printed_header ? ",\nand" : "which")
+                << " doesn't have these expected elements: ";
+            printed_header2 = true;
+          }
+          UniversalPrint(*it, os);
+        }
+      }
+    }
+
+    return false;
+  }
+
+ private:
+  const StlContainer expected_;
+};
+
+// A comparator functor that uses the < operator to compare two values.
+struct LessComparator {
+  template <typename T, typename U>
+  bool operator()(const T& lhs, const U& rhs) const { return lhs < rhs; }
+};
+
+// Implements WhenSortedBy(comparator, container_matcher).
+template <typename Comparator, typename ContainerMatcher>
+class WhenSortedByMatcher {
+ public:
+  WhenSortedByMatcher(const Comparator& comparator,
+                      const ContainerMatcher& matcher)
+      : comparator_(comparator), matcher_(matcher) {}
+
+  template <typename LhsContainer>
+  operator Matcher<LhsContainer>() const {
+    return MakeMatcher(new Impl<LhsContainer>(comparator_, matcher_));
+  }
+
+  template <typename LhsContainer>
+  class Impl : public MatcherInterface<LhsContainer> {
+   public:
+    typedef internal::StlContainerView<
+         GTEST_REMOVE_REFERENCE_AND_CONST_(LhsContainer)> LhsView;
+    typedef typename LhsView::type LhsStlContainer;
+    typedef typename LhsView::const_reference LhsStlContainerReference;
+    // Transforms std::pair<const Key, Value> into std::pair<Key, Value>
+    // so that we can match associative containers.
+    typedef typename RemoveConstFromKey<
+        typename LhsStlContainer::value_type>::type LhsValue;
+
+    Impl(const Comparator& comparator, const ContainerMatcher& matcher)
+        : comparator_(comparator), matcher_(matcher) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "(when sorted) ";
+      matcher_.DescribeTo(os);
+    }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "(when sorted) ";
+      matcher_.DescribeNegationTo(os);
+    }
+
+    bool MatchAndExplain(LhsContainer lhs,
+                         MatchResultListener* listener) const override {
+      LhsStlContainerReference lhs_stl_container = LhsView::ConstReference(lhs);
+      ::std::vector<LhsValue> sorted_container(lhs_stl_container.begin(),
+                                               lhs_stl_container.end());
+      ::std::sort(
+           sorted_container.begin(), sorted_container.end(), comparator_);
+
+      if (!listener->IsInterested()) {
+        // If the listener is not interested, we do not need to
+        // construct the inner explanation.
+        return matcher_.Matches(sorted_container);
+      }
+
+      *listener << "which is ";
+      UniversalPrint(sorted_container, listener->stream());
+      *listener << " when sorted";
+
+      StringMatchResultListener inner_listener;
+      const bool match = matcher_.MatchAndExplain(sorted_container,
+                                                  &inner_listener);
+      PrintIfNotEmpty(inner_listener.str(), listener->stream());
+      return match;
+    }
+
+   private:
+    const Comparator comparator_;
+    const Matcher<const ::std::vector<LhsValue>&> matcher_;
+
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(Impl);
+  };
+
+ private:
+  const Comparator comparator_;
+  const ContainerMatcher matcher_;
+};
+
+// Implements Pointwise(tuple_matcher, rhs_container).  tuple_matcher
+// must be able to be safely cast to Matcher<std::tuple<const T1&, const
+// T2&> >, where T1 and T2 are the types of elements in the LHS
+// container and the RHS container respectively.
+template <typename TupleMatcher, typename RhsContainer>
+class PointwiseMatcher {
+  GTEST_COMPILE_ASSERT_(
+      !IsHashTable<GTEST_REMOVE_REFERENCE_AND_CONST_(RhsContainer)>::value,
+      use_UnorderedPointwise_with_hash_tables);
+
+ public:
+  typedef internal::StlContainerView<RhsContainer> RhsView;
+  typedef typename RhsView::type RhsStlContainer;
+  typedef typename RhsStlContainer::value_type RhsValue;
+
+  static_assert(!std::is_const<RhsContainer>::value,
+                "RhsContainer type must not be const");
+  static_assert(!std::is_reference<RhsContainer>::value,
+                "RhsContainer type must not be a reference");
+
+  // Like ContainerEq, we make a copy of rhs in case the elements in
+  // it are modified after this matcher is created.
+  PointwiseMatcher(const TupleMatcher& tuple_matcher, const RhsContainer& rhs)
+      : tuple_matcher_(tuple_matcher), rhs_(RhsView::Copy(rhs)) {}
+
+  template <typename LhsContainer>
+  operator Matcher<LhsContainer>() const {
+    GTEST_COMPILE_ASSERT_(
+        !IsHashTable<GTEST_REMOVE_REFERENCE_AND_CONST_(LhsContainer)>::value,
+        use_UnorderedPointwise_with_hash_tables);
+
+    return Matcher<LhsContainer>(
+        new Impl<const LhsContainer&>(tuple_matcher_, rhs_));
+  }
+
+  template <typename LhsContainer>
+  class Impl : public MatcherInterface<LhsContainer> {
+   public:
+    typedef internal::StlContainerView<
+         GTEST_REMOVE_REFERENCE_AND_CONST_(LhsContainer)> LhsView;
+    typedef typename LhsView::type LhsStlContainer;
+    typedef typename LhsView::const_reference LhsStlContainerReference;
+    typedef typename LhsStlContainer::value_type LhsValue;
+    // We pass the LHS value and the RHS value to the inner matcher by
+    // reference, as they may be expensive to copy.  We must use tuple
+    // instead of pair here, as a pair cannot hold references (C++ 98,
+    // 20.2.2 [lib.pairs]).
+    typedef ::std::tuple<const LhsValue&, const RhsValue&> InnerMatcherArg;
+
+    Impl(const TupleMatcher& tuple_matcher, const RhsStlContainer& rhs)
+        // mono_tuple_matcher_ holds a monomorphic version of the tuple matcher.
+        : mono_tuple_matcher_(SafeMatcherCast<InnerMatcherArg>(tuple_matcher)),
+          rhs_(rhs) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "contains " << rhs_.size()
+          << " values, where each value and its corresponding value in ";
+      UniversalPrinter<RhsStlContainer>::Print(rhs_, os);
+      *os << " ";
+      mono_tuple_matcher_.DescribeTo(os);
+    }
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "doesn't contain exactly " << rhs_.size()
+          << " values, or contains a value x at some index i"
+          << " where x and the i-th value of ";
+      UniversalPrint(rhs_, os);
+      *os << " ";
+      mono_tuple_matcher_.DescribeNegationTo(os);
+    }
+
+    bool MatchAndExplain(LhsContainer lhs,
+                         MatchResultListener* listener) const override {
+      LhsStlContainerReference lhs_stl_container = LhsView::ConstReference(lhs);
+      const size_t actual_size = lhs_stl_container.size();
+      if (actual_size != rhs_.size()) {
+        *listener << "which contains " << actual_size << " values";
+        return false;
+      }
+
+      typename LhsStlContainer::const_iterator left = lhs_stl_container.begin();
+      typename RhsStlContainer::const_iterator right = rhs_.begin();
+      for (size_t i = 0; i != actual_size; ++i, ++left, ++right) {
+        if (listener->IsInterested()) {
+          StringMatchResultListener inner_listener;
+          // Create InnerMatcherArg as a temporarily object to avoid it outlives
+          // *left and *right. Dereference or the conversion to `const T&` may
+          // return temp objects, e.g for vector<bool>.
+          if (!mono_tuple_matcher_.MatchAndExplain(
+                  InnerMatcherArg(ImplicitCast_<const LhsValue&>(*left),
+                                  ImplicitCast_<const RhsValue&>(*right)),
+                  &inner_listener)) {
+            *listener << "where the value pair (";
+            UniversalPrint(*left, listener->stream());
+            *listener << ", ";
+            UniversalPrint(*right, listener->stream());
+            *listener << ") at index #" << i << " don't match";
+            PrintIfNotEmpty(inner_listener.str(), listener->stream());
+            return false;
+          }
+        } else {
+          if (!mono_tuple_matcher_.Matches(
+                  InnerMatcherArg(ImplicitCast_<const LhsValue&>(*left),
+                                  ImplicitCast_<const RhsValue&>(*right))))
+            return false;
+        }
+      }
+
+      return true;
+    }
+
+   private:
+    const Matcher<InnerMatcherArg> mono_tuple_matcher_;
+    const RhsStlContainer rhs_;
+  };
+
+ private:
+  const TupleMatcher tuple_matcher_;
+  const RhsStlContainer rhs_;
+};
+
+// Holds the logic common to ContainsMatcherImpl and EachMatcherImpl.
+template <typename Container>
+class QuantifierMatcherImpl : public MatcherInterface<Container> {
+ public:
+  typedef GTEST_REMOVE_REFERENCE_AND_CONST_(Container) RawContainer;
+  typedef StlContainerView<RawContainer> View;
+  typedef typename View::type StlContainer;
+  typedef typename View::const_reference StlContainerReference;
+  typedef typename StlContainer::value_type Element;
+
+  template <typename InnerMatcher>
+  explicit QuantifierMatcherImpl(InnerMatcher inner_matcher)
+      : inner_matcher_(
+           testing::SafeMatcherCast<const Element&>(inner_matcher)) {}
+
+  // Checks whether:
+  // * All elements in the container match, if all_elements_should_match.
+  // * Any element in the container matches, if !all_elements_should_match.
+  bool MatchAndExplainImpl(bool all_elements_should_match,
+                           Container container,
+                           MatchResultListener* listener) const {
+    StlContainerReference stl_container = View::ConstReference(container);
+    size_t i = 0;
+    for (typename StlContainer::const_iterator it = stl_container.begin();
+         it != stl_container.end(); ++it, ++i) {
+      StringMatchResultListener inner_listener;
+      const bool matches = inner_matcher_.MatchAndExplain(*it, &inner_listener);
+
+      if (matches != all_elements_should_match) {
+        *listener << "whose element #" << i
+                  << (matches ? " matches" : " doesn't match");
+        PrintIfNotEmpty(inner_listener.str(), listener->stream());
+        return !all_elements_should_match;
+      }
+    }
+    return all_elements_should_match;
+  }
+
+ protected:
+  const Matcher<const Element&> inner_matcher_;
+};
+
+// Implements Contains(element_matcher) for the given argument type Container.
+// Symmetric to EachMatcherImpl.
+template <typename Container>
+class ContainsMatcherImpl : public QuantifierMatcherImpl<Container> {
+ public:
+  template <typename InnerMatcher>
+  explicit ContainsMatcherImpl(InnerMatcher inner_matcher)
+      : QuantifierMatcherImpl<Container>(inner_matcher) {}
+
+  // Describes what this matcher does.
+  void DescribeTo(::std::ostream* os) const override {
+    *os << "contains at least one element that ";
+    this->inner_matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const override {
+    *os << "doesn't contain any element that ";
+    this->inner_matcher_.DescribeTo(os);
+  }
+
+  bool MatchAndExplain(Container container,
+                       MatchResultListener* listener) const override {
+    return this->MatchAndExplainImpl(false, container, listener);
+  }
+};
+
+// Implements Each(element_matcher) for the given argument type Container.
+// Symmetric to ContainsMatcherImpl.
+template <typename Container>
+class EachMatcherImpl : public QuantifierMatcherImpl<Container> {
+ public:
+  template <typename InnerMatcher>
+  explicit EachMatcherImpl(InnerMatcher inner_matcher)
+      : QuantifierMatcherImpl<Container>(inner_matcher) {}
+
+  // Describes what this matcher does.
+  void DescribeTo(::std::ostream* os) const override {
+    *os << "only contains elements that ";
+    this->inner_matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const override {
+    *os << "contains some element that ";
+    this->inner_matcher_.DescribeNegationTo(os);
+  }
+
+  bool MatchAndExplain(Container container,
+                       MatchResultListener* listener) const override {
+    return this->MatchAndExplainImpl(true, container, listener);
+  }
+};
+
+// Implements polymorphic Contains(element_matcher).
+template <typename M>
+class ContainsMatcher {
+ public:
+  explicit ContainsMatcher(M m) : inner_matcher_(m) {}
+
+  template <typename Container>
+  operator Matcher<Container>() const {
+    return Matcher<Container>(
+        new ContainsMatcherImpl<const Container&>(inner_matcher_));
+  }
+
+ private:
+  const M inner_matcher_;
+};
+
+// Implements polymorphic Each(element_matcher).
+template <typename M>
+class EachMatcher {
+ public:
+  explicit EachMatcher(M m) : inner_matcher_(m) {}
+
+  template <typename Container>
+  operator Matcher<Container>() const {
+    return Matcher<Container>(
+        new EachMatcherImpl<const Container&>(inner_matcher_));
+  }
+
+ private:
+  const M inner_matcher_;
+};
+
+struct Rank1 {};
+struct Rank0 : Rank1 {};
+
+namespace pair_getters {
+using std::get;
+template <typename T>
+auto First(T& x, Rank1) -> decltype(get<0>(x)) {  // NOLINT
+  return get<0>(x);
+}
+template <typename T>
+auto First(T& x, Rank0) -> decltype((x.first)) {  // NOLINT
+  return x.first;
+}
+
+template <typename T>
+auto Second(T& x, Rank1) -> decltype(get<1>(x)) {  // NOLINT
+  return get<1>(x);
+}
+template <typename T>
+auto Second(T& x, Rank0) -> decltype((x.second)) {  // NOLINT
+  return x.second;
+}
+}  // namespace pair_getters
+
+// Implements Key(inner_matcher) for the given argument pair type.
+// Key(inner_matcher) matches an std::pair whose 'first' field matches
+// inner_matcher.  For example, Contains(Key(Ge(5))) can be used to match an
+// std::map that contains at least one element whose key is >= 5.
+template <typename PairType>
+class KeyMatcherImpl : public MatcherInterface<PairType> {
+ public:
+  typedef GTEST_REMOVE_REFERENCE_AND_CONST_(PairType) RawPairType;
+  typedef typename RawPairType::first_type KeyType;
+
+  template <typename InnerMatcher>
+  explicit KeyMatcherImpl(InnerMatcher inner_matcher)
+      : inner_matcher_(
+          testing::SafeMatcherCast<const KeyType&>(inner_matcher)) {
+  }
+
+  // Returns true if and only if 'key_value.first' (the key) matches the inner
+  // matcher.
+  bool MatchAndExplain(PairType key_value,
+                       MatchResultListener* listener) const override {
+    StringMatchResultListener inner_listener;
+    const bool match = inner_matcher_.MatchAndExplain(
+        pair_getters::First(key_value, Rank0()), &inner_listener);
+    const std::string explanation = inner_listener.str();
+    if (explanation != "") {
+      *listener << "whose first field is a value " << explanation;
+    }
+    return match;
+  }
+
+  // Describes what this matcher does.
+  void DescribeTo(::std::ostream* os) const override {
+    *os << "has a key that ";
+    inner_matcher_.DescribeTo(os);
+  }
+
+  // Describes what the negation of this matcher does.
+  void DescribeNegationTo(::std::ostream* os) const override {
+    *os << "doesn't have a key that ";
+    inner_matcher_.DescribeTo(os);
+  }
+
+ private:
+  const Matcher<const KeyType&> inner_matcher_;
+};
+
+// Implements polymorphic Key(matcher_for_key).
+template <typename M>
+class KeyMatcher {
+ public:
+  explicit KeyMatcher(M m) : matcher_for_key_(m) {}
+
+  template <typename PairType>
+  operator Matcher<PairType>() const {
+    return Matcher<PairType>(
+        new KeyMatcherImpl<const PairType&>(matcher_for_key_));
+  }
+
+ private:
+  const M matcher_for_key_;
+};
+
+// Implements polymorphic Address(matcher_for_address).
+template <typename InnerMatcher>
+class AddressMatcher {
+ public:
+  explicit AddressMatcher(InnerMatcher m) : matcher_(m) {}
+
+  template <typename Type>
+  operator Matcher<Type>() const {  // NOLINT
+    return Matcher<Type>(new Impl<const Type&>(matcher_));
+  }
+
+ private:
+  // The monomorphic implementation that works for a particular object type.
+  template <typename Type>
+  class Impl : public MatcherInterface<Type> {
+   public:
+    using Address = const GTEST_REMOVE_REFERENCE_AND_CONST_(Type) *;
+    explicit Impl(const InnerMatcher& matcher)
+        : matcher_(MatcherCast<Address>(matcher)) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "has address that ";
+      matcher_.DescribeTo(os);
+    }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "does not have address that ";
+      matcher_.DescribeTo(os);
+    }
+
+    bool MatchAndExplain(Type object,
+                         MatchResultListener* listener) const override {
+      *listener << "which has address ";
+      Address address = std::addressof(object);
+      return MatchPrintAndExplain(address, matcher_, listener);
+    }
+
+   private:
+    const Matcher<Address> matcher_;
+  };
+  const InnerMatcher matcher_;
+};
+
+// Implements Pair(first_matcher, second_matcher) for the given argument pair
+// type with its two matchers. See Pair() function below.
+template <typename PairType>
+class PairMatcherImpl : public MatcherInterface<PairType> {
+ public:
+  typedef GTEST_REMOVE_REFERENCE_AND_CONST_(PairType) RawPairType;
+  typedef typename RawPairType::first_type FirstType;
+  typedef typename RawPairType::second_type SecondType;
+
+  template <typename FirstMatcher, typename SecondMatcher>
+  PairMatcherImpl(FirstMatcher first_matcher, SecondMatcher second_matcher)
+      : first_matcher_(
+            testing::SafeMatcherCast<const FirstType&>(first_matcher)),
+        second_matcher_(
+            testing::SafeMatcherCast<const SecondType&>(second_matcher)) {
+  }
+
+  // Describes what this matcher does.
+  void DescribeTo(::std::ostream* os) const override {
+    *os << "has a first field that ";
+    first_matcher_.DescribeTo(os);
+    *os << ", and has a second field that ";
+    second_matcher_.DescribeTo(os);
+  }
+
+  // Describes what the negation of this matcher does.
+  void DescribeNegationTo(::std::ostream* os) const override {
+    *os << "has a first field that ";
+    first_matcher_.DescribeNegationTo(os);
+    *os << ", or has a second field that ";
+    second_matcher_.DescribeNegationTo(os);
+  }
+
+  // Returns true if and only if 'a_pair.first' matches first_matcher and
+  // 'a_pair.second' matches second_matcher.
+  bool MatchAndExplain(PairType a_pair,
+                       MatchResultListener* listener) const override {
+    if (!listener->IsInterested()) {
+      // If the listener is not interested, we don't need to construct the
+      // explanation.
+      return first_matcher_.Matches(pair_getters::First(a_pair, Rank0())) &&
+             second_matcher_.Matches(pair_getters::Second(a_pair, Rank0()));
+    }
+    StringMatchResultListener first_inner_listener;
+    if (!first_matcher_.MatchAndExplain(pair_getters::First(a_pair, Rank0()),
+                                        &first_inner_listener)) {
+      *listener << "whose first field does not match";
+      PrintIfNotEmpty(first_inner_listener.str(), listener->stream());
+      return false;
+    }
+    StringMatchResultListener second_inner_listener;
+    if (!second_matcher_.MatchAndExplain(pair_getters::Second(a_pair, Rank0()),
+                                         &second_inner_listener)) {
+      *listener << "whose second field does not match";
+      PrintIfNotEmpty(second_inner_listener.str(), listener->stream());
+      return false;
+    }
+    ExplainSuccess(first_inner_listener.str(), second_inner_listener.str(),
+                   listener);
+    return true;
+  }
+
+ private:
+  void ExplainSuccess(const std::string& first_explanation,
+                      const std::string& second_explanation,
+                      MatchResultListener* listener) const {
+    *listener << "whose both fields match";
+    if (first_explanation != "") {
+      *listener << ", where the first field is a value " << first_explanation;
+    }
+    if (second_explanation != "") {
+      *listener << ", ";
+      if (first_explanation != "") {
+        *listener << "and ";
+      } else {
+        *listener << "where ";
+      }
+      *listener << "the second field is a value " << second_explanation;
+    }
+  }
+
+  const Matcher<const FirstType&> first_matcher_;
+  const Matcher<const SecondType&> second_matcher_;
+};
+
+// Implements polymorphic Pair(first_matcher, second_matcher).
+template <typename FirstMatcher, typename SecondMatcher>
+class PairMatcher {
+ public:
+  PairMatcher(FirstMatcher first_matcher, SecondMatcher second_matcher)
+      : first_matcher_(first_matcher), second_matcher_(second_matcher) {}
+
+  template <typename PairType>
+  operator Matcher<PairType> () const {
+    return Matcher<PairType>(
+        new PairMatcherImpl<const PairType&>(first_matcher_, second_matcher_));
+  }
+
+ private:
+  const FirstMatcher first_matcher_;
+  const SecondMatcher second_matcher_;
+};
+
+template <typename T, size_t... I>
+auto UnpackStructImpl(const T& t, IndexSequence<I...>, int)
+    -> decltype(std::tie(get<I>(t)...)) {
+  static_assert(std::tuple_size<T>::value == sizeof...(I),
+                "Number of arguments doesn't match the number of fields.");
+  return std::tie(get<I>(t)...);
+}
+
+#if defined(__cpp_structured_bindings) && __cpp_structured_bindings >= 201606
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<1>, char) {
+  const auto& [a] = t;
+  return std::tie(a);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<2>, char) {
+  const auto& [a, b] = t;
+  return std::tie(a, b);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<3>, char) {
+  const auto& [a, b, c] = t;
+  return std::tie(a, b, c);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<4>, char) {
+  const auto& [a, b, c, d] = t;
+  return std::tie(a, b, c, d);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<5>, char) {
+  const auto& [a, b, c, d, e] = t;
+  return std::tie(a, b, c, d, e);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<6>, char) {
+  const auto& [a, b, c, d, e, f] = t;
+  return std::tie(a, b, c, d, e, f);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<7>, char) {
+  const auto& [a, b, c, d, e, f, g] = t;
+  return std::tie(a, b, c, d, e, f, g);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<8>, char) {
+  const auto& [a, b, c, d, e, f, g, h] = t;
+  return std::tie(a, b, c, d, e, f, g, h);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<9>, char) {
+  const auto& [a, b, c, d, e, f, g, h, i] = t;
+  return std::tie(a, b, c, d, e, f, g, h, i);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<10>, char) {
+  const auto& [a, b, c, d, e, f, g, h, i, j] = t;
+  return std::tie(a, b, c, d, e, f, g, h, i, j);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<11>, char) {
+  const auto& [a, b, c, d, e, f, g, h, i, j, k] = t;
+  return std::tie(a, b, c, d, e, f, g, h, i, j, k);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<12>, char) {
+  const auto& [a, b, c, d, e, f, g, h, i, j, k, l] = t;
+  return std::tie(a, b, c, d, e, f, g, h, i, j, k, l);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<13>, char) {
+  const auto& [a, b, c, d, e, f, g, h, i, j, k, l, m] = t;
+  return std::tie(a, b, c, d, e, f, g, h, i, j, k, l, m);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<14>, char) {
+  const auto& [a, b, c, d, e, f, g, h, i, j, k, l, m, n] = t;
+  return std::tie(a, b, c, d, e, f, g, h, i, j, k, l, m, n);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<15>, char) {
+  const auto& [a, b, c, d, e, f, g, h, i, j, k, l, m, n, o] = t;
+  return std::tie(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o);
+}
+template <typename T>
+auto UnpackStructImpl(const T& t, MakeIndexSequence<16>, char) {
+  const auto& [a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p] = t;
+  return std::tie(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p);
+}
+#endif  // defined(__cpp_structured_bindings)
+
+template <size_t I, typename T>
+auto UnpackStruct(const T& t)
+    -> decltype((UnpackStructImpl)(t, MakeIndexSequence<I>{}, 0)) {
+  return (UnpackStructImpl)(t, MakeIndexSequence<I>{}, 0);
+}
+
+// Helper function to do comma folding in C++11.
+// The array ensures left-to-right order of evaluation.
+// Usage: VariadicExpand({expr...});
+template <typename T, size_t N>
+void VariadicExpand(const T (&)[N]) {}
+
+template <typename Struct, typename StructSize>
+class FieldsAreMatcherImpl;
+
+template <typename Struct, size_t... I>
+class FieldsAreMatcherImpl<Struct, IndexSequence<I...>>
+    : public MatcherInterface<Struct> {
+  using UnpackedType =
+      decltype(UnpackStruct<sizeof...(I)>(std::declval<const Struct&>()));
+  using MatchersType = std::tuple<
+      Matcher<const typename std::tuple_element<I, UnpackedType>::type&>...>;
+
+ public:
+  template <typename Inner>
+  explicit FieldsAreMatcherImpl(const Inner& matchers)
+      : matchers_(testing::SafeMatcherCast<
+                  const typename std::tuple_element<I, UnpackedType>::type&>(
+            std::get<I>(matchers))...) {}
+
+  void DescribeTo(::std::ostream* os) const override {
+    const char* separator = "";
+    VariadicExpand(
+        {(*os << separator << "has field #" << I << " that ",
+          std::get<I>(matchers_).DescribeTo(os), separator = ", and ")...});
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const override {
+    const char* separator = "";
+    VariadicExpand({(*os << separator << "has field #" << I << " that ",
+                     std::get<I>(matchers_).DescribeNegationTo(os),
+                     separator = ", or ")...});
+  }
+
+  bool MatchAndExplain(Struct t, MatchResultListener* listener) const override {
+    return MatchInternal((UnpackStruct<sizeof...(I)>)(t), listener);
+  }
+
+ private:
+  bool MatchInternal(UnpackedType tuple, MatchResultListener* listener) const {
+    if (!listener->IsInterested()) {
+      // If the listener is not interested, we don't need to construct the
+      // explanation.
+      bool good = true;
+      VariadicExpand({good = good && std::get<I>(matchers_).Matches(
+                                         std::get<I>(tuple))...});
+      return good;
+    }
+
+    size_t failed_pos = ~size_t{};
+
+    std::vector<StringMatchResultListener> inner_listener(sizeof...(I));
+
+    VariadicExpand(
+        {failed_pos == ~size_t{} && !std::get<I>(matchers_).MatchAndExplain(
+                                        std::get<I>(tuple), &inner_listener[I])
+             ? failed_pos = I
+             : 0 ...});
+    if (failed_pos != ~size_t{}) {
+      *listener << "whose field #" << failed_pos << " does not match";
+      PrintIfNotEmpty(inner_listener[failed_pos].str(), listener->stream());
+      return false;
+    }
+
+    *listener << "whose all elements match";
+    const char* separator = ", where";
+    for (size_t index = 0; index < sizeof...(I); ++index) {
+      const std::string str = inner_listener[index].str();
+      if (!str.empty()) {
+        *listener << separator << " field #" << index << " is a value " << str;
+        separator = ", and";
+      }
+    }
+
+    return true;
+  }
+
+  MatchersType matchers_;
+};
+
+template <typename... Inner>
+class FieldsAreMatcher {
+ public:
+  explicit FieldsAreMatcher(Inner... inner) : matchers_(std::move(inner)...) {}
+
+  template <typename Struct>
+  operator Matcher<Struct>() const {  // NOLINT
+    return Matcher<Struct>(
+        new FieldsAreMatcherImpl<const Struct&, IndexSequenceFor<Inner...>>(
+            matchers_));
+  }
+
+ private:
+  std::tuple<Inner...> matchers_;
+};
+
+// Implements ElementsAre() and ElementsAreArray().
+template <typename Container>
+class ElementsAreMatcherImpl : public MatcherInterface<Container> {
+ public:
+  typedef GTEST_REMOVE_REFERENCE_AND_CONST_(Container) RawContainer;
+  typedef internal::StlContainerView<RawContainer> View;
+  typedef typename View::type StlContainer;
+  typedef typename View::const_reference StlContainerReference;
+  typedef typename StlContainer::value_type Element;
+
+  // Constructs the matcher from a sequence of element values or
+  // element matchers.
+  template <typename InputIter>
+  ElementsAreMatcherImpl(InputIter first, InputIter last) {
+    while (first != last) {
+      matchers_.push_back(MatcherCast<const Element&>(*first++));
+    }
+  }
+
+  // Describes what this matcher does.
+  void DescribeTo(::std::ostream* os) const override {
+    if (count() == 0) {
+      *os << "is empty";
+    } else if (count() == 1) {
+      *os << "has 1 element that ";
+      matchers_[0].DescribeTo(os);
+    } else {
+      *os << "has " << Elements(count()) << " where\n";
+      for (size_t i = 0; i != count(); ++i) {
+        *os << "element #" << i << " ";
+        matchers_[i].DescribeTo(os);
+        if (i + 1 < count()) {
+          *os << ",\n";
+        }
+      }
+    }
+  }
+
+  // Describes what the negation of this matcher does.
+  void DescribeNegationTo(::std::ostream* os) const override {
+    if (count() == 0) {
+      *os << "isn't empty";
+      return;
+    }
+
+    *os << "doesn't have " << Elements(count()) << ", or\n";
+    for (size_t i = 0; i != count(); ++i) {
+      *os << "element #" << i << " ";
+      matchers_[i].DescribeNegationTo(os);
+      if (i + 1 < count()) {
+        *os << ", or\n";
+      }
+    }
+  }
+
+  bool MatchAndExplain(Container container,
+                       MatchResultListener* listener) const override {
+    // To work with stream-like "containers", we must only walk
+    // through the elements in one pass.
+
+    const bool listener_interested = listener->IsInterested();
+
+    // explanations[i] is the explanation of the element at index i.
+    ::std::vector<std::string> explanations(count());
+    StlContainerReference stl_container = View::ConstReference(container);
+    typename StlContainer::const_iterator it = stl_container.begin();
+    size_t exam_pos = 0;
+    bool mismatch_found = false;  // Have we found a mismatched element yet?
+
+    // Go through the elements and matchers in pairs, until we reach
+    // the end of either the elements or the matchers, or until we find a
+    // mismatch.
+    for (; it != stl_container.end() && exam_pos != count(); ++it, ++exam_pos) {
+      bool match;  // Does the current element match the current matcher?
+      if (listener_interested) {
+        StringMatchResultListener s;
+        match = matchers_[exam_pos].MatchAndExplain(*it, &s);
+        explanations[exam_pos] = s.str();
+      } else {
+        match = matchers_[exam_pos].Matches(*it);
+      }
+
+      if (!match) {
+        mismatch_found = true;
+        break;
+      }
+    }
+    // If mismatch_found is true, 'exam_pos' is the index of the mismatch.
+
+    // Find how many elements the actual container has.  We avoid
+    // calling size() s.t. this code works for stream-like "containers"
+    // that don't define size().
+    size_t actual_count = exam_pos;
+    for (; it != stl_container.end(); ++it) {
+      ++actual_count;
+    }
+
+    if (actual_count != count()) {
+      // The element count doesn't match.  If the container is empty,
+      // there's no need to explain anything as Google Mock already
+      // prints the empty container.  Otherwise we just need to show
+      // how many elements there actually are.
+      if (listener_interested && (actual_count != 0)) {
+        *listener << "which has " << Elements(actual_count);
+      }
+      return false;
+    }
+
+    if (mismatch_found) {
+      // The element count matches, but the exam_pos-th element doesn't match.
+      if (listener_interested) {
+        *listener << "whose element #" << exam_pos << " doesn't match";
+        PrintIfNotEmpty(explanations[exam_pos], listener->stream());
+      }
+      return false;
+    }
+
+    // Every element matches its expectation.  We need to explain why
+    // (the obvious ones can be skipped).
+    if (listener_interested) {
+      bool reason_printed = false;
+      for (size_t i = 0; i != count(); ++i) {
+        const std::string& s = explanations[i];
+        if (!s.empty()) {
+          if (reason_printed) {
+            *listener << ",\nand ";
+          }
+          *listener << "whose element #" << i << " matches, " << s;
+          reason_printed = true;
+        }
+      }
+    }
+    return true;
+  }
+
+ private:
+  static Message Elements(size_t count) {
+    return Message() << count << (count == 1 ? " element" : " elements");
+  }
+
+  size_t count() const { return matchers_.size(); }
+
+  ::std::vector<Matcher<const Element&> > matchers_;
+};
+
+// Connectivity matrix of (elements X matchers), in element-major order.
+// Initially, there are no edges.
+// Use NextGraph() to iterate over all possible edge configurations.
+// Use Randomize() to generate a random edge configuration.
+class GTEST_API_ MatchMatrix {
+ public:
+  MatchMatrix(size_t num_elements, size_t num_matchers)
+      : num_elements_(num_elements),
+        num_matchers_(num_matchers),
+        matched_(num_elements_* num_matchers_, 0) {
+  }
+
+  size_t LhsSize() const { return num_elements_; }
+  size_t RhsSize() const { return num_matchers_; }
+  bool HasEdge(size_t ilhs, size_t irhs) const {
+    return matched_[SpaceIndex(ilhs, irhs)] == 1;
+  }
+  void SetEdge(size_t ilhs, size_t irhs, bool b) {
+    matched_[SpaceIndex(ilhs, irhs)] = b ? 1 : 0;
+  }
+
+  // Treating the connectivity matrix as a (LhsSize()*RhsSize())-bit number,
+  // adds 1 to that number; returns false if incrementing the graph left it
+  // empty.
+  bool NextGraph();
+
+  void Randomize();
+
+  std::string DebugString() const;
+
+ private:
+  size_t SpaceIndex(size_t ilhs, size_t irhs) const {
+    return ilhs * num_matchers_ + irhs;
+  }
+
+  size_t num_elements_;
+  size_t num_matchers_;
+
+  // Each element is a char interpreted as bool. They are stored as a
+  // flattened array in lhs-major order, use 'SpaceIndex()' to translate
+  // a (ilhs, irhs) matrix coordinate into an offset.
+  ::std::vector<char> matched_;
+};
+
+typedef ::std::pair<size_t, size_t> ElementMatcherPair;
+typedef ::std::vector<ElementMatcherPair> ElementMatcherPairs;
+
+// Returns a maximum bipartite matching for the specified graph 'g'.
+// The matching is represented as a vector of {element, matcher} pairs.
+GTEST_API_ ElementMatcherPairs
+FindMaxBipartiteMatching(const MatchMatrix& g);
+
+struct UnorderedMatcherRequire {
+  enum Flags {
+    Superset = 1 << 0,
+    Subset = 1 << 1,
+    ExactMatch = Superset | Subset,
+  };
+};
+
+// Untyped base class for implementing UnorderedElementsAre.  By
+// putting logic that's not specific to the element type here, we
+// reduce binary bloat and increase compilation speed.
+class GTEST_API_ UnorderedElementsAreMatcherImplBase {
+ protected:
+  explicit UnorderedElementsAreMatcherImplBase(
+      UnorderedMatcherRequire::Flags matcher_flags)
+      : match_flags_(matcher_flags) {}
+
+  // A vector of matcher describers, one for each element matcher.
+  // Does not own the describers (and thus can be used only when the
+  // element matchers are alive).
+  typedef ::std::vector<const MatcherDescriberInterface*> MatcherDescriberVec;
+
+  // Describes this UnorderedElementsAre matcher.
+  void DescribeToImpl(::std::ostream* os) const;
+
+  // Describes the negation of this UnorderedElementsAre matcher.
+  void DescribeNegationToImpl(::std::ostream* os) const;
+
+  bool VerifyMatchMatrix(const ::std::vector<std::string>& element_printouts,
+                         const MatchMatrix& matrix,
+                         MatchResultListener* listener) const;
+
+  bool FindPairing(const MatchMatrix& matrix,
+                   MatchResultListener* listener) const;
+
+  MatcherDescriberVec& matcher_describers() {
+    return matcher_describers_;
+  }
+
+  static Message Elements(size_t n) {
+    return Message() << n << " element" << (n == 1 ? "" : "s");
+  }
+
+  UnorderedMatcherRequire::Flags match_flags() const { return match_flags_; }
+
+ private:
+  UnorderedMatcherRequire::Flags match_flags_;
+  MatcherDescriberVec matcher_describers_;
+};
+
+// Implements UnorderedElementsAre, UnorderedElementsAreArray, IsSubsetOf, and
+// IsSupersetOf.
+template <typename Container>
+class UnorderedElementsAreMatcherImpl
+    : public MatcherInterface<Container>,
+      public UnorderedElementsAreMatcherImplBase {
+ public:
+  typedef GTEST_REMOVE_REFERENCE_AND_CONST_(Container) RawContainer;
+  typedef internal::StlContainerView<RawContainer> View;
+  typedef typename View::type StlContainer;
+  typedef typename View::const_reference StlContainerReference;
+  typedef typename StlContainer::const_iterator StlContainerConstIterator;
+  typedef typename StlContainer::value_type Element;
+
+  template <typename InputIter>
+  UnorderedElementsAreMatcherImpl(UnorderedMatcherRequire::Flags matcher_flags,
+                                  InputIter first, InputIter last)
+      : UnorderedElementsAreMatcherImplBase(matcher_flags) {
+    for (; first != last; ++first) {
+      matchers_.push_back(MatcherCast<const Element&>(*first));
+    }
+    for (const auto& m : matchers_) {
+      matcher_describers().push_back(m.GetDescriber());
+    }
+  }
+
+  // Describes what this matcher does.
+  void DescribeTo(::std::ostream* os) const override {
+    return UnorderedElementsAreMatcherImplBase::DescribeToImpl(os);
+  }
+
+  // Describes what the negation of this matcher does.
+  void DescribeNegationTo(::std::ostream* os) const override {
+    return UnorderedElementsAreMatcherImplBase::DescribeNegationToImpl(os);
+  }
+
+  bool MatchAndExplain(Container container,
+                       MatchResultListener* listener) const override {
+    StlContainerReference stl_container = View::ConstReference(container);
+    ::std::vector<std::string> element_printouts;
+    MatchMatrix matrix =
+        AnalyzeElements(stl_container.begin(), stl_container.end(),
+                        &element_printouts, listener);
+
+    if (matrix.LhsSize() == 0 && matrix.RhsSize() == 0) {
+      return true;
+    }
+
+    if (match_flags() == UnorderedMatcherRequire::ExactMatch) {
+      if (matrix.LhsSize() != matrix.RhsSize()) {
+        // The element count doesn't match.  If the container is empty,
+        // there's no need to explain anything as Google Mock already
+        // prints the empty container. Otherwise we just need to show
+        // how many elements there actually are.
+        if (matrix.LhsSize() != 0 && listener->IsInterested()) {
+          *listener << "which has " << Elements(matrix.LhsSize());
+        }
+        return false;
+      }
+    }
+
+    return VerifyMatchMatrix(element_printouts, matrix, listener) &&
+           FindPairing(matrix, listener);
+  }
+
+ private:
+  template <typename ElementIter>
+  MatchMatrix AnalyzeElements(ElementIter elem_first, ElementIter elem_last,
+                              ::std::vector<std::string>* element_printouts,
+                              MatchResultListener* listener) const {
+    element_printouts->clear();
+    ::std::vector<char> did_match;
+    size_t num_elements = 0;
+    DummyMatchResultListener dummy;
+    for (; elem_first != elem_last; ++num_elements, ++elem_first) {
+      if (listener->IsInterested()) {
+        element_printouts->push_back(PrintToString(*elem_first));
+      }
+      for (size_t irhs = 0; irhs != matchers_.size(); ++irhs) {
+        did_match.push_back(
+            matchers_[irhs].MatchAndExplain(*elem_first, &dummy));
+      }
+    }
+
+    MatchMatrix matrix(num_elements, matchers_.size());
+    ::std::vector<char>::const_iterator did_match_iter = did_match.begin();
+    for (size_t ilhs = 0; ilhs != num_elements; ++ilhs) {
+      for (size_t irhs = 0; irhs != matchers_.size(); ++irhs) {
+        matrix.SetEdge(ilhs, irhs, *did_match_iter++ != 0);
+      }
+    }
+    return matrix;
+  }
+
+  ::std::vector<Matcher<const Element&> > matchers_;
+};
+
+// Functor for use in TransformTuple.
+// Performs MatcherCast<Target> on an input argument of any type.
+template <typename Target>
+struct CastAndAppendTransform {
+  template <typename Arg>
+  Matcher<Target> operator()(const Arg& a) const {
+    return MatcherCast<Target>(a);
+  }
+};
+
+// Implements UnorderedElementsAre.
+template <typename MatcherTuple>
+class UnorderedElementsAreMatcher {
+ public:
+  explicit UnorderedElementsAreMatcher(const MatcherTuple& args)
+      : matchers_(args) {}
+
+  template <typename Container>
+  operator Matcher<Container>() const {
+    typedef GTEST_REMOVE_REFERENCE_AND_CONST_(Container) RawContainer;
+    typedef typename internal::StlContainerView<RawContainer>::type View;
+    typedef typename View::value_type Element;
+    typedef ::std::vector<Matcher<const Element&> > MatcherVec;
+    MatcherVec matchers;
+    matchers.reserve(::std::tuple_size<MatcherTuple>::value);
+    TransformTupleValues(CastAndAppendTransform<const Element&>(), matchers_,
+                         ::std::back_inserter(matchers));
+    return Matcher<Container>(
+        new UnorderedElementsAreMatcherImpl<const Container&>(
+            UnorderedMatcherRequire::ExactMatch, matchers.begin(),
+            matchers.end()));
+  }
+
+ private:
+  const MatcherTuple matchers_;
+};
+
+// Implements ElementsAre.
+template <typename MatcherTuple>
+class ElementsAreMatcher {
+ public:
+  explicit ElementsAreMatcher(const MatcherTuple& args) : matchers_(args) {}
+
+  template <typename Container>
+  operator Matcher<Container>() const {
+    GTEST_COMPILE_ASSERT_(
+        !IsHashTable<GTEST_REMOVE_REFERENCE_AND_CONST_(Container)>::value ||
+            ::std::tuple_size<MatcherTuple>::value < 2,
+        use_UnorderedElementsAre_with_hash_tables);
+
+    typedef GTEST_REMOVE_REFERENCE_AND_CONST_(Container) RawContainer;
+    typedef typename internal::StlContainerView<RawContainer>::type View;
+    typedef typename View::value_type Element;
+    typedef ::std::vector<Matcher<const Element&> > MatcherVec;
+    MatcherVec matchers;
+    matchers.reserve(::std::tuple_size<MatcherTuple>::value);
+    TransformTupleValues(CastAndAppendTransform<const Element&>(), matchers_,
+                         ::std::back_inserter(matchers));
+    return Matcher<Container>(new ElementsAreMatcherImpl<const Container&>(
+        matchers.begin(), matchers.end()));
+  }
+
+ private:
+  const MatcherTuple matchers_;
+};
+
+// Implements UnorderedElementsAreArray(), IsSubsetOf(), and IsSupersetOf().
+template <typename T>
+class UnorderedElementsAreArrayMatcher {
+ public:
+  template <typename Iter>
+  UnorderedElementsAreArrayMatcher(UnorderedMatcherRequire::Flags match_flags,
+                                   Iter first, Iter last)
+      : match_flags_(match_flags), matchers_(first, last) {}
+
+  template <typename Container>
+  operator Matcher<Container>() const {
+    return Matcher<Container>(
+        new UnorderedElementsAreMatcherImpl<const Container&>(
+            match_flags_, matchers_.begin(), matchers_.end()));
+  }
+
+ private:
+  UnorderedMatcherRequire::Flags match_flags_;
+  ::std::vector<T> matchers_;
+};
+
+// Implements ElementsAreArray().
+template <typename T>
+class ElementsAreArrayMatcher {
+ public:
+  template <typename Iter>
+  ElementsAreArrayMatcher(Iter first, Iter last) : matchers_(first, last) {}
+
+  template <typename Container>
+  operator Matcher<Container>() const {
+    GTEST_COMPILE_ASSERT_(
+        !IsHashTable<GTEST_REMOVE_REFERENCE_AND_CONST_(Container)>::value,
+        use_UnorderedElementsAreArray_with_hash_tables);
+
+    return Matcher<Container>(new ElementsAreMatcherImpl<const Container&>(
+        matchers_.begin(), matchers_.end()));
+  }
+
+ private:
+  const ::std::vector<T> matchers_;
+};
+
+// Given a 2-tuple matcher tm of type Tuple2Matcher and a value second
+// of type Second, BoundSecondMatcher<Tuple2Matcher, Second>(tm,
+// second) is a polymorphic matcher that matches a value x if and only if
+// tm matches tuple (x, second).  Useful for implementing
+// UnorderedPointwise() in terms of UnorderedElementsAreArray().
+//
+// BoundSecondMatcher is copyable and assignable, as we need to put
+// instances of this class in a vector when implementing
+// UnorderedPointwise().
+template <typename Tuple2Matcher, typename Second>
+class BoundSecondMatcher {
+ public:
+  BoundSecondMatcher(const Tuple2Matcher& tm, const Second& second)
+      : tuple2_matcher_(tm), second_value_(second) {}
+
+  BoundSecondMatcher(const BoundSecondMatcher& other) = default;
+
+  template <typename T>
+  operator Matcher<T>() const {
+    return MakeMatcher(new Impl<T>(tuple2_matcher_, second_value_));
+  }
+
+  // We have to define this for UnorderedPointwise() to compile in
+  // C++98 mode, as it puts BoundSecondMatcher instances in a vector,
+  // which requires the elements to be assignable in C++98.  The
+  // compiler cannot generate the operator= for us, as Tuple2Matcher
+  // and Second may not be assignable.
+  //
+  // However, this should never be called, so the implementation just
+  // need to assert.
+  void operator=(const BoundSecondMatcher& /*rhs*/) {
+    GTEST_LOG_(FATAL) << "BoundSecondMatcher should never be assigned.";
+  }
+
+ private:
+  template <typename T>
+  class Impl : public MatcherInterface<T> {
+   public:
+    typedef ::std::tuple<T, Second> ArgTuple;
+
+    Impl(const Tuple2Matcher& tm, const Second& second)
+        : mono_tuple2_matcher_(SafeMatcherCast<const ArgTuple&>(tm)),
+          second_value_(second) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "and ";
+      UniversalPrint(second_value_, os);
+      *os << " ";
+      mono_tuple2_matcher_.DescribeTo(os);
+    }
+
+    bool MatchAndExplain(T x, MatchResultListener* listener) const override {
+      return mono_tuple2_matcher_.MatchAndExplain(ArgTuple(x, second_value_),
+                                                  listener);
+    }
+
+   private:
+    const Matcher<const ArgTuple&> mono_tuple2_matcher_;
+    const Second second_value_;
+  };
+
+  const Tuple2Matcher tuple2_matcher_;
+  const Second second_value_;
+};
+
+// Given a 2-tuple matcher tm and a value second,
+// MatcherBindSecond(tm, second) returns a matcher that matches a
+// value x if and only if tm matches tuple (x, second).  Useful for
+// implementing UnorderedPointwise() in terms of UnorderedElementsAreArray().
+template <typename Tuple2Matcher, typename Second>
+BoundSecondMatcher<Tuple2Matcher, Second> MatcherBindSecond(
+    const Tuple2Matcher& tm, const Second& second) {
+  return BoundSecondMatcher<Tuple2Matcher, Second>(tm, second);
+}
+
+// Returns the description for a matcher defined using the MATCHER*()
+// macro where the user-supplied description string is "", if
+// 'negation' is false; otherwise returns the description of the
+// negation of the matcher.  'param_values' contains a list of strings
+// that are the print-out of the matcher's parameters.
+GTEST_API_ std::string FormatMatcherDescription(bool negation,
+                                                const char* matcher_name,
+                                                const Strings& param_values);
+
+// Implements a matcher that checks the value of a optional<> type variable.
+template <typename ValueMatcher>
+class OptionalMatcher {
+ public:
+  explicit OptionalMatcher(const ValueMatcher& value_matcher)
+      : value_matcher_(value_matcher) {}
+
+  template <typename Optional>
+  operator Matcher<Optional>() const {
+    return Matcher<Optional>(new Impl<const Optional&>(value_matcher_));
+  }
+
+  template <typename Optional>
+  class Impl : public MatcherInterface<Optional> {
+   public:
+    typedef GTEST_REMOVE_REFERENCE_AND_CONST_(Optional) OptionalView;
+    typedef typename OptionalView::value_type ValueType;
+    explicit Impl(const ValueMatcher& value_matcher)
+        : value_matcher_(MatcherCast<ValueType>(value_matcher)) {}
+
+    void DescribeTo(::std::ostream* os) const override {
+      *os << "value ";
+      value_matcher_.DescribeTo(os);
+    }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      *os << "value ";
+      value_matcher_.DescribeNegationTo(os);
+    }
+
+    bool MatchAndExplain(Optional optional,
+                         MatchResultListener* listener) const override {
+      if (!optional) {
+        *listener << "which is not engaged";
+        return false;
+      }
+      const ValueType& value = *optional;
+      StringMatchResultListener value_listener;
+      const bool match = value_matcher_.MatchAndExplain(value, &value_listener);
+      *listener << "whose value " << PrintToString(value)
+                << (match ? " matches" : " doesn't match");
+      PrintIfNotEmpty(value_listener.str(), listener->stream());
+      return match;
+    }
+
+   private:
+    const Matcher<ValueType> value_matcher_;
+  };
+
+ private:
+  const ValueMatcher value_matcher_;
+};
+
+namespace variant_matcher {
+// Overloads to allow VariantMatcher to do proper ADL lookup.
+template <typename T>
+void holds_alternative() {}
+template <typename T>
+void get() {}
+
+// Implements a matcher that checks the value of a variant<> type variable.
+template <typename T>
+class VariantMatcher {
+ public:
+  explicit VariantMatcher(::testing::Matcher<const T&> matcher)
+      : matcher_(std::move(matcher)) {}
+
+  template <typename Variant>
+  bool MatchAndExplain(const Variant& value,
+                       ::testing::MatchResultListener* listener) const {
+    using std::get;
+    if (!listener->IsInterested()) {
+      return holds_alternative<T>(value) && matcher_.Matches(get<T>(value));
+    }
+
+    if (!holds_alternative<T>(value)) {
+      *listener << "whose value is not of type '" << GetTypeName() << "'";
+      return false;
+    }
+
+    const T& elem = get<T>(value);
+    StringMatchResultListener elem_listener;
+    const bool match = matcher_.MatchAndExplain(elem, &elem_listener);
+    *listener << "whose value " << PrintToString(elem)
+              << (match ? " matches" : " doesn't match");
+    PrintIfNotEmpty(elem_listener.str(), listener->stream());
+    return match;
+  }
+
+  void DescribeTo(std::ostream* os) const {
+    *os << "is a variant<> with value of type '" << GetTypeName()
+        << "' and the value ";
+    matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(std::ostream* os) const {
+    *os << "is a variant<> with value of type other than '" << GetTypeName()
+        << "' or the value ";
+    matcher_.DescribeNegationTo(os);
+  }
+
+ private:
+  static std::string GetTypeName() {
+#if GTEST_HAS_RTTI
+    GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(
+        return internal::GetTypeName<T>());
+#endif
+    return "the element type";
+  }
+
+  const ::testing::Matcher<const T&> matcher_;
+};
+
+}  // namespace variant_matcher
+
+namespace any_cast_matcher {
+
+// Overloads to allow AnyCastMatcher to do proper ADL lookup.
+template <typename T>
+void any_cast() {}
+
+// Implements a matcher that any_casts the value.
+template <typename T>
+class AnyCastMatcher {
+ public:
+  explicit AnyCastMatcher(const ::testing::Matcher<const T&>& matcher)
+      : matcher_(matcher) {}
+
+  template <typename AnyType>
+  bool MatchAndExplain(const AnyType& value,
+                       ::testing::MatchResultListener* listener) const {
+    if (!listener->IsInterested()) {
+      const T* ptr = any_cast<T>(&value);
+      return ptr != nullptr && matcher_.Matches(*ptr);
+    }
+
+    const T* elem = any_cast<T>(&value);
+    if (elem == nullptr) {
+      *listener << "whose value is not of type '" << GetTypeName() << "'";
+      return false;
+    }
+
+    StringMatchResultListener elem_listener;
+    const bool match = matcher_.MatchAndExplain(*elem, &elem_listener);
+    *listener << "whose value " << PrintToString(*elem)
+              << (match ? " matches" : " doesn't match");
+    PrintIfNotEmpty(elem_listener.str(), listener->stream());
+    return match;
+  }
+
+  void DescribeTo(std::ostream* os) const {
+    *os << "is an 'any' type with value of type '" << GetTypeName()
+        << "' and the value ";
+    matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(std::ostream* os) const {
+    *os << "is an 'any' type with value of type other than '" << GetTypeName()
+        << "' or the value ";
+    matcher_.DescribeNegationTo(os);
+  }
+
+ private:
+  static std::string GetTypeName() {
+#if GTEST_HAS_RTTI
+    GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(
+        return internal::GetTypeName<T>());
+#endif
+    return "the element type";
+  }
+
+  const ::testing::Matcher<const T&> matcher_;
+};
+
+}  // namespace any_cast_matcher
+
+// Implements the Args() matcher.
+template <class ArgsTuple, size_t... k>
+class ArgsMatcherImpl : public MatcherInterface<ArgsTuple> {
+ public:
+  using RawArgsTuple = typename std::decay<ArgsTuple>::type;
+  using SelectedArgs =
+      std::tuple<typename std::tuple_element<k, RawArgsTuple>::type...>;
+  using MonomorphicInnerMatcher = Matcher<const SelectedArgs&>;
+
+  template <typename InnerMatcher>
+  explicit ArgsMatcherImpl(const InnerMatcher& inner_matcher)
+      : inner_matcher_(SafeMatcherCast<const SelectedArgs&>(inner_matcher)) {}
+
+  bool MatchAndExplain(ArgsTuple args,
+                       MatchResultListener* listener) const override {
+    // Workaround spurious C4100 on MSVC<=15.7 when k is empty.
+    (void)args;
+    const SelectedArgs& selected_args =
+        std::forward_as_tuple(std::get<k>(args)...);
+    if (!listener->IsInterested()) return inner_matcher_.Matches(selected_args);
+
+    PrintIndices(listener->stream());
+    *listener << "are " << PrintToString(selected_args);
+
+    StringMatchResultListener inner_listener;
+    const bool match =
+        inner_matcher_.MatchAndExplain(selected_args, &inner_listener);
+    PrintIfNotEmpty(inner_listener.str(), listener->stream());
+    return match;
+  }
+
+  void DescribeTo(::std::ostream* os) const override {
+    *os << "are a tuple ";
+    PrintIndices(os);
+    inner_matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const override {
+    *os << "are a tuple ";
+    PrintIndices(os);
+    inner_matcher_.DescribeNegationTo(os);
+  }
+
+ private:
+  // Prints the indices of the selected fields.
+  static void PrintIndices(::std::ostream* os) {
+    *os << "whose fields (";
+    const char* sep = "";
+    // Workaround spurious C4189 on MSVC<=15.7 when k is empty.
+    (void)sep;
+    const char* dummy[] = {"", (*os << sep << "#" << k, sep = ", ")...};
+    (void)dummy;
+    *os << ") ";
+  }
+
+  MonomorphicInnerMatcher inner_matcher_;
+};
+
+template <class InnerMatcher, size_t... k>
+class ArgsMatcher {
+ public:
+  explicit ArgsMatcher(InnerMatcher inner_matcher)
+      : inner_matcher_(std::move(inner_matcher)) {}
+
+  template <typename ArgsTuple>
+  operator Matcher<ArgsTuple>() const {  // NOLINT
+    return MakeMatcher(new ArgsMatcherImpl<ArgsTuple, k...>(inner_matcher_));
+  }
+
+ private:
+  InnerMatcher inner_matcher_;
+};
+
+}  // namespace internal
+
+// ElementsAreArray(iterator_first, iterator_last)
+// ElementsAreArray(pointer, count)
+// ElementsAreArray(array)
+// ElementsAreArray(container)
+// ElementsAreArray({ e1, e2, ..., en })
+//
+// The ElementsAreArray() functions are like ElementsAre(...), except
+// that they are given a homogeneous sequence rather than taking each
+// element as a function argument. The sequence can be specified as an
+// array, a pointer and count, a vector, an initializer list, or an
+// STL iterator range. In each of these cases, the underlying sequence
+// can be either a sequence of values or a sequence of matchers.
+//
+// All forms of ElementsAreArray() make a copy of the input matcher sequence.
+
+template <typename Iter>
+inline internal::ElementsAreArrayMatcher<
+    typename ::std::iterator_traits<Iter>::value_type>
+ElementsAreArray(Iter first, Iter last) {
+  typedef typename ::std::iterator_traits<Iter>::value_type T;
+  return internal::ElementsAreArrayMatcher<T>(first, last);
+}
+
+template <typename T>
+inline internal::ElementsAreArrayMatcher<T> ElementsAreArray(
+    const T* pointer, size_t count) {
+  return ElementsAreArray(pointer, pointer + count);
+}
+
+template <typename T, size_t N>
+inline internal::ElementsAreArrayMatcher<T> ElementsAreArray(
+    const T (&array)[N]) {
+  return ElementsAreArray(array, N);
+}
+
+template <typename Container>
+inline internal::ElementsAreArrayMatcher<typename Container::value_type>
+ElementsAreArray(const Container& container) {
+  return ElementsAreArray(container.begin(), container.end());
+}
+
+template <typename T>
+inline internal::ElementsAreArrayMatcher<T>
+ElementsAreArray(::std::initializer_list<T> xs) {
+  return ElementsAreArray(xs.begin(), xs.end());
+}
+
+// UnorderedElementsAreArray(iterator_first, iterator_last)
+// UnorderedElementsAreArray(pointer, count)
+// UnorderedElementsAreArray(array)
+// UnorderedElementsAreArray(container)
+// UnorderedElementsAreArray({ e1, e2, ..., en })
+//
+// UnorderedElementsAreArray() verifies that a bijective mapping onto a
+// collection of matchers exists.
+//
+// The matchers can be specified as an array, a pointer and count, a container,
+// an initializer list, or an STL iterator range. In each of these cases, the
+// underlying matchers can be either values or matchers.
+
+template <typename Iter>
+inline internal::UnorderedElementsAreArrayMatcher<
+    typename ::std::iterator_traits<Iter>::value_type>
+UnorderedElementsAreArray(Iter first, Iter last) {
+  typedef typename ::std::iterator_traits<Iter>::value_type T;
+  return internal::UnorderedElementsAreArrayMatcher<T>(
+      internal::UnorderedMatcherRequire::ExactMatch, first, last);
+}
+
+template <typename T>
+inline internal::UnorderedElementsAreArrayMatcher<T>
+UnorderedElementsAreArray(const T* pointer, size_t count) {
+  return UnorderedElementsAreArray(pointer, pointer + count);
+}
+
+template <typename T, size_t N>
+inline internal::UnorderedElementsAreArrayMatcher<T>
+UnorderedElementsAreArray(const T (&array)[N]) {
+  return UnorderedElementsAreArray(array, N);
+}
+
+template <typename Container>
+inline internal::UnorderedElementsAreArrayMatcher<
+    typename Container::value_type>
+UnorderedElementsAreArray(const Container& container) {
+  return UnorderedElementsAreArray(container.begin(), container.end());
+}
+
+template <typename T>
+inline internal::UnorderedElementsAreArrayMatcher<T>
+UnorderedElementsAreArray(::std::initializer_list<T> xs) {
+  return UnorderedElementsAreArray(xs.begin(), xs.end());
+}
+
+// _ is a matcher that matches anything of any type.
+//
+// This definition is fine as:
+//
+//   1. The C++ standard permits using the name _ in a namespace that
+//      is not the global namespace or ::std.
+//   2. The AnythingMatcher class has no data member or constructor,
+//      so it's OK to create global variables of this type.
+//   3. c-style has approved of using _ in this case.
+const internal::AnythingMatcher _ = {};
+// Creates a matcher that matches any value of the given type T.
+template <typename T>
+inline Matcher<T> A() {
+  return _;
+}
+
+// Creates a matcher that matches any value of the given type T.
+template <typename T>
+inline Matcher<T> An() {
+  return _;
+}
+
+template <typename T, typename M>
+Matcher<T> internal::MatcherCastImpl<T, M>::CastImpl(
+    const M& value, std::false_type /* convertible_to_matcher */,
+    std::false_type /* convertible_to_T */) {
+  return Eq(value);
+}
+
+// Creates a polymorphic matcher that matches any NULL pointer.
+inline PolymorphicMatcher<internal::IsNullMatcher > IsNull() {
+  return MakePolymorphicMatcher(internal::IsNullMatcher());
+}
+
+// Creates a polymorphic matcher that matches any non-NULL pointer.
+// This is convenient as Not(NULL) doesn't compile (the compiler
+// thinks that that expression is comparing a pointer with an integer).
+inline PolymorphicMatcher<internal::NotNullMatcher > NotNull() {
+  return MakePolymorphicMatcher(internal::NotNullMatcher());
+}
+
+// Creates a polymorphic matcher that matches any argument that
+// references variable x.
+template <typename T>
+inline internal::RefMatcher<T&> Ref(T& x) {  // NOLINT
+  return internal::RefMatcher<T&>(x);
+}
+
+// Creates a polymorphic matcher that matches any NaN floating point.
+inline PolymorphicMatcher<internal::IsNanMatcher> IsNan() {
+  return MakePolymorphicMatcher(internal::IsNanMatcher());
+}
+
+// Creates a matcher that matches any double argument approximately
+// equal to rhs, where two NANs are considered unequal.
+inline internal::FloatingEqMatcher<double> DoubleEq(double rhs) {
+  return internal::FloatingEqMatcher<double>(rhs, false);
+}
+
+// Creates a matcher that matches any double argument approximately
+// equal to rhs, including NaN values when rhs is NaN.
+inline internal::FloatingEqMatcher<double> NanSensitiveDoubleEq(double rhs) {
+  return internal::FloatingEqMatcher<double>(rhs, true);
+}
+
+// Creates a matcher that matches any double argument approximately equal to
+// rhs, up to the specified max absolute error bound, where two NANs are
+// considered unequal.  The max absolute error bound must be non-negative.
+inline internal::FloatingEqMatcher<double> DoubleNear(
+    double rhs, double max_abs_error) {
+  return internal::FloatingEqMatcher<double>(rhs, false, max_abs_error);
+}
+
+// Creates a matcher that matches any double argument approximately equal to
+// rhs, up to the specified max absolute error bound, including NaN values when
+// rhs is NaN.  The max absolute error bound must be non-negative.
+inline internal::FloatingEqMatcher<double> NanSensitiveDoubleNear(
+    double rhs, double max_abs_error) {
+  return internal::FloatingEqMatcher<double>(rhs, true, max_abs_error);
+}
+
+// Creates a matcher that matches any float argument approximately
+// equal to rhs, where two NANs are considered unequal.
+inline internal::FloatingEqMatcher<float> FloatEq(float rhs) {
+  return internal::FloatingEqMatcher<float>(rhs, false);
+}
+
+// Creates a matcher that matches any float argument approximately
+// equal to rhs, including NaN values when rhs is NaN.
+inline internal::FloatingEqMatcher<float> NanSensitiveFloatEq(float rhs) {
+  return internal::FloatingEqMatcher<float>(rhs, true);
+}
+
+// Creates a matcher that matches any float argument approximately equal to
+// rhs, up to the specified max absolute error bound, where two NANs are
+// considered unequal.  The max absolute error bound must be non-negative.
+inline internal::FloatingEqMatcher<float> FloatNear(
+    float rhs, float max_abs_error) {
+  return internal::FloatingEqMatcher<float>(rhs, false, max_abs_error);
+}
+
+// Creates a matcher that matches any float argument approximately equal to
+// rhs, up to the specified max absolute error bound, including NaN values when
+// rhs is NaN.  The max absolute error bound must be non-negative.
+inline internal::FloatingEqMatcher<float> NanSensitiveFloatNear(
+    float rhs, float max_abs_error) {
+  return internal::FloatingEqMatcher<float>(rhs, true, max_abs_error);
+}
+
+// Creates a matcher that matches a pointer (raw or smart) that points
+// to a value that matches inner_matcher.
+template <typename InnerMatcher>
+inline internal::PointeeMatcher<InnerMatcher> Pointee(
+    const InnerMatcher& inner_matcher) {
+  return internal::PointeeMatcher<InnerMatcher>(inner_matcher);
+}
+
+#if GTEST_HAS_RTTI
+// Creates a matcher that matches a pointer or reference that matches
+// inner_matcher when dynamic_cast<To> is applied.
+// The result of dynamic_cast<To> is forwarded to the inner matcher.
+// If To is a pointer and the cast fails, the inner matcher will receive NULL.
+// If To is a reference and the cast fails, this matcher returns false
+// immediately.
+template <typename To>
+inline PolymorphicMatcher<internal::WhenDynamicCastToMatcher<To> >
+WhenDynamicCastTo(const Matcher<To>& inner_matcher) {
+  return MakePolymorphicMatcher(
+      internal::WhenDynamicCastToMatcher<To>(inner_matcher));
+}
+#endif  // GTEST_HAS_RTTI
+
+// Creates a matcher that matches an object whose given field matches
+// 'matcher'.  For example,
+//   Field(&Foo::number, Ge(5))
+// matches a Foo object x if and only if x.number >= 5.
+template <typename Class, typename FieldType, typename FieldMatcher>
+inline PolymorphicMatcher<
+  internal::FieldMatcher<Class, FieldType> > Field(
+    FieldType Class::*field, const FieldMatcher& matcher) {
+  return MakePolymorphicMatcher(
+      internal::FieldMatcher<Class, FieldType>(
+          field, MatcherCast<const FieldType&>(matcher)));
+  // The call to MatcherCast() is required for supporting inner
+  // matchers of compatible types.  For example, it allows
+  //   Field(&Foo::bar, m)
+  // to compile where bar is an int32 and m is a matcher for int64.
+}
+
+// Same as Field() but also takes the name of the field to provide better error
+// messages.
+template <typename Class, typename FieldType, typename FieldMatcher>
+inline PolymorphicMatcher<internal::FieldMatcher<Class, FieldType> > Field(
+    const std::string& field_name, FieldType Class::*field,
+    const FieldMatcher& matcher) {
+  return MakePolymorphicMatcher(internal::FieldMatcher<Class, FieldType>(
+      field_name, field, MatcherCast<const FieldType&>(matcher)));
+}
+
+// Creates a matcher that matches an object whose given property
+// matches 'matcher'.  For example,
+//   Property(&Foo::str, StartsWith("hi"))
+// matches a Foo object x if and only if x.str() starts with "hi".
+template <typename Class, typename PropertyType, typename PropertyMatcher>
+inline PolymorphicMatcher<internal::PropertyMatcher<
+    Class, PropertyType, PropertyType (Class::*)() const> >
+Property(PropertyType (Class::*property)() const,
+         const PropertyMatcher& matcher) {
+  return MakePolymorphicMatcher(
+      internal::PropertyMatcher<Class, PropertyType,
+                                PropertyType (Class::*)() const>(
+          property, MatcherCast<const PropertyType&>(matcher)));
+  // The call to MatcherCast() is required for supporting inner
+  // matchers of compatible types.  For example, it allows
+  //   Property(&Foo::bar, m)
+  // to compile where bar() returns an int32 and m is a matcher for int64.
+}
+
+// Same as Property() above, but also takes the name of the property to provide
+// better error messages.
+template <typename Class, typename PropertyType, typename PropertyMatcher>
+inline PolymorphicMatcher<internal::PropertyMatcher<
+    Class, PropertyType, PropertyType (Class::*)() const> >
+Property(const std::string& property_name,
+         PropertyType (Class::*property)() const,
+         const PropertyMatcher& matcher) {
+  return MakePolymorphicMatcher(
+      internal::PropertyMatcher<Class, PropertyType,
+                                PropertyType (Class::*)() const>(
+          property_name, property, MatcherCast<const PropertyType&>(matcher)));
+}
+
+// The same as above but for reference-qualified member functions.
+template <typename Class, typename PropertyType, typename PropertyMatcher>
+inline PolymorphicMatcher<internal::PropertyMatcher<
+    Class, PropertyType, PropertyType (Class::*)() const &> >
+Property(PropertyType (Class::*property)() const &,
+         const PropertyMatcher& matcher) {
+  return MakePolymorphicMatcher(
+      internal::PropertyMatcher<Class, PropertyType,
+                                PropertyType (Class::*)() const&>(
+          property, MatcherCast<const PropertyType&>(matcher)));
+}
+
+// Three-argument form for reference-qualified member functions.
+template <typename Class, typename PropertyType, typename PropertyMatcher>
+inline PolymorphicMatcher<internal::PropertyMatcher<
+    Class, PropertyType, PropertyType (Class::*)() const &> >
+Property(const std::string& property_name,
+         PropertyType (Class::*property)() const &,
+         const PropertyMatcher& matcher) {
+  return MakePolymorphicMatcher(
+      internal::PropertyMatcher<Class, PropertyType,
+                                PropertyType (Class::*)() const&>(
+          property_name, property, MatcherCast<const PropertyType&>(matcher)));
+}
+
+// Creates a matcher that matches an object if and only if the result of
+// applying a callable to x matches 'matcher'. For example,
+//   ResultOf(f, StartsWith("hi"))
+// matches a Foo object x if and only if f(x) starts with "hi".
+// `callable` parameter can be a function, function pointer, or a functor. It is
+// required to keep no state affecting the results of the calls on it and make
+// no assumptions about how many calls will be made. Any state it keeps must be
+// protected from the concurrent access.
+template <typename Callable, typename InnerMatcher>
+internal::ResultOfMatcher<Callable, InnerMatcher> ResultOf(
+    Callable callable, InnerMatcher matcher) {
+  return internal::ResultOfMatcher<Callable, InnerMatcher>(
+      std::move(callable), std::move(matcher));
+}
+
+// String matchers.
+
+// Matches a string equal to str.
+template <typename T = std::string>
+PolymorphicMatcher<internal::StrEqualityMatcher<std::string> > StrEq(
+    const internal::StringLike<T>& str) {
+  return MakePolymorphicMatcher(
+      internal::StrEqualityMatcher<std::string>(std::string(str), true, true));
+}
+
+// Matches a string not equal to str.
+template <typename T = std::string>
+PolymorphicMatcher<internal::StrEqualityMatcher<std::string> > StrNe(
+    const internal::StringLike<T>& str) {
+  return MakePolymorphicMatcher(
+      internal::StrEqualityMatcher<std::string>(std::string(str), false, true));
+}
+
+// Matches a string equal to str, ignoring case.
+template <typename T = std::string>
+PolymorphicMatcher<internal::StrEqualityMatcher<std::string> > StrCaseEq(
+    const internal::StringLike<T>& str) {
+  return MakePolymorphicMatcher(
+      internal::StrEqualityMatcher<std::string>(std::string(str), true, false));
+}
+
+// Matches a string not equal to str, ignoring case.
+template <typename T = std::string>
+PolymorphicMatcher<internal::StrEqualityMatcher<std::string> > StrCaseNe(
+    const internal::StringLike<T>& str) {
+  return MakePolymorphicMatcher(internal::StrEqualityMatcher<std::string>(
+      std::string(str), false, false));
+}
+
+// Creates a matcher that matches any string, std::string, or C string
+// that contains the given substring.
+template <typename T = std::string>
+PolymorphicMatcher<internal::HasSubstrMatcher<std::string> > HasSubstr(
+    const internal::StringLike<T>& substring) {
+  return MakePolymorphicMatcher(
+      internal::HasSubstrMatcher<std::string>(std::string(substring)));
+}
+
+// Matches a string that starts with 'prefix' (case-sensitive).
+template <typename T = std::string>
+PolymorphicMatcher<internal::StartsWithMatcher<std::string> > StartsWith(
+    const internal::StringLike<T>& prefix) {
+  return MakePolymorphicMatcher(
+      internal::StartsWithMatcher<std::string>(std::string(prefix)));
+}
+
+// Matches a string that ends with 'suffix' (case-sensitive).
+template <typename T = std::string>
+PolymorphicMatcher<internal::EndsWithMatcher<std::string> > EndsWith(
+    const internal::StringLike<T>& suffix) {
+  return MakePolymorphicMatcher(
+      internal::EndsWithMatcher<std::string>(std::string(suffix)));
+}
+
+#if GTEST_HAS_STD_WSTRING
+// Wide string matchers.
+
+// Matches a string equal to str.
+inline PolymorphicMatcher<internal::StrEqualityMatcher<std::wstring> > StrEq(
+    const std::wstring& str) {
+  return MakePolymorphicMatcher(
+      internal::StrEqualityMatcher<std::wstring>(str, true, true));
+}
+
+// Matches a string not equal to str.
+inline PolymorphicMatcher<internal::StrEqualityMatcher<std::wstring> > StrNe(
+    const std::wstring& str) {
+  return MakePolymorphicMatcher(
+      internal::StrEqualityMatcher<std::wstring>(str, false, true));
+}
+
+// Matches a string equal to str, ignoring case.
+inline PolymorphicMatcher<internal::StrEqualityMatcher<std::wstring> >
+StrCaseEq(const std::wstring& str) {
+  return MakePolymorphicMatcher(
+      internal::StrEqualityMatcher<std::wstring>(str, true, false));
+}
+
+// Matches a string not equal to str, ignoring case.
+inline PolymorphicMatcher<internal::StrEqualityMatcher<std::wstring> >
+StrCaseNe(const std::wstring& str) {
+  return MakePolymorphicMatcher(
+      internal::StrEqualityMatcher<std::wstring>(str, false, false));
+}
+
+// Creates a matcher that matches any ::wstring, std::wstring, or C wide string
+// that contains the given substring.
+inline PolymorphicMatcher<internal::HasSubstrMatcher<std::wstring> > HasSubstr(
+    const std::wstring& substring) {
+  return MakePolymorphicMatcher(
+      internal::HasSubstrMatcher<std::wstring>(substring));
+}
+
+// Matches a string that starts with 'prefix' (case-sensitive).
+inline PolymorphicMatcher<internal::StartsWithMatcher<std::wstring> >
+StartsWith(const std::wstring& prefix) {
+  return MakePolymorphicMatcher(
+      internal::StartsWithMatcher<std::wstring>(prefix));
+}
+
+// Matches a string that ends with 'suffix' (case-sensitive).
+inline PolymorphicMatcher<internal::EndsWithMatcher<std::wstring> > EndsWith(
+    const std::wstring& suffix) {
+  return MakePolymorphicMatcher(
+      internal::EndsWithMatcher<std::wstring>(suffix));
+}
+
+#endif  // GTEST_HAS_STD_WSTRING
+
+// Creates a polymorphic matcher that matches a 2-tuple where the
+// first field == the second field.
+inline internal::Eq2Matcher Eq() { return internal::Eq2Matcher(); }
+
+// Creates a polymorphic matcher that matches a 2-tuple where the
+// first field >= the second field.
+inline internal::Ge2Matcher Ge() { return internal::Ge2Matcher(); }
+
+// Creates a polymorphic matcher that matches a 2-tuple where the
+// first field > the second field.
+inline internal::Gt2Matcher Gt() { return internal::Gt2Matcher(); }
+
+// Creates a polymorphic matcher that matches a 2-tuple where the
+// first field <= the second field.
+inline internal::Le2Matcher Le() { return internal::Le2Matcher(); }
+
+// Creates a polymorphic matcher that matches a 2-tuple where the
+// first field < the second field.
+inline internal::Lt2Matcher Lt() { return internal::Lt2Matcher(); }
+
+// Creates a polymorphic matcher that matches a 2-tuple where the
+// first field != the second field.
+inline internal::Ne2Matcher Ne() { return internal::Ne2Matcher(); }
+
+// Creates a polymorphic matcher that matches a 2-tuple where
+// FloatEq(first field) matches the second field.
+inline internal::FloatingEq2Matcher<float> FloatEq() {
+  return internal::FloatingEq2Matcher<float>();
+}
+
+// Creates a polymorphic matcher that matches a 2-tuple where
+// DoubleEq(first field) matches the second field.
+inline internal::FloatingEq2Matcher<double> DoubleEq() {
+  return internal::FloatingEq2Matcher<double>();
+}
+
+// Creates a polymorphic matcher that matches a 2-tuple where
+// FloatEq(first field) matches the second field with NaN equality.
+inline internal::FloatingEq2Matcher<float> NanSensitiveFloatEq() {
+  return internal::FloatingEq2Matcher<float>(true);
+}
+
+// Creates a polymorphic matcher that matches a 2-tuple where
+// DoubleEq(first field) matches the second field with NaN equality.
+inline internal::FloatingEq2Matcher<double> NanSensitiveDoubleEq() {
+  return internal::FloatingEq2Matcher<double>(true);
+}
+
+// Creates a polymorphic matcher that matches a 2-tuple where
+// FloatNear(first field, max_abs_error) matches the second field.
+inline internal::FloatingEq2Matcher<float> FloatNear(float max_abs_error) {
+  return internal::FloatingEq2Matcher<float>(max_abs_error);
+}
+
+// Creates a polymorphic matcher that matches a 2-tuple where
+// DoubleNear(first field, max_abs_error) matches the second field.
+inline internal::FloatingEq2Matcher<double> DoubleNear(double max_abs_error) {
+  return internal::FloatingEq2Matcher<double>(max_abs_error);
+}
+
+// Creates a polymorphic matcher that matches a 2-tuple where
+// FloatNear(first field, max_abs_error) matches the second field with NaN
+// equality.
+inline internal::FloatingEq2Matcher<float> NanSensitiveFloatNear(
+    float max_abs_error) {
+  return internal::FloatingEq2Matcher<float>(max_abs_error, true);
+}
+
+// Creates a polymorphic matcher that matches a 2-tuple where
+// DoubleNear(first field, max_abs_error) matches the second field with NaN
+// equality.
+inline internal::FloatingEq2Matcher<double> NanSensitiveDoubleNear(
+    double max_abs_error) {
+  return internal::FloatingEq2Matcher<double>(max_abs_error, true);
+}
+
+// Creates a matcher that matches any value of type T that m doesn't
+// match.
+template <typename InnerMatcher>
+inline internal::NotMatcher<InnerMatcher> Not(InnerMatcher m) {
+  return internal::NotMatcher<InnerMatcher>(m);
+}
+
+// Returns a matcher that matches anything that satisfies the given
+// predicate.  The predicate can be any unary function or functor
+// whose return type can be implicitly converted to bool.
+template <typename Predicate>
+inline PolymorphicMatcher<internal::TrulyMatcher<Predicate> >
+Truly(Predicate pred) {
+  return MakePolymorphicMatcher(internal::TrulyMatcher<Predicate>(pred));
+}
+
+// Returns a matcher that matches the container size. The container must
+// support both size() and size_type which all STL-like containers provide.
+// Note that the parameter 'size' can be a value of type size_type as well as
+// matcher. For instance:
+//   EXPECT_THAT(container, SizeIs(2));     // Checks container has 2 elements.
+//   EXPECT_THAT(container, SizeIs(Le(2));  // Checks container has at most 2.
+template <typename SizeMatcher>
+inline internal::SizeIsMatcher<SizeMatcher>
+SizeIs(const SizeMatcher& size_matcher) {
+  return internal::SizeIsMatcher<SizeMatcher>(size_matcher);
+}
+
+// Returns a matcher that matches the distance between the container's begin()
+// iterator and its end() iterator, i.e. the size of the container. This matcher
+// can be used instead of SizeIs with containers such as std::forward_list which
+// do not implement size(). The container must provide const_iterator (with
+// valid iterator_traits), begin() and end().
+template <typename DistanceMatcher>
+inline internal::BeginEndDistanceIsMatcher<DistanceMatcher>
+BeginEndDistanceIs(const DistanceMatcher& distance_matcher) {
+  return internal::BeginEndDistanceIsMatcher<DistanceMatcher>(distance_matcher);
+}
+
+// Returns a matcher that matches an equal container.
+// This matcher behaves like Eq(), but in the event of mismatch lists the
+// values that are included in one container but not the other. (Duplicate
+// values and order differences are not explained.)
+template <typename Container>
+inline PolymorphicMatcher<internal::ContainerEqMatcher<
+    typename std::remove_const<Container>::type>>
+ContainerEq(const Container& rhs) {
+  return MakePolymorphicMatcher(internal::ContainerEqMatcher<Container>(rhs));
+}
+
+// Returns a matcher that matches a container that, when sorted using
+// the given comparator, matches container_matcher.
+template <typename Comparator, typename ContainerMatcher>
+inline internal::WhenSortedByMatcher<Comparator, ContainerMatcher>
+WhenSortedBy(const Comparator& comparator,
+             const ContainerMatcher& container_matcher) {
+  return internal::WhenSortedByMatcher<Comparator, ContainerMatcher>(
+      comparator, container_matcher);
+}
+
+// Returns a matcher that matches a container that, when sorted using
+// the < operator, matches container_matcher.
+template <typename ContainerMatcher>
+inline internal::WhenSortedByMatcher<internal::LessComparator, ContainerMatcher>
+WhenSorted(const ContainerMatcher& container_matcher) {
+  return
+      internal::WhenSortedByMatcher<internal::LessComparator, ContainerMatcher>(
+          internal::LessComparator(), container_matcher);
+}
+
+// Matches an STL-style container or a native array that contains the
+// same number of elements as in rhs, where its i-th element and rhs's
+// i-th element (as a pair) satisfy the given pair matcher, for all i.
+// TupleMatcher must be able to be safely cast to Matcher<std::tuple<const
+// T1&, const T2&> >, where T1 and T2 are the types of elements in the
+// LHS container and the RHS container respectively.
+template <typename TupleMatcher, typename Container>
+inline internal::PointwiseMatcher<TupleMatcher,
+                                  typename std::remove_const<Container>::type>
+Pointwise(const TupleMatcher& tuple_matcher, const Container& rhs) {
+  return internal::PointwiseMatcher<TupleMatcher, Container>(tuple_matcher,
+                                                             rhs);
+}
+
+
+// Supports the Pointwise(m, {a, b, c}) syntax.
+template <typename TupleMatcher, typename T>
+inline internal::PointwiseMatcher<TupleMatcher, std::vector<T> > Pointwise(
+    const TupleMatcher& tuple_matcher, std::initializer_list<T> rhs) {
+  return Pointwise(tuple_matcher, std::vector<T>(rhs));
+}
+
+
+// UnorderedPointwise(pair_matcher, rhs) matches an STL-style
+// container or a native array that contains the same number of
+// elements as in rhs, where in some permutation of the container, its
+// i-th element and rhs's i-th element (as a pair) satisfy the given
+// pair matcher, for all i.  Tuple2Matcher must be able to be safely
+// cast to Matcher<std::tuple<const T1&, const T2&> >, where T1 and T2 are
+// the types of elements in the LHS container and the RHS container
+// respectively.
+//
+// This is like Pointwise(pair_matcher, rhs), except that the element
+// order doesn't matter.
+template <typename Tuple2Matcher, typename RhsContainer>
+inline internal::UnorderedElementsAreArrayMatcher<
+    typename internal::BoundSecondMatcher<
+        Tuple2Matcher,
+        typename internal::StlContainerView<
+            typename std::remove_const<RhsContainer>::type>::type::value_type>>
+UnorderedPointwise(const Tuple2Matcher& tuple2_matcher,
+                   const RhsContainer& rhs_container) {
+  // RhsView allows the same code to handle RhsContainer being a
+  // STL-style container and it being a native C-style array.
+  typedef typename internal::StlContainerView<RhsContainer> RhsView;
+  typedef typename RhsView::type RhsStlContainer;
+  typedef typename RhsStlContainer::value_type Second;
+  const RhsStlContainer& rhs_stl_container =
+      RhsView::ConstReference(rhs_container);
+
+  // Create a matcher for each element in rhs_container.
+  ::std::vector<internal::BoundSecondMatcher<Tuple2Matcher, Second> > matchers;
+  for (typename RhsStlContainer::const_iterator it = rhs_stl_container.begin();
+       it != rhs_stl_container.end(); ++it) {
+    matchers.push_back(
+        internal::MatcherBindSecond(tuple2_matcher, *it));
+  }
+
+  // Delegate the work to UnorderedElementsAreArray().
+  return UnorderedElementsAreArray(matchers);
+}
+
+
+// Supports the UnorderedPointwise(m, {a, b, c}) syntax.
+template <typename Tuple2Matcher, typename T>
+inline internal::UnorderedElementsAreArrayMatcher<
+    typename internal::BoundSecondMatcher<Tuple2Matcher, T> >
+UnorderedPointwise(const Tuple2Matcher& tuple2_matcher,
+                   std::initializer_list<T> rhs) {
+  return UnorderedPointwise(tuple2_matcher, std::vector<T>(rhs));
+}
+
+
+// Matches an STL-style container or a native array that contains at
+// least one element matching the given value or matcher.
+//
+// Examples:
+//   ::std::set<int> page_ids;
+//   page_ids.insert(3);
+//   page_ids.insert(1);
+//   EXPECT_THAT(page_ids, Contains(1));
+//   EXPECT_THAT(page_ids, Contains(Gt(2)));
+//   EXPECT_THAT(page_ids, Not(Contains(4)));
+//
+//   ::std::map<int, size_t> page_lengths;
+//   page_lengths[1] = 100;
+//   EXPECT_THAT(page_lengths,
+//               Contains(::std::pair<const int, size_t>(1, 100)));
+//
+//   const char* user_ids[] = { "joe", "mike", "tom" };
+//   EXPECT_THAT(user_ids, Contains(Eq(::std::string("tom"))));
+template <typename M>
+inline internal::ContainsMatcher<M> Contains(M matcher) {
+  return internal::ContainsMatcher<M>(matcher);
+}
+
+// IsSupersetOf(iterator_first, iterator_last)
+// IsSupersetOf(pointer, count)
+// IsSupersetOf(array)
+// IsSupersetOf(container)
+// IsSupersetOf({e1, e2, ..., en})
+//
+// IsSupersetOf() verifies that a surjective partial mapping onto a collection
+// of matchers exists. In other words, a container matches
+// IsSupersetOf({e1, ..., en}) if and only if there is a permutation
+// {y1, ..., yn} of some of the container's elements where y1 matches e1,
+// ..., and yn matches en. Obviously, the size of the container must be >= n
+// in order to have a match. Examples:
+//
+// - {1, 2, 3} matches IsSupersetOf({Ge(3), Ne(0)}), as 3 matches Ge(3) and
+//   1 matches Ne(0).
+// - {1, 2} doesn't match IsSupersetOf({Eq(1), Lt(2)}), even though 1 matches
+//   both Eq(1) and Lt(2). The reason is that different matchers must be used
+//   for elements in different slots of the container.
+// - {1, 1, 2} matches IsSupersetOf({Eq(1), Lt(2)}), as (the first) 1 matches
+//   Eq(1) and (the second) 1 matches Lt(2).
+// - {1, 2, 3} matches IsSupersetOf(Gt(1), Gt(1)), as 2 matches (the first)
+//   Gt(1) and 3 matches (the second) Gt(1).
+//
+// The matchers can be specified as an array, a pointer and count, a container,
+// an initializer list, or an STL iterator range. In each of these cases, the
+// underlying matchers can be either values or matchers.
+
+template <typename Iter>
+inline internal::UnorderedElementsAreArrayMatcher<
+    typename ::std::iterator_traits<Iter>::value_type>
+IsSupersetOf(Iter first, Iter last) {
+  typedef typename ::std::iterator_traits<Iter>::value_type T;
+  return internal::UnorderedElementsAreArrayMatcher<T>(
+      internal::UnorderedMatcherRequire::Superset, first, last);
+}
+
+template <typename T>
+inline internal::UnorderedElementsAreArrayMatcher<T> IsSupersetOf(
+    const T* pointer, size_t count) {
+  return IsSupersetOf(pointer, pointer + count);
+}
+
+template <typename T, size_t N>
+inline internal::UnorderedElementsAreArrayMatcher<T> IsSupersetOf(
+    const T (&array)[N]) {
+  return IsSupersetOf(array, N);
+}
+
+template <typename Container>
+inline internal::UnorderedElementsAreArrayMatcher<
+    typename Container::value_type>
+IsSupersetOf(const Container& container) {
+  return IsSupersetOf(container.begin(), container.end());
+}
+
+template <typename T>
+inline internal::UnorderedElementsAreArrayMatcher<T> IsSupersetOf(
+    ::std::initializer_list<T> xs) {
+  return IsSupersetOf(xs.begin(), xs.end());
+}
+
+// IsSubsetOf(iterator_first, iterator_last)
+// IsSubsetOf(pointer, count)
+// IsSubsetOf(array)
+// IsSubsetOf(container)
+// IsSubsetOf({e1, e2, ..., en})
+//
+// IsSubsetOf() verifies that an injective mapping onto a collection of matchers
+// exists.  In other words, a container matches IsSubsetOf({e1, ..., en}) if and
+// only if there is a subset of matchers {m1, ..., mk} which would match the
+// container using UnorderedElementsAre.  Obviously, the size of the container
+// must be <= n in order to have a match. Examples:
+//
+// - {1} matches IsSubsetOf({Gt(0), Lt(0)}), as 1 matches Gt(0).
+// - {1, -1} matches IsSubsetOf({Lt(0), Gt(0)}), as 1 matches Gt(0) and -1
+//   matches Lt(0).
+// - {1, 2} doesn't matches IsSubsetOf({Gt(0), Lt(0)}), even though 1 and 2 both
+//   match Gt(0). The reason is that different matchers must be used for
+//   elements in different slots of the container.
+//
+// The matchers can be specified as an array, a pointer and count, a container,
+// an initializer list, or an STL iterator range. In each of these cases, the
+// underlying matchers can be either values or matchers.
+
+template <typename Iter>
+inline internal::UnorderedElementsAreArrayMatcher<
+    typename ::std::iterator_traits<Iter>::value_type>
+IsSubsetOf(Iter first, Iter last) {
+  typedef typename ::std::iterator_traits<Iter>::value_type T;
+  return internal::UnorderedElementsAreArrayMatcher<T>(
+      internal::UnorderedMatcherRequire::Subset, first, last);
+}
+
+template <typename T>
+inline internal::UnorderedElementsAreArrayMatcher<T> IsSubsetOf(
+    const T* pointer, size_t count) {
+  return IsSubsetOf(pointer, pointer + count);
+}
+
+template <typename T, size_t N>
+inline internal::UnorderedElementsAreArrayMatcher<T> IsSubsetOf(
+    const T (&array)[N]) {
+  return IsSubsetOf(array, N);
+}
+
+template <typename Container>
+inline internal::UnorderedElementsAreArrayMatcher<
+    typename Container::value_type>
+IsSubsetOf(const Container& container) {
+  return IsSubsetOf(container.begin(), container.end());
+}
+
+template <typename T>
+inline internal::UnorderedElementsAreArrayMatcher<T> IsSubsetOf(
+    ::std::initializer_list<T> xs) {
+  return IsSubsetOf(xs.begin(), xs.end());
+}
+
+// Matches an STL-style container or a native array that contains only
+// elements matching the given value or matcher.
+//
+// Each(m) is semantically equivalent to Not(Contains(Not(m))). Only
+// the messages are different.
+//
+// Examples:
+//   ::std::set<int> page_ids;
+//   // Each(m) matches an empty container, regardless of what m is.
+//   EXPECT_THAT(page_ids, Each(Eq(1)));
+//   EXPECT_THAT(page_ids, Each(Eq(77)));
+//
+//   page_ids.insert(3);
+//   EXPECT_THAT(page_ids, Each(Gt(0)));
+//   EXPECT_THAT(page_ids, Not(Each(Gt(4))));
+//   page_ids.insert(1);
+//   EXPECT_THAT(page_ids, Not(Each(Lt(2))));
+//
+//   ::std::map<int, size_t> page_lengths;
+//   page_lengths[1] = 100;
+//   page_lengths[2] = 200;
+//   page_lengths[3] = 300;
+//   EXPECT_THAT(page_lengths, Not(Each(Pair(1, 100))));
+//   EXPECT_THAT(page_lengths, Each(Key(Le(3))));
+//
+//   const char* user_ids[] = { "joe", "mike", "tom" };
+//   EXPECT_THAT(user_ids, Not(Each(Eq(::std::string("tom")))));
+template <typename M>
+inline internal::EachMatcher<M> Each(M matcher) {
+  return internal::EachMatcher<M>(matcher);
+}
+
+// Key(inner_matcher) matches an std::pair whose 'first' field matches
+// inner_matcher.  For example, Contains(Key(Ge(5))) can be used to match an
+// std::map that contains at least one element whose key is >= 5.
+template <typename M>
+inline internal::KeyMatcher<M> Key(M inner_matcher) {
+  return internal::KeyMatcher<M>(inner_matcher);
+}
+
+// Pair(first_matcher, second_matcher) matches a std::pair whose 'first' field
+// matches first_matcher and whose 'second' field matches second_matcher.  For
+// example, EXPECT_THAT(map_type, ElementsAre(Pair(Ge(5), "foo"))) can be used
+// to match a std::map<int, string> that contains exactly one element whose key
+// is >= 5 and whose value equals "foo".
+template <typename FirstMatcher, typename SecondMatcher>
+inline internal::PairMatcher<FirstMatcher, SecondMatcher>
+Pair(FirstMatcher first_matcher, SecondMatcher second_matcher) {
+  return internal::PairMatcher<FirstMatcher, SecondMatcher>(
+      first_matcher, second_matcher);
+}
+
+namespace no_adl {
+// FieldsAre(matchers...) matches piecewise the fields of compatible structs.
+// These include those that support `get<I>(obj)`, and when structured bindings
+// are enabled any class that supports them.
+// In particular, `std::tuple`, `std::pair`, `std::array` and aggregate types.
+template <typename... M>
+internal::FieldsAreMatcher<typename std::decay<M>::type...> FieldsAre(
+    M&&... matchers) {
+  return internal::FieldsAreMatcher<typename std::decay<M>::type...>(
+      std::forward<M>(matchers)...);
+}
+
+// Creates a matcher that matches a pointer (raw or smart) that matches
+// inner_matcher.
+template <typename InnerMatcher>
+inline internal::PointerMatcher<InnerMatcher> Pointer(
+    const InnerMatcher& inner_matcher) {
+  return internal::PointerMatcher<InnerMatcher>(inner_matcher);
+}
+
+// Creates a matcher that matches an object that has an address that matches
+// inner_matcher.
+template <typename InnerMatcher>
+inline internal::AddressMatcher<InnerMatcher> Address(
+    const InnerMatcher& inner_matcher) {
+  return internal::AddressMatcher<InnerMatcher>(inner_matcher);
+}
+}  // namespace no_adl
+
+// Returns a predicate that is satisfied by anything that matches the
+// given matcher.
+template <typename M>
+inline internal::MatcherAsPredicate<M> Matches(M matcher) {
+  return internal::MatcherAsPredicate<M>(matcher);
+}
+
+// Returns true if and only if the value matches the matcher.
+template <typename T, typename M>
+inline bool Value(const T& value, M matcher) {
+  return testing::Matches(matcher)(value);
+}
+
+// Matches the value against the given matcher and explains the match
+// result to listener.
+template <typename T, typename M>
+inline bool ExplainMatchResult(
+    M matcher, const T& value, MatchResultListener* listener) {
+  return SafeMatcherCast<const T&>(matcher).MatchAndExplain(value, listener);
+}
+
+// Returns a string representation of the given matcher.  Useful for description
+// strings of matchers defined using MATCHER_P* macros that accept matchers as
+// their arguments.  For example:
+//
+// MATCHER_P(XAndYThat, matcher,
+//           "X that " + DescribeMatcher<int>(matcher, negation) +
+//               " and Y that " + DescribeMatcher<double>(matcher, negation)) {
+//   return ExplainMatchResult(matcher, arg.x(), result_listener) &&
+//          ExplainMatchResult(matcher, arg.y(), result_listener);
+// }
+template <typename T, typename M>
+std::string DescribeMatcher(const M& matcher, bool negation = false) {
+  ::std::stringstream ss;
+  Matcher<T> monomorphic_matcher = SafeMatcherCast<T>(matcher);
+  if (negation) {
+    monomorphic_matcher.DescribeNegationTo(&ss);
+  } else {
+    monomorphic_matcher.DescribeTo(&ss);
+  }
+  return ss.str();
+}
+
+template <typename... Args>
+internal::ElementsAreMatcher<
+    std::tuple<typename std::decay<const Args&>::type...>>
+ElementsAre(const Args&... matchers) {
+  return internal::ElementsAreMatcher<
+      std::tuple<typename std::decay<const Args&>::type...>>(
+      std::make_tuple(matchers...));
+}
+
+template <typename... Args>
+internal::UnorderedElementsAreMatcher<
+    std::tuple<typename std::decay<const Args&>::type...>>
+UnorderedElementsAre(const Args&... matchers) {
+  return internal::UnorderedElementsAreMatcher<
+      std::tuple<typename std::decay<const Args&>::type...>>(
+      std::make_tuple(matchers...));
+}
+
+// Define variadic matcher versions.
+template <typename... Args>
+internal::AllOfMatcher<typename std::decay<const Args&>::type...> AllOf(
+    const Args&... matchers) {
+  return internal::AllOfMatcher<typename std::decay<const Args&>::type...>(
+      matchers...);
+}
+
+template <typename... Args>
+internal::AnyOfMatcher<typename std::decay<const Args&>::type...> AnyOf(
+    const Args&... matchers) {
+  return internal::AnyOfMatcher<typename std::decay<const Args&>::type...>(
+      matchers...);
+}
+
+// AnyOfArray(array)
+// AnyOfArray(pointer, count)
+// AnyOfArray(container)
+// AnyOfArray({ e1, e2, ..., en })
+// AnyOfArray(iterator_first, iterator_last)
+//
+// AnyOfArray() verifies whether a given value matches any member of a
+// collection of matchers.
+//
+// AllOfArray(array)
+// AllOfArray(pointer, count)
+// AllOfArray(container)
+// AllOfArray({ e1, e2, ..., en })
+// AllOfArray(iterator_first, iterator_last)
+//
+// AllOfArray() verifies whether a given value matches all members of a
+// collection of matchers.
+//
+// The matchers can be specified as an array, a pointer and count, a container,
+// an initializer list, or an STL iterator range. In each of these cases, the
+// underlying matchers can be either values or matchers.
+
+template <typename Iter>
+inline internal::AnyOfArrayMatcher<
+    typename ::std::iterator_traits<Iter>::value_type>
+AnyOfArray(Iter first, Iter last) {
+  return internal::AnyOfArrayMatcher<
+      typename ::std::iterator_traits<Iter>::value_type>(first, last);
+}
+
+template <typename Iter>
+inline internal::AllOfArrayMatcher<
+    typename ::std::iterator_traits<Iter>::value_type>
+AllOfArray(Iter first, Iter last) {
+  return internal::AllOfArrayMatcher<
+      typename ::std::iterator_traits<Iter>::value_type>(first, last);
+}
+
+template <typename T>
+inline internal::AnyOfArrayMatcher<T> AnyOfArray(const T* ptr, size_t count) {
+  return AnyOfArray(ptr, ptr + count);
+}
+
+template <typename T>
+inline internal::AllOfArrayMatcher<T> AllOfArray(const T* ptr, size_t count) {
+  return AllOfArray(ptr, ptr + count);
+}
+
+template <typename T, size_t N>
+inline internal::AnyOfArrayMatcher<T> AnyOfArray(const T (&array)[N]) {
+  return AnyOfArray(array, N);
+}
+
+template <typename T, size_t N>
+inline internal::AllOfArrayMatcher<T> AllOfArray(const T (&array)[N]) {
+  return AllOfArray(array, N);
+}
+
+template <typename Container>
+inline internal::AnyOfArrayMatcher<typename Container::value_type> AnyOfArray(
+    const Container& container) {
+  return AnyOfArray(container.begin(), container.end());
+}
+
+template <typename Container>
+inline internal::AllOfArrayMatcher<typename Container::value_type> AllOfArray(
+    const Container& container) {
+  return AllOfArray(container.begin(), container.end());
+}
+
+template <typename T>
+inline internal::AnyOfArrayMatcher<T> AnyOfArray(
+    ::std::initializer_list<T> xs) {
+  return AnyOfArray(xs.begin(), xs.end());
+}
+
+template <typename T>
+inline internal::AllOfArrayMatcher<T> AllOfArray(
+    ::std::initializer_list<T> xs) {
+  return AllOfArray(xs.begin(), xs.end());
+}
+
+// Args<N1, N2, ..., Nk>(a_matcher) matches a tuple if the selected
+// fields of it matches a_matcher.  C++ doesn't support default
+// arguments for function templates, so we have to overload it.
+template <size_t... k, typename InnerMatcher>
+internal::ArgsMatcher<typename std::decay<InnerMatcher>::type, k...> Args(
+    InnerMatcher&& matcher) {
+  return internal::ArgsMatcher<typename std::decay<InnerMatcher>::type, k...>(
+      std::forward<InnerMatcher>(matcher));
+}
+
+// AllArgs(m) is a synonym of m.  This is useful in
+//
+//   EXPECT_CALL(foo, Bar(_, _)).With(AllArgs(Eq()));
+//
+// which is easier to read than
+//
+//   EXPECT_CALL(foo, Bar(_, _)).With(Eq());
+template <typename InnerMatcher>
+inline InnerMatcher AllArgs(const InnerMatcher& matcher) { return matcher; }
+
+// Returns a matcher that matches the value of an optional<> type variable.
+// The matcher implementation only uses '!arg' and requires that the optional<>
+// type has a 'value_type' member type and that '*arg' is of type 'value_type'
+// and is printable using 'PrintToString'. It is compatible with
+// std::optional/std::experimental::optional.
+// Note that to compare an optional type variable against nullopt you should
+// use Eq(nullopt) and not Eq(Optional(nullopt)). The latter implies that the
+// optional value contains an optional itself.
+template <typename ValueMatcher>
+inline internal::OptionalMatcher<ValueMatcher> Optional(
+    const ValueMatcher& value_matcher) {
+  return internal::OptionalMatcher<ValueMatcher>(value_matcher);
+}
+
+// Returns a matcher that matches the value of a absl::any type variable.
+template <typename T>
+PolymorphicMatcher<internal::any_cast_matcher::AnyCastMatcher<T> > AnyWith(
+    const Matcher<const T&>& matcher) {
+  return MakePolymorphicMatcher(
+      internal::any_cast_matcher::AnyCastMatcher<T>(matcher));
+}
+
+// Returns a matcher that matches the value of a variant<> type variable.
+// The matcher implementation uses ADL to find the holds_alternative and get
+// functions.
+// It is compatible with std::variant.
+template <typename T>
+PolymorphicMatcher<internal::variant_matcher::VariantMatcher<T> > VariantWith(
+    const Matcher<const T&>& matcher) {
+  return MakePolymorphicMatcher(
+      internal::variant_matcher::VariantMatcher<T>(matcher));
+}
+
+#if GTEST_HAS_EXCEPTIONS
+
+// Anything inside the `internal` namespace is internal to the implementation
+// and must not be used in user code!
+namespace internal {
+
+class WithWhatMatcherImpl {
+ public:
+  WithWhatMatcherImpl(Matcher<std::string> matcher)
+      : matcher_(std::move(matcher)) {}
+
+  void DescribeTo(std::ostream* os) const {
+    *os << "contains .what() that ";
+    matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(std::ostream* os) const {
+    *os << "contains .what() that does not ";
+    matcher_.DescribeTo(os);
+  }
+
+  template <typename Err>
+  bool MatchAndExplain(const Err& err, MatchResultListener* listener) const {
+    *listener << "which contains .what() that ";
+    return matcher_.MatchAndExplain(err.what(), listener);
+  }
+
+ private:
+  const Matcher<std::string> matcher_;
+};
+
+inline PolymorphicMatcher<WithWhatMatcherImpl> WithWhat(
+    Matcher<std::string> m) {
+  return MakePolymorphicMatcher(WithWhatMatcherImpl(std::move(m)));
+}
+
+template <typename Err>
+class ExceptionMatcherImpl {
+  class NeverThrown {
+   public:
+    const char* what() const noexcept {
+      return "this exception should never be thrown";
+    }
+  };
+
+  // If the matchee raises an exception of a wrong type, we'd like to
+  // catch it and print its message and type. To do that, we add an additional
+  // catch clause:
+  //
+  //     try { ... }
+  //     catch (const Err&) { /* an expected exception */ }
+  //     catch (const std::exception&) { /* exception of a wrong type */ }
+  //
+  // However, if the `Err` itself is `std::exception`, we'd end up with two
+  // identical `catch` clauses:
+  //
+  //     try { ... }
+  //     catch (const std::exception&) { /* an expected exception */ }
+  //     catch (const std::exception&) { /* exception of a wrong type */ }
+  //
+  // This can cause a warning or an error in some compilers. To resolve
+  // the issue, we use a fake error type whenever `Err` is `std::exception`:
+  //
+  //     try { ... }
+  //     catch (const std::exception&) { /* an expected exception */ }
+  //     catch (const NeverThrown&) { /* exception of a wrong type */ }
+  using DefaultExceptionType = typename std::conditional<
+      std::is_same<typename std::remove_cv<
+                       typename std::remove_reference<Err>::type>::type,
+                   std::exception>::value,
+      const NeverThrown&, const std::exception&>::type;
+
+ public:
+  ExceptionMatcherImpl(Matcher<const Err&> matcher)
+      : matcher_(std::move(matcher)) {}
+
+  void DescribeTo(std::ostream* os) const {
+    *os << "throws an exception which is a " << GetTypeName<Err>();
+    *os << " which ";
+    matcher_.DescribeTo(os);
+  }
+
+  void DescribeNegationTo(std::ostream* os) const {
+    *os << "throws an exception which is not a " << GetTypeName<Err>();
+    *os << " which ";
+    matcher_.DescribeNegationTo(os);
+  }
+
+  template <typename T>
+  bool MatchAndExplain(T&& x, MatchResultListener* listener) const {
+    try {
+      (void)(std::forward<T>(x)());
+    } catch (const Err& err) {
+      *listener << "throws an exception which is a " << GetTypeName<Err>();
+      *listener << " ";
+      return matcher_.MatchAndExplain(err, listener);
+    } catch (DefaultExceptionType err) {
+#if GTEST_HAS_RTTI
+      *listener << "throws an exception of type " << GetTypeName(typeid(err));
+      *listener << " ";
+#else
+      *listener << "throws an std::exception-derived type ";
+#endif
+      *listener << "with description \"" << err.what() << "\"";
+      return false;
+    } catch (...) {
+      *listener << "throws an exception of an unknown type";
+      return false;
+    }
+
+    *listener << "does not throw any exception";
+    return false;
+  }
+
+ private:
+  const Matcher<const Err&> matcher_;
+};
+
+}  // namespace internal
+
+// Throws()
+// Throws(exceptionMatcher)
+// ThrowsMessage(messageMatcher)
+//
+// This matcher accepts a callable and verifies that when invoked, it throws
+// an exception with the given type and properties.
+//
+// Examples:
+//
+//   EXPECT_THAT(
+//       []() { throw std::runtime_error("message"); },
+//       Throws<std::runtime_error>());
+//
+//   EXPECT_THAT(
+//       []() { throw std::runtime_error("message"); },
+//       ThrowsMessage<std::runtime_error>(HasSubstr("message")));
+//
+//   EXPECT_THAT(
+//       []() { throw std::runtime_error("message"); },
+//       Throws<std::runtime_error>(
+//           Property(&std::runtime_error::what, HasSubstr("message"))));
+
+template <typename Err>
+PolymorphicMatcher<internal::ExceptionMatcherImpl<Err>> Throws() {
+  return MakePolymorphicMatcher(
+      internal::ExceptionMatcherImpl<Err>(A<const Err&>()));
+}
+
+template <typename Err, typename ExceptionMatcher>
+PolymorphicMatcher<internal::ExceptionMatcherImpl<Err>> Throws(
+    const ExceptionMatcher& exception_matcher) {
+  // Using matcher cast allows users to pass a matcher of a more broad type.
+  // For example user may want to pass Matcher<std::exception>
+  // to Throws<std::runtime_error>, or Matcher<int64> to Throws<int32>.
+  return MakePolymorphicMatcher(internal::ExceptionMatcherImpl<Err>(
+      SafeMatcherCast<const Err&>(exception_matcher)));
+}
+
+template <typename Err, typename MessageMatcher>
+PolymorphicMatcher<internal::ExceptionMatcherImpl<Err>> ThrowsMessage(
+    MessageMatcher&& message_matcher) {
+  static_assert(std::is_base_of<std::exception, Err>::value,
+                "expected an std::exception-derived type");
+  return Throws<Err>(internal::WithWhat(
+      MatcherCast<std::string>(std::forward<MessageMatcher>(message_matcher))));
+}
+
+#endif  // GTEST_HAS_EXCEPTIONS
+
+// These macros allow using matchers to check values in Google Test
+// tests.  ASSERT_THAT(value, matcher) and EXPECT_THAT(value, matcher)
+// succeed if and only if the value matches the matcher.  If the assertion
+// fails, the value and the description of the matcher will be printed.
+#define ASSERT_THAT(value, matcher) ASSERT_PRED_FORMAT1(\
+    ::testing::internal::MakePredicateFormatterFromMatcher(matcher), value)
+#define EXPECT_THAT(value, matcher) EXPECT_PRED_FORMAT1(\
+    ::testing::internal::MakePredicateFormatterFromMatcher(matcher), value)
+
+// MATCHER* macroses itself are listed below.
+#define MATCHER(name, description)                                             \
+  class name##Matcher                                                          \
+      : public ::testing::internal::MatcherBaseImpl<name##Matcher> {           \
+   public:                                                                     \
+    template <typename arg_type>                                               \
+    class gmock_Impl : public ::testing::MatcherInterface<const arg_type&> {   \
+     public:                                                                   \
+      gmock_Impl() {}                                                          \
+      bool MatchAndExplain(                                                    \
+          const arg_type& arg,                                                 \
+          ::testing::MatchResultListener* result_listener) const override;     \
+      void DescribeTo(::std::ostream* gmock_os) const override {               \
+        *gmock_os << FormatDescription(false);                                 \
+      }                                                                        \
+      void DescribeNegationTo(::std::ostream* gmock_os) const override {       \
+        *gmock_os << FormatDescription(true);                                  \
+      }                                                                        \
+                                                                               \
+     private:                                                                  \
+      ::std::string FormatDescription(bool negation) const {                   \
+        ::std::string gmock_description = (description);                       \
+        if (!gmock_description.empty()) {                                      \
+          return gmock_description;                                            \
+        }                                                                      \
+        return ::testing::internal::FormatMatcherDescription(negation, #name,  \
+                                                             {});              \
+      }                                                                        \
+    };                                                                         \
+  };                                                                           \
+  GTEST_ATTRIBUTE_UNUSED_ inline name##Matcher name() { return {}; }           \
+  template <typename arg_type>                                                 \
+  bool name##Matcher::gmock_Impl<arg_type>::MatchAndExplain(                   \
+      const arg_type& arg,                                                     \
+      ::testing::MatchResultListener* result_listener GTEST_ATTRIBUTE_UNUSED_) \
+      const
+
+#define MATCHER_P(name, p0, description) \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP, description, (p0))
+#define MATCHER_P2(name, p0, p1, description) \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP2, description, (p0, p1))
+#define MATCHER_P3(name, p0, p1, p2, description) \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP3, description, (p0, p1, p2))
+#define MATCHER_P4(name, p0, p1, p2, p3, description) \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP4, description, (p0, p1, p2, p3))
+#define MATCHER_P5(name, p0, p1, p2, p3, p4, description)    \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP5, description, \
+                         (p0, p1, p2, p3, p4))
+#define MATCHER_P6(name, p0, p1, p2, p3, p4, p5, description) \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP6, description,  \
+                         (p0, p1, p2, p3, p4, p5))
+#define MATCHER_P7(name, p0, p1, p2, p3, p4, p5, p6, description) \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP7, description,      \
+                         (p0, p1, p2, p3, p4, p5, p6))
+#define MATCHER_P8(name, p0, p1, p2, p3, p4, p5, p6, p7, description) \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP8, description,          \
+                         (p0, p1, p2, p3, p4, p5, p6, p7))
+#define MATCHER_P9(name, p0, p1, p2, p3, p4, p5, p6, p7, p8, description) \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP9, description,              \
+                         (p0, p1, p2, p3, p4, p5, p6, p7, p8))
+#define MATCHER_P10(name, p0, p1, p2, p3, p4, p5, p6, p7, p8, p9, description) \
+  GMOCK_INTERNAL_MATCHER(name, name##MatcherP10, description,                  \
+                         (p0, p1, p2, p3, p4, p5, p6, p7, p8, p9))
+
+#define GMOCK_INTERNAL_MATCHER(name, full_name, description, args)             \
+  template <GMOCK_INTERNAL_MATCHER_TEMPLATE_PARAMS(args)>                      \
+  class full_name : public ::testing::internal::MatcherBaseImpl<               \
+                        full_name<GMOCK_INTERNAL_MATCHER_TYPE_PARAMS(args)>> { \
+   public:                                                                     \
+    using full_name::MatcherBaseImpl::MatcherBaseImpl;                         \
+    template <typename arg_type>                                               \
+    class gmock_Impl : public ::testing::MatcherInterface<const arg_type&> {   \
+     public:                                                                   \
+      explicit gmock_Impl(GMOCK_INTERNAL_MATCHER_FUNCTION_ARGS(args))          \
+          : GMOCK_INTERNAL_MATCHER_FORWARD_ARGS(args) {}                       \
+      bool MatchAndExplain(                                                    \
+          const arg_type& arg,                                                 \
+          ::testing::MatchResultListener* result_listener) const override;     \
+      void DescribeTo(::std::ostream* gmock_os) const override {               \
+        *gmock_os << FormatDescription(false);                                 \
+      }                                                                        \
+      void DescribeNegationTo(::std::ostream* gmock_os) const override {       \
+        *gmock_os << FormatDescription(true);                                  \
+      }                                                                        \
+      GMOCK_INTERNAL_MATCHER_MEMBERS(args)                                     \
+                                                                               \
+     private:                                                                  \
+      ::std::string FormatDescription(bool negation) const {                   \
+        ::std::string gmock_description = (description);                       \
+        if (!gmock_description.empty()) {                                      \
+          return gmock_description;                                            \
+        }                                                                      \
+        return ::testing::internal::FormatMatcherDescription(                  \
+            negation, #name,                                                   \
+            ::testing::internal::UniversalTersePrintTupleFieldsToStrings(      \
+                ::std::tuple<GMOCK_INTERNAL_MATCHER_TYPE_PARAMS(args)>(        \
+                    GMOCK_INTERNAL_MATCHER_MEMBERS_USAGE(args))));             \
+      }                                                                        \
+    };                                                                         \
+  };                                                                           \
+  template <GMOCK_INTERNAL_MATCHER_TEMPLATE_PARAMS(args)>                      \
+  inline full_name<GMOCK_INTERNAL_MATCHER_TYPE_PARAMS(args)> name(             \
+      GMOCK_INTERNAL_MATCHER_FUNCTION_ARGS(args)) {                            \
+    return full_name<GMOCK_INTERNAL_MATCHER_TYPE_PARAMS(args)>(                \
+        GMOCK_INTERNAL_MATCHER_ARGS_USAGE(args));                              \
+  }                                                                            \
+  template <GMOCK_INTERNAL_MATCHER_TEMPLATE_PARAMS(args)>                      \
+  template <typename arg_type>                                                 \
+  bool full_name<GMOCK_INTERNAL_MATCHER_TYPE_PARAMS(args)>::gmock_Impl<        \
+      arg_type>::MatchAndExplain(const arg_type& arg,                          \
+                                 ::testing::MatchResultListener*               \
+                                     result_listener GTEST_ATTRIBUTE_UNUSED_)  \
+      const
+
+#define GMOCK_INTERNAL_MATCHER_TEMPLATE_PARAMS(args) \
+  GMOCK_PP_TAIL(                                     \
+      GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_MATCHER_TEMPLATE_PARAM, , args))
+#define GMOCK_INTERNAL_MATCHER_TEMPLATE_PARAM(i_unused, data_unused, arg) \
+  , typename arg##_type
+
+#define GMOCK_INTERNAL_MATCHER_TYPE_PARAMS(args) \
+  GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_MATCHER_TYPE_PARAM, , args))
+#define GMOCK_INTERNAL_MATCHER_TYPE_PARAM(i_unused, data_unused, arg) \
+  , arg##_type
+
+#define GMOCK_INTERNAL_MATCHER_FUNCTION_ARGS(args) \
+  GMOCK_PP_TAIL(dummy_first GMOCK_PP_FOR_EACH(     \
+      GMOCK_INTERNAL_MATCHER_FUNCTION_ARG, , args))
+#define GMOCK_INTERNAL_MATCHER_FUNCTION_ARG(i, data_unused, arg) \
+  , arg##_type gmock_p##i
+
+#define GMOCK_INTERNAL_MATCHER_FORWARD_ARGS(args) \
+  GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_MATCHER_FORWARD_ARG, , args))
+#define GMOCK_INTERNAL_MATCHER_FORWARD_ARG(i, data_unused, arg) \
+  , arg(::std::forward<arg##_type>(gmock_p##i))
+
+#define GMOCK_INTERNAL_MATCHER_MEMBERS(args) \
+  GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_MATCHER_MEMBER, , args)
+#define GMOCK_INTERNAL_MATCHER_MEMBER(i_unused, data_unused, arg) \
+  const arg##_type arg;
+
+#define GMOCK_INTERNAL_MATCHER_MEMBERS_USAGE(args) \
+  GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_MATCHER_MEMBER_USAGE, , args))
+#define GMOCK_INTERNAL_MATCHER_MEMBER_USAGE(i_unused, data_unused, arg) , arg
+
+#define GMOCK_INTERNAL_MATCHER_ARGS_USAGE(args) \
+  GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_MATCHER_ARG_USAGE, , args))
+#define GMOCK_INTERNAL_MATCHER_ARG_USAGE(i, data_unused, arg_unused) \
+  , gmock_p##i
+
+// To prevent ADL on certain functions we put them on a separate namespace.
+using namespace no_adl;  // NOLINT
+
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251 5046
+
+// Include any custom callback matchers added by the local installation.
+// We must include this header at the end to make sure it can use the
+// declarations from this file.
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Injection point for custom user configurations. See README for details
+//
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_CUSTOM_GMOCK_MATCHERS_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_CUSTOM_GMOCK_MATCHERS_H_
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_CUSTOM_GMOCK_MATCHERS_H_
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_MATCHERS_H_
+
+#if GTEST_HAS_EXCEPTIONS
+# include <stdexcept>  // NOLINT
+#endif
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+namespace testing {
+
+// An abstract handle of an expectation.
+class Expectation;
+
+// A set of expectation handles.
+class ExpectationSet;
+
+// Anything inside the 'internal' namespace IS INTERNAL IMPLEMENTATION
+// and MUST NOT BE USED IN USER CODE!!!
+namespace internal {
+
+// Implements a mock function.
+template <typename F> class FunctionMocker;
+
+// Base class for expectations.
+class ExpectationBase;
+
+// Implements an expectation.
+template <typename F> class TypedExpectation;
+
+// Helper class for testing the Expectation class template.
+class ExpectationTester;
+
+// Helper classes for implementing NiceMock, StrictMock, and NaggyMock.
+template <typename MockClass>
+class NiceMockImpl;
+template <typename MockClass>
+class StrictMockImpl;
+template <typename MockClass>
+class NaggyMockImpl;
+
+// Protects the mock object registry (in class Mock), all function
+// mockers, and all expectations.
+//
+// The reason we don't use more fine-grained protection is: when a
+// mock function Foo() is called, it needs to consult its expectations
+// to see which one should be picked.  If another thread is allowed to
+// call a mock function (either Foo() or a different one) at the same
+// time, it could affect the "retired" attributes of Foo()'s
+// expectations when InSequence() is used, and thus affect which
+// expectation gets picked.  Therefore, we sequence all mock function
+// calls to ensure the integrity of the mock objects' states.
+GTEST_API_ GTEST_DECLARE_STATIC_MUTEX_(g_gmock_mutex);
+
+// Untyped base class for ActionResultHolder<R>.
+class UntypedActionResultHolderBase;
+
+// Abstract base class of FunctionMocker.  This is the
+// type-agnostic part of the function mocker interface.  Its pure
+// virtual methods are implemented by FunctionMocker.
+class GTEST_API_ UntypedFunctionMockerBase {
+ public:
+  UntypedFunctionMockerBase();
+  virtual ~UntypedFunctionMockerBase();
+
+  // Verifies that all expectations on this mock function have been
+  // satisfied.  Reports one or more Google Test non-fatal failures
+  // and returns false if not.
+  bool VerifyAndClearExpectationsLocked()
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);
+
+  // Clears the ON_CALL()s set on this mock function.
+  virtual void ClearDefaultActionsLocked()
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) = 0;
+
+  // In all of the following Untyped* functions, it's the caller's
+  // responsibility to guarantee the correctness of the arguments'
+  // types.
+
+  // Performs the default action with the given arguments and returns
+  // the action's result.  The call description string will be used in
+  // the error message to describe the call in the case the default
+  // action fails.
+  // L = *
+  virtual UntypedActionResultHolderBase* UntypedPerformDefaultAction(
+      void* untyped_args, const std::string& call_description) const = 0;
+
+  // Performs the given action with the given arguments and returns
+  // the action's result.
+  // L = *
+  virtual UntypedActionResultHolderBase* UntypedPerformAction(
+      const void* untyped_action, void* untyped_args) const = 0;
+
+  // Writes a message that the call is uninteresting (i.e. neither
+  // explicitly expected nor explicitly unexpected) to the given
+  // ostream.
+  virtual void UntypedDescribeUninterestingCall(
+      const void* untyped_args,
+      ::std::ostream* os) const
+          GTEST_LOCK_EXCLUDED_(g_gmock_mutex) = 0;
+
+  // Returns the expectation that matches the given function arguments
+  // (or NULL is there's no match); when a match is found,
+  // untyped_action is set to point to the action that should be
+  // performed (or NULL if the action is "do default"), and
+  // is_excessive is modified to indicate whether the call exceeds the
+  // expected number.
+  virtual const ExpectationBase* UntypedFindMatchingExpectation(
+      const void* untyped_args,
+      const void** untyped_action, bool* is_excessive,
+      ::std::ostream* what, ::std::ostream* why)
+          GTEST_LOCK_EXCLUDED_(g_gmock_mutex) = 0;
+
+  // Prints the given function arguments to the ostream.
+  virtual void UntypedPrintArgs(const void* untyped_args,
+                                ::std::ostream* os) const = 0;
+
+  // Sets the mock object this mock method belongs to, and registers
+  // this information in the global mock registry.  Will be called
+  // whenever an EXPECT_CALL() or ON_CALL() is executed on this mock
+  // method.
+  void RegisterOwner(const void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(g_gmock_mutex);
+
+  // Sets the mock object this mock method belongs to, and sets the
+  // name of the mock function.  Will be called upon each invocation
+  // of this mock function.
+  void SetOwnerAndName(const void* mock_obj, const char* name)
+      GTEST_LOCK_EXCLUDED_(g_gmock_mutex);
+
+  // Returns the mock object this mock method belongs to.  Must be
+  // called after RegisterOwner() or SetOwnerAndName() has been
+  // called.
+  const void* MockObject() const
+      GTEST_LOCK_EXCLUDED_(g_gmock_mutex);
+
+  // Returns the name of this mock method.  Must be called after
+  // SetOwnerAndName() has been called.
+  const char* Name() const
+      GTEST_LOCK_EXCLUDED_(g_gmock_mutex);
+
+  // Returns the result of invoking this mock function with the given
+  // arguments.  This function can be safely called from multiple
+  // threads concurrently.  The caller is responsible for deleting the
+  // result.
+  UntypedActionResultHolderBase* UntypedInvokeWith(void* untyped_args)
+      GTEST_LOCK_EXCLUDED_(g_gmock_mutex);
+
+ protected:
+  typedef std::vector<const void*> UntypedOnCallSpecs;
+
+  using UntypedExpectations = std::vector<std::shared_ptr<ExpectationBase>>;
+
+  // Returns an Expectation object that references and co-owns exp,
+  // which must be an expectation on this mock function.
+  Expectation GetHandleOf(ExpectationBase* exp);
+
+  // Address of the mock object this mock method belongs to.  Only
+  // valid after this mock method has been called or
+  // ON_CALL/EXPECT_CALL has been invoked on it.
+  const void* mock_obj_;  // Protected by g_gmock_mutex.
+
+  // Name of the function being mocked.  Only valid after this mock
+  // method has been called.
+  const char* name_;  // Protected by g_gmock_mutex.
+
+  // All default action specs for this function mocker.
+  UntypedOnCallSpecs untyped_on_call_specs_;
+
+  // All expectations for this function mocker.
+  //
+  // It's undefined behavior to interleave expectations (EXPECT_CALLs
+  // or ON_CALLs) and mock function calls.  Also, the order of
+  // expectations is important.  Therefore it's a logic race condition
+  // to read/write untyped_expectations_ concurrently.  In order for
+  // tools like tsan to catch concurrent read/write accesses to
+  // untyped_expectations, we deliberately leave accesses to it
+  // unprotected.
+  UntypedExpectations untyped_expectations_;
+};  // class UntypedFunctionMockerBase
+
+// Untyped base class for OnCallSpec<F>.
+class UntypedOnCallSpecBase {
+ public:
+  // The arguments are the location of the ON_CALL() statement.
+  UntypedOnCallSpecBase(const char* a_file, int a_line)
+      : file_(a_file), line_(a_line), last_clause_(kNone) {}
+
+  // Where in the source file was the default action spec defined?
+  const char* file() const { return file_; }
+  int line() const { return line_; }
+
+ protected:
+  // Gives each clause in the ON_CALL() statement a name.
+  enum Clause {
+    // Do not change the order of the enum members!  The run-time
+    // syntax checking relies on it.
+    kNone,
+    kWith,
+    kWillByDefault
+  };
+
+  // Asserts that the ON_CALL() statement has a certain property.
+  void AssertSpecProperty(bool property,
+                          const std::string& failure_message) const {
+    Assert(property, file_, line_, failure_message);
+  }
+
+  // Expects that the ON_CALL() statement has a certain property.
+  void ExpectSpecProperty(bool property,
+                          const std::string& failure_message) const {
+    Expect(property, file_, line_, failure_message);
+  }
+
+  const char* file_;
+  int line_;
+
+  // The last clause in the ON_CALL() statement as seen so far.
+  // Initially kNone and changes as the statement is parsed.
+  Clause last_clause_;
+};  // class UntypedOnCallSpecBase
+
+// This template class implements an ON_CALL spec.
+template <typename F>
+class OnCallSpec : public UntypedOnCallSpecBase {
+ public:
+  typedef typename Function<F>::ArgumentTuple ArgumentTuple;
+  typedef typename Function<F>::ArgumentMatcherTuple ArgumentMatcherTuple;
+
+  // Constructs an OnCallSpec object from the information inside
+  // the parenthesis of an ON_CALL() statement.
+  OnCallSpec(const char* a_file, int a_line,
+             const ArgumentMatcherTuple& matchers)
+      : UntypedOnCallSpecBase(a_file, a_line),
+        matchers_(matchers),
+        // By default, extra_matcher_ should match anything.  However,
+        // we cannot initialize it with _ as that causes ambiguity between
+        // Matcher's copy and move constructor for some argument types.
+        extra_matcher_(A<const ArgumentTuple&>()) {}
+
+  // Implements the .With() clause.
+  OnCallSpec& With(const Matcher<const ArgumentTuple&>& m) {
+    // Makes sure this is called at most once.
+    ExpectSpecProperty(last_clause_ < kWith,
+                       ".With() cannot appear "
+                       "more than once in an ON_CALL().");
+    last_clause_ = kWith;
+
+    extra_matcher_ = m;
+    return *this;
+  }
+
+  // Implements the .WillByDefault() clause.
+  OnCallSpec& WillByDefault(const Action<F>& action) {
+    ExpectSpecProperty(last_clause_ < kWillByDefault,
+                       ".WillByDefault() must appear "
+                       "exactly once in an ON_CALL().");
+    last_clause_ = kWillByDefault;
+
+    ExpectSpecProperty(!action.IsDoDefault(),
+                       "DoDefault() cannot be used in ON_CALL().");
+    action_ = action;
+    return *this;
+  }
+
+  // Returns true if and only if the given arguments match the matchers.
+  bool Matches(const ArgumentTuple& args) const {
+    return TupleMatches(matchers_, args) && extra_matcher_.Matches(args);
+  }
+
+  // Returns the action specified by the user.
+  const Action<F>& GetAction() const {
+    AssertSpecProperty(last_clause_ == kWillByDefault,
+                       ".WillByDefault() must appear exactly "
+                       "once in an ON_CALL().");
+    return action_;
+  }
+
+ private:
+  // The information in statement
+  //
+  //   ON_CALL(mock_object, Method(matchers))
+  //       .With(multi-argument-matcher)
+  //       .WillByDefault(action);
+  //
+  // is recorded in the data members like this:
+  //
+  //   source file that contains the statement => file_
+  //   line number of the statement            => line_
+  //   matchers                                => matchers_
+  //   multi-argument-matcher                  => extra_matcher_
+  //   action                                  => action_
+  ArgumentMatcherTuple matchers_;
+  Matcher<const ArgumentTuple&> extra_matcher_;
+  Action<F> action_;
+};  // class OnCallSpec
+
+// Possible reactions on uninteresting calls.
+enum CallReaction {
+  kAllow,
+  kWarn,
+  kFail,
+};
+
+}  // namespace internal
+
+// Utilities for manipulating mock objects.
+class GTEST_API_ Mock {
+ public:
+  // The following public methods can be called concurrently.
+
+  // Tells Google Mock to ignore mock_obj when checking for leaked
+  // mock objects.
+  static void AllowLeak(const void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Verifies and clears all expectations on the given mock object.
+  // If the expectations aren't satisfied, generates one or more
+  // Google Test non-fatal failures and returns false.
+  static bool VerifyAndClearExpectations(void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Verifies all expectations on the given mock object and clears its
+  // default actions and expectations.  Returns true if and only if the
+  // verification was successful.
+  static bool VerifyAndClear(void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Returns whether the mock was created as a naggy mock (default)
+  static bool IsNaggy(void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+  // Returns whether the mock was created as a nice mock
+  static bool IsNice(void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+  // Returns whether the mock was created as a strict mock
+  static bool IsStrict(void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+ private:
+  friend class internal::UntypedFunctionMockerBase;
+
+  // Needed for a function mocker to register itself (so that we know
+  // how to clear a mock object).
+  template <typename F>
+  friend class internal::FunctionMocker;
+
+  template <typename MockClass>
+  friend class internal::NiceMockImpl;
+  template <typename MockClass>
+  friend class internal::NaggyMockImpl;
+  template <typename MockClass>
+  friend class internal::StrictMockImpl;
+
+  // Tells Google Mock to allow uninteresting calls on the given mock
+  // object.
+  static void AllowUninterestingCalls(const void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Tells Google Mock to warn the user about uninteresting calls on
+  // the given mock object.
+  static void WarnUninterestingCalls(const void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Tells Google Mock to fail uninteresting calls on the given mock
+  // object.
+  static void FailUninterestingCalls(const void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Tells Google Mock the given mock object is being destroyed and
+  // its entry in the call-reaction table should be removed.
+  static void UnregisterCallReaction(const void* mock_obj)
+      GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Returns the reaction Google Mock will have on uninteresting calls
+  // made on the given mock object.
+  static internal::CallReaction GetReactionOnUninterestingCalls(
+      const void* mock_obj)
+          GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Verifies that all expectations on the given mock object have been
+  // satisfied.  Reports one or more Google Test non-fatal failures
+  // and returns false if not.
+  static bool VerifyAndClearExpectationsLocked(void* mock_obj)
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(internal::g_gmock_mutex);
+
+  // Clears all ON_CALL()s set on the given mock object.
+  static void ClearDefaultActionsLocked(void* mock_obj)
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(internal::g_gmock_mutex);
+
+  // Registers a mock object and a mock method it owns.
+  static void Register(
+      const void* mock_obj,
+      internal::UntypedFunctionMockerBase* mocker)
+          GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Tells Google Mock where in the source code mock_obj is used in an
+  // ON_CALL or EXPECT_CALL.  In case mock_obj is leaked, this
+  // information helps the user identify which object it is.
+  static void RegisterUseByOnCallOrExpectCall(
+      const void* mock_obj, const char* file, int line)
+          GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
+
+  // Unregisters a mock method; removes the owning mock object from
+  // the registry when the last mock method associated with it has
+  // been unregistered.  This is called only in the destructor of
+  // FunctionMocker.
+  static void UnregisterLocked(internal::UntypedFunctionMockerBase* mocker)
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(internal::g_gmock_mutex);
+};  // class Mock
+
+// An abstract handle of an expectation.  Useful in the .After()
+// clause of EXPECT_CALL() for setting the (partial) order of
+// expectations.  The syntax:
+//
+//   Expectation e1 = EXPECT_CALL(...)...;
+//   EXPECT_CALL(...).After(e1)...;
+//
+// sets two expectations where the latter can only be matched after
+// the former has been satisfied.
+//
+// Notes:
+//   - This class is copyable and has value semantics.
+//   - Constness is shallow: a const Expectation object itself cannot
+//     be modified, but the mutable methods of the ExpectationBase
+//     object it references can be called via expectation_base().
+
+class GTEST_API_ Expectation {
+ public:
+  // Constructs a null object that doesn't reference any expectation.
+  Expectation();
+  Expectation(Expectation&&) = default;
+  Expectation(const Expectation&) = default;
+  Expectation& operator=(Expectation&&) = default;
+  Expectation& operator=(const Expectation&) = default;
+  ~Expectation();
+
+  // This single-argument ctor must not be explicit, in order to support the
+  //   Expectation e = EXPECT_CALL(...);
+  // syntax.
+  //
+  // A TypedExpectation object stores its pre-requisites as
+  // Expectation objects, and needs to call the non-const Retire()
+  // method on the ExpectationBase objects they reference.  Therefore
+  // Expectation must receive a *non-const* reference to the
+  // ExpectationBase object.
+  Expectation(internal::ExpectationBase& exp);  // NOLINT
+
+  // The compiler-generated copy ctor and operator= work exactly as
+  // intended, so we don't need to define our own.
+
+  // Returns true if and only if rhs references the same expectation as this
+  // object does.
+  bool operator==(const Expectation& rhs) const {
+    return expectation_base_ == rhs.expectation_base_;
+  }
+
+  bool operator!=(const Expectation& rhs) const { return !(*this == rhs); }
+
+ private:
+  friend class ExpectationSet;
+  friend class Sequence;
+  friend class ::testing::internal::ExpectationBase;
+  friend class ::testing::internal::UntypedFunctionMockerBase;
+
+  template <typename F>
+  friend class ::testing::internal::FunctionMocker;
+
+  template <typename F>
+  friend class ::testing::internal::TypedExpectation;
+
+  // This comparator is needed for putting Expectation objects into a set.
+  class Less {
+   public:
+    bool operator()(const Expectation& lhs, const Expectation& rhs) const {
+      return lhs.expectation_base_.get() < rhs.expectation_base_.get();
+    }
+  };
+
+  typedef ::std::set<Expectation, Less> Set;
+
+  Expectation(
+      const std::shared_ptr<internal::ExpectationBase>& expectation_base);
+
+  // Returns the expectation this object references.
+  const std::shared_ptr<internal::ExpectationBase>& expectation_base() const {
+    return expectation_base_;
+  }
+
+  // A shared_ptr that co-owns the expectation this handle references.
+  std::shared_ptr<internal::ExpectationBase> expectation_base_;
+};
+
+// A set of expectation handles.  Useful in the .After() clause of
+// EXPECT_CALL() for setting the (partial) order of expectations.  The
+// syntax:
+//
+//   ExpectationSet es;
+//   es += EXPECT_CALL(...)...;
+//   es += EXPECT_CALL(...)...;
+//   EXPECT_CALL(...).After(es)...;
+//
+// sets three expectations where the last one can only be matched
+// after the first two have both been satisfied.
+//
+// This class is copyable and has value semantics.
+class ExpectationSet {
+ public:
+  // A bidirectional iterator that can read a const element in the set.
+  typedef Expectation::Set::const_iterator const_iterator;
+
+  // An object stored in the set.  This is an alias of Expectation.
+  typedef Expectation::Set::value_type value_type;
+
+  // Constructs an empty set.
+  ExpectationSet() {}
+
+  // This single-argument ctor must not be explicit, in order to support the
+  //   ExpectationSet es = EXPECT_CALL(...);
+  // syntax.
+  ExpectationSet(internal::ExpectationBase& exp) {  // NOLINT
+    *this += Expectation(exp);
+  }
+
+  // This single-argument ctor implements implicit conversion from
+  // Expectation and thus must not be explicit.  This allows either an
+  // Expectation or an ExpectationSet to be used in .After().
+  ExpectationSet(const Expectation& e) {  // NOLINT
+    *this += e;
+  }
+
+  // The compiler-generator ctor and operator= works exactly as
+  // intended, so we don't need to define our own.
+
+  // Returns true if and only if rhs contains the same set of Expectation
+  // objects as this does.
+  bool operator==(const ExpectationSet& rhs) const {
+    return expectations_ == rhs.expectations_;
+  }
+
+  bool operator!=(const ExpectationSet& rhs) const { return !(*this == rhs); }
+
+  // Implements the syntax
+  //   expectation_set += EXPECT_CALL(...);
+  ExpectationSet& operator+=(const Expectation& e) {
+    expectations_.insert(e);
+    return *this;
+  }
+
+  int size() const { return static_cast<int>(expectations_.size()); }
+
+  const_iterator begin() const { return expectations_.begin(); }
+  const_iterator end() const { return expectations_.end(); }
+
+ private:
+  Expectation::Set expectations_;
+};
+
+
+// Sequence objects are used by a user to specify the relative order
+// in which the expectations should match.  They are copyable (we rely
+// on the compiler-defined copy constructor and assignment operator).
+class GTEST_API_ Sequence {
+ public:
+  // Constructs an empty sequence.
+  Sequence() : last_expectation_(new Expectation) {}
+
+  // Adds an expectation to this sequence.  The caller must ensure
+  // that no other thread is accessing this Sequence object.
+  void AddExpectation(const Expectation& expectation) const;
+
+ private:
+  // The last expectation in this sequence.
+  std::shared_ptr<Expectation> last_expectation_;
+};  // class Sequence
+
+// An object of this type causes all EXPECT_CALL() statements
+// encountered in its scope to be put in an anonymous sequence.  The
+// work is done in the constructor and destructor.  You should only
+// create an InSequence object on the stack.
+//
+// The sole purpose for this class is to support easy definition of
+// sequential expectations, e.g.
+//
+//   {
+//     InSequence dummy;  // The name of the object doesn't matter.
+//
+//     // The following expectations must match in the order they appear.
+//     EXPECT_CALL(a, Bar())...;
+//     EXPECT_CALL(a, Baz())...;
+//     ...
+//     EXPECT_CALL(b, Xyz())...;
+//   }
+//
+// You can create InSequence objects in multiple threads, as long as
+// they are used to affect different mock objects.  The idea is that
+// each thread can create and set up its own mocks as if it's the only
+// thread.  However, for clarity of your tests we recommend you to set
+// up mocks in the main thread unless you have a good reason not to do
+// so.
+class GTEST_API_ InSequence {
+ public:
+  InSequence();
+  ~InSequence();
+ private:
+  bool sequence_created_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(InSequence);  // NOLINT
+} GTEST_ATTRIBUTE_UNUSED_;
+
+namespace internal {
+
+// Points to the implicit sequence introduced by a living InSequence
+// object (if any) in the current thread or NULL.
+GTEST_API_ extern ThreadLocal<Sequence*> g_gmock_implicit_sequence;
+
+// Base class for implementing expectations.
+//
+// There are two reasons for having a type-agnostic base class for
+// Expectation:
+//
+//   1. We need to store collections of expectations of different
+//   types (e.g. all pre-requisites of a particular expectation, all
+//   expectations in a sequence).  Therefore these expectation objects
+//   must share a common base class.
+//
+//   2. We can avoid binary code bloat by moving methods not depending
+//   on the template argument of Expectation to the base class.
+//
+// This class is internal and mustn't be used by user code directly.
+class GTEST_API_ ExpectationBase {
+ public:
+  // source_text is the EXPECT_CALL(...) source that created this Expectation.
+  ExpectationBase(const char* file, int line, const std::string& source_text);
+
+  virtual ~ExpectationBase();
+
+  // Where in the source file was the expectation spec defined?
+  const char* file() const { return file_; }
+  int line() const { return line_; }
+  const char* source_text() const { return source_text_.c_str(); }
+  // Returns the cardinality specified in the expectation spec.
+  const Cardinality& cardinality() const { return cardinality_; }
+
+  // Describes the source file location of this expectation.
+  void DescribeLocationTo(::std::ostream* os) const {
+    *os << FormatFileLocation(file(), line()) << " ";
+  }
+
+  // Describes how many times a function call matching this
+  // expectation has occurred.
+  void DescribeCallCountTo(::std::ostream* os) const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);
+
+  // If this mock method has an extra matcher (i.e. .With(matcher)),
+  // describes it to the ostream.
+  virtual void MaybeDescribeExtraMatcherTo(::std::ostream* os) = 0;
+
+ protected:
+  friend class ::testing::Expectation;
+  friend class UntypedFunctionMockerBase;
+
+  enum Clause {
+    // Don't change the order of the enum members!
+    kNone,
+    kWith,
+    kTimes,
+    kInSequence,
+    kAfter,
+    kWillOnce,
+    kWillRepeatedly,
+    kRetiresOnSaturation
+  };
+
+  typedef std::vector<const void*> UntypedActions;
+
+  // Returns an Expectation object that references and co-owns this
+  // expectation.
+  virtual Expectation GetHandle() = 0;
+
+  // Asserts that the EXPECT_CALL() statement has the given property.
+  void AssertSpecProperty(bool property,
+                          const std::string& failure_message) const {
+    Assert(property, file_, line_, failure_message);
+  }
+
+  // Expects that the EXPECT_CALL() statement has the given property.
+  void ExpectSpecProperty(bool property,
+                          const std::string& failure_message) const {
+    Expect(property, file_, line_, failure_message);
+  }
+
+  // Explicitly specifies the cardinality of this expectation.  Used
+  // by the subclasses to implement the .Times() clause.
+  void SpecifyCardinality(const Cardinality& cardinality);
+
+  // Returns true if and only if the user specified the cardinality
+  // explicitly using a .Times().
+  bool cardinality_specified() const { return cardinality_specified_; }
+
+  // Sets the cardinality of this expectation spec.
+  void set_cardinality(const Cardinality& a_cardinality) {
+    cardinality_ = a_cardinality;
+  }
+
+  // The following group of methods should only be called after the
+  // EXPECT_CALL() statement, and only when g_gmock_mutex is held by
+  // the current thread.
+
+  // Retires all pre-requisites of this expectation.
+  void RetireAllPreRequisites()
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);
+
+  // Returns true if and only if this expectation is retired.
+  bool is_retired() const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    return retired_;
+  }
+
+  // Retires this expectation.
+  void Retire()
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    retired_ = true;
+  }
+
+  // Returns true if and only if this expectation is satisfied.
+  bool IsSatisfied() const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    return cardinality().IsSatisfiedByCallCount(call_count_);
+  }
+
+  // Returns true if and only if this expectation is saturated.
+  bool IsSaturated() const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    return cardinality().IsSaturatedByCallCount(call_count_);
+  }
+
+  // Returns true if and only if this expectation is over-saturated.
+  bool IsOverSaturated() const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    return cardinality().IsOverSaturatedByCallCount(call_count_);
+  }
+
+  // Returns true if and only if all pre-requisites of this expectation are
+  // satisfied.
+  bool AllPrerequisitesAreSatisfied() const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);
+
+  // Adds unsatisfied pre-requisites of this expectation to 'result'.
+  void FindUnsatisfiedPrerequisites(ExpectationSet* result) const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);
+
+  // Returns the number this expectation has been invoked.
+  int call_count() const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    return call_count_;
+  }
+
+  // Increments the number this expectation has been invoked.
+  void IncrementCallCount()
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    call_count_++;
+  }
+
+  // Checks the action count (i.e. the number of WillOnce() and
+  // WillRepeatedly() clauses) against the cardinality if this hasn't
+  // been done before.  Prints a warning if there are too many or too
+  // few actions.
+  void CheckActionCountIfNotDone() const
+      GTEST_LOCK_EXCLUDED_(mutex_);
+
+  friend class ::testing::Sequence;
+  friend class ::testing::internal::ExpectationTester;
+
+  template <typename Function>
+  friend class TypedExpectation;
+
+  // Implements the .Times() clause.
+  void UntypedTimes(const Cardinality& a_cardinality);
+
+  // This group of fields are part of the spec and won't change after
+  // an EXPECT_CALL() statement finishes.
+  const char* file_;          // The file that contains the expectation.
+  int line_;                  // The line number of the expectation.
+  const std::string source_text_;  // The EXPECT_CALL(...) source text.
+  // True if and only if the cardinality is specified explicitly.
+  bool cardinality_specified_;
+  Cardinality cardinality_;            // The cardinality of the expectation.
+  // The immediate pre-requisites (i.e. expectations that must be
+  // satisfied before this expectation can be matched) of this
+  // expectation.  We use std::shared_ptr in the set because we want an
+  // Expectation object to be co-owned by its FunctionMocker and its
+  // successors.  This allows multiple mock objects to be deleted at
+  // different times.
+  ExpectationSet immediate_prerequisites_;
+
+  // This group of fields are the current state of the expectation,
+  // and can change as the mock function is called.
+  int call_count_;  // How many times this expectation has been invoked.
+  bool retired_;    // True if and only if this expectation has retired.
+  UntypedActions untyped_actions_;
+  bool extra_matcher_specified_;
+  bool repeated_action_specified_;  // True if a WillRepeatedly() was specified.
+  bool retires_on_saturation_;
+  Clause last_clause_;
+  mutable bool action_count_checked_;  // Under mutex_.
+  mutable Mutex mutex_;  // Protects action_count_checked_.
+};  // class ExpectationBase
+
+// Impements an expectation for the given function type.
+template <typename F>
+class TypedExpectation : public ExpectationBase {
+ public:
+  typedef typename Function<F>::ArgumentTuple ArgumentTuple;
+  typedef typename Function<F>::ArgumentMatcherTuple ArgumentMatcherTuple;
+  typedef typename Function<F>::Result Result;
+
+  TypedExpectation(FunctionMocker<F>* owner, const char* a_file, int a_line,
+                   const std::string& a_source_text,
+                   const ArgumentMatcherTuple& m)
+      : ExpectationBase(a_file, a_line, a_source_text),
+        owner_(owner),
+        matchers_(m),
+        // By default, extra_matcher_ should match anything.  However,
+        // we cannot initialize it with _ as that causes ambiguity between
+        // Matcher's copy and move constructor for some argument types.
+        extra_matcher_(A<const ArgumentTuple&>()),
+        repeated_action_(DoDefault()) {}
+
+  ~TypedExpectation() override {
+    // Check the validity of the action count if it hasn't been done
+    // yet (for example, if the expectation was never used).
+    CheckActionCountIfNotDone();
+    for (UntypedActions::const_iterator it = untyped_actions_.begin();
+         it != untyped_actions_.end(); ++it) {
+      delete static_cast<const Action<F>*>(*it);
+    }
+  }
+
+  // Implements the .With() clause.
+  TypedExpectation& With(const Matcher<const ArgumentTuple&>& m) {
+    if (last_clause_ == kWith) {
+      ExpectSpecProperty(false,
+                         ".With() cannot appear "
+                         "more than once in an EXPECT_CALL().");
+    } else {
+      ExpectSpecProperty(last_clause_ < kWith,
+                         ".With() must be the first "
+                         "clause in an EXPECT_CALL().");
+    }
+    last_clause_ = kWith;
+
+    extra_matcher_ = m;
+    extra_matcher_specified_ = true;
+    return *this;
+  }
+
+  // Implements the .Times() clause.
+  TypedExpectation& Times(const Cardinality& a_cardinality) {
+    ExpectationBase::UntypedTimes(a_cardinality);
+    return *this;
+  }
+
+  // Implements the .Times() clause.
+  TypedExpectation& Times(int n) {
+    return Times(Exactly(n));
+  }
+
+  // Implements the .InSequence() clause.
+  TypedExpectation& InSequence(const Sequence& s) {
+    ExpectSpecProperty(last_clause_ <= kInSequence,
+                       ".InSequence() cannot appear after .After(),"
+                       " .WillOnce(), .WillRepeatedly(), or "
+                       ".RetiresOnSaturation().");
+    last_clause_ = kInSequence;
+
+    s.AddExpectation(GetHandle());
+    return *this;
+  }
+  TypedExpectation& InSequence(const Sequence& s1, const Sequence& s2) {
+    return InSequence(s1).InSequence(s2);
+  }
+  TypedExpectation& InSequence(const Sequence& s1, const Sequence& s2,
+                               const Sequence& s3) {
+    return InSequence(s1, s2).InSequence(s3);
+  }
+  TypedExpectation& InSequence(const Sequence& s1, const Sequence& s2,
+                               const Sequence& s3, const Sequence& s4) {
+    return InSequence(s1, s2, s3).InSequence(s4);
+  }
+  TypedExpectation& InSequence(const Sequence& s1, const Sequence& s2,
+                               const Sequence& s3, const Sequence& s4,
+                               const Sequence& s5) {
+    return InSequence(s1, s2, s3, s4).InSequence(s5);
+  }
+
+  // Implements that .After() clause.
+  TypedExpectation& After(const ExpectationSet& s) {
+    ExpectSpecProperty(last_clause_ <= kAfter,
+                       ".After() cannot appear after .WillOnce(),"
+                       " .WillRepeatedly(), or "
+                       ".RetiresOnSaturation().");
+    last_clause_ = kAfter;
+
+    for (ExpectationSet::const_iterator it = s.begin(); it != s.end(); ++it) {
+      immediate_prerequisites_ += *it;
+    }
+    return *this;
+  }
+  TypedExpectation& After(const ExpectationSet& s1, const ExpectationSet& s2) {
+    return After(s1).After(s2);
+  }
+  TypedExpectation& After(const ExpectationSet& s1, const ExpectationSet& s2,
+                          const ExpectationSet& s3) {
+    return After(s1, s2).After(s3);
+  }
+  TypedExpectation& After(const ExpectationSet& s1, const ExpectationSet& s2,
+                          const ExpectationSet& s3, const ExpectationSet& s4) {
+    return After(s1, s2, s3).After(s4);
+  }
+  TypedExpectation& After(const ExpectationSet& s1, const ExpectationSet& s2,
+                          const ExpectationSet& s3, const ExpectationSet& s4,
+                          const ExpectationSet& s5) {
+    return After(s1, s2, s3, s4).After(s5);
+  }
+
+  // Implements the .WillOnce() clause.
+  TypedExpectation& WillOnce(const Action<F>& action) {
+    ExpectSpecProperty(last_clause_ <= kWillOnce,
+                       ".WillOnce() cannot appear after "
+                       ".WillRepeatedly() or .RetiresOnSaturation().");
+    last_clause_ = kWillOnce;
+
+    untyped_actions_.push_back(new Action<F>(action));
+    if (!cardinality_specified()) {
+      set_cardinality(Exactly(static_cast<int>(untyped_actions_.size())));
+    }
+    return *this;
+  }
+
+  // Implements the .WillRepeatedly() clause.
+  TypedExpectation& WillRepeatedly(const Action<F>& action) {
+    if (last_clause_ == kWillRepeatedly) {
+      ExpectSpecProperty(false,
+                         ".WillRepeatedly() cannot appear "
+                         "more than once in an EXPECT_CALL().");
+    } else {
+      ExpectSpecProperty(last_clause_ < kWillRepeatedly,
+                         ".WillRepeatedly() cannot appear "
+                         "after .RetiresOnSaturation().");
+    }
+    last_clause_ = kWillRepeatedly;
+    repeated_action_specified_ = true;
+
+    repeated_action_ = action;
+    if (!cardinality_specified()) {
+      set_cardinality(AtLeast(static_cast<int>(untyped_actions_.size())));
+    }
+
+    // Now that no more action clauses can be specified, we check
+    // whether their count makes sense.
+    CheckActionCountIfNotDone();
+    return *this;
+  }
+
+  // Implements the .RetiresOnSaturation() clause.
+  TypedExpectation& RetiresOnSaturation() {
+    ExpectSpecProperty(last_clause_ < kRetiresOnSaturation,
+                       ".RetiresOnSaturation() cannot appear "
+                       "more than once.");
+    last_clause_ = kRetiresOnSaturation;
+    retires_on_saturation_ = true;
+
+    // Now that no more action clauses can be specified, we check
+    // whether their count makes sense.
+    CheckActionCountIfNotDone();
+    return *this;
+  }
+
+  // Returns the matchers for the arguments as specified inside the
+  // EXPECT_CALL() macro.
+  const ArgumentMatcherTuple& matchers() const {
+    return matchers_;
+  }
+
+  // Returns the matcher specified by the .With() clause.
+  const Matcher<const ArgumentTuple&>& extra_matcher() const {
+    return extra_matcher_;
+  }
+
+  // Returns the action specified by the .WillRepeatedly() clause.
+  const Action<F>& repeated_action() const { return repeated_action_; }
+
+  // If this mock method has an extra matcher (i.e. .With(matcher)),
+  // describes it to the ostream.
+  void MaybeDescribeExtraMatcherTo(::std::ostream* os) override {
+    if (extra_matcher_specified_) {
+      *os << "    Expected args: ";
+      extra_matcher_.DescribeTo(os);
+      *os << "\n";
+    }
+  }
+
+ private:
+  template <typename Function>
+  friend class FunctionMocker;
+
+  // Returns an Expectation object that references and co-owns this
+  // expectation.
+  Expectation GetHandle() override { return owner_->GetHandleOf(this); }
+
+  // The following methods will be called only after the EXPECT_CALL()
+  // statement finishes and when the current thread holds
+  // g_gmock_mutex.
+
+  // Returns true if and only if this expectation matches the given arguments.
+  bool Matches(const ArgumentTuple& args) const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    return TupleMatches(matchers_, args) && extra_matcher_.Matches(args);
+  }
+
+  // Returns true if and only if this expectation should handle the given
+  // arguments.
+  bool ShouldHandleArguments(const ArgumentTuple& args) const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+
+    // In case the action count wasn't checked when the expectation
+    // was defined (e.g. if this expectation has no WillRepeatedly()
+    // or RetiresOnSaturation() clause), we check it when the
+    // expectation is used for the first time.
+    CheckActionCountIfNotDone();
+    return !is_retired() && AllPrerequisitesAreSatisfied() && Matches(args);
+  }
+
+  // Describes the result of matching the arguments against this
+  // expectation to the given ostream.
+  void ExplainMatchResultTo(
+      const ArgumentTuple& args,
+      ::std::ostream* os) const
+          GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+
+    if (is_retired()) {
+      *os << "         Expected: the expectation is active\n"
+          << "           Actual: it is retired\n";
+    } else if (!Matches(args)) {
+      if (!TupleMatches(matchers_, args)) {
+        ExplainMatchFailureTupleTo(matchers_, args, os);
+      }
+      StringMatchResultListener listener;
+      if (!extra_matcher_.MatchAndExplain(args, &listener)) {
+        *os << "    Expected args: ";
+        extra_matcher_.DescribeTo(os);
+        *os << "\n           Actual: don't match";
+
+        internal::PrintIfNotEmpty(listener.str(), os);
+        *os << "\n";
+      }
+    } else if (!AllPrerequisitesAreSatisfied()) {
+      *os << "         Expected: all pre-requisites are satisfied\n"
+          << "           Actual: the following immediate pre-requisites "
+          << "are not satisfied:\n";
+      ExpectationSet unsatisfied_prereqs;
+      FindUnsatisfiedPrerequisites(&unsatisfied_prereqs);
+      int i = 0;
+      for (ExpectationSet::const_iterator it = unsatisfied_prereqs.begin();
+           it != unsatisfied_prereqs.end(); ++it) {
+        it->expectation_base()->DescribeLocationTo(os);
+        *os << "pre-requisite #" << i++ << "\n";
+      }
+      *os << "                   (end of pre-requisites)\n";
+    } else {
+      // This line is here just for completeness' sake.  It will never
+      // be executed as currently the ExplainMatchResultTo() function
+      // is called only when the mock function call does NOT match the
+      // expectation.
+      *os << "The call matches the expectation.\n";
+    }
+  }
+
+  // Returns the action that should be taken for the current invocation.
+  const Action<F>& GetCurrentAction(const FunctionMocker<F>* mocker,
+                                    const ArgumentTuple& args) const
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    const int count = call_count();
+    Assert(count >= 1, __FILE__, __LINE__,
+           "call_count() is <= 0 when GetCurrentAction() is "
+           "called - this should never happen.");
+
+    const int action_count = static_cast<int>(untyped_actions_.size());
+    if (action_count > 0 && !repeated_action_specified_ &&
+        count > action_count) {
+      // If there is at least one WillOnce() and no WillRepeatedly(),
+      // we warn the user when the WillOnce() clauses ran out.
+      ::std::stringstream ss;
+      DescribeLocationTo(&ss);
+      ss << "Actions ran out in " << source_text() << "...\n"
+         << "Called " << count << " times, but only "
+         << action_count << " WillOnce()"
+         << (action_count == 1 ? " is" : "s are") << " specified - ";
+      mocker->DescribeDefaultActionTo(args, &ss);
+      Log(kWarning, ss.str(), 1);
+    }
+
+    return count <= action_count
+               ? *static_cast<const Action<F>*>(
+                     untyped_actions_[static_cast<size_t>(count - 1)])
+               : repeated_action();
+  }
+
+  // Given the arguments of a mock function call, if the call will
+  // over-saturate this expectation, returns the default action;
+  // otherwise, returns the next action in this expectation.  Also
+  // describes *what* happened to 'what', and explains *why* Google
+  // Mock does it to 'why'.  This method is not const as it calls
+  // IncrementCallCount().  A return value of NULL means the default
+  // action.
+  const Action<F>* GetActionForArguments(const FunctionMocker<F>* mocker,
+                                         const ArgumentTuple& args,
+                                         ::std::ostream* what,
+                                         ::std::ostream* why)
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    if (IsSaturated()) {
+      // We have an excessive call.
+      IncrementCallCount();
+      *what << "Mock function called more times than expected - ";
+      mocker->DescribeDefaultActionTo(args, what);
+      DescribeCallCountTo(why);
+
+      return nullptr;
+    }
+
+    IncrementCallCount();
+    RetireAllPreRequisites();
+
+    if (retires_on_saturation_ && IsSaturated()) {
+      Retire();
+    }
+
+    // Must be done after IncrementCount()!
+    *what << "Mock function call matches " << source_text() <<"...\n";
+    return &(GetCurrentAction(mocker, args));
+  }
+
+  // All the fields below won't change once the EXPECT_CALL()
+  // statement finishes.
+  FunctionMocker<F>* const owner_;
+  ArgumentMatcherTuple matchers_;
+  Matcher<const ArgumentTuple&> extra_matcher_;
+  Action<F> repeated_action_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(TypedExpectation);
+};  // class TypedExpectation
+
+// A MockSpec object is used by ON_CALL() or EXPECT_CALL() for
+// specifying the default behavior of, or expectation on, a mock
+// function.
+
+// Note: class MockSpec really belongs to the ::testing namespace.
+// However if we define it in ::testing, MSVC will complain when
+// classes in ::testing::internal declare it as a friend class
+// template.  To workaround this compiler bug, we define MockSpec in
+// ::testing::internal and import it into ::testing.
+
+// Logs a message including file and line number information.
+GTEST_API_ void LogWithLocation(testing::internal::LogSeverity severity,
+                                const char* file, int line,
+                                const std::string& message);
+
+template <typename F>
+class MockSpec {
+ public:
+  typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
+  typedef typename internal::Function<F>::ArgumentMatcherTuple
+      ArgumentMatcherTuple;
+
+  // Constructs a MockSpec object, given the function mocker object
+  // that the spec is associated with.
+  MockSpec(internal::FunctionMocker<F>* function_mocker,
+           const ArgumentMatcherTuple& matchers)
+      : function_mocker_(function_mocker), matchers_(matchers) {}
+
+  // Adds a new default action spec to the function mocker and returns
+  // the newly created spec.
+  internal::OnCallSpec<F>& InternalDefaultActionSetAt(
+      const char* file, int line, const char* obj, const char* call) {
+    LogWithLocation(internal::kInfo, file, line,
+                    std::string("ON_CALL(") + obj + ", " + call + ") invoked");
+    return function_mocker_->AddNewOnCallSpec(file, line, matchers_);
+  }
+
+  // Adds a new expectation spec to the function mocker and returns
+  // the newly created spec.
+  internal::TypedExpectation<F>& InternalExpectedAt(
+      const char* file, int line, const char* obj, const char* call) {
+    const std::string source_text(std::string("EXPECT_CALL(") + obj + ", " +
+                                  call + ")");
+    LogWithLocation(internal::kInfo, file, line, source_text + " invoked");
+    return function_mocker_->AddNewExpectation(
+        file, line, source_text, matchers_);
+  }
+
+  // This operator overload is used to swallow the superfluous parameter list
+  // introduced by the ON/EXPECT_CALL macros. See the macro comments for more
+  // explanation.
+  MockSpec<F>& operator()(const internal::WithoutMatchers&, void* const) {
+    return *this;
+  }
+
+ private:
+  template <typename Function>
+  friend class internal::FunctionMocker;
+
+  // The function mocker that owns this spec.
+  internal::FunctionMocker<F>* const function_mocker_;
+  // The argument matchers specified in the spec.
+  ArgumentMatcherTuple matchers_;
+};  // class MockSpec
+
+// Wrapper type for generically holding an ordinary value or lvalue reference.
+// If T is not a reference type, it must be copyable or movable.
+// ReferenceOrValueWrapper<T> is movable, and will also be copyable unless
+// T is a move-only value type (which means that it will always be copyable
+// if the current platform does not support move semantics).
+//
+// The primary template defines handling for values, but function header
+// comments describe the contract for the whole template (including
+// specializations).
+template <typename T>
+class ReferenceOrValueWrapper {
+ public:
+  // Constructs a wrapper from the given value/reference.
+  explicit ReferenceOrValueWrapper(T value)
+      : value_(std::move(value)) {
+  }
+
+  // Unwraps and returns the underlying value/reference, exactly as
+  // originally passed. The behavior of calling this more than once on
+  // the same object is unspecified.
+  T Unwrap() { return std::move(value_); }
+
+  // Provides nondestructive access to the underlying value/reference.
+  // Always returns a const reference (more precisely,
+  // const std::add_lvalue_reference<T>::type). The behavior of calling this
+  // after calling Unwrap on the same object is unspecified.
+  const T& Peek() const {
+    return value_;
+  }
+
+ private:
+  T value_;
+};
+
+// Specialization for lvalue reference types. See primary template
+// for documentation.
+template <typename T>
+class ReferenceOrValueWrapper<T&> {
+ public:
+  // Workaround for debatable pass-by-reference lint warning (c-library-team
+  // policy precludes NOLINT in this context)
+  typedef T& reference;
+  explicit ReferenceOrValueWrapper(reference ref)
+      : value_ptr_(&ref) {}
+  T& Unwrap() { return *value_ptr_; }
+  const T& Peek() const { return *value_ptr_; }
+
+ private:
+  T* value_ptr_;
+};
+
+// C++ treats the void type specially.  For example, you cannot define
+// a void-typed variable or pass a void value to a function.
+// ActionResultHolder<T> holds a value of type T, where T must be a
+// copyable type or void (T doesn't need to be default-constructable).
+// It hides the syntactic difference between void and other types, and
+// is used to unify the code for invoking both void-returning and
+// non-void-returning mock functions.
+
+// Untyped base class for ActionResultHolder<T>.
+class UntypedActionResultHolderBase {
+ public:
+  virtual ~UntypedActionResultHolderBase() {}
+
+  // Prints the held value as an action's result to os.
+  virtual void PrintAsActionResult(::std::ostream* os) const = 0;
+};
+
+// This generic definition is used when T is not void.
+template <typename T>
+class ActionResultHolder : public UntypedActionResultHolderBase {
+ public:
+  // Returns the held value. Must not be called more than once.
+  T Unwrap() {
+    return result_.Unwrap();
+  }
+
+  // Prints the held value as an action's result to os.
+  void PrintAsActionResult(::std::ostream* os) const override {
+    *os << "\n          Returns: ";
+    // T may be a reference type, so we don't use UniversalPrint().
+    UniversalPrinter<T>::Print(result_.Peek(), os);
+  }
+
+  // Performs the given mock function's default action and returns the
+  // result in a new-ed ActionResultHolder.
+  template <typename F>
+  static ActionResultHolder* PerformDefaultAction(
+      const FunctionMocker<F>* func_mocker,
+      typename Function<F>::ArgumentTuple&& args,
+      const std::string& call_description) {
+    return new ActionResultHolder(Wrapper(func_mocker->PerformDefaultAction(
+        std::move(args), call_description)));
+  }
+
+  // Performs the given action and returns the result in a new-ed
+  // ActionResultHolder.
+  template <typename F>
+  static ActionResultHolder* PerformAction(
+      const Action<F>& action, typename Function<F>::ArgumentTuple&& args) {
+    return new ActionResultHolder(
+        Wrapper(action.Perform(std::move(args))));
+  }
+
+ private:
+  typedef ReferenceOrValueWrapper<T> Wrapper;
+
+  explicit ActionResultHolder(Wrapper result)
+      : result_(std::move(result)) {
+  }
+
+  Wrapper result_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ActionResultHolder);
+};
+
+// Specialization for T = void.
+template <>
+class ActionResultHolder<void> : public UntypedActionResultHolderBase {
+ public:
+  void Unwrap() { }
+
+  void PrintAsActionResult(::std::ostream* /* os */) const override {}
+
+  // Performs the given mock function's default action and returns ownership
+  // of an empty ActionResultHolder*.
+  template <typename F>
+  static ActionResultHolder* PerformDefaultAction(
+      const FunctionMocker<F>* func_mocker,
+      typename Function<F>::ArgumentTuple&& args,
+      const std::string& call_description) {
+    func_mocker->PerformDefaultAction(std::move(args), call_description);
+    return new ActionResultHolder;
+  }
+
+  // Performs the given action and returns ownership of an empty
+  // ActionResultHolder*.
+  template <typename F>
+  static ActionResultHolder* PerformAction(
+      const Action<F>& action, typename Function<F>::ArgumentTuple&& args) {
+    action.Perform(std::move(args));
+    return new ActionResultHolder;
+  }
+
+ private:
+  ActionResultHolder() {}
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ActionResultHolder);
+};
+
+template <typename F>
+class FunctionMocker;
+
+template <typename R, typename... Args>
+class FunctionMocker<R(Args...)> final : public UntypedFunctionMockerBase {
+  using F = R(Args...);
+
+ public:
+  using Result = R;
+  using ArgumentTuple = std::tuple<Args...>;
+  using ArgumentMatcherTuple = std::tuple<Matcher<Args>...>;
+
+  FunctionMocker() {}
+
+  // There is no generally useful and implementable semantics of
+  // copying a mock object, so copying a mock is usually a user error.
+  // Thus we disallow copying function mockers.  If the user really
+  // wants to copy a mock object, they should implement their own copy
+  // operation, for example:
+  //
+  //   class MockFoo : public Foo {
+  //    public:
+  //     // Defines a copy constructor explicitly.
+  //     MockFoo(const MockFoo& src) {}
+  //     ...
+  //   };
+  FunctionMocker(const FunctionMocker&) = delete;
+  FunctionMocker& operator=(const FunctionMocker&) = delete;
+
+  // The destructor verifies that all expectations on this mock
+  // function have been satisfied.  If not, it will report Google Test
+  // non-fatal failures for the violations.
+  ~FunctionMocker() override GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+    MutexLock l(&g_gmock_mutex);
+    VerifyAndClearExpectationsLocked();
+    Mock::UnregisterLocked(this);
+    ClearDefaultActionsLocked();
+  }
+
+  // Returns the ON_CALL spec that matches this mock function with the
+  // given arguments; returns NULL if no matching ON_CALL is found.
+  // L = *
+  const OnCallSpec<F>* FindOnCallSpec(
+      const ArgumentTuple& args) const {
+    for (UntypedOnCallSpecs::const_reverse_iterator it
+             = untyped_on_call_specs_.rbegin();
+         it != untyped_on_call_specs_.rend(); ++it) {
+      const OnCallSpec<F>* spec = static_cast<const OnCallSpec<F>*>(*it);
+      if (spec->Matches(args))
+        return spec;
+    }
+
+    return nullptr;
+  }
+
+  // Performs the default action of this mock function on the given
+  // arguments and returns the result. Asserts (or throws if
+  // exceptions are enabled) with a helpful call descrption if there
+  // is no valid return value. This method doesn't depend on the
+  // mutable state of this object, and thus can be called concurrently
+  // without locking.
+  // L = *
+  Result PerformDefaultAction(ArgumentTuple&& args,
+                              const std::string& call_description) const {
+    const OnCallSpec<F>* const spec =
+        this->FindOnCallSpec(args);
+    if (spec != nullptr) {
+      return spec->GetAction().Perform(std::move(args));
+    }
+    const std::string message =
+        call_description +
+        "\n    The mock function has no default action "
+        "set, and its return type has no default value set.";
+#if GTEST_HAS_EXCEPTIONS
+    if (!DefaultValue<Result>::Exists()) {
+      throw std::runtime_error(message);
+    }
+#else
+    Assert(DefaultValue<Result>::Exists(), "", -1, message);
+#endif
+    return DefaultValue<Result>::Get();
+  }
+
+  // Performs the default action with the given arguments and returns
+  // the action's result.  The call description string will be used in
+  // the error message to describe the call in the case the default
+  // action fails.  The caller is responsible for deleting the result.
+  // L = *
+  UntypedActionResultHolderBase* UntypedPerformDefaultAction(
+      void* untyped_args,  // must point to an ArgumentTuple
+      const std::string& call_description) const override {
+    ArgumentTuple* args = static_cast<ArgumentTuple*>(untyped_args);
+    return ResultHolder::PerformDefaultAction(this, std::move(*args),
+                                              call_description);
+  }
+
+  // Performs the given action with the given arguments and returns
+  // the action's result.  The caller is responsible for deleting the
+  // result.
+  // L = *
+  UntypedActionResultHolderBase* UntypedPerformAction(
+      const void* untyped_action, void* untyped_args) const override {
+    // Make a copy of the action before performing it, in case the
+    // action deletes the mock object (and thus deletes itself).
+    const Action<F> action = *static_cast<const Action<F>*>(untyped_action);
+    ArgumentTuple* args = static_cast<ArgumentTuple*>(untyped_args);
+    return ResultHolder::PerformAction(action, std::move(*args));
+  }
+
+  // Implements UntypedFunctionMockerBase::ClearDefaultActionsLocked():
+  // clears the ON_CALL()s set on this mock function.
+  void ClearDefaultActionsLocked() override
+      GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+
+    // Deleting our default actions may trigger other mock objects to be
+    // deleted, for example if an action contains a reference counted smart
+    // pointer to that mock object, and that is the last reference. So if we
+    // delete our actions within the context of the global mutex we may deadlock
+    // when this method is called again. Instead, make a copy of the set of
+    // actions to delete, clear our set within the mutex, and then delete the
+    // actions outside of the mutex.
+    UntypedOnCallSpecs specs_to_delete;
+    untyped_on_call_specs_.swap(specs_to_delete);
+
+    g_gmock_mutex.Unlock();
+    for (UntypedOnCallSpecs::const_iterator it =
+             specs_to_delete.begin();
+         it != specs_to_delete.end(); ++it) {
+      delete static_cast<const OnCallSpec<F>*>(*it);
+    }
+
+    // Lock the mutex again, since the caller expects it to be locked when we
+    // return.
+    g_gmock_mutex.Lock();
+  }
+
+  // Returns the result of invoking this mock function with the given
+  // arguments.  This function can be safely called from multiple
+  // threads concurrently.
+  Result Invoke(Args... args) GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+    ArgumentTuple tuple(std::forward<Args>(args)...);
+    std::unique_ptr<ResultHolder> holder(DownCast_<ResultHolder*>(
+        this->UntypedInvokeWith(static_cast<void*>(&tuple))));
+    return holder->Unwrap();
+  }
+
+  MockSpec<F> With(Matcher<Args>... m) {
+    return MockSpec<F>(this, ::std::make_tuple(std::move(m)...));
+  }
+
+ protected:
+  template <typename Function>
+  friend class MockSpec;
+
+  typedef ActionResultHolder<Result> ResultHolder;
+
+  // Adds and returns a default action spec for this mock function.
+  OnCallSpec<F>& AddNewOnCallSpec(
+      const char* file, int line,
+      const ArgumentMatcherTuple& m)
+          GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+    Mock::RegisterUseByOnCallOrExpectCall(MockObject(), file, line);
+    OnCallSpec<F>* const on_call_spec = new OnCallSpec<F>(file, line, m);
+    untyped_on_call_specs_.push_back(on_call_spec);
+    return *on_call_spec;
+  }
+
+  // Adds and returns an expectation spec for this mock function.
+  TypedExpectation<F>& AddNewExpectation(const char* file, int line,
+                                         const std::string& source_text,
+                                         const ArgumentMatcherTuple& m)
+      GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+    Mock::RegisterUseByOnCallOrExpectCall(MockObject(), file, line);
+    TypedExpectation<F>* const expectation =
+        new TypedExpectation<F>(this, file, line, source_text, m);
+    const std::shared_ptr<ExpectationBase> untyped_expectation(expectation);
+    // See the definition of untyped_expectations_ for why access to
+    // it is unprotected here.
+    untyped_expectations_.push_back(untyped_expectation);
+
+    // Adds this expectation into the implicit sequence if there is one.
+    Sequence* const implicit_sequence = g_gmock_implicit_sequence.get();
+    if (implicit_sequence != nullptr) {
+      implicit_sequence->AddExpectation(Expectation(untyped_expectation));
+    }
+
+    return *expectation;
+  }
+
+ private:
+  template <typename Func> friend class TypedExpectation;
+
+  // Some utilities needed for implementing UntypedInvokeWith().
+
+  // Describes what default action will be performed for the given
+  // arguments.
+  // L = *
+  void DescribeDefaultActionTo(const ArgumentTuple& args,
+                               ::std::ostream* os) const {
+    const OnCallSpec<F>* const spec = FindOnCallSpec(args);
+
+    if (spec == nullptr) {
+      *os << (std::is_void<Result>::value ? "returning directly.\n"
+                                          : "returning default value.\n");
+    } else {
+      *os << "taking default action specified at:\n"
+          << FormatFileLocation(spec->file(), spec->line()) << "\n";
+    }
+  }
+
+  // Writes a message that the call is uninteresting (i.e. neither
+  // explicitly expected nor explicitly unexpected) to the given
+  // ostream.
+  void UntypedDescribeUninterestingCall(const void* untyped_args,
+                                        ::std::ostream* os) const override
+      GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+    const ArgumentTuple& args =
+        *static_cast<const ArgumentTuple*>(untyped_args);
+    *os << "Uninteresting mock function call - ";
+    DescribeDefaultActionTo(args, os);
+    *os << "    Function call: " << Name();
+    UniversalPrint(args, os);
+  }
+
+  // Returns the expectation that matches the given function arguments
+  // (or NULL is there's no match); when a match is found,
+  // untyped_action is set to point to the action that should be
+  // performed (or NULL if the action is "do default"), and
+  // is_excessive is modified to indicate whether the call exceeds the
+  // expected number.
+  //
+  // Critical section: We must find the matching expectation and the
+  // corresponding action that needs to be taken in an ATOMIC
+  // transaction.  Otherwise another thread may call this mock
+  // method in the middle and mess up the state.
+  //
+  // However, performing the action has to be left out of the critical
+  // section.  The reason is that we have no control on what the
+  // action does (it can invoke an arbitrary user function or even a
+  // mock function) and excessive locking could cause a dead lock.
+  const ExpectationBase* UntypedFindMatchingExpectation(
+      const void* untyped_args, const void** untyped_action, bool* is_excessive,
+      ::std::ostream* what, ::std::ostream* why) override
+      GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
+    const ArgumentTuple& args =
+        *static_cast<const ArgumentTuple*>(untyped_args);
+    MutexLock l(&g_gmock_mutex);
+    TypedExpectation<F>* exp = this->FindMatchingExpectationLocked(args);
+    if (exp == nullptr) {  // A match wasn't found.
+      this->FormatUnexpectedCallMessageLocked(args, what, why);
+      return nullptr;
+    }
+
+    // This line must be done before calling GetActionForArguments(),
+    // which will increment the call count for *exp and thus affect
+    // its saturation status.
+    *is_excessive = exp->IsSaturated();
+    const Action<F>* action = exp->GetActionForArguments(this, args, what, why);
+    if (action != nullptr && action->IsDoDefault())
+      action = nullptr;  // Normalize "do default" to NULL.
+    *untyped_action = action;
+    return exp;
+  }
+
+  // Prints the given function arguments to the ostream.
+  void UntypedPrintArgs(const void* untyped_args,
+                        ::std::ostream* os) const override {
+    const ArgumentTuple& args =
+        *static_cast<const ArgumentTuple*>(untyped_args);
+    UniversalPrint(args, os);
+  }
+
+  // Returns the expectation that matches the arguments, or NULL if no
+  // expectation matches them.
+  TypedExpectation<F>* FindMatchingExpectationLocked(
+      const ArgumentTuple& args) const
+          GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    // See the definition of untyped_expectations_ for why access to
+    // it is unprotected here.
+    for (typename UntypedExpectations::const_reverse_iterator it =
+             untyped_expectations_.rbegin();
+         it != untyped_expectations_.rend(); ++it) {
+      TypedExpectation<F>* const exp =
+          static_cast<TypedExpectation<F>*>(it->get());
+      if (exp->ShouldHandleArguments(args)) {
+        return exp;
+      }
+    }
+    return nullptr;
+  }
+
+  // Returns a message that the arguments don't match any expectation.
+  void FormatUnexpectedCallMessageLocked(
+      const ArgumentTuple& args,
+      ::std::ostream* os,
+      ::std::ostream* why) const
+          GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    *os << "\nUnexpected mock function call - ";
+    DescribeDefaultActionTo(args, os);
+    PrintTriedExpectationsLocked(args, why);
+  }
+
+  // Prints a list of expectations that have been tried against the
+  // current mock function call.
+  void PrintTriedExpectationsLocked(
+      const ArgumentTuple& args,
+      ::std::ostream* why) const
+          GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
+    g_gmock_mutex.AssertHeld();
+    const size_t count = untyped_expectations_.size();
+    *why << "Google Mock tried the following " << count << " "
+         << (count == 1 ? "expectation, but it didn't match" :
+             "expectations, but none matched")
+         << ":\n";
+    for (size_t i = 0; i < count; i++) {
+      TypedExpectation<F>* const expectation =
+          static_cast<TypedExpectation<F>*>(untyped_expectations_[i].get());
+      *why << "\n";
+      expectation->DescribeLocationTo(why);
+      if (count > 1) {
+        *why << "tried expectation #" << i << ": ";
+      }
+      *why << expectation->source_text() << "...\n";
+      expectation->ExplainMatchResultTo(args, why);
+      expectation->DescribeCallCountTo(why);
+    }
+  }
+};  // class FunctionMocker
+
+// Reports an uninteresting call (whose description is in msg) in the
+// manner specified by 'reaction'.
+void ReportUninterestingCall(CallReaction reaction, const std::string& msg);
+
+}  // namespace internal
+
+namespace internal {
+
+template <typename F>
+class MockFunction;
+
+template <typename R, typename... Args>
+class MockFunction<R(Args...)> {
+ public:
+  MockFunction(const MockFunction&) = delete;
+  MockFunction& operator=(const MockFunction&) = delete;
+
+  std::function<R(Args...)> AsStdFunction() {
+    return [this](Args... args) -> R {
+      return this->Call(std::forward<Args>(args)...);
+    };
+  }
+
+  // Implementation detail: the expansion of the MOCK_METHOD macro.
+  R Call(Args... args) {
+    mock_.SetOwnerAndName(this, "Call");
+    return mock_.Invoke(std::forward<Args>(args)...);
+  }
+
+  MockSpec<R(Args...)> gmock_Call(Matcher<Args>... m) {
+    mock_.RegisterOwner(this);
+    return mock_.With(std::move(m)...);
+  }
+
+  MockSpec<R(Args...)> gmock_Call(const WithoutMatchers&, R (*)(Args...)) {
+    return this->gmock_Call(::testing::A<Args>()...);
+  }
+
+ protected:
+  MockFunction() = default;
+  ~MockFunction() = default;
+
+ private:
+  FunctionMocker<R(Args...)> mock_;
+};
+
+/*
+The SignatureOf<F> struct is a meta-function returning function signature
+corresponding to the provided F argument.
+
+It makes use of MockFunction easier by allowing it to accept more F arguments
+than just function signatures.
+
+Specializations provided here cover only a signature type itself and
+std::function. However, if need be it can be easily extended to cover also other
+types (like for example boost::function).
+*/
+
+template <typename F>
+struct SignatureOf;
+
+template <typename R, typename... Args>
+struct SignatureOf<R(Args...)> {
+  using type = R(Args...);
+};
+
+template <typename F>
+struct SignatureOf<std::function<F>> : SignatureOf<F> {};
+
+template <typename F>
+using SignatureOfT = typename SignatureOf<F>::type;
+
+}  // namespace internal
+
+// A MockFunction<F> type has one mock method whose type is
+// internal::SignatureOfT<F>.  It is useful when you just want your
+// test code to emit some messages and have Google Mock verify the
+// right messages are sent (and perhaps at the right times).  For
+// example, if you are exercising code:
+//
+//   Foo(1);
+//   Foo(2);
+//   Foo(3);
+//
+// and want to verify that Foo(1) and Foo(3) both invoke
+// mock.Bar("a"), but Foo(2) doesn't invoke anything, you can write:
+//
+// TEST(FooTest, InvokesBarCorrectly) {
+//   MyMock mock;
+//   MockFunction<void(string check_point_name)> check;
+//   {
+//     InSequence s;
+//
+//     EXPECT_CALL(mock, Bar("a"));
+//     EXPECT_CALL(check, Call("1"));
+//     EXPECT_CALL(check, Call("2"));
+//     EXPECT_CALL(mock, Bar("a"));
+//   }
+//   Foo(1);
+//   check.Call("1");
+//   Foo(2);
+//   check.Call("2");
+//   Foo(3);
+// }
+//
+// The expectation spec says that the first Bar("a") must happen
+// before check point "1", the second Bar("a") must happen after check
+// point "2", and nothing should happen between the two check
+// points. The explicit check points make it easy to tell which
+// Bar("a") is called by which call to Foo().
+//
+// MockFunction<F> can also be used to exercise code that accepts
+// std::function<internal::SignatureOfT<F>> callbacks. To do so, use
+// AsStdFunction() method to create std::function proxy forwarding to
+// original object's Call. Example:
+//
+// TEST(FooTest, RunsCallbackWithBarArgument) {
+//   MockFunction<int(string)> callback;
+//   EXPECT_CALL(callback, Call("bar")).WillOnce(Return(1));
+//   Foo(callback.AsStdFunction());
+// }
+//
+// The internal::SignatureOfT<F> indirection allows to use other types
+// than just function signature type. This is typically useful when
+// providing a mock for a predefined std::function type. Example:
+//
+// using FilterPredicate = std::function<bool(string)>;
+// void MyFilterAlgorithm(FilterPredicate predicate);
+//
+// TEST(FooTest, FilterPredicateAlwaysAccepts) {
+//   MockFunction<FilterPredicate> predicateMock;
+//   EXPECT_CALL(predicateMock, Call(_)).WillRepeatedly(Return(true));
+//   MyFilterAlgorithm(predicateMock.AsStdFunction());
+// }
+template <typename F>
+class MockFunction : public internal::MockFunction<internal::SignatureOfT<F>> {
+  using Base = internal::MockFunction<internal::SignatureOfT<F>>;
+
+ public:
+  using Base::Base;
+};
+
+// The style guide prohibits "using" statements in a namespace scope
+// inside a header file.  However, the MockSpec class template is
+// meant to be defined in the ::testing namespace.  The following line
+// is just a trick for working around a bug in MSVC 8.0, which cannot
+// handle it if we define MockSpec in ::testing.
+using internal::MockSpec;
+
+// Const(x) is a convenient function for obtaining a const reference
+// to x.  This is useful for setting expectations on an overloaded
+// const mock method, e.g.
+//
+//   class MockFoo : public FooInterface {
+//    public:
+//     MOCK_METHOD0(Bar, int());
+//     MOCK_CONST_METHOD0(Bar, int&());
+//   };
+//
+//   MockFoo foo;
+//   // Expects a call to non-const MockFoo::Bar().
+//   EXPECT_CALL(foo, Bar());
+//   // Expects a call to const MockFoo::Bar().
+//   EXPECT_CALL(Const(foo), Bar());
+template <typename T>
+inline const T& Const(const T& x) { return x; }
+
+// Constructs an Expectation object that references and co-owns exp.
+inline Expectation::Expectation(internal::ExpectationBase& exp)  // NOLINT
+    : expectation_base_(exp.GetHandle().expectation_base()) {}
+
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+// Implementation for ON_CALL and EXPECT_CALL macros. A separate macro is
+// required to avoid compile errors when the name of the method used in call is
+// a result of macro expansion. See CompilesWithMethodNameExpandedFromMacro
+// tests in internal/gmock-spec-builders_test.cc for more details.
+//
+// This macro supports statements both with and without parameter matchers. If
+// the parameter list is omitted, gMock will accept any parameters, which allows
+// tests to be written that don't need to encode the number of method
+// parameter. This technique may only be used for non-overloaded methods.
+//
+//   // These are the same:
+//   ON_CALL(mock, NoArgsMethod()).WillByDefault(...);
+//   ON_CALL(mock, NoArgsMethod).WillByDefault(...);
+//
+//   // As are these:
+//   ON_CALL(mock, TwoArgsMethod(_, _)).WillByDefault(...);
+//   ON_CALL(mock, TwoArgsMethod).WillByDefault(...);
+//
+//   // Can also specify args if you want, of course:
+//   ON_CALL(mock, TwoArgsMethod(_, 45)).WillByDefault(...);
+//
+//   // Overloads work as long as you specify parameters:
+//   ON_CALL(mock, OverloadedMethod(_)).WillByDefault(...);
+//   ON_CALL(mock, OverloadedMethod(_, _)).WillByDefault(...);
+//
+//   // Oops! Which overload did you want?
+//   ON_CALL(mock, OverloadedMethod).WillByDefault(...);
+//     => ERROR: call to member function 'gmock_OverloadedMethod' is ambiguous
+//
+// How this works: The mock class uses two overloads of the gmock_Method
+// expectation setter method plus an operator() overload on the MockSpec object.
+// In the matcher list form, the macro expands to:
+//
+//   // This statement:
+//   ON_CALL(mock, TwoArgsMethod(_, 45))...
+//
+//   // ...expands to:
+//   mock.gmock_TwoArgsMethod(_, 45)(WithoutMatchers(), nullptr)...
+//   |-------------v---------------||------------v-------------|
+//       invokes first overload        swallowed by operator()
+//
+//   // ...which is essentially:
+//   mock.gmock_TwoArgsMethod(_, 45)...
+//
+// Whereas the form without a matcher list:
+//
+//   // This statement:
+//   ON_CALL(mock, TwoArgsMethod)...
+//
+//   // ...expands to:
+//   mock.gmock_TwoArgsMethod(WithoutMatchers(), nullptr)...
+//   |-----------------------v--------------------------|
+//                 invokes second overload
+//
+//   // ...which is essentially:
+//   mock.gmock_TwoArgsMethod(_, _)...
+//
+// The WithoutMatchers() argument is used to disambiguate overloads and to
+// block the caller from accidentally invoking the second overload directly. The
+// second argument is an internal type derived from the method signature. The
+// failure to disambiguate two overloads of this method in the ON_CALL statement
+// is how we block callers from setting expectations on overloaded methods.
+#define GMOCK_ON_CALL_IMPL_(mock_expr, Setter, call)                    \
+  ((mock_expr).gmock_##call)(::testing::internal::GetWithoutMatchers(), \
+                             nullptr)                                   \
+      .Setter(__FILE__, __LINE__, #mock_expr, #call)
+
+#define ON_CALL(obj, call) \
+  GMOCK_ON_CALL_IMPL_(obj, InternalDefaultActionSetAt, call)
+
+#define EXPECT_CALL(obj, call) \
+  GMOCK_ON_CALL_IMPL_(obj, InternalExpectedAt, call)
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_SPEC_BUILDERS_H_
+
+namespace testing {
+namespace internal {
+template <typename T>
+using identity_t = T;
+
+template <typename Pattern>
+struct ThisRefAdjuster {
+  template <typename T>
+  using AdjustT = typename std::conditional<
+      std::is_const<typename std::remove_reference<Pattern>::type>::value,
+      typename std::conditional<std::is_lvalue_reference<Pattern>::value,
+                                const T&, const T&&>::type,
+      typename std::conditional<std::is_lvalue_reference<Pattern>::value, T&,
+                                T&&>::type>::type;
+
+  template <typename MockType>
+  static AdjustT<MockType> Adjust(const MockType& mock) {
+    return static_cast<AdjustT<MockType>>(const_cast<MockType&>(mock));
+  }
+};
+
+}  // namespace internal
+
+// The style guide prohibits "using" statements in a namespace scope
+// inside a header file.  However, the FunctionMocker class template
+// is meant to be defined in the ::testing namespace.  The following
+// line is just a trick for working around a bug in MSVC 8.0, which
+// cannot handle it if we define FunctionMocker in ::testing.
+using internal::FunctionMocker;
+}  // namespace testing
+
+#define MOCK_METHOD(...) \
+  GMOCK_PP_VARIADIC_CALL(GMOCK_INTERNAL_MOCK_METHOD_ARG_, __VA_ARGS__)
+
+#define GMOCK_INTERNAL_MOCK_METHOD_ARG_1(...) \
+  GMOCK_INTERNAL_WRONG_ARITY(__VA_ARGS__)
+
+#define GMOCK_INTERNAL_MOCK_METHOD_ARG_2(...) \
+  GMOCK_INTERNAL_WRONG_ARITY(__VA_ARGS__)
+
+#define GMOCK_INTERNAL_MOCK_METHOD_ARG_3(_Ret, _MethodName, _Args) \
+  GMOCK_INTERNAL_MOCK_METHOD_ARG_4(_Ret, _MethodName, _Args, ())
+
+#define GMOCK_INTERNAL_MOCK_METHOD_ARG_4(_Ret, _MethodName, _Args, _Spec)     \
+  GMOCK_INTERNAL_ASSERT_PARENTHESIS(_Args);                                   \
+  GMOCK_INTERNAL_ASSERT_PARENTHESIS(_Spec);                                   \
+  GMOCK_INTERNAL_ASSERT_VALID_SIGNATURE(                                      \
+      GMOCK_PP_NARG0 _Args, GMOCK_INTERNAL_SIGNATURE(_Ret, _Args));           \
+  GMOCK_INTERNAL_ASSERT_VALID_SPEC(_Spec)                                     \
+  GMOCK_INTERNAL_MOCK_METHOD_IMPL(                                            \
+      GMOCK_PP_NARG0 _Args, _MethodName, GMOCK_INTERNAL_HAS_CONST(_Spec),     \
+      GMOCK_INTERNAL_HAS_OVERRIDE(_Spec), GMOCK_INTERNAL_HAS_FINAL(_Spec),    \
+      GMOCK_INTERNAL_GET_NOEXCEPT_SPEC(_Spec),                                \
+      GMOCK_INTERNAL_GET_CALLTYPE(_Spec), GMOCK_INTERNAL_GET_REF_SPEC(_Spec), \
+      (GMOCK_INTERNAL_SIGNATURE(_Ret, _Args)))
+
+#define GMOCK_INTERNAL_MOCK_METHOD_ARG_5(...) \
+  GMOCK_INTERNAL_WRONG_ARITY(__VA_ARGS__)
+
+#define GMOCK_INTERNAL_MOCK_METHOD_ARG_6(...) \
+  GMOCK_INTERNAL_WRONG_ARITY(__VA_ARGS__)
+
+#define GMOCK_INTERNAL_MOCK_METHOD_ARG_7(...) \
+  GMOCK_INTERNAL_WRONG_ARITY(__VA_ARGS__)
+
+#define GMOCK_INTERNAL_WRONG_ARITY(...)                                      \
+  static_assert(                                                             \
+      false,                                                                 \
+      "MOCK_METHOD must be called with 3 or 4 arguments. _Ret, "             \
+      "_MethodName, _Args and optionally _Spec. _Args and _Spec must be "    \
+      "enclosed in parentheses. If _Ret is a type with unprotected commas, " \
+      "it must also be enclosed in parentheses.")
+
+#define GMOCK_INTERNAL_ASSERT_PARENTHESIS(_Tuple) \
+  static_assert(                                  \
+      GMOCK_PP_IS_ENCLOSED_PARENS(_Tuple),        \
+      GMOCK_PP_STRINGIZE(_Tuple) " should be enclosed in parentheses.")
+
+#define GMOCK_INTERNAL_ASSERT_VALID_SIGNATURE(_N, ...)                 \
+  static_assert(                                                       \
+      std::is_function<__VA_ARGS__>::value,                            \
+      "Signature must be a function type, maybe return type contains " \
+      "unprotected comma.");                                           \
+  static_assert(                                                       \
+      ::testing::tuple_size<typename ::testing::internal::Function<    \
+              __VA_ARGS__>::ArgumentTuple>::value == _N,               \
+      "This method does not take " GMOCK_PP_STRINGIZE(                 \
+          _N) " arguments. Parenthesize all types with unprotected commas.")
+
+#define GMOCK_INTERNAL_ASSERT_VALID_SPEC(_Spec) \
+  GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_ASSERT_VALID_SPEC_ELEMENT, ~, _Spec)
+
+#define GMOCK_INTERNAL_MOCK_METHOD_IMPL(_N, _MethodName, _Constness,           \
+                                        _Override, _Final, _NoexceptSpec,      \
+                                        _CallType, _RefSpec, _Signature)       \
+  typename ::testing::internal::Function<GMOCK_PP_REMOVE_PARENS(               \
+      _Signature)>::Result                                                     \
+  GMOCK_INTERNAL_EXPAND(_CallType)                                             \
+      _MethodName(GMOCK_PP_REPEAT(GMOCK_INTERNAL_PARAMETER, _Signature, _N))   \
+          GMOCK_PP_IF(_Constness, const, ) _RefSpec _NoexceptSpec              \
+          GMOCK_PP_IF(_Override, override, ) GMOCK_PP_IF(_Final, final, ) {    \
+    GMOCK_MOCKER_(_N, _Constness, _MethodName)                                 \
+        .SetOwnerAndName(this, #_MethodName);                                  \
+    return GMOCK_MOCKER_(_N, _Constness, _MethodName)                          \
+        .Invoke(GMOCK_PP_REPEAT(GMOCK_INTERNAL_FORWARD_ARG, _Signature, _N));  \
+  }                                                                            \
+  ::testing::MockSpec<GMOCK_PP_REMOVE_PARENS(_Signature)> gmock_##_MethodName( \
+      GMOCK_PP_REPEAT(GMOCK_INTERNAL_MATCHER_PARAMETER, _Signature, _N))       \
+      GMOCK_PP_IF(_Constness, const, ) _RefSpec {                              \
+    GMOCK_MOCKER_(_N, _Constness, _MethodName).RegisterOwner(this);            \
+    return GMOCK_MOCKER_(_N, _Constness, _MethodName)                          \
+        .With(GMOCK_PP_REPEAT(GMOCK_INTERNAL_MATCHER_ARGUMENT, , _N));         \
+  }                                                                            \
+  ::testing::MockSpec<GMOCK_PP_REMOVE_PARENS(_Signature)> gmock_##_MethodName( \
+      const ::testing::internal::WithoutMatchers&,                             \
+      GMOCK_PP_IF(_Constness, const, )::testing::internal::Function<           \
+          GMOCK_PP_REMOVE_PARENS(_Signature)>*) const _RefSpec _NoexceptSpec { \
+    return ::testing::internal::ThisRefAdjuster<GMOCK_PP_IF(                   \
+        _Constness, const, ) int _RefSpec>::Adjust(*this)                      \
+        .gmock_##_MethodName(GMOCK_PP_REPEAT(                                  \
+            GMOCK_INTERNAL_A_MATCHER_ARGUMENT, _Signature, _N));               \
+  }                                                                            \
+  mutable ::testing::FunctionMocker<GMOCK_PP_REMOVE_PARENS(_Signature)>        \
+      GMOCK_MOCKER_(_N, _Constness, _MethodName)
+
+#define GMOCK_INTERNAL_EXPAND(...) __VA_ARGS__
+
+// Five Valid modifiers.
+#define GMOCK_INTERNAL_HAS_CONST(_Tuple) \
+  GMOCK_PP_HAS_COMMA(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_DETECT_CONST, ~, _Tuple))
+
+#define GMOCK_INTERNAL_HAS_OVERRIDE(_Tuple) \
+  GMOCK_PP_HAS_COMMA(                       \
+      GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_DETECT_OVERRIDE, ~, _Tuple))
+
+#define GMOCK_INTERNAL_HAS_FINAL(_Tuple) \
+  GMOCK_PP_HAS_COMMA(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_DETECT_FINAL, ~, _Tuple))
+
+#define GMOCK_INTERNAL_GET_NOEXCEPT_SPEC(_Tuple) \
+  GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_NOEXCEPT_SPEC_IF_NOEXCEPT, ~, _Tuple)
+
+#define GMOCK_INTERNAL_NOEXCEPT_SPEC_IF_NOEXCEPT(_i, _, _elem)          \
+  GMOCK_PP_IF(                                                          \
+      GMOCK_PP_HAS_COMMA(GMOCK_INTERNAL_DETECT_NOEXCEPT(_i, _, _elem)), \
+      _elem, )
+
+#define GMOCK_INTERNAL_GET_REF_SPEC(_Tuple) \
+  GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_REF_SPEC_IF_REF, ~, _Tuple)
+
+#define GMOCK_INTERNAL_REF_SPEC_IF_REF(_i, _, _elem)                       \
+  GMOCK_PP_IF(GMOCK_PP_HAS_COMMA(GMOCK_INTERNAL_DETECT_REF(_i, _, _elem)), \
+              GMOCK_PP_CAT(GMOCK_INTERNAL_UNPACK_, _elem), )
+
+#define GMOCK_INTERNAL_GET_CALLTYPE(_Tuple) \
+  GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_GET_CALLTYPE_IMPL, ~, _Tuple)
+
+#define GMOCK_INTERNAL_ASSERT_VALID_SPEC_ELEMENT(_i, _, _elem)            \
+  static_assert(                                                          \
+      (GMOCK_PP_HAS_COMMA(GMOCK_INTERNAL_DETECT_CONST(_i, _, _elem)) +    \
+       GMOCK_PP_HAS_COMMA(GMOCK_INTERNAL_DETECT_OVERRIDE(_i, _, _elem)) + \
+       GMOCK_PP_HAS_COMMA(GMOCK_INTERNAL_DETECT_FINAL(_i, _, _elem)) +    \
+       GMOCK_PP_HAS_COMMA(GMOCK_INTERNAL_DETECT_NOEXCEPT(_i, _, _elem)) + \
+       GMOCK_PP_HAS_COMMA(GMOCK_INTERNAL_DETECT_REF(_i, _, _elem)) +      \
+       GMOCK_INTERNAL_IS_CALLTYPE(_elem)) == 1,                           \
+      GMOCK_PP_STRINGIZE(                                                 \
+          _elem) " cannot be recognized as a valid specification modifier.");
+
+// Modifiers implementation.
+#define GMOCK_INTERNAL_DETECT_CONST(_i, _, _elem) \
+  GMOCK_PP_CAT(GMOCK_INTERNAL_DETECT_CONST_I_, _elem)
+
+#define GMOCK_INTERNAL_DETECT_CONST_I_const ,
+
+#define GMOCK_INTERNAL_DETECT_OVERRIDE(_i, _, _elem) \
+  GMOCK_PP_CAT(GMOCK_INTERNAL_DETECT_OVERRIDE_I_, _elem)
+
+#define GMOCK_INTERNAL_DETECT_OVERRIDE_I_override ,
+
+#define GMOCK_INTERNAL_DETECT_FINAL(_i, _, _elem) \
+  GMOCK_PP_CAT(GMOCK_INTERNAL_DETECT_FINAL_I_, _elem)
+
+#define GMOCK_INTERNAL_DETECT_FINAL_I_final ,
+
+#define GMOCK_INTERNAL_DETECT_NOEXCEPT(_i, _, _elem) \
+  GMOCK_PP_CAT(GMOCK_INTERNAL_DETECT_NOEXCEPT_I_, _elem)
+
+#define GMOCK_INTERNAL_DETECT_NOEXCEPT_I_noexcept ,
+
+#define GMOCK_INTERNAL_DETECT_REF(_i, _, _elem) \
+  GMOCK_PP_CAT(GMOCK_INTERNAL_DETECT_REF_I_, _elem)
+
+#define GMOCK_INTERNAL_DETECT_REF_I_ref ,
+
+#define GMOCK_INTERNAL_UNPACK_ref(x) x
+
+#define GMOCK_INTERNAL_GET_CALLTYPE_IMPL(_i, _, _elem)           \
+  GMOCK_PP_IF(GMOCK_INTERNAL_IS_CALLTYPE(_elem),                 \
+              GMOCK_INTERNAL_GET_VALUE_CALLTYPE, GMOCK_PP_EMPTY) \
+  (_elem)
+
+// TODO(iserna): GMOCK_INTERNAL_IS_CALLTYPE and
+// GMOCK_INTERNAL_GET_VALUE_CALLTYPE needed more expansions to work on windows
+// maybe they can be simplified somehow.
+#define GMOCK_INTERNAL_IS_CALLTYPE(_arg) \
+  GMOCK_INTERNAL_IS_CALLTYPE_I(          \
+      GMOCK_PP_CAT(GMOCK_INTERNAL_IS_CALLTYPE_HELPER_, _arg))
+#define GMOCK_INTERNAL_IS_CALLTYPE_I(_arg) GMOCK_PP_IS_ENCLOSED_PARENS(_arg)
+
+#define GMOCK_INTERNAL_GET_VALUE_CALLTYPE(_arg) \
+  GMOCK_INTERNAL_GET_VALUE_CALLTYPE_I(          \
+      GMOCK_PP_CAT(GMOCK_INTERNAL_IS_CALLTYPE_HELPER_, _arg))
+#define GMOCK_INTERNAL_GET_VALUE_CALLTYPE_I(_arg) \
+  GMOCK_PP_IDENTITY _arg
+
+#define GMOCK_INTERNAL_IS_CALLTYPE_HELPER_Calltype
+
+// Note: The use of `identity_t` here allows _Ret to represent return types that
+// would normally need to be specified in a different way. For example, a method
+// returning a function pointer must be written as
+//
+// fn_ptr_return_t (*method(method_args_t...))(fn_ptr_args_t...)
+//
+// But we only support placing the return type at the beginning. To handle this,
+// we wrap all calls in identity_t, so that a declaration will be expanded to
+//
+// identity_t<fn_ptr_return_t (*)(fn_ptr_args_t...)> method(method_args_t...)
+//
+// This allows us to work around the syntactic oddities of function/method
+// types.
+#define GMOCK_INTERNAL_SIGNATURE(_Ret, _Args)                                 \
+  ::testing::internal::identity_t<GMOCK_PP_IF(GMOCK_PP_IS_BEGIN_PARENS(_Ret), \
+                                              GMOCK_PP_REMOVE_PARENS,         \
+                                              GMOCK_PP_IDENTITY)(_Ret)>(      \
+      GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_GET_TYPE, _, _Args))
+
+#define GMOCK_INTERNAL_GET_TYPE(_i, _, _elem)                          \
+  GMOCK_PP_COMMA_IF(_i)                                                \
+  GMOCK_PP_IF(GMOCK_PP_IS_BEGIN_PARENS(_elem), GMOCK_PP_REMOVE_PARENS, \
+              GMOCK_PP_IDENTITY)                                       \
+  (_elem)
+
+#define GMOCK_INTERNAL_PARAMETER(_i, _Signature, _)            \
+  GMOCK_PP_COMMA_IF(_i)                                        \
+  GMOCK_INTERNAL_ARG_O(_i, GMOCK_PP_REMOVE_PARENS(_Signature)) \
+  gmock_a##_i
+
+#define GMOCK_INTERNAL_FORWARD_ARG(_i, _Signature, _) \
+  GMOCK_PP_COMMA_IF(_i)                               \
+  ::std::forward<GMOCK_INTERNAL_ARG_O(                \
+      _i, GMOCK_PP_REMOVE_PARENS(_Signature))>(gmock_a##_i)
+
+#define GMOCK_INTERNAL_MATCHER_PARAMETER(_i, _Signature, _)        \
+  GMOCK_PP_COMMA_IF(_i)                                            \
+  GMOCK_INTERNAL_MATCHER_O(_i, GMOCK_PP_REMOVE_PARENS(_Signature)) \
+  gmock_a##_i
+
+#define GMOCK_INTERNAL_MATCHER_ARGUMENT(_i, _1, _2) \
+  GMOCK_PP_COMMA_IF(_i)                             \
+  gmock_a##_i
+
+#define GMOCK_INTERNAL_A_MATCHER_ARGUMENT(_i, _Signature, _) \
+  GMOCK_PP_COMMA_IF(_i)                                      \
+  ::testing::A<GMOCK_INTERNAL_ARG_O(_i, GMOCK_PP_REMOVE_PARENS(_Signature))>()
+
+#define GMOCK_INTERNAL_ARG_O(_i, ...) \
+  typename ::testing::internal::Function<__VA_ARGS__>::template Arg<_i>::type
+
+#define GMOCK_INTERNAL_MATCHER_O(_i, ...)                          \
+  const ::testing::Matcher<typename ::testing::internal::Function< \
+      __VA_ARGS__>::template Arg<_i>::type>&
+
+#define MOCK_METHOD0(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 0, __VA_ARGS__)
+#define MOCK_METHOD1(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 1, __VA_ARGS__)
+#define MOCK_METHOD2(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 2, __VA_ARGS__)
+#define MOCK_METHOD3(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 3, __VA_ARGS__)
+#define MOCK_METHOD4(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 4, __VA_ARGS__)
+#define MOCK_METHOD5(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 5, __VA_ARGS__)
+#define MOCK_METHOD6(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 6, __VA_ARGS__)
+#define MOCK_METHOD7(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 7, __VA_ARGS__)
+#define MOCK_METHOD8(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 8, __VA_ARGS__)
+#define MOCK_METHOD9(m, ...) GMOCK_INTERNAL_MOCK_METHODN(, , m, 9, __VA_ARGS__)
+#define MOCK_METHOD10(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, , m, 10, __VA_ARGS__)
+
+#define MOCK_CONST_METHOD0(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 0, __VA_ARGS__)
+#define MOCK_CONST_METHOD1(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 1, __VA_ARGS__)
+#define MOCK_CONST_METHOD2(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 2, __VA_ARGS__)
+#define MOCK_CONST_METHOD3(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 3, __VA_ARGS__)
+#define MOCK_CONST_METHOD4(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 4, __VA_ARGS__)
+#define MOCK_CONST_METHOD5(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 5, __VA_ARGS__)
+#define MOCK_CONST_METHOD6(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 6, __VA_ARGS__)
+#define MOCK_CONST_METHOD7(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 7, __VA_ARGS__)
+#define MOCK_CONST_METHOD8(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 8, __VA_ARGS__)
+#define MOCK_CONST_METHOD9(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 9, __VA_ARGS__)
+#define MOCK_CONST_METHOD10(m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, , m, 10, __VA_ARGS__)
+
+#define MOCK_METHOD0_T(m, ...) MOCK_METHOD0(m, __VA_ARGS__)
+#define MOCK_METHOD1_T(m, ...) MOCK_METHOD1(m, __VA_ARGS__)
+#define MOCK_METHOD2_T(m, ...) MOCK_METHOD2(m, __VA_ARGS__)
+#define MOCK_METHOD3_T(m, ...) MOCK_METHOD3(m, __VA_ARGS__)
+#define MOCK_METHOD4_T(m, ...) MOCK_METHOD4(m, __VA_ARGS__)
+#define MOCK_METHOD5_T(m, ...) MOCK_METHOD5(m, __VA_ARGS__)
+#define MOCK_METHOD6_T(m, ...) MOCK_METHOD6(m, __VA_ARGS__)
+#define MOCK_METHOD7_T(m, ...) MOCK_METHOD7(m, __VA_ARGS__)
+#define MOCK_METHOD8_T(m, ...) MOCK_METHOD8(m, __VA_ARGS__)
+#define MOCK_METHOD9_T(m, ...) MOCK_METHOD9(m, __VA_ARGS__)
+#define MOCK_METHOD10_T(m, ...) MOCK_METHOD10(m, __VA_ARGS__)
+
+#define MOCK_CONST_METHOD0_T(m, ...) MOCK_CONST_METHOD0(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD1_T(m, ...) MOCK_CONST_METHOD1(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD2_T(m, ...) MOCK_CONST_METHOD2(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD3_T(m, ...) MOCK_CONST_METHOD3(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD4_T(m, ...) MOCK_CONST_METHOD4(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD5_T(m, ...) MOCK_CONST_METHOD5(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD6_T(m, ...) MOCK_CONST_METHOD6(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD7_T(m, ...) MOCK_CONST_METHOD7(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD8_T(m, ...) MOCK_CONST_METHOD8(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD9_T(m, ...) MOCK_CONST_METHOD9(m, __VA_ARGS__)
+#define MOCK_CONST_METHOD10_T(m, ...) MOCK_CONST_METHOD10(m, __VA_ARGS__)
+
+#define MOCK_METHOD0_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 0, __VA_ARGS__)
+#define MOCK_METHOD1_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 1, __VA_ARGS__)
+#define MOCK_METHOD2_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 2, __VA_ARGS__)
+#define MOCK_METHOD3_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 3, __VA_ARGS__)
+#define MOCK_METHOD4_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 4, __VA_ARGS__)
+#define MOCK_METHOD5_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 5, __VA_ARGS__)
+#define MOCK_METHOD6_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 6, __VA_ARGS__)
+#define MOCK_METHOD7_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 7, __VA_ARGS__)
+#define MOCK_METHOD8_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 8, __VA_ARGS__)
+#define MOCK_METHOD9_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 9, __VA_ARGS__)
+#define MOCK_METHOD10_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(, ct, m, 10, __VA_ARGS__)
+
+#define MOCK_CONST_METHOD0_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 0, __VA_ARGS__)
+#define MOCK_CONST_METHOD1_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 1, __VA_ARGS__)
+#define MOCK_CONST_METHOD2_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 2, __VA_ARGS__)
+#define MOCK_CONST_METHOD3_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 3, __VA_ARGS__)
+#define MOCK_CONST_METHOD4_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 4, __VA_ARGS__)
+#define MOCK_CONST_METHOD5_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 5, __VA_ARGS__)
+#define MOCK_CONST_METHOD6_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 6, __VA_ARGS__)
+#define MOCK_CONST_METHOD7_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 7, __VA_ARGS__)
+#define MOCK_CONST_METHOD8_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 8, __VA_ARGS__)
+#define MOCK_CONST_METHOD9_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 9, __VA_ARGS__)
+#define MOCK_CONST_METHOD10_WITH_CALLTYPE(ct, m, ...) \
+  GMOCK_INTERNAL_MOCK_METHODN(const, ct, m, 10, __VA_ARGS__)
+
+#define MOCK_METHOD0_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD0_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD1_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD1_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD2_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD2_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD3_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD3_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD4_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD4_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD5_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD5_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD6_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD6_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD7_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD7_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD8_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD8_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD9_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD9_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_METHOD10_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_METHOD10_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+
+#define MOCK_CONST_METHOD0_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD0_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD1_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD1_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD2_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD2_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD3_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD3_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD4_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD4_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD5_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD5_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD6_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD6_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD7_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD7_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD8_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD8_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD9_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD9_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+#define MOCK_CONST_METHOD10_T_WITH_CALLTYPE(ct, m, ...) \
+  MOCK_CONST_METHOD10_WITH_CALLTYPE(ct, m, __VA_ARGS__)
+
+#define GMOCK_INTERNAL_MOCK_METHODN(constness, ct, Method, args_num, ...) \
+  GMOCK_INTERNAL_ASSERT_VALID_SIGNATURE(                                  \
+      args_num, ::testing::internal::identity_t<__VA_ARGS__>);            \
+  GMOCK_INTERNAL_MOCK_METHOD_IMPL(                                        \
+      args_num, Method, GMOCK_PP_NARG0(constness), 0, 0, , ct, ,          \
+      (::testing::internal::identity_t<__VA_ARGS__>))
+
+#define GMOCK_MOCKER_(arity, constness, Method) \
+  GTEST_CONCAT_TOKEN_(gmock##constness##arity##_##Method##_, __LINE__)
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_GMOCK_FUNCTION_MOCKER_H_
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file implements some commonly used variadic actions.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_MORE_ACTIONS_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_MORE_ACTIONS_H_
+
+#include <memory>
+#include <utility>
+
+
+// Include any custom callback actions added by the local installation.
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_CUSTOM_GMOCK_GENERATED_ACTIONS_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_CUSTOM_GMOCK_GENERATED_ACTIONS_H_
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_INTERNAL_CUSTOM_GMOCK_GENERATED_ACTIONS_H_
+
+// Sometimes you want to give an action explicit template parameters
+// that cannot be inferred from its value parameters.  ACTION() and
+// ACTION_P*() don't support that.  ACTION_TEMPLATE() remedies that
+// and can be viewed as an extension to ACTION() and ACTION_P*().
+//
+// The syntax:
+//
+//   ACTION_TEMPLATE(ActionName,
+//                   HAS_m_TEMPLATE_PARAMS(kind1, name1, ..., kind_m, name_m),
+//                   AND_n_VALUE_PARAMS(p1, ..., p_n)) { statements; }
+//
+// defines an action template that takes m explicit template
+// parameters and n value parameters.  name_i is the name of the i-th
+// template parameter, and kind_i specifies whether it's a typename,
+// an integral constant, or a template.  p_i is the name of the i-th
+// value parameter.
+//
+// Example:
+//
+//   // DuplicateArg<k, T>(output) converts the k-th argument of the mock
+//   // function to type T and copies it to *output.
+//   ACTION_TEMPLATE(DuplicateArg,
+//                   HAS_2_TEMPLATE_PARAMS(int, k, typename, T),
+//                   AND_1_VALUE_PARAMS(output)) {
+//     *output = T(::std::get<k>(args));
+//   }
+//   ...
+//     int n;
+//     EXPECT_CALL(mock, Foo(_, _))
+//         .WillOnce(DuplicateArg<1, unsigned char>(&n));
+//
+// To create an instance of an action template, write:
+//
+//   ActionName<t1, ..., t_m>(v1, ..., v_n)
+//
+// where the ts are the template arguments and the vs are the value
+// arguments.  The value argument types are inferred by the compiler.
+// If you want to explicitly specify the value argument types, you can
+// provide additional template arguments:
+//
+//   ActionName<t1, ..., t_m, u1, ..., u_k>(v1, ..., v_n)
+//
+// where u_i is the desired type of v_i.
+//
+// ACTION_TEMPLATE and ACTION/ACTION_P* can be overloaded on the
+// number of value parameters, but not on the number of template
+// parameters.  Without the restriction, the meaning of the following
+// is unclear:
+//
+//   OverloadedAction<int, bool>(x);
+//
+// Are we using a single-template-parameter action where 'bool' refers
+// to the type of x, or are we using a two-template-parameter action
+// where the compiler is asked to infer the type of x?
+//
+// Implementation notes:
+//
+// GMOCK_INTERNAL_*_HAS_m_TEMPLATE_PARAMS and
+// GMOCK_INTERNAL_*_AND_n_VALUE_PARAMS are internal macros for
+// implementing ACTION_TEMPLATE.  The main trick we use is to create
+// new macro invocations when expanding a macro.  For example, we have
+//
+//   #define ACTION_TEMPLATE(name, template_params, value_params)
+//       ... GMOCK_INTERNAL_DECL_##template_params ...
+//
+// which causes ACTION_TEMPLATE(..., HAS_1_TEMPLATE_PARAMS(typename, T), ...)
+// to expand to
+//
+//       ... GMOCK_INTERNAL_DECL_HAS_1_TEMPLATE_PARAMS(typename, T) ...
+//
+// Since GMOCK_INTERNAL_DECL_HAS_1_TEMPLATE_PARAMS is a macro, the
+// preprocessor will continue to expand it to
+//
+//       ... typename T ...
+//
+// This technique conforms to the C++ standard and is portable.  It
+// allows us to implement action templates using O(N) code, where N is
+// the maximum number of template/value parameters supported.  Without
+// using it, we'd have to devote O(N^2) amount of code to implement all
+// combinations of m and n.
+
+// Declares the template parameters.
+#define GMOCK_INTERNAL_DECL_HAS_1_TEMPLATE_PARAMS(kind0, name0) kind0 name0
+#define GMOCK_INTERNAL_DECL_HAS_2_TEMPLATE_PARAMS(kind0, name0, kind1, \
+    name1) kind0 name0, kind1 name1
+#define GMOCK_INTERNAL_DECL_HAS_3_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2) kind0 name0, kind1 name1, kind2 name2
+#define GMOCK_INTERNAL_DECL_HAS_4_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3) kind0 name0, kind1 name1, kind2 name2, \
+    kind3 name3
+#define GMOCK_INTERNAL_DECL_HAS_5_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4) kind0 name0, kind1 name1, \
+    kind2 name2, kind3 name3, kind4 name4
+#define GMOCK_INTERNAL_DECL_HAS_6_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4, kind5, name5) kind0 name0, \
+    kind1 name1, kind2 name2, kind3 name3, kind4 name4, kind5 name5
+#define GMOCK_INTERNAL_DECL_HAS_7_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4, kind5, name5, kind6, \
+    name6) kind0 name0, kind1 name1, kind2 name2, kind3 name3, kind4 name4, \
+    kind5 name5, kind6 name6
+#define GMOCK_INTERNAL_DECL_HAS_8_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4, kind5, name5, kind6, name6, \
+    kind7, name7) kind0 name0, kind1 name1, kind2 name2, kind3 name3, \
+    kind4 name4, kind5 name5, kind6 name6, kind7 name7
+#define GMOCK_INTERNAL_DECL_HAS_9_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4, kind5, name5, kind6, name6, \
+    kind7, name7, kind8, name8) kind0 name0, kind1 name1, kind2 name2, \
+    kind3 name3, kind4 name4, kind5 name5, kind6 name6, kind7 name7, \
+    kind8 name8
+#define GMOCK_INTERNAL_DECL_HAS_10_TEMPLATE_PARAMS(kind0, name0, kind1, \
+    name1, kind2, name2, kind3, name3, kind4, name4, kind5, name5, kind6, \
+    name6, kind7, name7, kind8, name8, kind9, name9) kind0 name0, \
+    kind1 name1, kind2 name2, kind3 name3, kind4 name4, kind5 name5, \
+    kind6 name6, kind7 name7, kind8 name8, kind9 name9
+
+// Lists the template parameters.
+#define GMOCK_INTERNAL_LIST_HAS_1_TEMPLATE_PARAMS(kind0, name0) name0
+#define GMOCK_INTERNAL_LIST_HAS_2_TEMPLATE_PARAMS(kind0, name0, kind1, \
+    name1) name0, name1
+#define GMOCK_INTERNAL_LIST_HAS_3_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2) name0, name1, name2
+#define GMOCK_INTERNAL_LIST_HAS_4_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3) name0, name1, name2, name3
+#define GMOCK_INTERNAL_LIST_HAS_5_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4) name0, name1, name2, name3, \
+    name4
+#define GMOCK_INTERNAL_LIST_HAS_6_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4, kind5, name5) name0, name1, \
+    name2, name3, name4, name5
+#define GMOCK_INTERNAL_LIST_HAS_7_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4, kind5, name5, kind6, \
+    name6) name0, name1, name2, name3, name4, name5, name6
+#define GMOCK_INTERNAL_LIST_HAS_8_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4, kind5, name5, kind6, name6, \
+    kind7, name7) name0, name1, name2, name3, name4, name5, name6, name7
+#define GMOCK_INTERNAL_LIST_HAS_9_TEMPLATE_PARAMS(kind0, name0, kind1, name1, \
+    kind2, name2, kind3, name3, kind4, name4, kind5, name5, kind6, name6, \
+    kind7, name7, kind8, name8) name0, name1, name2, name3, name4, name5, \
+    name6, name7, name8
+#define GMOCK_INTERNAL_LIST_HAS_10_TEMPLATE_PARAMS(kind0, name0, kind1, \
+    name1, kind2, name2, kind3, name3, kind4, name4, kind5, name5, kind6, \
+    name6, kind7, name7, kind8, name8, kind9, name9) name0, name1, name2, \
+    name3, name4, name5, name6, name7, name8, name9
+
+// Declares the types of value parameters.
+#define GMOCK_INTERNAL_DECL_TYPE_AND_0_VALUE_PARAMS()
+#define GMOCK_INTERNAL_DECL_TYPE_AND_1_VALUE_PARAMS(p0) , typename p0##_type
+#define GMOCK_INTERNAL_DECL_TYPE_AND_2_VALUE_PARAMS(p0, p1) , \
+    typename p0##_type, typename p1##_type
+#define GMOCK_INTERNAL_DECL_TYPE_AND_3_VALUE_PARAMS(p0, p1, p2) , \
+    typename p0##_type, typename p1##_type, typename p2##_type
+#define GMOCK_INTERNAL_DECL_TYPE_AND_4_VALUE_PARAMS(p0, p1, p2, p3) , \
+    typename p0##_type, typename p1##_type, typename p2##_type, \
+    typename p3##_type
+#define GMOCK_INTERNAL_DECL_TYPE_AND_5_VALUE_PARAMS(p0, p1, p2, p3, p4) , \
+    typename p0##_type, typename p1##_type, typename p2##_type, \
+    typename p3##_type, typename p4##_type
+#define GMOCK_INTERNAL_DECL_TYPE_AND_6_VALUE_PARAMS(p0, p1, p2, p3, p4, p5) , \
+    typename p0##_type, typename p1##_type, typename p2##_type, \
+    typename p3##_type, typename p4##_type, typename p5##_type
+#define GMOCK_INTERNAL_DECL_TYPE_AND_7_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6) , typename p0##_type, typename p1##_type, typename p2##_type, \
+    typename p3##_type, typename p4##_type, typename p5##_type, \
+    typename p6##_type
+#define GMOCK_INTERNAL_DECL_TYPE_AND_8_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6, p7) , typename p0##_type, typename p1##_type, typename p2##_type, \
+    typename p3##_type, typename p4##_type, typename p5##_type, \
+    typename p6##_type, typename p7##_type
+#define GMOCK_INTERNAL_DECL_TYPE_AND_9_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6, p7, p8) , typename p0##_type, typename p1##_type, typename p2##_type, \
+    typename p3##_type, typename p4##_type, typename p5##_type, \
+    typename p6##_type, typename p7##_type, typename p8##_type
+#define GMOCK_INTERNAL_DECL_TYPE_AND_10_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6, p7, p8, p9) , typename p0##_type, typename p1##_type, \
+    typename p2##_type, typename p3##_type, typename p4##_type, \
+    typename p5##_type, typename p6##_type, typename p7##_type, \
+    typename p8##_type, typename p9##_type
+
+// Initializes the value parameters.
+#define GMOCK_INTERNAL_INIT_AND_0_VALUE_PARAMS()\
+    ()
+#define GMOCK_INTERNAL_INIT_AND_1_VALUE_PARAMS(p0)\
+    (p0##_type gmock_p0) : p0(::std::move(gmock_p0))
+#define GMOCK_INTERNAL_INIT_AND_2_VALUE_PARAMS(p0, p1)\
+    (p0##_type gmock_p0, p1##_type gmock_p1) : p0(::std::move(gmock_p0)), \
+        p1(::std::move(gmock_p1))
+#define GMOCK_INTERNAL_INIT_AND_3_VALUE_PARAMS(p0, p1, p2)\
+    (p0##_type gmock_p0, p1##_type gmock_p1, \
+        p2##_type gmock_p2) : p0(::std::move(gmock_p0)), \
+        p1(::std::move(gmock_p1)), p2(::std::move(gmock_p2))
+#define GMOCK_INTERNAL_INIT_AND_4_VALUE_PARAMS(p0, p1, p2, p3)\
+    (p0##_type gmock_p0, p1##_type gmock_p1, p2##_type gmock_p2, \
+        p3##_type gmock_p3) : p0(::std::move(gmock_p0)), \
+        p1(::std::move(gmock_p1)), p2(::std::move(gmock_p2)), \
+        p3(::std::move(gmock_p3))
+#define GMOCK_INTERNAL_INIT_AND_5_VALUE_PARAMS(p0, p1, p2, p3, p4)\
+    (p0##_type gmock_p0, p1##_type gmock_p1, p2##_type gmock_p2, \
+        p3##_type gmock_p3, p4##_type gmock_p4) : p0(::std::move(gmock_p0)), \
+        p1(::std::move(gmock_p1)), p2(::std::move(gmock_p2)), \
+        p3(::std::move(gmock_p3)), p4(::std::move(gmock_p4))
+#define GMOCK_INTERNAL_INIT_AND_6_VALUE_PARAMS(p0, p1, p2, p3, p4, p5)\
+    (p0##_type gmock_p0, p1##_type gmock_p1, p2##_type gmock_p2, \
+        p3##_type gmock_p3, p4##_type gmock_p4, \
+        p5##_type gmock_p5) : p0(::std::move(gmock_p0)), \
+        p1(::std::move(gmock_p1)), p2(::std::move(gmock_p2)), \
+        p3(::std::move(gmock_p3)), p4(::std::move(gmock_p4)), \
+        p5(::std::move(gmock_p5))
+#define GMOCK_INTERNAL_INIT_AND_7_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6)\
+    (p0##_type gmock_p0, p1##_type gmock_p1, p2##_type gmock_p2, \
+        p3##_type gmock_p3, p4##_type gmock_p4, p5##_type gmock_p5, \
+        p6##_type gmock_p6) : p0(::std::move(gmock_p0)), \
+        p1(::std::move(gmock_p1)), p2(::std::move(gmock_p2)), \
+        p3(::std::move(gmock_p3)), p4(::std::move(gmock_p4)), \
+        p5(::std::move(gmock_p5)), p6(::std::move(gmock_p6))
+#define GMOCK_INTERNAL_INIT_AND_8_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, p7)\
+    (p0##_type gmock_p0, p1##_type gmock_p1, p2##_type gmock_p2, \
+        p3##_type gmock_p3, p4##_type gmock_p4, p5##_type gmock_p5, \
+        p6##_type gmock_p6, p7##_type gmock_p7) : p0(::std::move(gmock_p0)), \
+        p1(::std::move(gmock_p1)), p2(::std::move(gmock_p2)), \
+        p3(::std::move(gmock_p3)), p4(::std::move(gmock_p4)), \
+        p5(::std::move(gmock_p5)), p6(::std::move(gmock_p6)), \
+        p7(::std::move(gmock_p7))
+#define GMOCK_INTERNAL_INIT_AND_9_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8)\
+    (p0##_type gmock_p0, p1##_type gmock_p1, p2##_type gmock_p2, \
+        p3##_type gmock_p3, p4##_type gmock_p4, p5##_type gmock_p5, \
+        p6##_type gmock_p6, p7##_type gmock_p7, \
+        p8##_type gmock_p8) : p0(::std::move(gmock_p0)), \
+        p1(::std::move(gmock_p1)), p2(::std::move(gmock_p2)), \
+        p3(::std::move(gmock_p3)), p4(::std::move(gmock_p4)), \
+        p5(::std::move(gmock_p5)), p6(::std::move(gmock_p6)), \
+        p7(::std::move(gmock_p7)), p8(::std::move(gmock_p8))
+#define GMOCK_INTERNAL_INIT_AND_10_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8, p9)\
+    (p0##_type gmock_p0, p1##_type gmock_p1, p2##_type gmock_p2, \
+        p3##_type gmock_p3, p4##_type gmock_p4, p5##_type gmock_p5, \
+        p6##_type gmock_p6, p7##_type gmock_p7, p8##_type gmock_p8, \
+        p9##_type gmock_p9) : p0(::std::move(gmock_p0)), \
+        p1(::std::move(gmock_p1)), p2(::std::move(gmock_p2)), \
+        p3(::std::move(gmock_p3)), p4(::std::move(gmock_p4)), \
+        p5(::std::move(gmock_p5)), p6(::std::move(gmock_p6)), \
+        p7(::std::move(gmock_p7)), p8(::std::move(gmock_p8)), \
+        p9(::std::move(gmock_p9))
+
+// Defines the copy constructor
+#define GMOCK_INTERNAL_DEFN_COPY_AND_0_VALUE_PARAMS() \
+    {}  // Avoid https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82134
+#define GMOCK_INTERNAL_DEFN_COPY_AND_1_VALUE_PARAMS(...) = default;
+#define GMOCK_INTERNAL_DEFN_COPY_AND_2_VALUE_PARAMS(...) = default;
+#define GMOCK_INTERNAL_DEFN_COPY_AND_3_VALUE_PARAMS(...) = default;
+#define GMOCK_INTERNAL_DEFN_COPY_AND_4_VALUE_PARAMS(...) = default;
+#define GMOCK_INTERNAL_DEFN_COPY_AND_5_VALUE_PARAMS(...) = default;
+#define GMOCK_INTERNAL_DEFN_COPY_AND_6_VALUE_PARAMS(...) = default;
+#define GMOCK_INTERNAL_DEFN_COPY_AND_7_VALUE_PARAMS(...) = default;
+#define GMOCK_INTERNAL_DEFN_COPY_AND_8_VALUE_PARAMS(...) = default;
+#define GMOCK_INTERNAL_DEFN_COPY_AND_9_VALUE_PARAMS(...) = default;
+#define GMOCK_INTERNAL_DEFN_COPY_AND_10_VALUE_PARAMS(...) = default;
+
+// Declares the fields for storing the value parameters.
+#define GMOCK_INTERNAL_DEFN_AND_0_VALUE_PARAMS()
+#define GMOCK_INTERNAL_DEFN_AND_1_VALUE_PARAMS(p0) p0##_type p0;
+#define GMOCK_INTERNAL_DEFN_AND_2_VALUE_PARAMS(p0, p1) p0##_type p0; \
+    p1##_type p1;
+#define GMOCK_INTERNAL_DEFN_AND_3_VALUE_PARAMS(p0, p1, p2) p0##_type p0; \
+    p1##_type p1; p2##_type p2;
+#define GMOCK_INTERNAL_DEFN_AND_4_VALUE_PARAMS(p0, p1, p2, p3) p0##_type p0; \
+    p1##_type p1; p2##_type p2; p3##_type p3;
+#define GMOCK_INTERNAL_DEFN_AND_5_VALUE_PARAMS(p0, p1, p2, p3, \
+    p4) p0##_type p0; p1##_type p1; p2##_type p2; p3##_type p3; p4##_type p4;
+#define GMOCK_INTERNAL_DEFN_AND_6_VALUE_PARAMS(p0, p1, p2, p3, p4, \
+    p5) p0##_type p0; p1##_type p1; p2##_type p2; p3##_type p3; p4##_type p4; \
+    p5##_type p5;
+#define GMOCK_INTERNAL_DEFN_AND_7_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6) p0##_type p0; p1##_type p1; p2##_type p2; p3##_type p3; p4##_type p4; \
+    p5##_type p5; p6##_type p6;
+#define GMOCK_INTERNAL_DEFN_AND_8_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7) p0##_type p0; p1##_type p1; p2##_type p2; p3##_type p3; p4##_type p4; \
+    p5##_type p5; p6##_type p6; p7##_type p7;
+#define GMOCK_INTERNAL_DEFN_AND_9_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8) p0##_type p0; p1##_type p1; p2##_type p2; p3##_type p3; \
+    p4##_type p4; p5##_type p5; p6##_type p6; p7##_type p7; p8##_type p8;
+#define GMOCK_INTERNAL_DEFN_AND_10_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8, p9) p0##_type p0; p1##_type p1; p2##_type p2; p3##_type p3; \
+    p4##_type p4; p5##_type p5; p6##_type p6; p7##_type p7; p8##_type p8; \
+    p9##_type p9;
+
+// Lists the value parameters.
+#define GMOCK_INTERNAL_LIST_AND_0_VALUE_PARAMS()
+#define GMOCK_INTERNAL_LIST_AND_1_VALUE_PARAMS(p0) p0
+#define GMOCK_INTERNAL_LIST_AND_2_VALUE_PARAMS(p0, p1) p0, p1
+#define GMOCK_INTERNAL_LIST_AND_3_VALUE_PARAMS(p0, p1, p2) p0, p1, p2
+#define GMOCK_INTERNAL_LIST_AND_4_VALUE_PARAMS(p0, p1, p2, p3) p0, p1, p2, p3
+#define GMOCK_INTERNAL_LIST_AND_5_VALUE_PARAMS(p0, p1, p2, p3, p4) p0, p1, \
+    p2, p3, p4
+#define GMOCK_INTERNAL_LIST_AND_6_VALUE_PARAMS(p0, p1, p2, p3, p4, p5) p0, \
+    p1, p2, p3, p4, p5
+#define GMOCK_INTERNAL_LIST_AND_7_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6) p0, p1, p2, p3, p4, p5, p6
+#define GMOCK_INTERNAL_LIST_AND_8_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7) p0, p1, p2, p3, p4, p5, p6, p7
+#define GMOCK_INTERNAL_LIST_AND_9_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8) p0, p1, p2, p3, p4, p5, p6, p7, p8
+#define GMOCK_INTERNAL_LIST_AND_10_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8, p9) p0, p1, p2, p3, p4, p5, p6, p7, p8, p9
+
+// Lists the value parameter types.
+#define GMOCK_INTERNAL_LIST_TYPE_AND_0_VALUE_PARAMS()
+#define GMOCK_INTERNAL_LIST_TYPE_AND_1_VALUE_PARAMS(p0) , p0##_type
+#define GMOCK_INTERNAL_LIST_TYPE_AND_2_VALUE_PARAMS(p0, p1) , p0##_type, \
+    p1##_type
+#define GMOCK_INTERNAL_LIST_TYPE_AND_3_VALUE_PARAMS(p0, p1, p2) , p0##_type, \
+    p1##_type, p2##_type
+#define GMOCK_INTERNAL_LIST_TYPE_AND_4_VALUE_PARAMS(p0, p1, p2, p3) , \
+    p0##_type, p1##_type, p2##_type, p3##_type
+#define GMOCK_INTERNAL_LIST_TYPE_AND_5_VALUE_PARAMS(p0, p1, p2, p3, p4) , \
+    p0##_type, p1##_type, p2##_type, p3##_type, p4##_type
+#define GMOCK_INTERNAL_LIST_TYPE_AND_6_VALUE_PARAMS(p0, p1, p2, p3, p4, p5) , \
+    p0##_type, p1##_type, p2##_type, p3##_type, p4##_type, p5##_type
+#define GMOCK_INTERNAL_LIST_TYPE_AND_7_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6) , p0##_type, p1##_type, p2##_type, p3##_type, p4##_type, p5##_type, \
+    p6##_type
+#define GMOCK_INTERNAL_LIST_TYPE_AND_8_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6, p7) , p0##_type, p1##_type, p2##_type, p3##_type, p4##_type, \
+    p5##_type, p6##_type, p7##_type
+#define GMOCK_INTERNAL_LIST_TYPE_AND_9_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6, p7, p8) , p0##_type, p1##_type, p2##_type, p3##_type, p4##_type, \
+    p5##_type, p6##_type, p7##_type, p8##_type
+#define GMOCK_INTERNAL_LIST_TYPE_AND_10_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6, p7, p8, p9) , p0##_type, p1##_type, p2##_type, p3##_type, p4##_type, \
+    p5##_type, p6##_type, p7##_type, p8##_type, p9##_type
+
+// Declares the value parameters.
+#define GMOCK_INTERNAL_DECL_AND_0_VALUE_PARAMS()
+#define GMOCK_INTERNAL_DECL_AND_1_VALUE_PARAMS(p0) p0##_type p0
+#define GMOCK_INTERNAL_DECL_AND_2_VALUE_PARAMS(p0, p1) p0##_type p0, \
+    p1##_type p1
+#define GMOCK_INTERNAL_DECL_AND_3_VALUE_PARAMS(p0, p1, p2) p0##_type p0, \
+    p1##_type p1, p2##_type p2
+#define GMOCK_INTERNAL_DECL_AND_4_VALUE_PARAMS(p0, p1, p2, p3) p0##_type p0, \
+    p1##_type p1, p2##_type p2, p3##_type p3
+#define GMOCK_INTERNAL_DECL_AND_5_VALUE_PARAMS(p0, p1, p2, p3, \
+    p4) p0##_type p0, p1##_type p1, p2##_type p2, p3##_type p3, p4##_type p4
+#define GMOCK_INTERNAL_DECL_AND_6_VALUE_PARAMS(p0, p1, p2, p3, p4, \
+    p5) p0##_type p0, p1##_type p1, p2##_type p2, p3##_type p3, p4##_type p4, \
+    p5##_type p5
+#define GMOCK_INTERNAL_DECL_AND_7_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, \
+    p6) p0##_type p0, p1##_type p1, p2##_type p2, p3##_type p3, p4##_type p4, \
+    p5##_type p5, p6##_type p6
+#define GMOCK_INTERNAL_DECL_AND_8_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7) p0##_type p0, p1##_type p1, p2##_type p2, p3##_type p3, p4##_type p4, \
+    p5##_type p5, p6##_type p6, p7##_type p7
+#define GMOCK_INTERNAL_DECL_AND_9_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8) p0##_type p0, p1##_type p1, p2##_type p2, p3##_type p3, \
+    p4##_type p4, p5##_type p5, p6##_type p6, p7##_type p7, p8##_type p8
+#define GMOCK_INTERNAL_DECL_AND_10_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8, p9) p0##_type p0, p1##_type p1, p2##_type p2, p3##_type p3, \
+    p4##_type p4, p5##_type p5, p6##_type p6, p7##_type p7, p8##_type p8, \
+    p9##_type p9
+
+// The suffix of the class template implementing the action template.
+#define GMOCK_INTERNAL_COUNT_AND_0_VALUE_PARAMS()
+#define GMOCK_INTERNAL_COUNT_AND_1_VALUE_PARAMS(p0) P
+#define GMOCK_INTERNAL_COUNT_AND_2_VALUE_PARAMS(p0, p1) P2
+#define GMOCK_INTERNAL_COUNT_AND_3_VALUE_PARAMS(p0, p1, p2) P3
+#define GMOCK_INTERNAL_COUNT_AND_4_VALUE_PARAMS(p0, p1, p2, p3) P4
+#define GMOCK_INTERNAL_COUNT_AND_5_VALUE_PARAMS(p0, p1, p2, p3, p4) P5
+#define GMOCK_INTERNAL_COUNT_AND_6_VALUE_PARAMS(p0, p1, p2, p3, p4, p5) P6
+#define GMOCK_INTERNAL_COUNT_AND_7_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6) P7
+#define GMOCK_INTERNAL_COUNT_AND_8_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7) P8
+#define GMOCK_INTERNAL_COUNT_AND_9_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8) P9
+#define GMOCK_INTERNAL_COUNT_AND_10_VALUE_PARAMS(p0, p1, p2, p3, p4, p5, p6, \
+    p7, p8, p9) P10
+
+// The name of the class template implementing the action template.
+#define GMOCK_ACTION_CLASS_(name, value_params)\
+    GTEST_CONCAT_TOKEN_(name##Action, GMOCK_INTERNAL_COUNT_##value_params)
+
+#define ACTION_TEMPLATE(name, template_params, value_params)                   \
+  template <GMOCK_INTERNAL_DECL_##template_params                              \
+            GMOCK_INTERNAL_DECL_TYPE_##value_params>                           \
+  class GMOCK_ACTION_CLASS_(name, value_params) {                              \
+   public:                                                                     \
+    explicit GMOCK_ACTION_CLASS_(name, value_params)(                          \
+        GMOCK_INTERNAL_DECL_##value_params)                                    \
+        GMOCK_PP_IF(GMOCK_PP_IS_EMPTY(GMOCK_INTERNAL_COUNT_##value_params),    \
+                    = default; ,                                               \
+                    : impl_(std::make_shared<gmock_Impl>(                      \
+                                GMOCK_INTERNAL_LIST_##value_params)) { })      \
+    GMOCK_ACTION_CLASS_(name, value_params)(                                   \
+        const GMOCK_ACTION_CLASS_(name, value_params)&) noexcept               \
+        GMOCK_INTERNAL_DEFN_COPY_##value_params                                \
+    GMOCK_ACTION_CLASS_(name, value_params)(                                   \
+        GMOCK_ACTION_CLASS_(name, value_params)&&) noexcept                    \
+        GMOCK_INTERNAL_DEFN_COPY_##value_params                                \
+    template <typename F>                                                      \
+    operator ::testing::Action<F>() const {                                    \
+      return GMOCK_PP_IF(                                                      \
+          GMOCK_PP_IS_EMPTY(GMOCK_INTERNAL_COUNT_##value_params),              \
+                      (::testing::internal::MakeAction<F, gmock_Impl>()),      \
+                      (::testing::internal::MakeAction<F>(impl_)));            \
+    }                                                                          \
+   private:                                                                    \
+    class gmock_Impl {                                                         \
+     public:                                                                   \
+      explicit gmock_Impl GMOCK_INTERNAL_INIT_##value_params {}                \
+      template <typename function_type, typename return_type,                  \
+                typename args_type, GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>         \
+      return_type gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_) const;  \
+      GMOCK_INTERNAL_DEFN_##value_params                                       \
+    };                                                                         \
+    GMOCK_PP_IF(GMOCK_PP_IS_EMPTY(GMOCK_INTERNAL_COUNT_##value_params),        \
+                , std::shared_ptr<const gmock_Impl> impl_;)                    \
+  };                                                                           \
+  template <GMOCK_INTERNAL_DECL_##template_params                              \
+            GMOCK_INTERNAL_DECL_TYPE_##value_params>                           \
+  GMOCK_ACTION_CLASS_(name, value_params)<                                     \
+      GMOCK_INTERNAL_LIST_##template_params                                    \
+      GMOCK_INTERNAL_LIST_TYPE_##value_params> name(                           \
+          GMOCK_INTERNAL_DECL_##value_params) GTEST_MUST_USE_RESULT_;          \
+  template <GMOCK_INTERNAL_DECL_##template_params                              \
+            GMOCK_INTERNAL_DECL_TYPE_##value_params>                           \
+  inline GMOCK_ACTION_CLASS_(name, value_params)<                              \
+      GMOCK_INTERNAL_LIST_##template_params                                    \
+      GMOCK_INTERNAL_LIST_TYPE_##value_params> name(                           \
+          GMOCK_INTERNAL_DECL_##value_params) {                                \
+    return GMOCK_ACTION_CLASS_(name, value_params)<                            \
+        GMOCK_INTERNAL_LIST_##template_params                                  \
+        GMOCK_INTERNAL_LIST_TYPE_##value_params>(                              \
+            GMOCK_INTERNAL_LIST_##value_params);                               \
+  }                                                                            \
+  template <GMOCK_INTERNAL_DECL_##template_params                              \
+            GMOCK_INTERNAL_DECL_TYPE_##value_params>                           \
+  template <typename function_type, typename return_type, typename args_type,  \
+            GMOCK_ACTION_TEMPLATE_ARGS_NAMES_>                                 \
+  return_type GMOCK_ACTION_CLASS_(name, value_params)<                         \
+      GMOCK_INTERNAL_LIST_##template_params                                    \
+      GMOCK_INTERNAL_LIST_TYPE_##value_params>::gmock_Impl::gmock_PerformImpl( \
+          GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_) const
+
+namespace testing {
+
+// The ACTION*() macros trigger warning C4100 (unreferenced formal
+// parameter) in MSVC with -W4.  Unfortunately they cannot be fixed in
+// the macro definition, as the warnings are generated when the macro
+// is expanded and macro expansion cannot contain #pragma.  Therefore
+// we suppress them here.
+#ifdef _MSC_VER
+# pragma warning(push)
+# pragma warning(disable:4100)
+#endif
+
+namespace internal {
+
+// internal::InvokeArgument - a helper for InvokeArgument action.
+// The basic overloads are provided here for generic functors.
+// Overloads for other custom-callables are provided in the
+// internal/custom/gmock-generated-actions.h header.
+template <typename F, typename... Args>
+auto InvokeArgument(F f, Args... args) -> decltype(f(args...)) {
+  return f(args...);
+}
+
+template <std::size_t index, typename... Params>
+struct InvokeArgumentAction {
+  template <typename... Args>
+  auto operator()(Args&&... args) const -> decltype(internal::InvokeArgument(
+      std::get<index>(std::forward_as_tuple(std::forward<Args>(args)...)),
+      std::declval<const Params&>()...)) {
+    internal::FlatTuple<Args&&...> args_tuple(FlatTupleConstructTag{},
+                                              std::forward<Args>(args)...);
+    return params.Apply([&](const Params&... unpacked_params) {
+      auto&& callable = args_tuple.template Get<index>();
+      return internal::InvokeArgument(
+          std::forward<decltype(callable)>(callable), unpacked_params...);
+    });
+  }
+
+  internal::FlatTuple<Params...> params;
+};
+
+}  // namespace internal
+
+// The InvokeArgument<N>(a1, a2, ..., a_k) action invokes the N-th
+// (0-based) argument, which must be a k-ary callable, of the mock
+// function, with arguments a1, a2, ..., a_k.
+//
+// Notes:
+//
+//   1. The arguments are passed by value by default.  If you need to
+//   pass an argument by reference, wrap it inside std::ref().  For
+//   example,
+//
+//     InvokeArgument<1>(5, string("Hello"), std::ref(foo))
+//
+//   passes 5 and string("Hello") by value, and passes foo by
+//   reference.
+//
+//   2. If the callable takes an argument by reference but std::ref() is
+//   not used, it will receive the reference to a copy of the value,
+//   instead of the original value.  For example, when the 0-th
+//   argument of the mock function takes a const string&, the action
+//
+//     InvokeArgument<0>(string("Hello"))
+//
+//   makes a copy of the temporary string("Hello") object and passes a
+//   reference of the copy, instead of the original temporary object,
+//   to the callable.  This makes it easy for a user to define an
+//   InvokeArgument action from temporary values and have it performed
+//   later.
+template <std::size_t index, typename... Params>
+internal::InvokeArgumentAction<index, typename std::decay<Params>::type...>
+InvokeArgument(Params&&... params) {
+  return {internal::FlatTuple<typename std::decay<Params>::type...>(
+      internal::FlatTupleConstructTag{}, std::forward<Params>(params)...)};
+}
+
+#ifdef _MSC_VER
+# pragma warning(pop)
+#endif
+
+}  // namespace testing
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_MORE_ACTIONS_H_
+// Copyright 2013, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file implements some matchers that depend on gmock-matchers.h.
+//
+// Note that tests are implemented in gmock-matchers_test.cc rather than
+// gmock-more-matchers-test.cc.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_MORE_MATCHERS_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_MORE_MATCHERS_H_
+
+
+namespace testing {
+
+// Silence C4100 (unreferenced formal
+// parameter) for MSVC
+#ifdef _MSC_VER
+# pragma warning(push)
+# pragma warning(disable:4100)
+#if (_MSC_VER == 1900)
+// and silence C4800 (C4800: 'int *const ': forcing value
+// to bool 'true' or 'false') for MSVC 14
+# pragma warning(disable:4800)
+  #endif
+#endif
+
+// Defines a matcher that matches an empty container. The container must
+// support both size() and empty(), which all STL-like containers provide.
+MATCHER(IsEmpty, negation ? "isn't empty" : "is empty") {
+  if (arg.empty()) {
+    return true;
+  }
+  *result_listener << "whose size is " << arg.size();
+  return false;
+}
+
+// Define a matcher that matches a value that evaluates in boolean
+// context to true.  Useful for types that define "explicit operator
+// bool" operators and so can't be compared for equality with true
+// and false.
+MATCHER(IsTrue, negation ? "is false" : "is true") {
+  return static_cast<bool>(arg);
+}
+
+// Define a matcher that matches a value that evaluates in boolean
+// context to false.  Useful for types that define "explicit operator
+// bool" operators and so can't be compared for equality with true
+// and false.
+MATCHER(IsFalse, negation ? "is true" : "is false") {
+  return !static_cast<bool>(arg);
+}
+
+#ifdef _MSC_VER
+# pragma warning(pop)
+#endif
+
+
+}  // namespace testing
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_MORE_MATCHERS_H_
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Implements class templates NiceMock, NaggyMock, and StrictMock.
+//
+// Given a mock class MockFoo that is created using Google Mock,
+// NiceMock<MockFoo> is a subclass of MockFoo that allows
+// uninteresting calls (i.e. calls to mock methods that have no
+// EXPECT_CALL specs), NaggyMock<MockFoo> is a subclass of MockFoo
+// that prints a warning when an uninteresting call occurs, and
+// StrictMock<MockFoo> is a subclass of MockFoo that treats all
+// uninteresting calls as errors.
+//
+// Currently a mock is naggy by default, so MockFoo and
+// NaggyMock<MockFoo> behave like the same.  However, we will soon
+// switch the default behavior of mocks to be nice, as that in general
+// leads to more maintainable tests.  When that happens, MockFoo will
+// stop behaving like NaggyMock<MockFoo> and start behaving like
+// NiceMock<MockFoo>.
+//
+// NiceMock, NaggyMock, and StrictMock "inherit" the constructors of
+// their respective base class.  Therefore you can write
+// NiceMock<MockFoo>(5, "a") to construct a nice mock where MockFoo
+// has a constructor that accepts (int, const char*), for example.
+//
+// A known limitation is that NiceMock<MockFoo>, NaggyMock<MockFoo>,
+// and StrictMock<MockFoo> only works for mock methods defined using
+// the MOCK_METHOD* family of macros DIRECTLY in the MockFoo class.
+// If a mock method is defined in a base class of MockFoo, the "nice"
+// or "strict" modifier may not affect it, depending on the compiler.
+// In particular, nesting NiceMock, NaggyMock, and StrictMock is NOT
+// supported.
+
+// GOOGLETEST_CM0002 DO NOT DELETE
+
+#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_NICE_STRICT_H_
+#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_NICE_STRICT_H_
+
+#include <type_traits>
+
+
+namespace testing {
+template <class MockClass>
+class NiceMock;
+template <class MockClass>
+class NaggyMock;
+template <class MockClass>
+class StrictMock;
+
+namespace internal {
+template <typename T>
+std::true_type StrictnessModifierProbe(const NiceMock<T>&);
+template <typename T>
+std::true_type StrictnessModifierProbe(const NaggyMock<T>&);
+template <typename T>
+std::true_type StrictnessModifierProbe(const StrictMock<T>&);
+std::false_type StrictnessModifierProbe(...);
+
+template <typename T>
+constexpr bool HasStrictnessModifier() {
+  return decltype(StrictnessModifierProbe(std::declval<const T&>()))::value;
+}
+
+// Base classes that register and deregister with testing::Mock to alter the
+// default behavior around uninteresting calls. Inheriting from one of these
+// classes first and then MockClass ensures the MockClass constructor is run
+// after registration, and that the MockClass destructor runs before
+// deregistration. This guarantees that MockClass's constructor and destructor
+// run with the same level of strictness as its instance methods.
+
+#if GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MINGW && \
+    (defined(_MSC_VER) || defined(__clang__))
+// We need to mark these classes with this declspec to ensure that
+// the empty base class optimization is performed.
+#define GTEST_INTERNAL_EMPTY_BASE_CLASS __declspec(empty_bases)
+#else
+#define GTEST_INTERNAL_EMPTY_BASE_CLASS
+#endif
+
+template <typename Base>
+class NiceMockImpl {
+ public:
+  NiceMockImpl() { ::testing::Mock::AllowUninterestingCalls(this); }
+
+  ~NiceMockImpl() { ::testing::Mock::UnregisterCallReaction(this); }
+};
+
+template <typename Base>
+class NaggyMockImpl {
+ public:
+  NaggyMockImpl() { ::testing::Mock::WarnUninterestingCalls(this); }
+
+  ~NaggyMockImpl() { ::testing::Mock::UnregisterCallReaction(this); }
+};
+
+template <typename Base>
+class StrictMockImpl {
+ public:
+  StrictMockImpl() { ::testing::Mock::FailUninterestingCalls(this); }
+
+  ~StrictMockImpl() { ::testing::Mock::UnregisterCallReaction(this); }
+};
+
+}  // namespace internal
+
+template <class MockClass>
+class GTEST_INTERNAL_EMPTY_BASE_CLASS NiceMock
+    : private internal::NiceMockImpl<MockClass>,
+      public MockClass {
+ public:
+  static_assert(!internal::HasStrictnessModifier<MockClass>(),
+                "Can't apply NiceMock to a class hierarchy that already has a "
+                "strictness modifier. See "
+                "https://google.github.io/googletest/"
+                "gmock_cook_book.html#NiceStrictNaggy");
+  NiceMock() : MockClass() {
+    static_assert(sizeof(*this) == sizeof(MockClass),
+                  "The impl subclass shouldn't introduce any padding");
+  }
+
+  // Ideally, we would inherit base class's constructors through a using
+  // declaration, which would preserve their visibility. However, many existing
+  // tests rely on the fact that current implementation reexports protected
+  // constructors as public. These tests would need to be cleaned up first.
+
+  // Single argument constructor is special-cased so that it can be
+  // made explicit.
+  template <typename A>
+  explicit NiceMock(A&& arg) : MockClass(std::forward<A>(arg)) {
+    static_assert(sizeof(*this) == sizeof(MockClass),
+                  "The impl subclass shouldn't introduce any padding");
+  }
+
+  template <typename TArg1, typename TArg2, typename... An>
+  NiceMock(TArg1&& arg1, TArg2&& arg2, An&&... args)
+      : MockClass(std::forward<TArg1>(arg1), std::forward<TArg2>(arg2),
+                  std::forward<An>(args)...) {
+    static_assert(sizeof(*this) == sizeof(MockClass),
+                  "The impl subclass shouldn't introduce any padding");
+  }
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(NiceMock);
+};
+
+template <class MockClass>
+class GTEST_INTERNAL_EMPTY_BASE_CLASS NaggyMock
+    : private internal::NaggyMockImpl<MockClass>,
+      public MockClass {
+  static_assert(!internal::HasStrictnessModifier<MockClass>(),
+                "Can't apply NaggyMock to a class hierarchy that already has a "
+                "strictness modifier. See "
+                "https://google.github.io/googletest/"
+                "gmock_cook_book.html#NiceStrictNaggy");
+
+ public:
+  NaggyMock() : MockClass() {
+    static_assert(sizeof(*this) == sizeof(MockClass),
+                  "The impl subclass shouldn't introduce any padding");
+  }
+
+  // Ideally, we would inherit base class's constructors through a using
+  // declaration, which would preserve their visibility. However, many existing
+  // tests rely on the fact that current implementation reexports protected
+  // constructors as public. These tests would need to be cleaned up first.
+
+  // Single argument constructor is special-cased so that it can be
+  // made explicit.
+  template <typename A>
+  explicit NaggyMock(A&& arg) : MockClass(std::forward<A>(arg)) {
+    static_assert(sizeof(*this) == sizeof(MockClass),
+                  "The impl subclass shouldn't introduce any padding");
+  }
+
+  template <typename TArg1, typename TArg2, typename... An>
+  NaggyMock(TArg1&& arg1, TArg2&& arg2, An&&... args)
+      : MockClass(std::forward<TArg1>(arg1), std::forward<TArg2>(arg2),
+                  std::forward<An>(args)...) {
+    static_assert(sizeof(*this) == sizeof(MockClass),
+                  "The impl subclass shouldn't introduce any padding");
+  }
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(NaggyMock);
+};
+
+template <class MockClass>
+class GTEST_INTERNAL_EMPTY_BASE_CLASS StrictMock
+    : private internal::StrictMockImpl<MockClass>,
+      public MockClass {
+ public:
+  static_assert(
+      !internal::HasStrictnessModifier<MockClass>(),
+      "Can't apply StrictMock to a class hierarchy that already has a "
+      "strictness modifier. See "
+      "https://google.github.io/googletest/"
+      "gmock_cook_book.html#NiceStrictNaggy");
+  StrictMock() : MockClass() {
+    static_assert(sizeof(*this) == sizeof(MockClass),
+                  "The impl subclass shouldn't introduce any padding");
+  }
+
+  // Ideally, we would inherit base class's constructors through a using
+  // declaration, which would preserve their visibility. However, many existing
+  // tests rely on the fact that current implementation reexports protected
+  // constructors as public. These tests would need to be cleaned up first.
+
+  // Single argument constructor is special-cased so that it can be
+  // made explicit.
+  template <typename A>
+  explicit StrictMock(A&& arg) : MockClass(std::forward<A>(arg)) {
+    static_assert(sizeof(*this) == sizeof(MockClass),
+                  "The impl subclass shouldn't introduce any padding");
+  }
+
+  template <typename TArg1, typename TArg2, typename... An>
+  StrictMock(TArg1&& arg1, TArg2&& arg2, An&&... args)
+      : MockClass(std::forward<TArg1>(arg1), std::forward<TArg2>(arg2),
+                  std::forward<An>(args)...) {
+    static_assert(sizeof(*this) == sizeof(MockClass),
+                  "The impl subclass shouldn't introduce any padding");
+  }
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(StrictMock);
+};
+
+#undef GTEST_INTERNAL_EMPTY_BASE_CLASS
+
+}  // namespace testing
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_NICE_STRICT_H_
+
+namespace testing {
+
+// Declares Google Mock flags that we want a user to use programmatically.
+GMOCK_DECLARE_bool_(catch_leaked_mocks);
+GMOCK_DECLARE_string_(verbose);
+GMOCK_DECLARE_int32_(default_mock_behavior);
+
+// Initializes Google Mock.  This must be called before running the
+// tests.  In particular, it parses the command line for the flags
+// that Google Mock recognizes.  Whenever a Google Mock flag is seen,
+// it is removed from argv, and *argc is decremented.
+//
+// No value is returned.  Instead, the Google Mock flag variables are
+// updated.
+//
+// Since Google Test is needed for Google Mock to work, this function
+// also initializes Google Test and parses its flags, if that hasn't
+// been done.
+GTEST_API_ void InitGoogleMock(int* argc, char** argv);
+
+// This overloaded version can be used in Windows programs compiled in
+// UNICODE mode.
+GTEST_API_ void InitGoogleMock(int* argc, wchar_t** argv);
+
+// This overloaded version can be used on Arduino/embedded platforms where
+// there is no argc/argv.
+GTEST_API_ void InitGoogleMock();
+
+}  // namespace testing
+
+#endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_H_
diff --git a/src/fmt/test/gtest/gtest/gtest-spi.h b/src/fmt/test/gtest/gtest/gtest-spi.h
new file mode 100644
index 000000000..eacef4466
--- /dev/null
+++ b/src/fmt/test/gtest/gtest/gtest-spi.h
@@ -0,0 +1,238 @@
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// Utilities for testing Google Test itself and code that uses Google Test
+// (e.g. frameworks built on top of Google Test).
+
+// GOOGLETEST_CM0004 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_SPI_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_SPI_H_
+
+#include "gtest/gtest.h"
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+namespace testing {
+
+// This helper class can be used to mock out Google Test failure reporting
+// so that we can test Google Test or code that builds on Google Test.
+//
+// An object of this class appends a TestPartResult object to the
+// TestPartResultArray object given in the constructor whenever a Google Test
+// failure is reported. It can either intercept only failures that are
+// generated in the same thread that created this object or it can intercept
+// all generated failures. The scope of this mock object can be controlled with
+// the second argument to the two arguments constructor.
+class GTEST_API_ ScopedFakeTestPartResultReporter
+    : public TestPartResultReporterInterface {
+ public:
+  // The two possible mocking modes of this object.
+  enum InterceptMode {
+    INTERCEPT_ONLY_CURRENT_THREAD,  // Intercepts only thread local failures.
+    INTERCEPT_ALL_THREADS           // Intercepts all failures.
+  };
+
+  // The c'tor sets this object as the test part result reporter used
+  // by Google Test.  The 'result' parameter specifies where to report the
+  // results. This reporter will only catch failures generated in the current
+  // thread. DEPRECATED
+  explicit ScopedFakeTestPartResultReporter(TestPartResultArray* result);
+
+  // Same as above, but you can choose the interception scope of this object.
+  ScopedFakeTestPartResultReporter(InterceptMode intercept_mode,
+                                   TestPartResultArray* result);
+
+  // The d'tor restores the previous test part result reporter.
+  ~ScopedFakeTestPartResultReporter() override;
+
+  // Appends the TestPartResult object to the TestPartResultArray
+  // received in the constructor.
+  //
+  // This method is from the TestPartResultReporterInterface
+  // interface.
+  void ReportTestPartResult(const TestPartResult& result) override;
+
+ private:
+  void Init();
+
+  const InterceptMode intercept_mode_;
+  TestPartResultReporterInterface* old_reporter_;
+  TestPartResultArray* const result_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ScopedFakeTestPartResultReporter);
+};
+
+namespace internal {
+
+// A helper class for implementing EXPECT_FATAL_FAILURE() and
+// EXPECT_NONFATAL_FAILURE().  Its destructor verifies that the given
+// TestPartResultArray contains exactly one failure that has the given
+// type and contains the given substring.  If that's not the case, a
+// non-fatal failure will be generated.
+class GTEST_API_ SingleFailureChecker {
+ public:
+  // The constructor remembers the arguments.
+  SingleFailureChecker(const TestPartResultArray* results,
+                       TestPartResult::Type type, const std::string& substr);
+  ~SingleFailureChecker();
+ private:
+  const TestPartResultArray* const results_;
+  const TestPartResult::Type type_;
+  const std::string substr_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(SingleFailureChecker);
+};
+
+}  // namespace internal
+
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+// A set of macros for testing Google Test assertions or code that's expected
+// to generate Google Test fatal failures.  It verifies that the given
+// statement will cause exactly one fatal Google Test failure with 'substr'
+// being part of the failure message.
+//
+// There are two different versions of this macro. EXPECT_FATAL_FAILURE only
+// affects and considers failures generated in the current thread and
+// EXPECT_FATAL_FAILURE_ON_ALL_THREADS does the same but for all threads.
+//
+// The verification of the assertion is done correctly even when the statement
+// throws an exception or aborts the current function.
+//
+// Known restrictions:
+//   - 'statement' cannot reference local non-static variables or
+//     non-static members of the current object.
+//   - 'statement' cannot return a value.
+//   - You cannot stream a failure message to this macro.
+//
+// Note that even though the implementations of the following two
+// macros are much alike, we cannot refactor them to use a common
+// helper macro, due to some peculiarity in how the preprocessor
+// works.  The AcceptsMacroThatExpandsToUnprotectedComma test in
+// gtest_unittest.cc will fail to compile if we do that.
+#define EXPECT_FATAL_FAILURE(statement, substr) \
+  do { \
+    class GTestExpectFatalFailureHelper {\
+     public:\
+      static void Execute() { statement; }\
+    };\
+    ::testing::TestPartResultArray gtest_failures;\
+    ::testing::internal::SingleFailureChecker gtest_checker(\
+        &gtest_failures, ::testing::TestPartResult::kFatalFailure, (substr));\
+    {\
+      ::testing::ScopedFakeTestPartResultReporter gtest_reporter(\
+          ::testing::ScopedFakeTestPartResultReporter:: \
+          INTERCEPT_ONLY_CURRENT_THREAD, &gtest_failures);\
+      GTestExpectFatalFailureHelper::Execute();\
+    }\
+  } while (::testing::internal::AlwaysFalse())
+
+#define EXPECT_FATAL_FAILURE_ON_ALL_THREADS(statement, substr) \
+  do { \
+    class GTestExpectFatalFailureHelper {\
+     public:\
+      static void Execute() { statement; }\
+    };\
+    ::testing::TestPartResultArray gtest_failures;\
+    ::testing::internal::SingleFailureChecker gtest_checker(\
+        &gtest_failures, ::testing::TestPartResult::kFatalFailure, (substr));\
+    {\
+      ::testing::ScopedFakeTestPartResultReporter gtest_reporter(\
+          ::testing::ScopedFakeTestPartResultReporter:: \
+          INTERCEPT_ALL_THREADS, &gtest_failures);\
+      GTestExpectFatalFailureHelper::Execute();\
+    }\
+  } while (::testing::internal::AlwaysFalse())
+
+// A macro for testing Google Test assertions or code that's expected to
+// generate Google Test non-fatal failures.  It asserts that the given
+// statement will cause exactly one non-fatal Google Test failure with 'substr'
+// being part of the failure message.
+//
+// There are two different versions of this macro. EXPECT_NONFATAL_FAILURE only
+// affects and considers failures generated in the current thread and
+// EXPECT_NONFATAL_FAILURE_ON_ALL_THREADS does the same but for all threads.
+//
+// 'statement' is allowed to reference local variables and members of
+// the current object.
+//
+// The verification of the assertion is done correctly even when the statement
+// throws an exception or aborts the current function.
+//
+// Known restrictions:
+//   - You cannot stream a failure message to this macro.
+//
+// Note that even though the implementations of the following two
+// macros are much alike, we cannot refactor them to use a common
+// helper macro, due to some peculiarity in how the preprocessor
+// works.  If we do that, the code won't compile when the user gives
+// EXPECT_NONFATAL_FAILURE() a statement that contains a macro that
+// expands to code containing an unprotected comma.  The
+// AcceptsMacroThatExpandsToUnprotectedComma test in gtest_unittest.cc
+// catches that.
+//
+// For the same reason, we have to write
+//   if (::testing::internal::AlwaysTrue()) { statement; }
+// instead of
+//   GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement)
+// to avoid an MSVC warning on unreachable code.
+#define EXPECT_NONFATAL_FAILURE(statement, substr) \
+  do {\
+    ::testing::TestPartResultArray gtest_failures;\
+    ::testing::internal::SingleFailureChecker gtest_checker(\
+        &gtest_failures, ::testing::TestPartResult::kNonFatalFailure, \
+        (substr));\
+    {\
+      ::testing::ScopedFakeTestPartResultReporter gtest_reporter(\
+          ::testing::ScopedFakeTestPartResultReporter:: \
+          INTERCEPT_ONLY_CURRENT_THREAD, &gtest_failures);\
+      if (::testing::internal::AlwaysTrue()) { statement; }\
+    }\
+  } while (::testing::internal::AlwaysFalse())
+
+#define EXPECT_NONFATAL_FAILURE_ON_ALL_THREADS(statement, substr) \
+  do {\
+    ::testing::TestPartResultArray gtest_failures;\
+    ::testing::internal::SingleFailureChecker gtest_checker(\
+        &gtest_failures, ::testing::TestPartResult::kNonFatalFailure, \
+        (substr));\
+    {\
+      ::testing::ScopedFakeTestPartResultReporter gtest_reporter(\
+          ::testing::ScopedFakeTestPartResultReporter::INTERCEPT_ALL_THREADS, \
+          &gtest_failures);\
+      if (::testing::internal::AlwaysTrue()) { statement; }\
+    }\
+  } while (::testing::internal::AlwaysFalse())
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_SPI_H_
diff --git a/src/fmt/test/gtest/gtest/gtest.h b/src/fmt/test/gtest/gtest/gtest.h
new file mode 100644
index 000000000..55a31d0a8
--- /dev/null
+++ b/src/fmt/test/gtest/gtest/gtest.h
@@ -0,0 +1,12398 @@
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// The Google C++ Testing and Mocking Framework (Google Test)
+//
+// This header file defines the public API for Google Test.  It should be
+// included by any test program that uses Google Test.
+//
+// IMPORTANT NOTE: Due to limitation of the C++ language, we have to
+// leave some internal implementation details in this header file.
+// They are clearly marked by comments like this:
+//
+//   // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+//
+// Such code is NOT meant to be used by a user directly, and is subject
+// to CHANGE WITHOUT NOTICE.  Therefore DO NOT DEPEND ON IT in a user
+// program!
+//
+// Acknowledgment: Google Test borrowed the idea of automatic test
+// registration from Barthelemy Dagenais' (barthelemy@prologique.com)
+// easyUnit framework.
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_H_
+
+#include <cstddef>
+#include <limits>
+#include <memory>
+#include <ostream>
+#include <type_traits>
+#include <vector>
+
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// The Google C++ Testing and Mocking Framework (Google Test)
+//
+// This header file declares functions and macros used internally by
+// Google Test.  They are subject to change without notice.
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_INTERNAL_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_INTERNAL_H_
+
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Low-level types and utilities for porting Google Test to various
+// platforms.  All macros ending with _ and symbols defined in an
+// internal namespace are subject to change without notice.  Code
+// outside Google Test MUST NOT USE THEM DIRECTLY.  Macros that don't
+// end with _ are part of Google Test's public API and can be used by
+// code outside Google Test.
+//
+// This file is fundamental to Google Test.  All other Google Test source
+// files are expected to #include this.  Therefore, it cannot #include
+// any other Google Test header.
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_H_
+
+// Environment-describing macros
+// -----------------------------
+//
+// Google Test can be used in many different environments.  Macros in
+// this section tell Google Test what kind of environment it is being
+// used in, such that Google Test can provide environment-specific
+// features and implementations.
+//
+// Google Test tries to automatically detect the properties of its
+// environment, so users usually don't need to worry about these
+// macros.  However, the automatic detection is not perfect.
+// Sometimes it's necessary for a user to define some of the following
+// macros in the build script to override Google Test's decisions.
+//
+// If the user doesn't define a macro in the list, Google Test will
+// provide a default definition.  After this header is #included, all
+// macros in this list will be defined to either 1 or 0.
+//
+// Notes to maintainers:
+//   - Each macro here is a user-tweakable knob; do not grow the list
+//     lightly.
+//   - Use #if to key off these macros.  Don't use #ifdef or "#if
+//     defined(...)", which will not work as these macros are ALWAYS
+//     defined.
+//
+//   GTEST_HAS_CLONE          - Define it to 1/0 to indicate that clone(2)
+//                              is/isn't available.
+//   GTEST_HAS_EXCEPTIONS     - Define it to 1/0 to indicate that exceptions
+//                              are enabled.
+//   GTEST_HAS_POSIX_RE       - Define it to 1/0 to indicate that POSIX regular
+//                              expressions are/aren't available.
+//   GTEST_HAS_PTHREAD        - Define it to 1/0 to indicate that <pthread.h>
+//                              is/isn't available.
+//   GTEST_HAS_RTTI           - Define it to 1/0 to indicate that RTTI is/isn't
+//                              enabled.
+//   GTEST_HAS_STD_WSTRING    - Define it to 1/0 to indicate that
+//                              std::wstring does/doesn't work (Google Test can
+//                              be used where std::wstring is unavailable).
+//   GTEST_HAS_SEH            - Define it to 1/0 to indicate whether the
+//                              compiler supports Microsoft's "Structured
+//                              Exception Handling".
+//   GTEST_HAS_STREAM_REDIRECTION
+//                            - Define it to 1/0 to indicate whether the
+//                              platform supports I/O stream redirection using
+//                              dup() and dup2().
+//   GTEST_LINKED_AS_SHARED_LIBRARY
+//                            - Define to 1 when compiling tests that use
+//                              Google Test as a shared library (known as
+//                              DLL on Windows).
+//   GTEST_CREATE_SHARED_LIBRARY
+//                            - Define to 1 when compiling Google Test itself
+//                              as a shared library.
+//   GTEST_DEFAULT_DEATH_TEST_STYLE
+//                            - The default value of --gtest_death_test_style.
+//                              The legacy default has been "fast" in the open
+//                              source version since 2008. The recommended value
+//                              is "threadsafe", and can be set in
+//                              custom/gtest-port.h.
+
+// Platform-indicating macros
+// --------------------------
+//
+// Macros indicating the platform on which Google Test is being used
+// (a macro is defined to 1 if compiled on the given platform;
+// otherwise UNDEFINED -- it's never defined to 0.).  Google Test
+// defines these macros automatically.  Code outside Google Test MUST
+// NOT define them.
+//
+//   GTEST_OS_AIX      - IBM AIX
+//   GTEST_OS_CYGWIN   - Cygwin
+//   GTEST_OS_DRAGONFLY - DragonFlyBSD
+//   GTEST_OS_FREEBSD  - FreeBSD
+//   GTEST_OS_FUCHSIA  - Fuchsia
+//   GTEST_OS_GNU_KFREEBSD - GNU/kFreeBSD
+//   GTEST_OS_HAIKU    - Haiku
+//   GTEST_OS_HPUX     - HP-UX
+//   GTEST_OS_LINUX    - Linux
+//     GTEST_OS_LINUX_ANDROID - Google Android
+//   GTEST_OS_MAC      - Mac OS X
+//     GTEST_OS_IOS    - iOS
+//   GTEST_OS_NACL     - Google Native Client (NaCl)
+//   GTEST_OS_NETBSD   - NetBSD
+//   GTEST_OS_OPENBSD  - OpenBSD
+//   GTEST_OS_OS2      - OS/2
+//   GTEST_OS_QNX      - QNX
+//   GTEST_OS_SOLARIS  - Sun Solaris
+//   GTEST_OS_WINDOWS  - Windows (Desktop, MinGW, or Mobile)
+//     GTEST_OS_WINDOWS_DESKTOP  - Windows Desktop
+//     GTEST_OS_WINDOWS_MINGW    - MinGW
+//     GTEST_OS_WINDOWS_MOBILE   - Windows Mobile
+//     GTEST_OS_WINDOWS_PHONE    - Windows Phone
+//     GTEST_OS_WINDOWS_RT       - Windows Store App/WinRT
+//   GTEST_OS_ZOS      - z/OS
+//
+// Among the platforms, Cygwin, Linux, Mac OS X, and Windows have the
+// most stable support.  Since core members of the Google Test project
+// don't have access to other platforms, support for them may be less
+// stable.  If you notice any problems on your platform, please notify
+// googletestframework@googlegroups.com (patches for fixing them are
+// even more welcome!).
+//
+// It is possible that none of the GTEST_OS_* macros are defined.
+
+// Feature-indicating macros
+// -------------------------
+//
+// Macros indicating which Google Test features are available (a macro
+// is defined to 1 if the corresponding feature is supported;
+// otherwise UNDEFINED -- it's never defined to 0.).  Google Test
+// defines these macros automatically.  Code outside Google Test MUST
+// NOT define them.
+//
+// These macros are public so that portable tests can be written.
+// Such tests typically surround code using a feature with an #if
+// which controls that code.  For example:
+//
+// #if GTEST_HAS_DEATH_TEST
+//   EXPECT_DEATH(DoSomethingDeadly());
+// #endif
+//
+//   GTEST_HAS_DEATH_TEST   - death tests
+//   GTEST_HAS_TYPED_TEST   - typed tests
+//   GTEST_HAS_TYPED_TEST_P - type-parameterized tests
+//   GTEST_IS_THREADSAFE    - Google Test is thread-safe.
+//   GOOGLETEST_CM0007 DO NOT DELETE
+//   GTEST_USES_POSIX_RE    - enhanced POSIX regex is used. Do not confuse with
+//                            GTEST_HAS_POSIX_RE (see above) which users can
+//                            define themselves.
+//   GTEST_USES_SIMPLE_RE   - our own simple regex is used;
+//                            the above RE\b(s) are mutually exclusive.
+
+// Misc public macros
+// ------------------
+//
+//   GTEST_FLAG(flag_name)  - references the variable corresponding to
+//                            the given Google Test flag.
+
+// Internal utilities
+// ------------------
+//
+// The following macros and utilities are for Google Test's INTERNAL
+// use only.  Code outside Google Test MUST NOT USE THEM DIRECTLY.
+//
+// Macros for basic C++ coding:
+//   GTEST_AMBIGUOUS_ELSE_BLOCKER_ - for disabling a gcc warning.
+//   GTEST_ATTRIBUTE_UNUSED_  - declares that a class' instances or a
+//                              variable don't have to be used.
+//   GTEST_DISALLOW_ASSIGN_   - disables copy operator=.
+//   GTEST_DISALLOW_COPY_AND_ASSIGN_ - disables copy ctor and operator=.
+//   GTEST_DISALLOW_MOVE_ASSIGN_   - disables move operator=.
+//   GTEST_DISALLOW_MOVE_AND_ASSIGN_ - disables move ctor and operator=.
+//   GTEST_MUST_USE_RESULT_   - declares that a function's result must be used.
+//   GTEST_INTENTIONAL_CONST_COND_PUSH_ - start code section where MSVC C4127 is
+//                                        suppressed (constant conditional).
+//   GTEST_INTENTIONAL_CONST_COND_POP_  - finish code section where MSVC C4127
+//                                        is suppressed.
+//   GTEST_INTERNAL_HAS_ANY - for enabling UniversalPrinter<std::any> or
+//                            UniversalPrinter<absl::any> specializations.
+//   GTEST_INTERNAL_HAS_OPTIONAL - for enabling UniversalPrinter<std::optional>
+//   or
+//                                 UniversalPrinter<absl::optional>
+//                                 specializations.
+//   GTEST_INTERNAL_HAS_STRING_VIEW - for enabling Matcher<std::string_view> or
+//                                    Matcher<absl::string_view>
+//                                    specializations.
+//   GTEST_INTERNAL_HAS_VARIANT - for enabling UniversalPrinter<std::variant> or
+//                                UniversalPrinter<absl::variant>
+//                                specializations.
+//
+// Synchronization:
+//   Mutex, MutexLock, ThreadLocal, GetThreadCount()
+//                            - synchronization primitives.
+//
+// Regular expressions:
+//   RE             - a simple regular expression class using the POSIX
+//                    Extended Regular Expression syntax on UNIX-like platforms
+//                    GOOGLETEST_CM0008 DO NOT DELETE
+//                    or a reduced regular exception syntax on other
+//                    platforms, including Windows.
+// Logging:
+//   GTEST_LOG_()   - logs messages at the specified severity level.
+//   LogToStderr()  - directs all log messages to stderr.
+//   FlushInfoLog() - flushes informational log messages.
+//
+// Stdout and stderr capturing:
+//   CaptureStdout()     - starts capturing stdout.
+//   GetCapturedStdout() - stops capturing stdout and returns the captured
+//                         string.
+//   CaptureStderr()     - starts capturing stderr.
+//   GetCapturedStderr() - stops capturing stderr and returns the captured
+//                         string.
+//
+// Integer types:
+//   TypeWithSize   - maps an integer to a int type.
+//   TimeInMillis   - integers of known sizes.
+//   BiggestInt     - the biggest signed integer type.
+//
+// Command-line utilities:
+//   GTEST_DECLARE_*()  - declares a flag.
+//   GTEST_DEFINE_*()   - defines a flag.
+//   GetInjectableArgvs() - returns the command line as a vector of strings.
+//
+// Environment variable utilities:
+//   GetEnv()             - gets the value of an environment variable.
+//   BoolFromGTestEnv()   - parses a bool environment variable.
+//   Int32FromGTestEnv()  - parses an int32_t environment variable.
+//   StringFromGTestEnv() - parses a string environment variable.
+//
+// Deprecation warnings:
+//   GTEST_INTERNAL_DEPRECATED(message) - attribute marking a function as
+//                                        deprecated; calling a marked function
+//                                        should generate a compiler warning
+
+#include <ctype.h>   // for isspace, etc
+#include <stddef.h>  // for ptrdiff_t
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <cerrno>
+#include <cstdint>
+#include <limits>
+#include <type_traits>
+
+#ifndef _WIN32_WCE
+# include <sys/types.h>
+# include <sys/stat.h>
+#endif  // !_WIN32_WCE
+
+#if defined __APPLE__
+# include <AvailabilityMacros.h>
+# include <TargetConditionals.h>
+#endif
+
+#include <iostream>  // NOLINT
+#include <locale>
+#include <memory>
+#include <string>  // NOLINT
+#include <tuple>
+#include <vector>  // NOLINT
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Injection point for custom user configurations. See README for details
+//
+// ** Custom implementation starts here **
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PORT_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PORT_H_
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PORT_H_
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// The Google C++ Testing and Mocking Framework (Google Test)
+//
+// This header file defines the GTEST_OS_* macro.
+// It is separate from gtest-port.h so that custom/gtest-port.h can include it.
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_ARCH_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_ARCH_H_
+
+// Determines the platform on which Google Test is compiled.
+#ifdef __CYGWIN__
+# define GTEST_OS_CYGWIN 1
+# elif defined(__MINGW__) || defined(__MINGW32__) || defined(__MINGW64__)
+#  define GTEST_OS_WINDOWS_MINGW 1
+#  define GTEST_OS_WINDOWS 1
+#elif defined _WIN32
+# define GTEST_OS_WINDOWS 1
+# ifdef _WIN32_WCE
+#  define GTEST_OS_WINDOWS_MOBILE 1
+# elif defined(WINAPI_FAMILY)
+#  include <winapifamily.h>
+#  if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+#   define GTEST_OS_WINDOWS_DESKTOP 1
+#  elif WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_PHONE_APP)
+#   define GTEST_OS_WINDOWS_PHONE 1
+#  elif WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP)
+#   define GTEST_OS_WINDOWS_RT 1
+#  elif WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_TV_TITLE)
+#   define GTEST_OS_WINDOWS_PHONE 1
+#   define GTEST_OS_WINDOWS_TV_TITLE 1
+#  else
+    // WINAPI_FAMILY defined but no known partition matched.
+    // Default to desktop.
+#   define GTEST_OS_WINDOWS_DESKTOP 1
+#  endif
+# else
+#  define GTEST_OS_WINDOWS_DESKTOP 1
+# endif  // _WIN32_WCE
+#elif defined __OS2__
+# define GTEST_OS_OS2 1
+#elif defined __APPLE__
+# define GTEST_OS_MAC 1
+# include <TargetConditionals.h>
+# if TARGET_OS_IPHONE
+#  define GTEST_OS_IOS 1
+# endif
+#elif defined __DragonFly__
+# define GTEST_OS_DRAGONFLY 1
+#elif defined __FreeBSD__
+# define GTEST_OS_FREEBSD 1
+#elif defined __Fuchsia__
+# define GTEST_OS_FUCHSIA 1
+#elif defined(__GLIBC__) && defined(__FreeBSD_kernel__)
+# define GTEST_OS_GNU_KFREEBSD 1
+#elif defined __linux__
+# define GTEST_OS_LINUX 1
+# if defined __ANDROID__
+#  define GTEST_OS_LINUX_ANDROID 1
+# endif
+#elif defined __MVS__
+# define GTEST_OS_ZOS 1
+#elif defined(__sun) && defined(__SVR4)
+# define GTEST_OS_SOLARIS 1
+#elif defined(_AIX)
+# define GTEST_OS_AIX 1
+#elif defined(__hpux)
+# define GTEST_OS_HPUX 1
+#elif defined __native_client__
+# define GTEST_OS_NACL 1
+#elif defined __NetBSD__
+# define GTEST_OS_NETBSD 1
+#elif defined __OpenBSD__
+# define GTEST_OS_OPENBSD 1
+#elif defined __QNX__
+# define GTEST_OS_QNX 1
+#elif defined(__HAIKU__)
+#define GTEST_OS_HAIKU 1
+#elif defined ESP8266
+#define GTEST_OS_ESP8266 1
+#elif defined ESP32
+#define GTEST_OS_ESP32 1
+#elif defined(__XTENSA__)
+#define GTEST_OS_XTENSA 1
+#endif  // __CYGWIN__
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_ARCH_H_
+
+#if !defined(GTEST_DEV_EMAIL_)
+# define GTEST_DEV_EMAIL_ "googletestframework@@googlegroups.com"
+# define GTEST_FLAG_PREFIX_ "gtest_"
+# define GTEST_FLAG_PREFIX_DASH_ "gtest-"
+# define GTEST_FLAG_PREFIX_UPPER_ "GTEST_"
+# define GTEST_NAME_ "Google Test"
+# define GTEST_PROJECT_URL_ "https://github.com/google/googletest/"
+#endif  // !defined(GTEST_DEV_EMAIL_)
+
+#if !defined(GTEST_INIT_GOOGLE_TEST_NAME_)
+# define GTEST_INIT_GOOGLE_TEST_NAME_ "testing::InitGoogleTest"
+#endif  // !defined(GTEST_INIT_GOOGLE_TEST_NAME_)
+
+// Determines the version of gcc that is used to compile this.
+#ifdef __GNUC__
+// 40302 means version 4.3.2.
+# define GTEST_GCC_VER_ \
+    (__GNUC__*10000 + __GNUC_MINOR__*100 + __GNUC_PATCHLEVEL__)
+#endif  // __GNUC__
+
+// Macros for disabling Microsoft Visual C++ warnings.
+//
+//   GTEST_DISABLE_MSC_WARNINGS_PUSH_(4800 4385)
+//   /* code that triggers warnings C4800 and C4385 */
+//   GTEST_DISABLE_MSC_WARNINGS_POP_()
+#if defined(_MSC_VER)
+# define GTEST_DISABLE_MSC_WARNINGS_PUSH_(warnings) \
+    __pragma(warning(push))                        \
+    __pragma(warning(disable: warnings))
+# define GTEST_DISABLE_MSC_WARNINGS_POP_()          \
+    __pragma(warning(pop))
+#else
+// Not all compilers are MSVC
+# define GTEST_DISABLE_MSC_WARNINGS_PUSH_(warnings)
+# define GTEST_DISABLE_MSC_WARNINGS_POP_()
+#endif
+
+// Clang on Windows does not understand MSVC's pragma warning.
+// We need clang-specific way to disable function deprecation warning.
+#ifdef __clang__
+# define GTEST_DISABLE_MSC_DEPRECATED_PUSH_()                         \
+    _Pragma("clang diagnostic push")                                  \
+    _Pragma("clang diagnostic ignored \"-Wdeprecated-declarations\"") \
+    _Pragma("clang diagnostic ignored \"-Wdeprecated-implementations\"")
+#define GTEST_DISABLE_MSC_DEPRECATED_POP_() \
+    _Pragma("clang diagnostic pop")
+#else
+# define GTEST_DISABLE_MSC_DEPRECATED_PUSH_() \
+    GTEST_DISABLE_MSC_WARNINGS_PUSH_(4996)
+# define GTEST_DISABLE_MSC_DEPRECATED_POP_() \
+    GTEST_DISABLE_MSC_WARNINGS_POP_()
+#endif
+
+// Brings in definitions for functions used in the testing::internal::posix
+// namespace (read, write, close, chdir, isatty, stat). We do not currently
+// use them on Windows Mobile.
+#if GTEST_OS_WINDOWS
+# if !GTEST_OS_WINDOWS_MOBILE
+#  include <direct.h>
+#  include <io.h>
+# endif
+// In order to avoid having to include <windows.h>, use forward declaration
+#if GTEST_OS_WINDOWS_MINGW && !defined(__MINGW64_VERSION_MAJOR)
+// MinGW defined _CRITICAL_SECTION and _RTL_CRITICAL_SECTION as two
+// separate (equivalent) structs, instead of using typedef
+typedef struct _CRITICAL_SECTION GTEST_CRITICAL_SECTION;
+#else
+// Assume CRITICAL_SECTION is a typedef of _RTL_CRITICAL_SECTION.
+// This assumption is verified by
+// WindowsTypesTest.CRITICAL_SECTIONIs_RTL_CRITICAL_SECTION.
+typedef struct _RTL_CRITICAL_SECTION GTEST_CRITICAL_SECTION;
+#endif
+#elif GTEST_OS_XTENSA
+#include <unistd.h>
+// Xtensa toolchains define strcasecmp in the string.h header instead of
+// strings.h. string.h is already included.
+#else
+// This assumes that non-Windows OSes provide unistd.h. For OSes where this
+// is not the case, we need to include headers that provide the functions
+// mentioned above.
+# include <unistd.h>
+# include <strings.h>
+#endif  // GTEST_OS_WINDOWS
+
+#if GTEST_OS_LINUX_ANDROID
+// Used to define __ANDROID_API__ matching the target NDK API level.
+#  include <android/api-level.h>  // NOLINT
+#endif
+
+// Defines this to true if and only if Google Test can use POSIX regular
+// expressions.
+#ifndef GTEST_HAS_POSIX_RE
+# if GTEST_OS_LINUX_ANDROID
+// On Android, <regex.h> is only available starting with Gingerbread.
+#  define GTEST_HAS_POSIX_RE (__ANDROID_API__ >= 9)
+# else
+#define GTEST_HAS_POSIX_RE (!GTEST_OS_WINDOWS && !GTEST_OS_XTENSA)
+# endif
+#endif
+
+#if GTEST_USES_PCRE
+// The appropriate headers have already been included.
+
+#elif GTEST_HAS_POSIX_RE
+
+// On some platforms, <regex.h> needs someone to define size_t, and
+// won't compile otherwise.  We can #include it here as we already
+// included <stdlib.h>, which is guaranteed to define size_t through
+// <stddef.h>.
+# include <regex.h>  // NOLINT
+
+# define GTEST_USES_POSIX_RE 1
+
+#elif GTEST_OS_WINDOWS
+
+// <regex.h> is not available on Windows.  Use our own simple regex
+// implementation instead.
+# define GTEST_USES_SIMPLE_RE 1
+
+#else
+
+// <regex.h> may not be available on this platform.  Use our own
+// simple regex implementation instead.
+# define GTEST_USES_SIMPLE_RE 1
+
+#endif  // GTEST_USES_PCRE
+
+#ifndef GTEST_HAS_EXCEPTIONS
+// The user didn't tell us whether exceptions are enabled, so we need
+// to figure it out.
+# if defined(_MSC_VER) && defined(_CPPUNWIND)
+// MSVC defines _CPPUNWIND to 1 if and only if exceptions are enabled.
+#  define GTEST_HAS_EXCEPTIONS 1
+# elif defined(__BORLANDC__)
+// C++Builder's implementation of the STL uses the _HAS_EXCEPTIONS
+// macro to enable exceptions, so we'll do the same.
+// Assumes that exceptions are enabled by default.
+#  ifndef _HAS_EXCEPTIONS
+#   define _HAS_EXCEPTIONS 1
+#  endif  // _HAS_EXCEPTIONS
+#  define GTEST_HAS_EXCEPTIONS _HAS_EXCEPTIONS
+# elif defined(__clang__)
+// clang defines __EXCEPTIONS if and only if exceptions are enabled before clang
+// 220714, but if and only if cleanups are enabled after that. In Obj-C++ files,
+// there can be cleanups for ObjC exceptions which also need cleanups, even if
+// C++ exceptions are disabled. clang has __has_feature(cxx_exceptions) which
+// checks for C++ exceptions starting at clang r206352, but which checked for
+// cleanups prior to that. To reliably check for C++ exception availability with
+// clang, check for
+// __EXCEPTIONS && __has_feature(cxx_exceptions).
+#  define GTEST_HAS_EXCEPTIONS (__EXCEPTIONS && __has_feature(cxx_exceptions))
+# elif defined(__GNUC__) && __EXCEPTIONS
+// gcc defines __EXCEPTIONS to 1 if and only if exceptions are enabled.
+#  define GTEST_HAS_EXCEPTIONS 1
+# elif defined(__SUNPRO_CC)
+// Sun Pro CC supports exceptions.  However, there is no compile-time way of
+// detecting whether they are enabled or not.  Therefore, we assume that
+// they are enabled unless the user tells us otherwise.
+#  define GTEST_HAS_EXCEPTIONS 1
+# elif defined(__IBMCPP__) && __EXCEPTIONS
+// xlC defines __EXCEPTIONS to 1 if and only if exceptions are enabled.
+#  define GTEST_HAS_EXCEPTIONS 1
+# elif defined(__HP_aCC)
+// Exception handling is in effect by default in HP aCC compiler. It has to
+// be turned of by +noeh compiler option if desired.
+#  define GTEST_HAS_EXCEPTIONS 1
+# else
+// For other compilers, we assume exceptions are disabled to be
+// conservative.
+#  define GTEST_HAS_EXCEPTIONS 0
+# endif  // defined(_MSC_VER) || defined(__BORLANDC__)
+#endif  // GTEST_HAS_EXCEPTIONS
+
+#ifndef GTEST_HAS_STD_WSTRING
+// The user didn't tell us whether ::std::wstring is available, so we need
+// to figure it out.
+// Cygwin 1.7 and below doesn't support ::std::wstring.
+// Solaris' libc++ doesn't support it either.  Android has
+// no support for it at least as recent as Froyo (2.2).
+#define GTEST_HAS_STD_WSTRING                                         \
+  (!(GTEST_OS_LINUX_ANDROID || GTEST_OS_CYGWIN || GTEST_OS_SOLARIS || \
+     GTEST_OS_HAIKU || GTEST_OS_ESP32 || GTEST_OS_ESP8266 || GTEST_OS_XTENSA))
+
+#endif  // GTEST_HAS_STD_WSTRING
+
+// Determines whether RTTI is available.
+#ifndef GTEST_HAS_RTTI
+// The user didn't tell us whether RTTI is enabled, so we need to
+// figure it out.
+
+# ifdef _MSC_VER
+
+#ifdef _CPPRTTI  // MSVC defines this macro if and only if RTTI is enabled.
+#   define GTEST_HAS_RTTI 1
+#  else
+#   define GTEST_HAS_RTTI 0
+#  endif
+
+// Starting with version 4.3.2, gcc defines __GXX_RTTI if and only if RTTI is
+// enabled.
+# elif defined(__GNUC__)
+
+#  ifdef __GXX_RTTI
+// When building against STLport with the Android NDK and with
+// -frtti -fno-exceptions, the build fails at link time with undefined
+// references to __cxa_bad_typeid. Note sure if STL or toolchain bug,
+// so disable RTTI when detected.
+#   if GTEST_OS_LINUX_ANDROID && defined(_STLPORT_MAJOR) && \
+       !defined(__EXCEPTIONS)
+#    define GTEST_HAS_RTTI 0
+#   else
+#    define GTEST_HAS_RTTI 1
+#   endif  // GTEST_OS_LINUX_ANDROID && __STLPORT_MAJOR && !__EXCEPTIONS
+#  else
+#   define GTEST_HAS_RTTI 0
+#  endif  // __GXX_RTTI
+
+// Clang defines __GXX_RTTI starting with version 3.0, but its manual recommends
+// using has_feature instead. has_feature(cxx_rtti) is supported since 2.7, the
+// first version with C++ support.
+# elif defined(__clang__)
+
+#  define GTEST_HAS_RTTI __has_feature(cxx_rtti)
+
+// Starting with version 9.0 IBM Visual Age defines __RTTI_ALL__ to 1 if
+// both the typeid and dynamic_cast features are present.
+# elif defined(__IBMCPP__) && (__IBMCPP__ >= 900)
+
+#  ifdef __RTTI_ALL__
+#   define GTEST_HAS_RTTI 1
+#  else
+#   define GTEST_HAS_RTTI 0
+#  endif
+
+# else
+
+// For all other compilers, we assume RTTI is enabled.
+#  define GTEST_HAS_RTTI 1
+
+# endif  // _MSC_VER
+
+#endif  // GTEST_HAS_RTTI
+
+// It's this header's responsibility to #include <typeinfo> when RTTI
+// is enabled.
+#if GTEST_HAS_RTTI
+# include <typeinfo>
+#endif
+
+// Determines whether Google Test can use the pthreads library.
+#ifndef GTEST_HAS_PTHREAD
+// The user didn't tell us explicitly, so we make reasonable assumptions about
+// which platforms have pthreads support.
+//
+// To disable threading support in Google Test, add -DGTEST_HAS_PTHREAD=0
+// to your compiler flags.
+#define GTEST_HAS_PTHREAD                                                      \
+  (GTEST_OS_LINUX || GTEST_OS_MAC || GTEST_OS_HPUX || GTEST_OS_QNX ||          \
+   GTEST_OS_FREEBSD || GTEST_OS_NACL || GTEST_OS_NETBSD || GTEST_OS_FUCHSIA || \
+   GTEST_OS_DRAGONFLY || GTEST_OS_GNU_KFREEBSD || GTEST_OS_OPENBSD ||          \
+   GTEST_OS_HAIKU)
+#endif  // GTEST_HAS_PTHREAD
+
+#if GTEST_HAS_PTHREAD
+// gtest-port.h guarantees to #include <pthread.h> when GTEST_HAS_PTHREAD is
+// true.
+# include <pthread.h>  // NOLINT
+
+// For timespec and nanosleep, used below.
+# include <time.h>  // NOLINT
+#endif
+
+// Determines whether clone(2) is supported.
+// Usually it will only be available on Linux, excluding
+// Linux on the Itanium architecture.
+// Also see http://linux.die.net/man/2/clone.
+#ifndef GTEST_HAS_CLONE
+// The user didn't tell us, so we need to figure it out.
+
+# if GTEST_OS_LINUX && !defined(__ia64__)
+#  if GTEST_OS_LINUX_ANDROID
+// On Android, clone() became available at different API levels for each 32-bit
+// architecture.
+#    if defined(__LP64__) || \
+        (defined(__arm__) && __ANDROID_API__ >= 9) || \
+        (defined(__mips__) && __ANDROID_API__ >= 12) || \
+        (defined(__i386__) && __ANDROID_API__ >= 17)
+#     define GTEST_HAS_CLONE 1
+#    else
+#     define GTEST_HAS_CLONE 0
+#    endif
+#  else
+#   define GTEST_HAS_CLONE 1
+#  endif
+# else
+#  define GTEST_HAS_CLONE 0
+# endif  // GTEST_OS_LINUX && !defined(__ia64__)
+
+#endif  // GTEST_HAS_CLONE
+
+// Determines whether to support stream redirection. This is used to test
+// output correctness and to implement death tests.
+#ifndef GTEST_HAS_STREAM_REDIRECTION
+// By default, we assume that stream redirection is supported on all
+// platforms except known mobile ones.
+#if GTEST_OS_WINDOWS_MOBILE || GTEST_OS_WINDOWS_PHONE || \
+    GTEST_OS_WINDOWS_RT || GTEST_OS_ESP8266 || GTEST_OS_XTENSA
+#  define GTEST_HAS_STREAM_REDIRECTION 0
+# else
+#  define GTEST_HAS_STREAM_REDIRECTION 1
+# endif  // !GTEST_OS_WINDOWS_MOBILE
+#endif  // GTEST_HAS_STREAM_REDIRECTION
+
+// Determines whether to support death tests.
+// pops up a dialog window that cannot be suppressed programmatically.
+#if (GTEST_OS_LINUX || GTEST_OS_CYGWIN || GTEST_OS_SOLARIS ||             \
+     (GTEST_OS_MAC && !GTEST_OS_IOS) ||                                   \
+     (GTEST_OS_WINDOWS_DESKTOP && _MSC_VER) || GTEST_OS_WINDOWS_MINGW ||  \
+     GTEST_OS_AIX || GTEST_OS_HPUX || GTEST_OS_OPENBSD || GTEST_OS_QNX || \
+     GTEST_OS_FREEBSD || GTEST_OS_NETBSD || GTEST_OS_FUCHSIA ||           \
+     GTEST_OS_DRAGONFLY || GTEST_OS_GNU_KFREEBSD || GTEST_OS_HAIKU)
+# define GTEST_HAS_DEATH_TEST 1
+#endif
+
+// Determines whether to support type-driven tests.
+
+// Typed tests need <typeinfo> and variadic macros, which GCC, VC++ 8.0,
+// Sun Pro CC, IBM Visual Age, and HP aCC support.
+#if defined(__GNUC__) || defined(_MSC_VER) || defined(__SUNPRO_CC) || \
+    defined(__IBMCPP__) || defined(__HP_aCC)
+# define GTEST_HAS_TYPED_TEST 1
+# define GTEST_HAS_TYPED_TEST_P 1
+#endif
+
+// Determines whether the system compiler uses UTF-16 for encoding wide strings.
+#define GTEST_WIDE_STRING_USES_UTF16_ \
+  (GTEST_OS_WINDOWS || GTEST_OS_CYGWIN || GTEST_OS_AIX || GTEST_OS_OS2)
+
+// Determines whether test results can be streamed to a socket.
+#if GTEST_OS_LINUX || GTEST_OS_GNU_KFREEBSD || GTEST_OS_DRAGONFLY || \
+    GTEST_OS_FREEBSD || GTEST_OS_NETBSD || GTEST_OS_OPENBSD
+# define GTEST_CAN_STREAM_RESULTS_ 1
+#endif
+
+// Defines some utility macros.
+
+// The GNU compiler emits a warning if nested "if" statements are followed by
+// an "else" statement and braces are not used to explicitly disambiguate the
+// "else" binding.  This leads to problems with code like:
+//
+//   if (gate)
+//     ASSERT_*(condition) << "Some message";
+//
+// The "switch (0) case 0:" idiom is used to suppress this.
+#ifdef __INTEL_COMPILER
+# define GTEST_AMBIGUOUS_ELSE_BLOCKER_
+#else
+# define GTEST_AMBIGUOUS_ELSE_BLOCKER_ switch (0) case 0: default:  // NOLINT
+#endif
+
+// Use this annotation at the end of a struct/class definition to
+// prevent the compiler from optimizing away instances that are never
+// used.  This is useful when all interesting logic happens inside the
+// c'tor and / or d'tor.  Example:
+//
+//   struct Foo {
+//     Foo() { ... }
+//   } GTEST_ATTRIBUTE_UNUSED_;
+//
+// Also use it after a variable or parameter declaration to tell the
+// compiler the variable/parameter does not have to be used.
+#if defined(__GNUC__) && !defined(COMPILER_ICC)
+# define GTEST_ATTRIBUTE_UNUSED_ __attribute__ ((unused))
+#elif defined(__clang__)
+# if __has_attribute(unused)
+#  define GTEST_ATTRIBUTE_UNUSED_ __attribute__ ((unused))
+# endif
+#endif
+#ifndef GTEST_ATTRIBUTE_UNUSED_
+# define GTEST_ATTRIBUTE_UNUSED_
+#endif
+
+// Use this annotation before a function that takes a printf format string.
+#if (defined(__GNUC__) || defined(__clang__)) && !defined(COMPILER_ICC)
+# if defined(__MINGW_PRINTF_FORMAT)
+// MinGW has two different printf implementations. Ensure the format macro
+// matches the selected implementation. See
+// https://sourceforge.net/p/mingw-w64/wiki2/gnu%20printf/.
+#  define GTEST_ATTRIBUTE_PRINTF_(string_index, first_to_check) \
+       __attribute__((__format__(__MINGW_PRINTF_FORMAT, string_index, \
+                                 first_to_check)))
+# else
+#  define GTEST_ATTRIBUTE_PRINTF_(string_index, first_to_check) \
+       __attribute__((__format__(__printf__, string_index, first_to_check)))
+# endif
+#else
+# define GTEST_ATTRIBUTE_PRINTF_(string_index, first_to_check)
+#endif
+
+
+// A macro to disallow copy operator=
+// This should be used in the private: declarations for a class.
+#define GTEST_DISALLOW_ASSIGN_(type) \
+  type& operator=(type const &) = delete
+
+// A macro to disallow copy constructor and operator=
+// This should be used in the private: declarations for a class.
+#define GTEST_DISALLOW_COPY_AND_ASSIGN_(type) \
+  type(type const&) = delete;                 \
+  type& operator=(type const&) = delete
+
+// A macro to disallow move operator=
+// This should be used in the private: declarations for a class.
+#define GTEST_DISALLOW_MOVE_ASSIGN_(type) \
+  type& operator=(type &&) noexcept = delete
+
+// A macro to disallow move constructor and operator=
+// This should be used in the private: declarations for a class.
+#define GTEST_DISALLOW_MOVE_AND_ASSIGN_(type) \
+  type(type&&) noexcept = delete;             \
+  type& operator=(type&&) noexcept = delete
+
+// Tell the compiler to warn about unused return values for functions declared
+// with this macro.  The macro should be used on function declarations
+// following the argument list:
+//
+//   Sprocket* AllocateSprocket() GTEST_MUST_USE_RESULT_;
+#if defined(__GNUC__) && !defined(COMPILER_ICC)
+# define GTEST_MUST_USE_RESULT_ __attribute__ ((warn_unused_result))
+#else
+# define GTEST_MUST_USE_RESULT_
+#endif  // __GNUC__ && !COMPILER_ICC
+
+// MS C++ compiler emits warning when a conditional expression is compile time
+// constant. In some contexts this warning is false positive and needs to be
+// suppressed. Use the following two macros in such cases:
+//
+// GTEST_INTENTIONAL_CONST_COND_PUSH_()
+// while (true) {
+// GTEST_INTENTIONAL_CONST_COND_POP_()
+// }
+# define GTEST_INTENTIONAL_CONST_COND_PUSH_() \
+    GTEST_DISABLE_MSC_WARNINGS_PUSH_(4127)
+# define GTEST_INTENTIONAL_CONST_COND_POP_() \
+    GTEST_DISABLE_MSC_WARNINGS_POP_()
+
+// Determine whether the compiler supports Microsoft's Structured Exception
+// Handling.  This is supported by several Windows compilers but generally
+// does not exist on any other system.
+#ifndef GTEST_HAS_SEH
+// The user didn't tell us, so we need to figure it out.
+
+# if defined(_MSC_VER) || defined(__BORLANDC__)
+// These two compilers are known to support SEH.
+#  define GTEST_HAS_SEH 1
+# else
+// Assume no SEH.
+#  define GTEST_HAS_SEH 0
+# endif
+
+#endif  // GTEST_HAS_SEH
+
+#ifndef GTEST_IS_THREADSAFE
+
+#define GTEST_IS_THREADSAFE                                                 \
+  (GTEST_HAS_MUTEX_AND_THREAD_LOCAL_ ||                                     \
+   (GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT) || \
+   GTEST_HAS_PTHREAD)
+
+#endif  // GTEST_IS_THREADSAFE
+
+// GTEST_API_ qualifies all symbols that must be exported. The definitions below
+// are guarded by #ifndef to give embedders a chance to define GTEST_API_ in
+// gtest/internal/custom/gtest-port.h
+#ifndef GTEST_API_
+
+#ifdef _MSC_VER
+# if GTEST_LINKED_AS_SHARED_LIBRARY
+#  define GTEST_API_ __declspec(dllimport)
+# elif GTEST_CREATE_SHARED_LIBRARY
+#  define GTEST_API_ __declspec(dllexport)
+# endif
+#elif __GNUC__ >= 4 || defined(__clang__)
+# define GTEST_API_ __attribute__((visibility ("default")))
+#endif  // _MSC_VER
+
+#endif  // GTEST_API_
+
+#ifndef GTEST_API_
+# define GTEST_API_
+#endif  // GTEST_API_
+
+#ifndef GTEST_DEFAULT_DEATH_TEST_STYLE
+# define GTEST_DEFAULT_DEATH_TEST_STYLE  "fast"
+#endif  // GTEST_DEFAULT_DEATH_TEST_STYLE
+
+#ifdef __GNUC__
+// Ask the compiler to never inline a given function.
+# define GTEST_NO_INLINE_ __attribute__((noinline))
+#else
+# define GTEST_NO_INLINE_
+#endif
+
+// _LIBCPP_VERSION is defined by the libc++ library from the LLVM project.
+#if !defined(GTEST_HAS_CXXABI_H_)
+# if defined(__GLIBCXX__) || (defined(_LIBCPP_VERSION) && !defined(_MSC_VER))
+#  define GTEST_HAS_CXXABI_H_ 1
+# else
+#  define GTEST_HAS_CXXABI_H_ 0
+# endif
+#endif
+
+// A function level attribute to disable checking for use of uninitialized
+// memory when built with MemorySanitizer.
+#if defined(__clang__)
+# if __has_feature(memory_sanitizer)
+#  define GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_ \
+       __attribute__((no_sanitize_memory))
+# else
+#  define GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
+# endif  // __has_feature(memory_sanitizer)
+#else
+# define GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
+#endif  // __clang__
+
+// A function level attribute to disable AddressSanitizer instrumentation.
+#if defined(__clang__)
+# if __has_feature(address_sanitizer)
+#  define GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_ \
+       __attribute__((no_sanitize_address))
+# else
+#  define GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
+# endif  // __has_feature(address_sanitizer)
+#else
+# define GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
+#endif  // __clang__
+
+// A function level attribute to disable HWAddressSanitizer instrumentation.
+#if defined(__clang__)
+# if __has_feature(hwaddress_sanitizer)
+#  define GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_ \
+       __attribute__((no_sanitize("hwaddress")))
+# else
+#  define GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_
+# endif  // __has_feature(hwaddress_sanitizer)
+#else
+# define GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_
+#endif  // __clang__
+
+// A function level attribute to disable ThreadSanitizer instrumentation.
+#if defined(__clang__)
+# if __has_feature(thread_sanitizer)
+#  define GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_ \
+       __attribute__((no_sanitize_thread))
+# else
+#  define GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
+# endif  // __has_feature(thread_sanitizer)
+#else
+# define GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
+#endif  // __clang__
+
+namespace testing {
+
+class Message;
+
+// Legacy imports for backwards compatibility.
+// New code should use std:: names directly.
+using std::get;
+using std::make_tuple;
+using std::tuple;
+using std::tuple_element;
+using std::tuple_size;
+
+namespace internal {
+
+// A secret type that Google Test users don't know about.  It has no
+// definition on purpose.  Therefore it's impossible to create a
+// Secret object, which is what we want.
+class Secret;
+
+// The GTEST_COMPILE_ASSERT_ is a legacy macro used to verify that a compile
+// time expression is true (in new code, use static_assert instead). For
+// example, you could use it to verify the size of a static array:
+//
+//   GTEST_COMPILE_ASSERT_(GTEST_ARRAY_SIZE_(names) == NUM_NAMES,
+//                         names_incorrect_size);
+//
+// The second argument to the macro must be a valid C++ identifier. If the
+// expression is false, compiler will issue an error containing this identifier.
+#define GTEST_COMPILE_ASSERT_(expr, msg) static_assert(expr, #msg)
+
+// A helper for suppressing warnings on constant condition.  It just
+// returns 'condition'.
+GTEST_API_ bool IsTrue(bool condition);
+
+// Defines RE.
+
+#if GTEST_USES_PCRE
+// if used, PCRE is injected by custom/gtest-port.h
+#elif GTEST_USES_POSIX_RE || GTEST_USES_SIMPLE_RE
+
+// A simple C++ wrapper for <regex.h>.  It uses the POSIX Extended
+// Regular Expression syntax.
+class GTEST_API_ RE {
+ public:
+  // A copy constructor is required by the Standard to initialize object
+  // references from r-values.
+  RE(const RE& other) { Init(other.pattern()); }
+
+  // Constructs an RE from a string.
+  RE(const ::std::string& regex) { Init(regex.c_str()); }  // NOLINT
+
+  RE(const char* regex) { Init(regex); }  // NOLINT
+  ~RE();
+
+  // Returns the string representation of the regex.
+  const char* pattern() const { return pattern_; }
+
+  // FullMatch(str, re) returns true if and only if regular expression re
+  // matches the entire str.
+  // PartialMatch(str, re) returns true if and only if regular expression re
+  // matches a substring of str (including str itself).
+  static bool FullMatch(const ::std::string& str, const RE& re) {
+    return FullMatch(str.c_str(), re);
+  }
+  static bool PartialMatch(const ::std::string& str, const RE& re) {
+    return PartialMatch(str.c_str(), re);
+  }
+
+  static bool FullMatch(const char* str, const RE& re);
+  static bool PartialMatch(const char* str, const RE& re);
+
+ private:
+  void Init(const char* regex);
+  const char* pattern_;
+  bool is_valid_;
+
+# if GTEST_USES_POSIX_RE
+
+  regex_t full_regex_;     // For FullMatch().
+  regex_t partial_regex_;  // For PartialMatch().
+
+# else  // GTEST_USES_SIMPLE_RE
+
+  const char* full_pattern_;  // For FullMatch();
+
+# endif
+};
+
+#endif  // GTEST_USES_PCRE
+
+// Formats a source file path and a line number as they would appear
+// in an error message from the compiler used to compile this code.
+GTEST_API_ ::std::string FormatFileLocation(const char* file, int line);
+
+// Formats a file location for compiler-independent XML output.
+// Although this function is not platform dependent, we put it next to
+// FormatFileLocation in order to contrast the two functions.
+GTEST_API_ ::std::string FormatCompilerIndependentFileLocation(const char* file,
+                                                               int line);
+
+// Defines logging utilities:
+//   GTEST_LOG_(severity) - logs messages at the specified severity level. The
+//                          message itself is streamed into the macro.
+//   LogToStderr()  - directs all log messages to stderr.
+//   FlushInfoLog() - flushes informational log messages.
+
+enum GTestLogSeverity {
+  GTEST_INFO,
+  GTEST_WARNING,
+  GTEST_ERROR,
+  GTEST_FATAL
+};
+
+// Formats log entry severity, provides a stream object for streaming the
+// log message, and terminates the message with a newline when going out of
+// scope.
+class GTEST_API_ GTestLog {
+ public:
+  GTestLog(GTestLogSeverity severity, const char* file, int line);
+
+  // Flushes the buffers and, if severity is GTEST_FATAL, aborts the program.
+  ~GTestLog();
+
+  ::std::ostream& GetStream() { return ::std::cerr; }
+
+ private:
+  const GTestLogSeverity severity_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(GTestLog);
+};
+
+#if !defined(GTEST_LOG_)
+
+# define GTEST_LOG_(severity) \
+    ::testing::internal::GTestLog(::testing::internal::GTEST_##severity, \
+                                  __FILE__, __LINE__).GetStream()
+
+inline void LogToStderr() {}
+inline void FlushInfoLog() { fflush(nullptr); }
+
+#endif  // !defined(GTEST_LOG_)
+
+#if !defined(GTEST_CHECK_)
+// INTERNAL IMPLEMENTATION - DO NOT USE.
+//
+// GTEST_CHECK_ is an all-mode assert. It aborts the program if the condition
+// is not satisfied.
+//  Synopsys:
+//    GTEST_CHECK_(boolean_condition);
+//     or
+//    GTEST_CHECK_(boolean_condition) << "Additional message";
+//
+//    This checks the condition and if the condition is not satisfied
+//    it prints message about the condition violation, including the
+//    condition itself, plus additional message streamed into it, if any,
+//    and then it aborts the program. It aborts the program irrespective of
+//    whether it is built in the debug mode or not.
+# define GTEST_CHECK_(condition) \
+    GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
+    if (::testing::internal::IsTrue(condition)) \
+      ; \
+    else \
+      GTEST_LOG_(FATAL) << "Condition " #condition " failed. "
+#endif  // !defined(GTEST_CHECK_)
+
+// An all-mode assert to verify that the given POSIX-style function
+// call returns 0 (indicating success).  Known limitation: this
+// doesn't expand to a balanced 'if' statement, so enclose the macro
+// in {} if you need to use it as the only statement in an 'if'
+// branch.
+#define GTEST_CHECK_POSIX_SUCCESS_(posix_call) \
+  if (const int gtest_error = (posix_call)) \
+    GTEST_LOG_(FATAL) << #posix_call << "failed with error " \
+                      << gtest_error
+
+// Transforms "T" into "const T&" according to standard reference collapsing
+// rules (this is only needed as a backport for C++98 compilers that do not
+// support reference collapsing). Specifically, it transforms:
+//
+//   char         ==> const char&
+//   const char   ==> const char&
+//   char&        ==> char&
+//   const char&  ==> const char&
+//
+// Note that the non-const reference will not have "const" added. This is
+// standard, and necessary so that "T" can always bind to "const T&".
+template <typename T>
+struct ConstRef { typedef const T& type; };
+template <typename T>
+struct ConstRef<T&> { typedef T& type; };
+
+// The argument T must depend on some template parameters.
+#define GTEST_REFERENCE_TO_CONST_(T) \
+  typename ::testing::internal::ConstRef<T>::type
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// Use ImplicitCast_ as a safe version of static_cast for upcasting in
+// the type hierarchy (e.g. casting a Foo* to a SuperclassOfFoo* or a
+// const Foo*).  When you use ImplicitCast_, the compiler checks that
+// the cast is safe.  Such explicit ImplicitCast_s are necessary in
+// surprisingly many situations where C++ demands an exact type match
+// instead of an argument type convertable to a target type.
+//
+// The syntax for using ImplicitCast_ is the same as for static_cast:
+//
+//   ImplicitCast_<ToType>(expr)
+//
+// ImplicitCast_ would have been part of the C++ standard library,
+// but the proposal was submitted too late.  It will probably make
+// its way into the language in the future.
+//
+// This relatively ugly name is intentional. It prevents clashes with
+// similar functions users may have (e.g., implicit_cast). The internal
+// namespace alone is not enough because the function can be found by ADL.
+template<typename To>
+inline To ImplicitCast_(To x) { return x; }
+
+// When you upcast (that is, cast a pointer from type Foo to type
+// SuperclassOfFoo), it's fine to use ImplicitCast_<>, since upcasts
+// always succeed.  When you downcast (that is, cast a pointer from
+// type Foo to type SubclassOfFoo), static_cast<> isn't safe, because
+// how do you know the pointer is really of type SubclassOfFoo?  It
+// could be a bare Foo, or of type DifferentSubclassOfFoo.  Thus,
+// when you downcast, you should use this macro.  In debug mode, we
+// use dynamic_cast<> to double-check the downcast is legal (we die
+// if it's not).  In normal mode, we do the efficient static_cast<>
+// instead.  Thus, it's important to test in debug mode to make sure
+// the cast is legal!
+//    This is the only place in the code we should use dynamic_cast<>.
+// In particular, you SHOULDN'T be using dynamic_cast<> in order to
+// do RTTI (eg code like this:
+//    if (dynamic_cast<Subclass1>(foo)) HandleASubclass1Object(foo);
+//    if (dynamic_cast<Subclass2>(foo)) HandleASubclass2Object(foo);
+// You should design the code some other way not to need this.
+//
+// This relatively ugly name is intentional. It prevents clashes with
+// similar functions users may have (e.g., down_cast). The internal
+// namespace alone is not enough because the function can be found by ADL.
+template<typename To, typename From>  // use like this: DownCast_<T*>(foo);
+inline To DownCast_(From* f) {  // so we only accept pointers
+  // Ensures that To is a sub-type of From *.  This test is here only
+  // for compile-time type checking, and has no overhead in an
+  // optimized build at run-time, as it will be optimized away
+  // completely.
+  GTEST_INTENTIONAL_CONST_COND_PUSH_()
+  if (false) {
+  GTEST_INTENTIONAL_CONST_COND_POP_()
+  const To to = nullptr;
+  ::testing::internal::ImplicitCast_<From*>(to);
+  }
+
+#if GTEST_HAS_RTTI
+  // RTTI: debug mode only!
+  GTEST_CHECK_(f == nullptr || dynamic_cast<To>(f) != nullptr);
+#endif
+  return static_cast<To>(f);
+}
+
+// Downcasts the pointer of type Base to Derived.
+// Derived must be a subclass of Base. The parameter MUST
+// point to a class of type Derived, not any subclass of it.
+// When RTTI is available, the function performs a runtime
+// check to enforce this.
+template <class Derived, class Base>
+Derived* CheckedDowncastToActualType(Base* base) {
+#if GTEST_HAS_RTTI
+  GTEST_CHECK_(typeid(*base) == typeid(Derived));
+#endif
+
+#if GTEST_HAS_DOWNCAST_
+  return ::down_cast<Derived*>(base);
+#elif GTEST_HAS_RTTI
+  return dynamic_cast<Derived*>(base);  // NOLINT
+#else
+  return static_cast<Derived*>(base);  // Poor man's downcast.
+#endif
+}
+
+#if GTEST_HAS_STREAM_REDIRECTION
+
+// Defines the stderr capturer:
+//   CaptureStdout     - starts capturing stdout.
+//   GetCapturedStdout - stops capturing stdout and returns the captured string.
+//   CaptureStderr     - starts capturing stderr.
+//   GetCapturedStderr - stops capturing stderr and returns the captured string.
+//
+GTEST_API_ void CaptureStdout();
+GTEST_API_ std::string GetCapturedStdout();
+GTEST_API_ void CaptureStderr();
+GTEST_API_ std::string GetCapturedStderr();
+
+#endif  // GTEST_HAS_STREAM_REDIRECTION
+// Returns the size (in bytes) of a file.
+GTEST_API_ size_t GetFileSize(FILE* file);
+
+// Reads the entire content of a file as a string.
+GTEST_API_ std::string ReadEntireFile(FILE* file);
+
+// All command line arguments.
+GTEST_API_ std::vector<std::string> GetArgvs();
+
+#if GTEST_HAS_DEATH_TEST
+
+std::vector<std::string> GetInjectableArgvs();
+// Deprecated: pass the args vector by value instead.
+void SetInjectableArgvs(const std::vector<std::string>* new_argvs);
+void SetInjectableArgvs(const std::vector<std::string>& new_argvs);
+void ClearInjectableArgvs();
+
+#endif  // GTEST_HAS_DEATH_TEST
+
+// Defines synchronization primitives.
+#if GTEST_IS_THREADSAFE
+# if GTEST_HAS_PTHREAD
+// Sleeps for (roughly) n milliseconds.  This function is only for testing
+// Google Test's own constructs.  Don't use it in user tests, either
+// directly or indirectly.
+inline void SleepMilliseconds(int n) {
+  const timespec time = {
+    0,                  // 0 seconds.
+    n * 1000L * 1000L,  // And n ms.
+  };
+  nanosleep(&time, nullptr);
+}
+# endif  // GTEST_HAS_PTHREAD
+
+# if GTEST_HAS_NOTIFICATION_
+// Notification has already been imported into the namespace.
+// Nothing to do here.
+
+# elif GTEST_HAS_PTHREAD
+// Allows a controller thread to pause execution of newly created
+// threads until notified.  Instances of this class must be created
+// and destroyed in the controller thread.
+//
+// This class is only for testing Google Test's own constructs. Do not
+// use it in user tests, either directly or indirectly.
+class Notification {
+ public:
+  Notification() : notified_(false) {
+    GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_init(&mutex_, nullptr));
+  }
+  ~Notification() {
+    pthread_mutex_destroy(&mutex_);
+  }
+
+  // Notifies all threads created with this notification to start. Must
+  // be called from the controller thread.
+  void Notify() {
+    pthread_mutex_lock(&mutex_);
+    notified_ = true;
+    pthread_mutex_unlock(&mutex_);
+  }
+
+  // Blocks until the controller thread notifies. Must be called from a test
+  // thread.
+  void WaitForNotification() {
+    for (;;) {
+      pthread_mutex_lock(&mutex_);
+      const bool notified = notified_;
+      pthread_mutex_unlock(&mutex_);
+      if (notified)
+        break;
+      SleepMilliseconds(10);
+    }
+  }
+
+ private:
+  pthread_mutex_t mutex_;
+  bool notified_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(Notification);
+};
+
+# elif GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT
+
+GTEST_API_ void SleepMilliseconds(int n);
+
+// Provides leak-safe Windows kernel handle ownership.
+// Used in death tests and in threading support.
+class GTEST_API_ AutoHandle {
+ public:
+  // Assume that Win32 HANDLE type is equivalent to void*. Doing so allows us to
+  // avoid including <windows.h> in this header file. Including <windows.h> is
+  // undesirable because it defines a lot of symbols and macros that tend to
+  // conflict with client code. This assumption is verified by
+  // WindowsTypesTest.HANDLEIsVoidStar.
+  typedef void* Handle;
+  AutoHandle();
+  explicit AutoHandle(Handle handle);
+
+  ~AutoHandle();
+
+  Handle Get() const;
+  void Reset();
+  void Reset(Handle handle);
+
+ private:
+  // Returns true if and only if the handle is a valid handle object that can be
+  // closed.
+  bool IsCloseable() const;
+
+  Handle handle_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(AutoHandle);
+};
+
+// Allows a controller thread to pause execution of newly created
+// threads until notified.  Instances of this class must be created
+// and destroyed in the controller thread.
+//
+// This class is only for testing Google Test's own constructs. Do not
+// use it in user tests, either directly or indirectly.
+class GTEST_API_ Notification {
+ public:
+  Notification();
+  void Notify();
+  void WaitForNotification();
+
+ private:
+  AutoHandle event_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(Notification);
+};
+# endif  // GTEST_HAS_NOTIFICATION_
+
+// On MinGW, we can have both GTEST_OS_WINDOWS and GTEST_HAS_PTHREAD
+// defined, but we don't want to use MinGW's pthreads implementation, which
+// has conformance problems with some versions of the POSIX standard.
+# if GTEST_HAS_PTHREAD && !GTEST_OS_WINDOWS_MINGW
+
+// As a C-function, ThreadFuncWithCLinkage cannot be templated itself.
+// Consequently, it cannot select a correct instantiation of ThreadWithParam
+// in order to call its Run(). Introducing ThreadWithParamBase as a
+// non-templated base class for ThreadWithParam allows us to bypass this
+// problem.
+class ThreadWithParamBase {
+ public:
+  virtual ~ThreadWithParamBase() {}
+  virtual void Run() = 0;
+};
+
+// pthread_create() accepts a pointer to a function type with the C linkage.
+// According to the Standard (7.5/1), function types with different linkages
+// are different even if they are otherwise identical.  Some compilers (for
+// example, SunStudio) treat them as different types.  Since class methods
+// cannot be defined with C-linkage we need to define a free C-function to
+// pass into pthread_create().
+extern "C" inline void* ThreadFuncWithCLinkage(void* thread) {
+  static_cast<ThreadWithParamBase*>(thread)->Run();
+  return nullptr;
+}
+
+// Helper class for testing Google Test's multi-threading constructs.
+// To use it, write:
+//
+//   void ThreadFunc(int param) { /* Do things with param */ }
+//   Notification thread_can_start;
+//   ...
+//   // The thread_can_start parameter is optional; you can supply NULL.
+//   ThreadWithParam<int> thread(&ThreadFunc, 5, &thread_can_start);
+//   thread_can_start.Notify();
+//
+// These classes are only for testing Google Test's own constructs. Do
+// not use them in user tests, either directly or indirectly.
+template <typename T>
+class ThreadWithParam : public ThreadWithParamBase {
+ public:
+  typedef void UserThreadFunc(T);
+
+  ThreadWithParam(UserThreadFunc* func, T param, Notification* thread_can_start)
+      : func_(func),
+        param_(param),
+        thread_can_start_(thread_can_start),
+        finished_(false) {
+    ThreadWithParamBase* const base = this;
+    // The thread can be created only after all fields except thread_
+    // have been initialized.
+    GTEST_CHECK_POSIX_SUCCESS_(
+        pthread_create(&thread_, nullptr, &ThreadFuncWithCLinkage, base));
+  }
+  ~ThreadWithParam() override { Join(); }
+
+  void Join() {
+    if (!finished_) {
+      GTEST_CHECK_POSIX_SUCCESS_(pthread_join(thread_, nullptr));
+      finished_ = true;
+    }
+  }
+
+  void Run() override {
+    if (thread_can_start_ != nullptr) thread_can_start_->WaitForNotification();
+    func_(param_);
+  }
+
+ private:
+  UserThreadFunc* const func_;  // User-supplied thread function.
+  const T param_;  // User-supplied parameter to the thread function.
+  // When non-NULL, used to block execution until the controller thread
+  // notifies.
+  Notification* const thread_can_start_;
+  bool finished_;  // true if and only if we know that the thread function has
+                   // finished.
+  pthread_t thread_;  // The native thread object.
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadWithParam);
+};
+# endif  // !GTEST_OS_WINDOWS && GTEST_HAS_PTHREAD ||
+         // GTEST_HAS_MUTEX_AND_THREAD_LOCAL_
+
+# if GTEST_HAS_MUTEX_AND_THREAD_LOCAL_
+// Mutex and ThreadLocal have already been imported into the namespace.
+// Nothing to do here.
+
+# elif GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT
+
+// Mutex implements mutex on Windows platforms.  It is used in conjunction
+// with class MutexLock:
+//
+//   Mutex mutex;
+//   ...
+//   MutexLock lock(&mutex);  // Acquires the mutex and releases it at the
+//                            // end of the current scope.
+//
+// A static Mutex *must* be defined or declared using one of the following
+// macros:
+//   GTEST_DEFINE_STATIC_MUTEX_(g_some_mutex);
+//   GTEST_DECLARE_STATIC_MUTEX_(g_some_mutex);
+//
+// (A non-static Mutex is defined/declared in the usual way).
+class GTEST_API_ Mutex {
+ public:
+  enum MutexType { kStatic = 0, kDynamic = 1 };
+  // We rely on kStaticMutex being 0 as it is to what the linker initializes
+  // type_ in static mutexes.  critical_section_ will be initialized lazily
+  // in ThreadSafeLazyInit().
+  enum StaticConstructorSelector { kStaticMutex = 0 };
+
+  // This constructor intentionally does nothing.  It relies on type_ being
+  // statically initialized to 0 (effectively setting it to kStatic) and on
+  // ThreadSafeLazyInit() to lazily initialize the rest of the members.
+  explicit Mutex(StaticConstructorSelector /*dummy*/) {}
+
+  Mutex();
+  ~Mutex();
+
+  void Lock();
+
+  void Unlock();
+
+  // Does nothing if the current thread holds the mutex. Otherwise, crashes
+  // with high probability.
+  void AssertHeld();
+
+ private:
+  // Initializes owner_thread_id_ and critical_section_ in static mutexes.
+  void ThreadSafeLazyInit();
+
+  // Per https://blogs.msdn.microsoft.com/oldnewthing/20040223-00/?p=40503,
+  // we assume that 0 is an invalid value for thread IDs.
+  unsigned int owner_thread_id_;
+
+  // For static mutexes, we rely on these members being initialized to zeros
+  // by the linker.
+  MutexType type_;
+  long critical_section_init_phase_;  // NOLINT
+  GTEST_CRITICAL_SECTION* critical_section_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(Mutex);
+};
+
+# define GTEST_DECLARE_STATIC_MUTEX_(mutex) \
+    extern ::testing::internal::Mutex mutex
+
+# define GTEST_DEFINE_STATIC_MUTEX_(mutex) \
+    ::testing::internal::Mutex mutex(::testing::internal::Mutex::kStaticMutex)
+
+// We cannot name this class MutexLock because the ctor declaration would
+// conflict with a macro named MutexLock, which is defined on some
+// platforms. That macro is used as a defensive measure to prevent against
+// inadvertent misuses of MutexLock like "MutexLock(&mu)" rather than
+// "MutexLock l(&mu)".  Hence the typedef trick below.
+class GTestMutexLock {
+ public:
+  explicit GTestMutexLock(Mutex* mutex)
+      : mutex_(mutex) { mutex_->Lock(); }
+
+  ~GTestMutexLock() { mutex_->Unlock(); }
+
+ private:
+  Mutex* const mutex_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(GTestMutexLock);
+};
+
+typedef GTestMutexLock MutexLock;
+
+// Base class for ValueHolder<T>.  Allows a caller to hold and delete a value
+// without knowing its type.
+class ThreadLocalValueHolderBase {
+ public:
+  virtual ~ThreadLocalValueHolderBase() {}
+};
+
+// Provides a way for a thread to send notifications to a ThreadLocal
+// regardless of its parameter type.
+class ThreadLocalBase {
+ public:
+  // Creates a new ValueHolder<T> object holding a default value passed to
+  // this ThreadLocal<T>'s constructor and returns it.  It is the caller's
+  // responsibility not to call this when the ThreadLocal<T> instance already
+  // has a value on the current thread.
+  virtual ThreadLocalValueHolderBase* NewValueForCurrentThread() const = 0;
+
+ protected:
+  ThreadLocalBase() {}
+  virtual ~ThreadLocalBase() {}
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadLocalBase);
+};
+
+// Maps a thread to a set of ThreadLocals that have values instantiated on that
+// thread and notifies them when the thread exits.  A ThreadLocal instance is
+// expected to persist until all threads it has values on have terminated.
+class GTEST_API_ ThreadLocalRegistry {
+ public:
+  // Registers thread_local_instance as having value on the current thread.
+  // Returns a value that can be used to identify the thread from other threads.
+  static ThreadLocalValueHolderBase* GetValueOnCurrentThread(
+      const ThreadLocalBase* thread_local_instance);
+
+  // Invoked when a ThreadLocal instance is destroyed.
+  static void OnThreadLocalDestroyed(
+      const ThreadLocalBase* thread_local_instance);
+};
+
+class GTEST_API_ ThreadWithParamBase {
+ public:
+  void Join();
+
+ protected:
+  class Runnable {
+   public:
+    virtual ~Runnable() {}
+    virtual void Run() = 0;
+  };
+
+  ThreadWithParamBase(Runnable *runnable, Notification* thread_can_start);
+  virtual ~ThreadWithParamBase();
+
+ private:
+  AutoHandle thread_;
+};
+
+// Helper class for testing Google Test's multi-threading constructs.
+template <typename T>
+class ThreadWithParam : public ThreadWithParamBase {
+ public:
+  typedef void UserThreadFunc(T);
+
+  ThreadWithParam(UserThreadFunc* func, T param, Notification* thread_can_start)
+      : ThreadWithParamBase(new RunnableImpl(func, param), thread_can_start) {
+  }
+  virtual ~ThreadWithParam() {}
+
+ private:
+  class RunnableImpl : public Runnable {
+   public:
+    RunnableImpl(UserThreadFunc* func, T param)
+        : func_(func),
+          param_(param) {
+    }
+    virtual ~RunnableImpl() {}
+    virtual void Run() {
+      func_(param_);
+    }
+
+   private:
+    UserThreadFunc* const func_;
+    const T param_;
+
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(RunnableImpl);
+  };
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadWithParam);
+};
+
+// Implements thread-local storage on Windows systems.
+//
+//   // Thread 1
+//   ThreadLocal<int> tl(100);  // 100 is the default value for each thread.
+//
+//   // Thread 2
+//   tl.set(150);  // Changes the value for thread 2 only.
+//   EXPECT_EQ(150, tl.get());
+//
+//   // Thread 1
+//   EXPECT_EQ(100, tl.get());  // In thread 1, tl has the original value.
+//   tl.set(200);
+//   EXPECT_EQ(200, tl.get());
+//
+// The template type argument T must have a public copy constructor.
+// In addition, the default ThreadLocal constructor requires T to have
+// a public default constructor.
+//
+// The users of a TheadLocal instance have to make sure that all but one
+// threads (including the main one) using that instance have exited before
+// destroying it. Otherwise, the per-thread objects managed for them by the
+// ThreadLocal instance are not guaranteed to be destroyed on all platforms.
+//
+// Google Test only uses global ThreadLocal objects.  That means they
+// will die after main() has returned.  Therefore, no per-thread
+// object managed by Google Test will be leaked as long as all threads
+// using Google Test have exited when main() returns.
+template <typename T>
+class ThreadLocal : public ThreadLocalBase {
+ public:
+  ThreadLocal() : default_factory_(new DefaultValueHolderFactory()) {}
+  explicit ThreadLocal(const T& value)
+      : default_factory_(new InstanceValueHolderFactory(value)) {}
+
+  ~ThreadLocal() { ThreadLocalRegistry::OnThreadLocalDestroyed(this); }
+
+  T* pointer() { return GetOrCreateValue(); }
+  const T* pointer() const { return GetOrCreateValue(); }
+  const T& get() const { return *pointer(); }
+  void set(const T& value) { *pointer() = value; }
+
+ private:
+  // Holds a value of T.  Can be deleted via its base class without the caller
+  // knowing the type of T.
+  class ValueHolder : public ThreadLocalValueHolderBase {
+   public:
+    ValueHolder() : value_() {}
+    explicit ValueHolder(const T& value) : value_(value) {}
+
+    T* pointer() { return &value_; }
+
+   private:
+    T value_;
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(ValueHolder);
+  };
+
+
+  T* GetOrCreateValue() const {
+    return static_cast<ValueHolder*>(
+        ThreadLocalRegistry::GetValueOnCurrentThread(this))->pointer();
+  }
+
+  virtual ThreadLocalValueHolderBase* NewValueForCurrentThread() const {
+    return default_factory_->MakeNewHolder();
+  }
+
+  class ValueHolderFactory {
+   public:
+    ValueHolderFactory() {}
+    virtual ~ValueHolderFactory() {}
+    virtual ValueHolder* MakeNewHolder() const = 0;
+
+   private:
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(ValueHolderFactory);
+  };
+
+  class DefaultValueHolderFactory : public ValueHolderFactory {
+   public:
+    DefaultValueHolderFactory() {}
+    ValueHolder* MakeNewHolder() const override { return new ValueHolder(); }
+
+   private:
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(DefaultValueHolderFactory);
+  };
+
+  class InstanceValueHolderFactory : public ValueHolderFactory {
+   public:
+    explicit InstanceValueHolderFactory(const T& value) : value_(value) {}
+    ValueHolder* MakeNewHolder() const override {
+      return new ValueHolder(value_);
+    }
+
+   private:
+    const T value_;  // The value for each thread.
+
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(InstanceValueHolderFactory);
+  };
+
+  std::unique_ptr<ValueHolderFactory> default_factory_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadLocal);
+};
+
+# elif GTEST_HAS_PTHREAD
+
+// MutexBase and Mutex implement mutex on pthreads-based platforms.
+class MutexBase {
+ public:
+  // Acquires this mutex.
+  void Lock() {
+    GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_lock(&mutex_));
+    owner_ = pthread_self();
+    has_owner_ = true;
+  }
+
+  // Releases this mutex.
+  void Unlock() {
+    // Since the lock is being released the owner_ field should no longer be
+    // considered valid. We don't protect writing to has_owner_ here, as it's
+    // the caller's responsibility to ensure that the current thread holds the
+    // mutex when this is called.
+    has_owner_ = false;
+    GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_unlock(&mutex_));
+  }
+
+  // Does nothing if the current thread holds the mutex. Otherwise, crashes
+  // with high probability.
+  void AssertHeld() const {
+    GTEST_CHECK_(has_owner_ && pthread_equal(owner_, pthread_self()))
+        << "The current thread is not holding the mutex @" << this;
+  }
+
+  // A static mutex may be used before main() is entered.  It may even
+  // be used before the dynamic initialization stage.  Therefore we
+  // must be able to initialize a static mutex object at link time.
+  // This means MutexBase has to be a POD and its member variables
+  // have to be public.
+ public:
+  pthread_mutex_t mutex_;  // The underlying pthread mutex.
+  // has_owner_ indicates whether the owner_ field below contains a valid thread
+  // ID and is therefore safe to inspect (e.g., to use in pthread_equal()). All
+  // accesses to the owner_ field should be protected by a check of this field.
+  // An alternative might be to memset() owner_ to all zeros, but there's no
+  // guarantee that a zero'd pthread_t is necessarily invalid or even different
+  // from pthread_self().
+  bool has_owner_;
+  pthread_t owner_;  // The thread holding the mutex.
+};
+
+// Forward-declares a static mutex.
+#  define GTEST_DECLARE_STATIC_MUTEX_(mutex) \
+     extern ::testing::internal::MutexBase mutex
+
+// Defines and statically (i.e. at link time) initializes a static mutex.
+// The initialization list here does not explicitly initialize each field,
+// instead relying on default initialization for the unspecified fields. In
+// particular, the owner_ field (a pthread_t) is not explicitly initialized.
+// This allows initialization to work whether pthread_t is a scalar or struct.
+// The flag -Wmissing-field-initializers must not be specified for this to work.
+#define GTEST_DEFINE_STATIC_MUTEX_(mutex) \
+  ::testing::internal::MutexBase mutex = {PTHREAD_MUTEX_INITIALIZER, false, 0}
+
+// The Mutex class can only be used for mutexes created at runtime. It
+// shares its API with MutexBase otherwise.
+class Mutex : public MutexBase {
+ public:
+  Mutex() {
+    GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_init(&mutex_, nullptr));
+    has_owner_ = false;
+  }
+  ~Mutex() {
+    GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_destroy(&mutex_));
+  }
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(Mutex);
+};
+
+// We cannot name this class MutexLock because the ctor declaration would
+// conflict with a macro named MutexLock, which is defined on some
+// platforms. That macro is used as a defensive measure to prevent against
+// inadvertent misuses of MutexLock like "MutexLock(&mu)" rather than
+// "MutexLock l(&mu)".  Hence the typedef trick below.
+class GTestMutexLock {
+ public:
+  explicit GTestMutexLock(MutexBase* mutex)
+      : mutex_(mutex) { mutex_->Lock(); }
+
+  ~GTestMutexLock() { mutex_->Unlock(); }
+
+ private:
+  MutexBase* const mutex_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(GTestMutexLock);
+};
+
+typedef GTestMutexLock MutexLock;
+
+// Helpers for ThreadLocal.
+
+// pthread_key_create() requires DeleteThreadLocalValue() to have
+// C-linkage.  Therefore it cannot be templatized to access
+// ThreadLocal<T>.  Hence the need for class
+// ThreadLocalValueHolderBase.
+class ThreadLocalValueHolderBase {
+ public:
+  virtual ~ThreadLocalValueHolderBase() {}
+};
+
+// Called by pthread to delete thread-local data stored by
+// pthread_setspecific().
+extern "C" inline void DeleteThreadLocalValue(void* value_holder) {
+  delete static_cast<ThreadLocalValueHolderBase*>(value_holder);
+}
+
+// Implements thread-local storage on pthreads-based systems.
+template <typename T>
+class GTEST_API_ ThreadLocal {
+ public:
+  ThreadLocal()
+      : key_(CreateKey()), default_factory_(new DefaultValueHolderFactory()) {}
+  explicit ThreadLocal(const T& value)
+      : key_(CreateKey()),
+        default_factory_(new InstanceValueHolderFactory(value)) {}
+
+  ~ThreadLocal() {
+    // Destroys the managed object for the current thread, if any.
+    DeleteThreadLocalValue(pthread_getspecific(key_));
+
+    // Releases resources associated with the key.  This will *not*
+    // delete managed objects for other threads.
+    GTEST_CHECK_POSIX_SUCCESS_(pthread_key_delete(key_));
+  }
+
+  T* pointer() { return GetOrCreateValue(); }
+  const T* pointer() const { return GetOrCreateValue(); }
+  const T& get() const { return *pointer(); }
+  void set(const T& value) { *pointer() = value; }
+
+ private:
+  // Holds a value of type T.
+  class ValueHolder : public ThreadLocalValueHolderBase {
+   public:
+    ValueHolder() : value_() {}
+    explicit ValueHolder(const T& value) : value_(value) {}
+
+    T* pointer() { return &value_; }
+
+   private:
+    T value_;
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(ValueHolder);
+  };
+
+  static pthread_key_t CreateKey() {
+    pthread_key_t key;
+    // When a thread exits, DeleteThreadLocalValue() will be called on
+    // the object managed for that thread.
+    GTEST_CHECK_POSIX_SUCCESS_(
+        pthread_key_create(&key, &DeleteThreadLocalValue));
+    return key;
+  }
+
+  T* GetOrCreateValue() const {
+    ThreadLocalValueHolderBase* const holder =
+        static_cast<ThreadLocalValueHolderBase*>(pthread_getspecific(key_));
+    if (holder != nullptr) {
+      return CheckedDowncastToActualType<ValueHolder>(holder)->pointer();
+    }
+
+    ValueHolder* const new_holder = default_factory_->MakeNewHolder();
+    ThreadLocalValueHolderBase* const holder_base = new_holder;
+    GTEST_CHECK_POSIX_SUCCESS_(pthread_setspecific(key_, holder_base));
+    return new_holder->pointer();
+  }
+
+  class ValueHolderFactory {
+   public:
+    ValueHolderFactory() {}
+    virtual ~ValueHolderFactory() {}
+    virtual ValueHolder* MakeNewHolder() const = 0;
+
+   private:
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(ValueHolderFactory);
+  };
+
+  class DefaultValueHolderFactory : public ValueHolderFactory {
+   public:
+    DefaultValueHolderFactory() {}
+    ValueHolder* MakeNewHolder() const override { return new ValueHolder(); }
+
+   private:
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(DefaultValueHolderFactory);
+  };
+
+  class InstanceValueHolderFactory : public ValueHolderFactory {
+   public:
+    explicit InstanceValueHolderFactory(const T& value) : value_(value) {}
+    ValueHolder* MakeNewHolder() const override {
+      return new ValueHolder(value_);
+    }
+
+   private:
+    const T value_;  // The value for each thread.
+
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(InstanceValueHolderFactory);
+  };
+
+  // A key pthreads uses for looking up per-thread values.
+  const pthread_key_t key_;
+  std::unique_ptr<ValueHolderFactory> default_factory_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadLocal);
+};
+
+# endif  // GTEST_HAS_MUTEX_AND_THREAD_LOCAL_
+
+#else  // GTEST_IS_THREADSAFE
+
+// A dummy implementation of synchronization primitives (mutex, lock,
+// and thread-local variable).  Necessary for compiling Google Test where
+// mutex is not supported - using Google Test in multiple threads is not
+// supported on such platforms.
+
+class Mutex {
+ public:
+  Mutex() {}
+  void Lock() {}
+  void Unlock() {}
+  void AssertHeld() const {}
+};
+
+# define GTEST_DECLARE_STATIC_MUTEX_(mutex) \
+  extern ::testing::internal::Mutex mutex
+
+# define GTEST_DEFINE_STATIC_MUTEX_(mutex) ::testing::internal::Mutex mutex
+
+// We cannot name this class MutexLock because the ctor declaration would
+// conflict with a macro named MutexLock, which is defined on some
+// platforms. That macro is used as a defensive measure to prevent against
+// inadvertent misuses of MutexLock like "MutexLock(&mu)" rather than
+// "MutexLock l(&mu)".  Hence the typedef trick below.
+class GTestMutexLock {
+ public:
+  explicit GTestMutexLock(Mutex*) {}  // NOLINT
+};
+
+typedef GTestMutexLock MutexLock;
+
+template <typename T>
+class GTEST_API_ ThreadLocal {
+ public:
+  ThreadLocal() : value_() {}
+  explicit ThreadLocal(const T& value) : value_(value) {}
+  T* pointer() { return &value_; }
+  const T* pointer() const { return &value_; }
+  const T& get() const { return value_; }
+  void set(const T& value) { value_ = value; }
+ private:
+  T value_;
+};
+
+#endif  // GTEST_IS_THREADSAFE
+
+// Returns the number of threads running in the process, or 0 to indicate that
+// we cannot detect it.
+GTEST_API_ size_t GetThreadCount();
+
+#if GTEST_OS_WINDOWS
+# define GTEST_PATH_SEP_ "\\"
+# define GTEST_HAS_ALT_PATH_SEP_ 1
+#else
+# define GTEST_PATH_SEP_ "/"
+# define GTEST_HAS_ALT_PATH_SEP_ 0
+#endif  // GTEST_OS_WINDOWS
+
+// Utilities for char.
+
+// isspace(int ch) and friends accept an unsigned char or EOF.  char
+// may be signed, depending on the compiler (or compiler flags).
+// Therefore we need to cast a char to unsigned char before calling
+// isspace(), etc.
+
+inline bool IsAlpha(char ch) {
+  return isalpha(static_cast<unsigned char>(ch)) != 0;
+}
+inline bool IsAlNum(char ch) {
+  return isalnum(static_cast<unsigned char>(ch)) != 0;
+}
+inline bool IsDigit(char ch) {
+  return isdigit(static_cast<unsigned char>(ch)) != 0;
+}
+inline bool IsLower(char ch) {
+  return islower(static_cast<unsigned char>(ch)) != 0;
+}
+inline bool IsSpace(char ch) {
+  return isspace(static_cast<unsigned char>(ch)) != 0;
+}
+inline bool IsUpper(char ch) {
+  return isupper(static_cast<unsigned char>(ch)) != 0;
+}
+inline bool IsXDigit(char ch) {
+  return isxdigit(static_cast<unsigned char>(ch)) != 0;
+}
+#ifdef __cpp_char8_t
+inline bool IsXDigit(char8_t ch) {
+  return isxdigit(static_cast<unsigned char>(ch)) != 0;
+}
+#endif
+inline bool IsXDigit(char16_t ch) {
+  const unsigned char low_byte = static_cast<unsigned char>(ch);
+  return ch == low_byte && isxdigit(low_byte) != 0;
+}
+inline bool IsXDigit(char32_t ch) {
+  const unsigned char low_byte = static_cast<unsigned char>(ch);
+  return ch == low_byte && isxdigit(low_byte) != 0;
+}
+inline bool IsXDigit(wchar_t ch) {
+  const unsigned char low_byte = static_cast<unsigned char>(ch);
+  return ch == low_byte && isxdigit(low_byte) != 0;
+}
+
+inline char ToLower(char ch) {
+  return static_cast<char>(tolower(static_cast<unsigned char>(ch)));
+}
+inline char ToUpper(char ch) {
+  return static_cast<char>(toupper(static_cast<unsigned char>(ch)));
+}
+
+inline std::string StripTrailingSpaces(std::string str) {
+  std::string::iterator it = str.end();
+  while (it != str.begin() && IsSpace(*--it))
+    it = str.erase(it);
+  return str;
+}
+
+// The testing::internal::posix namespace holds wrappers for common
+// POSIX functions.  These wrappers hide the differences between
+// Windows/MSVC and POSIX systems.  Since some compilers define these
+// standard functions as macros, the wrapper cannot have the same name
+// as the wrapped function.
+
+namespace posix {
+
+// Functions with a different name on Windows.
+
+#if GTEST_OS_WINDOWS
+
+typedef struct _stat StatStruct;
+
+# ifdef __BORLANDC__
+inline int DoIsATTY(int fd) { return isatty(fd); }
+inline int StrCaseCmp(const char* s1, const char* s2) {
+  return stricmp(s1, s2);
+}
+inline char* StrDup(const char* src) { return strdup(src); }
+# else  // !__BORLANDC__
+#  if GTEST_OS_WINDOWS_MOBILE
+inline int DoIsATTY(int /* fd */) { return 0; }
+#  else
+inline int DoIsATTY(int fd) { return _isatty(fd); }
+#  endif  // GTEST_OS_WINDOWS_MOBILE
+inline int StrCaseCmp(const char* s1, const char* s2) {
+  return _stricmp(s1, s2);
+}
+inline char* StrDup(const char* src) { return _strdup(src); }
+# endif  // __BORLANDC__
+
+# if GTEST_OS_WINDOWS_MOBILE
+inline int FileNo(FILE* file) { return reinterpret_cast<int>(_fileno(file)); }
+// Stat(), RmDir(), and IsDir() are not needed on Windows CE at this
+// time and thus not defined there.
+# else
+inline int FileNo(FILE* file) { return _fileno(file); }
+inline int Stat(const char* path, StatStruct* buf) { return _stat(path, buf); }
+inline int RmDir(const char* dir) { return _rmdir(dir); }
+inline bool IsDir(const StatStruct& st) {
+  return (_S_IFDIR & st.st_mode) != 0;
+}
+# endif  // GTEST_OS_WINDOWS_MOBILE
+
+#elif GTEST_OS_ESP8266
+typedef struct stat StatStruct;
+
+inline int FileNo(FILE* file) { return fileno(file); }
+inline int DoIsATTY(int fd) { return isatty(fd); }
+inline int Stat(const char* path, StatStruct* buf) {
+  // stat function not implemented on ESP8266
+  return 0;
+}
+inline int StrCaseCmp(const char* s1, const char* s2) {
+  return strcasecmp(s1, s2);
+}
+inline char* StrDup(const char* src) { return strdup(src); }
+inline int RmDir(const char* dir) { return rmdir(dir); }
+inline bool IsDir(const StatStruct& st) { return S_ISDIR(st.st_mode); }
+
+#else
+
+typedef struct stat StatStruct;
+
+inline int FileNo(FILE* file) { return fileno(file); }
+inline int DoIsATTY(int fd) { return isatty(fd); }
+inline int Stat(const char* path, StatStruct* buf) { return stat(path, buf); }
+inline int StrCaseCmp(const char* s1, const char* s2) {
+  return strcasecmp(s1, s2);
+}
+inline char* StrDup(const char* src) { return strdup(src); }
+inline int RmDir(const char* dir) { return rmdir(dir); }
+inline bool IsDir(const StatStruct& st) { return S_ISDIR(st.st_mode); }
+
+#endif  // GTEST_OS_WINDOWS
+
+inline int IsATTY(int fd) {
+  // DoIsATTY might change errno (for example ENOTTY in case you redirect stdout
+  // to a file on Linux), which is unexpected, so save the previous value, and
+  // restore it after the call.
+  int savedErrno = errno;
+  int isAttyValue = DoIsATTY(fd);
+  errno = savedErrno;
+
+  return isAttyValue;
+}
+
+// Functions deprecated by MSVC 8.0.
+
+GTEST_DISABLE_MSC_DEPRECATED_PUSH_()
+
+// ChDir(), FReopen(), FDOpen(), Read(), Write(), Close(), and
+// StrError() aren't needed on Windows CE at this time and thus not
+// defined there.
+
+#if !GTEST_OS_WINDOWS_MOBILE && !GTEST_OS_WINDOWS_PHONE && \
+    !GTEST_OS_WINDOWS_RT && !GTEST_OS_ESP8266 && !GTEST_OS_XTENSA
+inline int ChDir(const char* dir) { return chdir(dir); }
+#endif
+inline FILE* FOpen(const char* path, const char* mode) {
+#if GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MINGW
+  struct wchar_codecvt : public std::codecvt<wchar_t, char, std::mbstate_t> {};
+  std::wstring_convert<wchar_codecvt> converter;
+  std::wstring wide_path = converter.from_bytes(path);
+  std::wstring wide_mode = converter.from_bytes(mode);
+  return _wfopen(wide_path.c_str(), wide_mode.c_str());
+#else  // GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MINGW
+  return fopen(path, mode);
+#endif  // GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_MINGW
+}
+#if !GTEST_OS_WINDOWS_MOBILE
+inline FILE *FReopen(const char* path, const char* mode, FILE* stream) {
+  return freopen(path, mode, stream);
+}
+inline FILE* FDOpen(int fd, const char* mode) { return fdopen(fd, mode); }
+#endif
+inline int FClose(FILE* fp) { return fclose(fp); }
+#if !GTEST_OS_WINDOWS_MOBILE
+inline int Read(int fd, void* buf, unsigned int count) {
+  return static_cast<int>(read(fd, buf, count));
+}
+inline int Write(int fd, const void* buf, unsigned int count) {
+  return static_cast<int>(write(fd, buf, count));
+}
+inline int Close(int fd) { return close(fd); }
+inline const char* StrError(int errnum) { return strerror(errnum); }
+#endif
+inline const char* GetEnv(const char* name) {
+#if GTEST_OS_WINDOWS_MOBILE || GTEST_OS_WINDOWS_PHONE || \
+    GTEST_OS_WINDOWS_RT || GTEST_OS_ESP8266 || GTEST_OS_XTENSA
+  // We are on an embedded platform, which has no environment variables.
+  static_cast<void>(name);  // To prevent 'unused argument' warning.
+  return nullptr;
+#elif defined(__BORLANDC__) || defined(__SunOS_5_8) || defined(__SunOS_5_9)
+  // Environment variables which we programmatically clear will be set to the
+  // empty string rather than unset (NULL).  Handle that case.
+  const char* const env = getenv(name);
+  return (env != nullptr && env[0] != '\0') ? env : nullptr;
+#else
+  return getenv(name);
+#endif
+}
+
+GTEST_DISABLE_MSC_DEPRECATED_POP_()
+
+#if GTEST_OS_WINDOWS_MOBILE
+// Windows CE has no C library. The abort() function is used in
+// several places in Google Test. This implementation provides a reasonable
+// imitation of standard behaviour.
+[[noreturn]] void Abort();
+#else
+[[noreturn]] inline void Abort() { abort(); }
+#endif  // GTEST_OS_WINDOWS_MOBILE
+
+}  // namespace posix
+
+// MSVC "deprecates" snprintf and issues warnings wherever it is used.  In
+// order to avoid these warnings, we need to use _snprintf or _snprintf_s on
+// MSVC-based platforms.  We map the GTEST_SNPRINTF_ macro to the appropriate
+// function in order to achieve that.  We use macro definition here because
+// snprintf is a variadic function.
+#if _MSC_VER && !GTEST_OS_WINDOWS_MOBILE
+// MSVC 2005 and above support variadic macros.
+# define GTEST_SNPRINTF_(buffer, size, format, ...) \
+     _snprintf_s(buffer, size, size, format, __VA_ARGS__)
+#elif defined(_MSC_VER)
+// Windows CE does not define _snprintf_s
+# define GTEST_SNPRINTF_ _snprintf
+#else
+# define GTEST_SNPRINTF_ snprintf
+#endif
+
+// The biggest signed integer type the compiler supports.
+//
+// long long is guaranteed to be at least 64-bits in C++11.
+using BiggestInt = long long;  // NOLINT
+
+// The maximum number a BiggestInt can represent.
+constexpr BiggestInt kMaxBiggestInt = (std::numeric_limits<BiggestInt>::max)();
+
+// This template class serves as a compile-time function from size to
+// type.  It maps a size in bytes to a primitive type with that
+// size. e.g.
+//
+//   TypeWithSize<4>::UInt
+//
+// is typedef-ed to be unsigned int (unsigned integer made up of 4
+// bytes).
+//
+// Such functionality should belong to STL, but I cannot find it
+// there.
+//
+// Google Test uses this class in the implementation of floating-point
+// comparison.
+//
+// For now it only handles UInt (unsigned int) as that's all Google Test
+// needs.  Other types can be easily added in the future if need
+// arises.
+template <size_t size>
+class TypeWithSize {
+ public:
+  // This prevents the user from using TypeWithSize<N> with incorrect
+  // values of N.
+  using UInt = void;
+};
+
+// The specialization for size 4.
+template <>
+class TypeWithSize<4> {
+ public:
+  using Int = std::int32_t;
+  using UInt = std::uint32_t;
+};
+
+// The specialization for size 8.
+template <>
+class TypeWithSize<8> {
+ public:
+  using Int = std::int64_t;
+  using UInt = std::uint64_t;
+};
+
+// Integer types of known sizes.
+using TimeInMillis = int64_t;  // Represents time in milliseconds.
+
+// Utilities for command line flags and environment variables.
+
+// Macro for referencing flags.
+#if !defined(GTEST_FLAG)
+# define GTEST_FLAG(name) FLAGS_gtest_##name
+#endif  // !defined(GTEST_FLAG)
+
+#if !defined(GTEST_USE_OWN_FLAGFILE_FLAG_)
+# define GTEST_USE_OWN_FLAGFILE_FLAG_ 1
+#endif  // !defined(GTEST_USE_OWN_FLAGFILE_FLAG_)
+
+#if !defined(GTEST_DECLARE_bool_)
+# define GTEST_FLAG_SAVER_ ::testing::internal::GTestFlagSaver
+
+// Macros for declaring flags.
+# define GTEST_DECLARE_bool_(name) GTEST_API_ extern bool GTEST_FLAG(name)
+# define GTEST_DECLARE_int32_(name) \
+    GTEST_API_ extern std::int32_t GTEST_FLAG(name)
+# define GTEST_DECLARE_string_(name) \
+    GTEST_API_ extern ::std::string GTEST_FLAG(name)
+
+// Macros for defining flags.
+# define GTEST_DEFINE_bool_(name, default_val, doc) \
+    GTEST_API_ bool GTEST_FLAG(name) = (default_val)
+# define GTEST_DEFINE_int32_(name, default_val, doc) \
+    GTEST_API_ std::int32_t GTEST_FLAG(name) = (default_val)
+# define GTEST_DEFINE_string_(name, default_val, doc) \
+    GTEST_API_ ::std::string GTEST_FLAG(name) = (default_val)
+
+#endif  // !defined(GTEST_DECLARE_bool_)
+
+// Thread annotations
+#if !defined(GTEST_EXCLUSIVE_LOCK_REQUIRED_)
+# define GTEST_EXCLUSIVE_LOCK_REQUIRED_(locks)
+# define GTEST_LOCK_EXCLUDED_(locks)
+#endif  // !defined(GTEST_EXCLUSIVE_LOCK_REQUIRED_)
+
+// Parses 'str' for a 32-bit signed integer.  If successful, writes the result
+// to *value and returns true; otherwise leaves *value unchanged and returns
+// false.
+GTEST_API_ bool ParseInt32(const Message& src_text, const char* str,
+                           int32_t* value);
+
+// Parses a bool/int32_t/string from the environment variable
+// corresponding to the given Google Test flag.
+bool BoolFromGTestEnv(const char* flag, bool default_val);
+GTEST_API_ int32_t Int32FromGTestEnv(const char* flag, int32_t default_val);
+std::string OutputFlagAlsoCheckEnvVar();
+const char* StringFromGTestEnv(const char* flag, const char* default_val);
+
+}  // namespace internal
+}  // namespace testing
+
+#if !defined(GTEST_INTERNAL_DEPRECATED)
+
+// Internal Macro to mark an API deprecated, for googletest usage only
+// Usage: class GTEST_INTERNAL_DEPRECATED(message) MyClass or
+// GTEST_INTERNAL_DEPRECATED(message) <return_type> myFunction(); Every usage of
+// a deprecated entity will trigger a warning when compiled with
+// `-Wdeprecated-declarations` option (clang, gcc, any __GNUC__ compiler).
+// For msvc /W3 option will need to be used
+// Note that for 'other' compilers this macro evaluates to nothing to prevent
+// compilations errors.
+#if defined(_MSC_VER)
+#define GTEST_INTERNAL_DEPRECATED(message) __declspec(deprecated(message))
+#elif defined(__GNUC__)
+#define GTEST_INTERNAL_DEPRECATED(message) __attribute__((deprecated(message)))
+#else
+#define GTEST_INTERNAL_DEPRECATED(message)
+#endif
+
+#endif  // !defined(GTEST_INTERNAL_DEPRECATED)
+
+#if GTEST_HAS_ABSL
+// Always use absl::any for UniversalPrinter<> specializations if googletest
+// is built with absl support.
+#define GTEST_INTERNAL_HAS_ANY 1
+#include "absl/types/any.h"
+namespace testing {
+namespace internal {
+using Any = ::absl::any;
+}  // namespace internal
+}  // namespace testing
+#else
+#ifdef __has_include
+#if __has_include(<any>) && __cplusplus >= 201703L
+// Otherwise for C++17 and higher use std::any for UniversalPrinter<>
+// specializations.
+#define GTEST_INTERNAL_HAS_ANY 1
+#include <any>
+namespace testing {
+namespace internal {
+using Any = ::std::any;
+}  // namespace internal
+}  // namespace testing
+// The case where absl is configured NOT to alias std::any is not
+// supported.
+#endif  // __has_include(<any>) && __cplusplus >= 201703L
+#endif  // __has_include
+#endif  // GTEST_HAS_ABSL
+
+#if GTEST_HAS_ABSL
+// Always use absl::optional for UniversalPrinter<> specializations if
+// googletest is built with absl support.
+#define GTEST_INTERNAL_HAS_OPTIONAL 1
+#include "absl/types/optional.h"
+namespace testing {
+namespace internal {
+template <typename T>
+using Optional = ::absl::optional<T>;
+}  // namespace internal
+}  // namespace testing
+#else
+#ifdef __has_include
+#if __has_include(<optional>) && __cplusplus >= 201703L
+// Otherwise for C++17 and higher use std::optional for UniversalPrinter<>
+// specializations.
+#define GTEST_INTERNAL_HAS_OPTIONAL 1
+#include <optional>
+namespace testing {
+namespace internal {
+template <typename T>
+using Optional = ::std::optional<T>;
+}  // namespace internal
+}  // namespace testing
+// The case where absl is configured NOT to alias std::optional is not
+// supported.
+#endif  // __has_include(<optional>) && __cplusplus >= 201703L
+#endif  // __has_include
+#endif  // GTEST_HAS_ABSL
+
+#if GTEST_HAS_ABSL
+// Always use absl::string_view for Matcher<> specializations if googletest
+// is built with absl support.
+# define GTEST_INTERNAL_HAS_STRING_VIEW 1
+#include "absl/strings/string_view.h"
+namespace testing {
+namespace internal {
+using StringView = ::absl::string_view;
+}  // namespace internal
+}  // namespace testing
+#else
+# ifdef __has_include
+#   if __has_include(<string_view>) && __cplusplus >= 201703L
+// Otherwise for C++17 and higher use std::string_view for Matcher<>
+// specializations.
+#   define GTEST_INTERNAL_HAS_STRING_VIEW 1
+#include <string_view>
+namespace testing {
+namespace internal {
+using StringView = ::std::string_view;
+}  // namespace internal
+}  // namespace testing
+// The case where absl is configured NOT to alias std::string_view is not
+// supported.
+#  endif  // __has_include(<string_view>) && __cplusplus >= 201703L
+# endif  // __has_include
+#endif  // GTEST_HAS_ABSL
+
+#if GTEST_HAS_ABSL
+// Always use absl::variant for UniversalPrinter<> specializations if googletest
+// is built with absl support.
+#define GTEST_INTERNAL_HAS_VARIANT 1
+#include "absl/types/variant.h"
+namespace testing {
+namespace internal {
+template <typename... T>
+using Variant = ::absl::variant<T...>;
+}  // namespace internal
+}  // namespace testing
+#else
+#ifdef __has_include
+#if __has_include(<variant>) && __cplusplus >= 201703L
+// Otherwise for C++17 and higher use std::variant for UniversalPrinter<>
+// specializations.
+#define GTEST_INTERNAL_HAS_VARIANT 1
+#include <variant>
+namespace testing {
+namespace internal {
+template <typename... T>
+using Variant = ::std::variant<T...>;
+}  // namespace internal
+}  // namespace testing
+// The case where absl is configured NOT to alias std::variant is not supported.
+#endif  // __has_include(<variant>) && __cplusplus >= 201703L
+#endif  // __has_include
+#endif  // GTEST_HAS_ABSL
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_H_
+
+#if GTEST_OS_LINUX
+# include <stdlib.h>
+# include <sys/types.h>
+# include <sys/wait.h>
+# include <unistd.h>
+#endif  // GTEST_OS_LINUX
+
+#if GTEST_HAS_EXCEPTIONS
+# include <stdexcept>
+#endif
+
+#include <ctype.h>
+#include <float.h>
+#include <string.h>
+#include <cstdint>
+#include <iomanip>
+#include <limits>
+#include <map>
+#include <set>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// The Google C++ Testing and Mocking Framework (Google Test)
+//
+// This header file defines the Message class.
+//
+// IMPORTANT NOTE: Due to limitation of the C++ language, we have to
+// leave some internal implementation details in this header file.
+// They are clearly marked by comments like this:
+//
+//   // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+//
+// Such code is NOT meant to be used by a user directly, and is subject
+// to CHANGE WITHOUT NOTICE.  Therefore DO NOT DEPEND ON IT in a user
+// program!
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
+
+#include <limits>
+#include <memory>
+#include <sstream>
+
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+// Ensures that there is at least one operator<< in the global namespace.
+// See Message& operator<<(...) below for why.
+void operator<<(const testing::internal::Secret&, int);
+
+namespace testing {
+
+// The Message class works like an ostream repeater.
+//
+// Typical usage:
+//
+//   1. You stream a bunch of values to a Message object.
+//      It will remember the text in a stringstream.
+//   2. Then you stream the Message object to an ostream.
+//      This causes the text in the Message to be streamed
+//      to the ostream.
+//
+// For example;
+//
+//   testing::Message foo;
+//   foo << 1 << " != " << 2;
+//   std::cout << foo;
+//
+// will print "1 != 2".
+//
+// Message is not intended to be inherited from.  In particular, its
+// destructor is not virtual.
+//
+// Note that stringstream behaves differently in gcc and in MSVC.  You
+// can stream a NULL char pointer to it in the former, but not in the
+// latter (it causes an access violation if you do).  The Message
+// class hides this difference by treating a NULL char pointer as
+// "(null)".
+class GTEST_API_ Message {
+ private:
+  // The type of basic IO manipulators (endl, ends, and flush) for
+  // narrow streams.
+  typedef std::ostream& (*BasicNarrowIoManip)(std::ostream&);
+
+ public:
+  // Constructs an empty Message.
+  Message();
+
+  // Copy constructor.
+  Message(const Message& msg) : ss_(new ::std::stringstream) {  // NOLINT
+    *ss_ << msg.GetString();
+  }
+
+  // Constructs a Message from a C-string.
+  explicit Message(const char* str) : ss_(new ::std::stringstream) {
+    *ss_ << str;
+  }
+
+  // Streams a non-pointer value to this object.
+  template <typename T>
+  inline Message& operator <<(const T& val) {
+    // Some libraries overload << for STL containers.  These
+    // overloads are defined in the global namespace instead of ::std.
+    //
+    // C++'s symbol lookup rule (i.e. Koenig lookup) says that these
+    // overloads are visible in either the std namespace or the global
+    // namespace, but not other namespaces, including the testing
+    // namespace which Google Test's Message class is in.
+    //
+    // To allow STL containers (and other types that has a << operator
+    // defined in the global namespace) to be used in Google Test
+    // assertions, testing::Message must access the custom << operator
+    // from the global namespace.  With this using declaration,
+    // overloads of << defined in the global namespace and those
+    // visible via Koenig lookup are both exposed in this function.
+    using ::operator <<;
+    *ss_ << val;
+    return *this;
+  }
+
+  // Streams a pointer value to this object.
+  //
+  // This function is an overload of the previous one.  When you
+  // stream a pointer to a Message, this definition will be used as it
+  // is more specialized.  (The C++ Standard, section
+  // [temp.func.order].)  If you stream a non-pointer, then the
+  // previous definition will be used.
+  //
+  // The reason for this overload is that streaming a NULL pointer to
+  // ostream is undefined behavior.  Depending on the compiler, you
+  // may get "0", "(nil)", "(null)", or an access violation.  To
+  // ensure consistent result across compilers, we always treat NULL
+  // as "(null)".
+  template <typename T>
+  inline Message& operator <<(T* const& pointer) {  // NOLINT
+    if (pointer == nullptr) {
+      *ss_ << "(null)";
+    } else {
+      *ss_ << pointer;
+    }
+    return *this;
+  }
+
+  // Since the basic IO manipulators are overloaded for both narrow
+  // and wide streams, we have to provide this specialized definition
+  // of operator <<, even though its body is the same as the
+  // templatized version above.  Without this definition, streaming
+  // endl or other basic IO manipulators to Message will confuse the
+  // compiler.
+  Message& operator <<(BasicNarrowIoManip val) {
+    *ss_ << val;
+    return *this;
+  }
+
+  // Instead of 1/0, we want to see true/false for bool values.
+  Message& operator <<(bool b) {
+    return *this << (b ? "true" : "false");
+  }
+
+  // These two overloads allow streaming a wide C string to a Message
+  // using the UTF-8 encoding.
+  Message& operator <<(const wchar_t* wide_c_str);
+  Message& operator <<(wchar_t* wide_c_str);
+
+#if GTEST_HAS_STD_WSTRING
+  // Converts the given wide string to a narrow string using the UTF-8
+  // encoding, and streams the result to this Message object.
+  Message& operator <<(const ::std::wstring& wstr);
+#endif  // GTEST_HAS_STD_WSTRING
+
+  // Gets the text streamed to this object so far as an std::string.
+  // Each '\0' character in the buffer is replaced with "\\0".
+  //
+  // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+  std::string GetString() const;
+
+ private:
+  // We'll hold the text streamed to this object here.
+  const std::unique_ptr< ::std::stringstream> ss_;
+
+  // We declare (but don't implement) this to prevent the compiler
+  // from implementing the assignment operator.
+  void operator=(const Message&);
+};
+
+// Streams a Message to an ostream.
+inline std::ostream& operator <<(std::ostream& os, const Message& sb) {
+  return os << sb.GetString();
+}
+
+namespace internal {
+
+// Converts a streamable value to an std::string.  A NULL pointer is
+// converted to "(null)".  When the input value is a ::string,
+// ::std::string, ::wstring, or ::std::wstring object, each NUL
+// character in it is replaced with "\\0".
+template <typename T>
+std::string StreamableToString(const T& streamable) {
+  return (Message() << streamable).GetString();
+}
+
+}  // namespace internal
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Google Test filepath utilities
+//
+// This header file declares classes and functions used internally by
+// Google Test.  They are subject to change without notice.
+//
+// This file is #included in gtest/internal/gtest-internal.h.
+// Do not include this header file separately!
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_FILEPATH_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_FILEPATH_H_
+
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// The Google C++ Testing and Mocking Framework (Google Test)
+//
+// This header file declares the String class and functions used internally by
+// Google Test.  They are subject to change without notice. They should not used
+// by code external to Google Test.
+//
+// This header file is #included by gtest-internal.h.
+// It should not be #included by other files.
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_STRING_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_STRING_H_
+
+#ifdef __BORLANDC__
+// string.h is not guaranteed to provide strcpy on C++ Builder.
+# include <mem.h>
+#endif
+
+#include <string.h>
+#include <cstdint>
+#include <string>
+
+
+namespace testing {
+namespace internal {
+
+// String - an abstract class holding static string utilities.
+class GTEST_API_ String {
+ public:
+  // Static utility methods
+
+  // Clones a 0-terminated C string, allocating memory using new.  The
+  // caller is responsible for deleting the return value using
+  // delete[].  Returns the cloned string, or NULL if the input is
+  // NULL.
+  //
+  // This is different from strdup() in string.h, which allocates
+  // memory using malloc().
+  static const char* CloneCString(const char* c_str);
+
+#if GTEST_OS_WINDOWS_MOBILE
+  // Windows CE does not have the 'ANSI' versions of Win32 APIs. To be
+  // able to pass strings to Win32 APIs on CE we need to convert them
+  // to 'Unicode', UTF-16.
+
+  // Creates a UTF-16 wide string from the given ANSI string, allocating
+  // memory using new. The caller is responsible for deleting the return
+  // value using delete[]. Returns the wide string, or NULL if the
+  // input is NULL.
+  //
+  // The wide string is created using the ANSI codepage (CP_ACP) to
+  // match the behaviour of the ANSI versions of Win32 calls and the
+  // C runtime.
+  static LPCWSTR AnsiToUtf16(const char* c_str);
+
+  // Creates an ANSI string from the given wide string, allocating
+  // memory using new. The caller is responsible for deleting the return
+  // value using delete[]. Returns the ANSI string, or NULL if the
+  // input is NULL.
+  //
+  // The returned string is created using the ANSI codepage (CP_ACP) to
+  // match the behaviour of the ANSI versions of Win32 calls and the
+  // C runtime.
+  static const char* Utf16ToAnsi(LPCWSTR utf16_str);
+#endif
+
+  // Compares two C strings.  Returns true if and only if they have the same
+  // content.
+  //
+  // Unlike strcmp(), this function can handle NULL argument(s).  A
+  // NULL C string is considered different to any non-NULL C string,
+  // including the empty string.
+  static bool CStringEquals(const char* lhs, const char* rhs);
+
+  // Converts a wide C string to a String using the UTF-8 encoding.
+  // NULL will be converted to "(null)".  If an error occurred during
+  // the conversion, "(failed to convert from wide string)" is
+  // returned.
+  static std::string ShowWideCString(const wchar_t* wide_c_str);
+
+  // Compares two wide C strings.  Returns true if and only if they have the
+  // same content.
+  //
+  // Unlike wcscmp(), this function can handle NULL argument(s).  A
+  // NULL C string is considered different to any non-NULL C string,
+  // including the empty string.
+  static bool WideCStringEquals(const wchar_t* lhs, const wchar_t* rhs);
+
+  // Compares two C strings, ignoring case.  Returns true if and only if
+  // they have the same content.
+  //
+  // Unlike strcasecmp(), this function can handle NULL argument(s).
+  // A NULL C string is considered different to any non-NULL C string,
+  // including the empty string.
+  static bool CaseInsensitiveCStringEquals(const char* lhs,
+                                           const char* rhs);
+
+  // Compares two wide C strings, ignoring case.  Returns true if and only if
+  // they have the same content.
+  //
+  // Unlike wcscasecmp(), this function can handle NULL argument(s).
+  // A NULL C string is considered different to any non-NULL wide C string,
+  // including the empty string.
+  // NB: The implementations on different platforms slightly differ.
+  // On windows, this method uses _wcsicmp which compares according to LC_CTYPE
+  // environment variable. On GNU platform this method uses wcscasecmp
+  // which compares according to LC_CTYPE category of the current locale.
+  // On MacOS X, it uses towlower, which also uses LC_CTYPE category of the
+  // current locale.
+  static bool CaseInsensitiveWideCStringEquals(const wchar_t* lhs,
+                                               const wchar_t* rhs);
+
+  // Returns true if and only if the given string ends with the given suffix,
+  // ignoring case. Any string is considered to end with an empty suffix.
+  static bool EndsWithCaseInsensitive(
+      const std::string& str, const std::string& suffix);
+
+  // Formats an int value as "%02d".
+  static std::string FormatIntWidth2(int value);  // "%02d" for width == 2
+
+  // Formats an int value to given width with leading zeros.
+  static std::string FormatIntWidthN(int value, int width);
+
+  // Formats an int value as "%X".
+  static std::string FormatHexInt(int value);
+
+  // Formats an int value as "%X".
+  static std::string FormatHexUInt32(uint32_t value);
+
+  // Formats a byte as "%02X".
+  static std::string FormatByte(unsigned char value);
+
+ private:
+  String();  // Not meant to be instantiated.
+};  // class String
+
+// Gets the content of the stringstream's buffer as an std::string.  Each '\0'
+// character in the buffer is replaced with "\\0".
+GTEST_API_ std::string StringStreamToString(::std::stringstream* stream);
+
+}  // namespace internal
+}  // namespace testing
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_STRING_H_
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+namespace testing {
+namespace internal {
+
+// FilePath - a class for file and directory pathname manipulation which
+// handles platform-specific conventions (like the pathname separator).
+// Used for helper functions for naming files in a directory for xml output.
+// Except for Set methods, all methods are const or static, which provides an
+// "immutable value object" -- useful for peace of mind.
+// A FilePath with a value ending in a path separator ("like/this/") represents
+// a directory, otherwise it is assumed to represent a file. In either case,
+// it may or may not represent an actual file or directory in the file system.
+// Names are NOT checked for syntax correctness -- no checking for illegal
+// characters, malformed paths, etc.
+
+class GTEST_API_ FilePath {
+ public:
+  FilePath() : pathname_("") { }
+  FilePath(const FilePath& rhs) : pathname_(rhs.pathname_) { }
+
+  explicit FilePath(const std::string& pathname) : pathname_(pathname) {
+    Normalize();
+  }
+
+  FilePath& operator=(const FilePath& rhs) {
+    Set(rhs);
+    return *this;
+  }
+
+  void Set(const FilePath& rhs) {
+    pathname_ = rhs.pathname_;
+  }
+
+  const std::string& string() const { return pathname_; }
+  const char* c_str() const { return pathname_.c_str(); }
+
+  // Returns the current working directory, or "" if unsuccessful.
+  static FilePath GetCurrentDir();
+
+  // Given directory = "dir", base_name = "test", number = 0,
+  // extension = "xml", returns "dir/test.xml". If number is greater
+  // than zero (e.g., 12), returns "dir/test_12.xml".
+  // On Windows platform, uses \ as the separator rather than /.
+  static FilePath MakeFileName(const FilePath& directory,
+                               const FilePath& base_name,
+                               int number,
+                               const char* extension);
+
+  // Given directory = "dir", relative_path = "test.xml",
+  // returns "dir/test.xml".
+  // On Windows, uses \ as the separator rather than /.
+  static FilePath ConcatPaths(const FilePath& directory,
+                              const FilePath& relative_path);
+
+  // Returns a pathname for a file that does not currently exist. The pathname
+  // will be directory/base_name.extension or
+  // directory/base_name_<number>.extension if directory/base_name.extension
+  // already exists. The number will be incremented until a pathname is found
+  // that does not already exist.
+  // Examples: 'dir/foo_test.xml' or 'dir/foo_test_1.xml'.
+  // There could be a race condition if two or more processes are calling this
+  // function at the same time -- they could both pick the same filename.
+  static FilePath GenerateUniqueFileName(const FilePath& directory,
+                                         const FilePath& base_name,
+                                         const char* extension);
+
+  // Returns true if and only if the path is "".
+  bool IsEmpty() const { return pathname_.empty(); }
+
+  // If input name has a trailing separator character, removes it and returns
+  // the name, otherwise return the name string unmodified.
+  // On Windows platform, uses \ as the separator, other platforms use /.
+  FilePath RemoveTrailingPathSeparator() const;
+
+  // Returns a copy of the FilePath with the directory part removed.
+  // Example: FilePath("path/to/file").RemoveDirectoryName() returns
+  // FilePath("file"). If there is no directory part ("just_a_file"), it returns
+  // the FilePath unmodified. If there is no file part ("just_a_dir/") it
+  // returns an empty FilePath ("").
+  // On Windows platform, '\' is the path separator, otherwise it is '/'.
+  FilePath RemoveDirectoryName() const;
+
+  // RemoveFileName returns the directory path with the filename removed.
+  // Example: FilePath("path/to/file").RemoveFileName() returns "path/to/".
+  // If the FilePath is "a_file" or "/a_file", RemoveFileName returns
+  // FilePath("./") or, on Windows, FilePath(".\\"). If the filepath does
+  // not have a file, like "just/a/dir/", it returns the FilePath unmodified.
+  // On Windows platform, '\' is the path separator, otherwise it is '/'.
+  FilePath RemoveFileName() const;
+
+  // Returns a copy of the FilePath with the case-insensitive extension removed.
+  // Example: FilePath("dir/file.exe").RemoveExtension("EXE") returns
+  // FilePath("dir/file"). If a case-insensitive extension is not
+  // found, returns a copy of the original FilePath.
+  FilePath RemoveExtension(const char* extension) const;
+
+  // Creates directories so that path exists. Returns true if successful or if
+  // the directories already exist; returns false if unable to create
+  // directories for any reason. Will also return false if the FilePath does
+  // not represent a directory (that is, it doesn't end with a path separator).
+  bool CreateDirectoriesRecursively() const;
+
+  // Create the directory so that path exists. Returns true if successful or
+  // if the directory already exists; returns false if unable to create the
+  // directory for any reason, including if the parent directory does not
+  // exist. Not named "CreateDirectory" because that's a macro on Windows.
+  bool CreateFolder() const;
+
+  // Returns true if FilePath describes something in the file-system,
+  // either a file, directory, or whatever, and that something exists.
+  bool FileOrDirectoryExists() const;
+
+  // Returns true if pathname describes a directory in the file-system
+  // that exists.
+  bool DirectoryExists() const;
+
+  // Returns true if FilePath ends with a path separator, which indicates that
+  // it is intended to represent a directory. Returns false otherwise.
+  // This does NOT check that a directory (or file) actually exists.
+  bool IsDirectory() const;
+
+  // Returns true if pathname describes a root directory. (Windows has one
+  // root directory per disk drive.)
+  bool IsRootDirectory() const;
+
+  // Returns true if pathname describes an absolute path.
+  bool IsAbsolutePath() const;
+
+ private:
+  // Replaces multiple consecutive separators with a single separator.
+  // For example, "bar///foo" becomes "bar/foo". Does not eliminate other
+  // redundancies that might be in a pathname involving "." or "..".
+  //
+  // A pathname with multiple consecutive separators may occur either through
+  // user error or as a result of some scripts or APIs that generate a pathname
+  // with a trailing separator. On other platforms the same API or script
+  // may NOT generate a pathname with a trailing "/". Then elsewhere that
+  // pathname may have another "/" and pathname components added to it,
+  // without checking for the separator already being there.
+  // The script language and operating system may allow paths like "foo//bar"
+  // but some of the functions in FilePath will not handle that correctly. In
+  // particular, RemoveTrailingPathSeparator() only removes one separator, and
+  // it is called in CreateDirectoriesRecursively() assuming that it will change
+  // a pathname from directory syntax (trailing separator) to filename syntax.
+  //
+  // On Windows this method also replaces the alternate path separator '/' with
+  // the primary path separator '\\', so that for example "bar\\/\\foo" becomes
+  // "bar\\foo".
+
+  void Normalize();
+
+  // Returns a pointer to the last occurrence of a valid path separator in
+  // the FilePath. On Windows, for example, both '/' and '\' are valid path
+  // separators. Returns NULL if no path separator was found.
+  const char* FindLastPathSeparator() const;
+
+  std::string pathname_;
+};  // class FilePath
+
+}  // namespace internal
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_FILEPATH_H_
+// Copyright 2008 Google Inc.
+// All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Type utilities needed for implementing typed and type-parameterized
+// tests.
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_TYPE_UTIL_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_TYPE_UTIL_H_
+
+
+// #ifdef __GNUC__ is too general here.  It is possible to use gcc without using
+// libstdc++ (which is where cxxabi.h comes from).
+# if GTEST_HAS_CXXABI_H_
+#  include <cxxabi.h>
+# elif defined(__HP_aCC)
+#  include <acxx_demangle.h>
+# endif  // GTEST_HASH_CXXABI_H_
+
+namespace testing {
+namespace internal {
+
+// Canonicalizes a given name with respect to the Standard C++ Library.
+// This handles removing the inline namespace within `std` that is
+// used by various standard libraries (e.g., `std::__1`).  Names outside
+// of namespace std are returned unmodified.
+inline std::string CanonicalizeForStdLibVersioning(std::string s) {
+  static const char prefix[] = "std::__";
+  if (s.compare(0, strlen(prefix), prefix) == 0) {
+    std::string::size_type end = s.find("::", strlen(prefix));
+    if (end != s.npos) {
+      // Erase everything between the initial `std` and the second `::`.
+      s.erase(strlen("std"), end - strlen("std"));
+    }
+  }
+  return s;
+}
+
+#if GTEST_HAS_RTTI
+// GetTypeName(const std::type_info&) returns a human-readable name of type T.
+inline std::string GetTypeName(const std::type_info& type) {
+  const char* const name = type.name();
+#if GTEST_HAS_CXXABI_H_ || defined(__HP_aCC)
+  int status = 0;
+  // gcc's implementation of typeid(T).name() mangles the type name,
+  // so we have to demangle it.
+#if GTEST_HAS_CXXABI_H_
+  using abi::__cxa_demangle;
+#endif  // GTEST_HAS_CXXABI_H_
+  char* const readable_name = __cxa_demangle(name, nullptr, nullptr, &status);
+  const std::string name_str(status == 0 ? readable_name : name);
+  free(readable_name);
+  return CanonicalizeForStdLibVersioning(name_str);
+#else
+  return name;
+#endif  // GTEST_HAS_CXXABI_H_ || __HP_aCC
+}
+#endif  // GTEST_HAS_RTTI
+
+// GetTypeName<T>() returns a human-readable name of type T if and only if
+// RTTI is enabled, otherwise it returns a dummy type name.
+// NB: This function is also used in Google Mock, so don't move it inside of
+// the typed-test-only section below.
+template <typename T>
+std::string GetTypeName() {
+#if GTEST_HAS_RTTI
+  return GetTypeName(typeid(T));
+#else
+  return "<type>";
+#endif  // GTEST_HAS_RTTI
+}
+
+// A unique type indicating an empty node
+struct None {};
+
+# define GTEST_TEMPLATE_ template <typename T> class
+
+// The template "selector" struct TemplateSel<Tmpl> is used to
+// represent Tmpl, which must be a class template with one type
+// parameter, as a type.  TemplateSel<Tmpl>::Bind<T>::type is defined
+// as the type Tmpl<T>.  This allows us to actually instantiate the
+// template "selected" by TemplateSel<Tmpl>.
+//
+// This trick is necessary for simulating typedef for class templates,
+// which C++ doesn't support directly.
+template <GTEST_TEMPLATE_ Tmpl>
+struct TemplateSel {
+  template <typename T>
+  struct Bind {
+    typedef Tmpl<T> type;
+  };
+};
+
+# define GTEST_BIND_(TmplSel, T) \
+  TmplSel::template Bind<T>::type
+
+template <GTEST_TEMPLATE_ Head_, GTEST_TEMPLATE_... Tail_>
+struct Templates {
+  using Head = TemplateSel<Head_>;
+  using Tail = Templates<Tail_...>;
+};
+
+template <GTEST_TEMPLATE_ Head_>
+struct Templates<Head_> {
+  using Head = TemplateSel<Head_>;
+  using Tail = None;
+};
+
+// Tuple-like type lists
+template <typename Head_, typename... Tail_>
+struct Types {
+  using Head = Head_;
+  using Tail = Types<Tail_...>;
+};
+
+template <typename Head_>
+struct Types<Head_> {
+  using Head = Head_;
+  using Tail = None;
+};
+
+// Helper metafunctions to tell apart a single type from types
+// generated by ::testing::Types
+template <typename... Ts>
+struct ProxyTypeList {
+  using type = Types<Ts...>;
+};
+
+template <typename>
+struct is_proxy_type_list : std::false_type {};
+
+template <typename... Ts>
+struct is_proxy_type_list<ProxyTypeList<Ts...>> : std::true_type {};
+
+// Generator which conditionally creates type lists.
+// It recognizes if a requested type list should be created
+// and prevents creating a new type list nested within another one.
+template <typename T>
+struct GenerateTypeList {
+ private:
+  using proxy = typename std::conditional<is_proxy_type_list<T>::value, T,
+                                          ProxyTypeList<T>>::type;
+
+ public:
+  using type = typename proxy::type;
+};
+
+}  // namespace internal
+
+template <typename... Ts>
+using Types = internal::ProxyTypeList<Ts...>;
+
+}  // namespace testing
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_TYPE_UTIL_H_
+
+// Due to C++ preprocessor weirdness, we need double indirection to
+// concatenate two tokens when one of them is __LINE__.  Writing
+//
+//   foo ## __LINE__
+//
+// will result in the token foo__LINE__, instead of foo followed by
+// the current line number.  For more details, see
+// http://www.parashift.com/c++-faq-lite/misc-technical-issues.html#faq-39.6
+#define GTEST_CONCAT_TOKEN_(foo, bar) GTEST_CONCAT_TOKEN_IMPL_(foo, bar)
+#define GTEST_CONCAT_TOKEN_IMPL_(foo, bar) foo ## bar
+
+// Stringifies its argument.
+// Work around a bug in visual studio which doesn't accept code like this:
+//
+//   #define GTEST_STRINGIFY_(name) #name
+//   #define MACRO(a, b, c) ... GTEST_STRINGIFY_(a) ...
+//   MACRO(, x, y)
+//
+// Complaining about the argument to GTEST_STRINGIFY_ being empty.
+// This is allowed by the spec.
+#define GTEST_STRINGIFY_HELPER_(name, ...) #name
+#define GTEST_STRINGIFY_(...) GTEST_STRINGIFY_HELPER_(__VA_ARGS__, )
+
+namespace proto2 {
+class MessageLite;
+}
+
+namespace testing {
+
+// Forward declarations.
+
+class AssertionResult;                 // Result of an assertion.
+class Message;                         // Represents a failure message.
+class Test;                            // Represents a test.
+class TestInfo;                        // Information about a test.
+class TestPartResult;                  // Result of a test part.
+class UnitTest;                        // A collection of test suites.
+
+template <typename T>
+::std::string PrintToString(const T& value);
+
+namespace internal {
+
+struct TraceInfo;                      // Information about a trace point.
+class TestInfoImpl;                    // Opaque implementation of TestInfo
+class UnitTestImpl;                    // Opaque implementation of UnitTest
+
+// The text used in failure messages to indicate the start of the
+// stack trace.
+GTEST_API_ extern const char kStackTraceMarker[];
+
+// An IgnoredValue object can be implicitly constructed from ANY value.
+class IgnoredValue {
+  struct Sink {};
+ public:
+  // This constructor template allows any value to be implicitly
+  // converted to IgnoredValue.  The object has no data member and
+  // doesn't try to remember anything about the argument.  We
+  // deliberately omit the 'explicit' keyword in order to allow the
+  // conversion to be implicit.
+  // Disable the conversion if T already has a magical conversion operator.
+  // Otherwise we get ambiguity.
+  template <typename T,
+            typename std::enable_if<!std::is_convertible<T, Sink>::value,
+                                    int>::type = 0>
+  IgnoredValue(const T& /* ignored */) {}  // NOLINT(runtime/explicit)
+};
+
+// Appends the user-supplied message to the Google-Test-generated message.
+GTEST_API_ std::string AppendUserMessage(
+    const std::string& gtest_msg, const Message& user_msg);
+
+#if GTEST_HAS_EXCEPTIONS
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4275 \
+/* an exported class was derived from a class that was not exported */)
+
+// This exception is thrown by (and only by) a failed Google Test
+// assertion when GTEST_FLAG(throw_on_failure) is true (if exceptions
+// are enabled).  We derive it from std::runtime_error, which is for
+// errors presumably detectable only at run time.  Since
+// std::runtime_error inherits from std::exception, many testing
+// frameworks know how to extract and print the message inside it.
+class GTEST_API_ GoogleTestFailureException : public ::std::runtime_error {
+ public:
+  explicit GoogleTestFailureException(const TestPartResult& failure);
+};
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4275
+
+#endif  // GTEST_HAS_EXCEPTIONS
+
+namespace edit_distance {
+// Returns the optimal edits to go from 'left' to 'right'.
+// All edits cost the same, with replace having lower priority than
+// add/remove.
+// Simple implementation of the Wagner-Fischer algorithm.
+// See http://en.wikipedia.org/wiki/Wagner-Fischer_algorithm
+enum EditType { kMatch, kAdd, kRemove, kReplace };
+GTEST_API_ std::vector<EditType> CalculateOptimalEdits(
+    const std::vector<size_t>& left, const std::vector<size_t>& right);
+
+// Same as above, but the input is represented as strings.
+GTEST_API_ std::vector<EditType> CalculateOptimalEdits(
+    const std::vector<std::string>& left,
+    const std::vector<std::string>& right);
+
+// Create a diff of the input strings in Unified diff format.
+GTEST_API_ std::string CreateUnifiedDiff(const std::vector<std::string>& left,
+                                         const std::vector<std::string>& right,
+                                         size_t context = 2);
+
+}  // namespace edit_distance
+
+// Calculate the diff between 'left' and 'right' and return it in unified diff
+// format.
+// If not null, stores in 'total_line_count' the total number of lines found
+// in left + right.
+GTEST_API_ std::string DiffStrings(const std::string& left,
+                                   const std::string& right,
+                                   size_t* total_line_count);
+
+// Constructs and returns the message for an equality assertion
+// (e.g. ASSERT_EQ, EXPECT_STREQ, etc) failure.
+//
+// The first four parameters are the expressions used in the assertion
+// and their values, as strings.  For example, for ASSERT_EQ(foo, bar)
+// where foo is 5 and bar is 6, we have:
+//
+//   expected_expression: "foo"
+//   actual_expression:   "bar"
+//   expected_value:      "5"
+//   actual_value:        "6"
+//
+// The ignoring_case parameter is true if and only if the assertion is a
+// *_STRCASEEQ*.  When it's true, the string " (ignoring case)" will
+// be inserted into the message.
+GTEST_API_ AssertionResult EqFailure(const char* expected_expression,
+                                     const char* actual_expression,
+                                     const std::string& expected_value,
+                                     const std::string& actual_value,
+                                     bool ignoring_case);
+
+// Constructs a failure message for Boolean assertions such as EXPECT_TRUE.
+GTEST_API_ std::string GetBoolAssertionFailureMessage(
+    const AssertionResult& assertion_result,
+    const char* expression_text,
+    const char* actual_predicate_value,
+    const char* expected_predicate_value);
+
+// This template class represents an IEEE floating-point number
+// (either single-precision or double-precision, depending on the
+// template parameters).
+//
+// The purpose of this class is to do more sophisticated number
+// comparison.  (Due to round-off error, etc, it's very unlikely that
+// two floating-points will be equal exactly.  Hence a naive
+// comparison by the == operation often doesn't work.)
+//
+// Format of IEEE floating-point:
+//
+//   The most-significant bit being the leftmost, an IEEE
+//   floating-point looks like
+//
+//     sign_bit exponent_bits fraction_bits
+//
+//   Here, sign_bit is a single bit that designates the sign of the
+//   number.
+//
+//   For float, there are 8 exponent bits and 23 fraction bits.
+//
+//   For double, there are 11 exponent bits and 52 fraction bits.
+//
+//   More details can be found at
+//   http://en.wikipedia.org/wiki/IEEE_floating-point_standard.
+//
+// Template parameter:
+//
+//   RawType: the raw floating-point type (either float or double)
+template <typename RawType>
+class FloatingPoint {
+ public:
+  // Defines the unsigned integer type that has the same size as the
+  // floating point number.
+  typedef typename TypeWithSize<sizeof(RawType)>::UInt Bits;
+
+  // Constants.
+
+  // # of bits in a number.
+  static const size_t kBitCount = 8*sizeof(RawType);
+
+  // # of fraction bits in a number.
+  static const size_t kFractionBitCount =
+    std::numeric_limits<RawType>::digits - 1;
+
+  // # of exponent bits in a number.
+  static const size_t kExponentBitCount = kBitCount - 1 - kFractionBitCount;
+
+  // The mask for the sign bit.
+  static const Bits kSignBitMask = static_cast<Bits>(1) << (kBitCount - 1);
+
+  // The mask for the fraction bits.
+  static const Bits kFractionBitMask =
+    ~static_cast<Bits>(0) >> (kExponentBitCount + 1);
+
+  // The mask for the exponent bits.
+  static const Bits kExponentBitMask = ~(kSignBitMask | kFractionBitMask);
+
+  // How many ULP's (Units in the Last Place) we want to tolerate when
+  // comparing two numbers.  The larger the value, the more error we
+  // allow.  A 0 value means that two numbers must be exactly the same
+  // to be considered equal.
+  //
+  // The maximum error of a single floating-point operation is 0.5
+  // units in the last place.  On Intel CPU's, all floating-point
+  // calculations are done with 80-bit precision, while double has 64
+  // bits.  Therefore, 4 should be enough for ordinary use.
+  //
+  // See the following article for more details on ULP:
+  // http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
+  static const uint32_t kMaxUlps = 4;
+
+  // Constructs a FloatingPoint from a raw floating-point number.
+  //
+  // On an Intel CPU, passing a non-normalized NAN (Not a Number)
+  // around may change its bits, although the new value is guaranteed
+  // to be also a NAN.  Therefore, don't expect this constructor to
+  // preserve the bits in x when x is a NAN.
+  explicit FloatingPoint(const RawType& x) { u_.value_ = x; }
+
+  // Static methods
+
+  // Reinterprets a bit pattern as a floating-point number.
+  //
+  // This function is needed to test the AlmostEquals() method.
+  static RawType ReinterpretBits(const Bits bits) {
+    FloatingPoint fp(0);
+    fp.u_.bits_ = bits;
+    return fp.u_.value_;
+  }
+
+  // Returns the floating-point number that represent positive infinity.
+  static RawType Infinity() {
+    return ReinterpretBits(kExponentBitMask);
+  }
+
+  // Returns the maximum representable finite floating-point number.
+  static RawType Max();
+
+  // Non-static methods
+
+  // Returns the bits that represents this number.
+  const Bits &bits() const { return u_.bits_; }
+
+  // Returns the exponent bits of this number.
+  Bits exponent_bits() const { return kExponentBitMask & u_.bits_; }
+
+  // Returns the fraction bits of this number.
+  Bits fraction_bits() const { return kFractionBitMask & u_.bits_; }
+
+  // Returns the sign bit of this number.
+  Bits sign_bit() const { return kSignBitMask & u_.bits_; }
+
+  // Returns true if and only if this is NAN (not a number).
+  bool is_nan() const {
+    // It's a NAN if the exponent bits are all ones and the fraction
+    // bits are not entirely zeros.
+    return (exponent_bits() == kExponentBitMask) && (fraction_bits() != 0);
+  }
+
+  // Returns true if and only if this number is at most kMaxUlps ULP's away
+  // from rhs.  In particular, this function:
+  //
+  //   - returns false if either number is (or both are) NAN.
+  //   - treats really large numbers as almost equal to infinity.
+  //   - thinks +0.0 and -0.0 are 0 DLP's apart.
+  bool AlmostEquals(const FloatingPoint& rhs) const {
+    // The IEEE standard says that any comparison operation involving
+    // a NAN must return false.
+    if (is_nan() || rhs.is_nan()) return false;
+
+    return DistanceBetweenSignAndMagnitudeNumbers(u_.bits_, rhs.u_.bits_)
+        <= kMaxUlps;
+  }
+
+ private:
+  // The data type used to store the actual floating-point number.
+  union FloatingPointUnion {
+    RawType value_;  // The raw floating-point number.
+    Bits bits_;      // The bits that represent the number.
+  };
+
+  // Converts an integer from the sign-and-magnitude representation to
+  // the biased representation.  More precisely, let N be 2 to the
+  // power of (kBitCount - 1), an integer x is represented by the
+  // unsigned number x + N.
+  //
+  // For instance,
+  //
+  //   -N + 1 (the most negative number representable using
+  //          sign-and-magnitude) is represented by 1;
+  //   0      is represented by N; and
+  //   N - 1  (the biggest number representable using
+  //          sign-and-magnitude) is represented by 2N - 1.
+  //
+  // Read http://en.wikipedia.org/wiki/Signed_number_representations
+  // for more details on signed number representations.
+  static Bits SignAndMagnitudeToBiased(const Bits &sam) {
+    if (kSignBitMask & sam) {
+      // sam represents a negative number.
+      return ~sam + 1;
+    } else {
+      // sam represents a positive number.
+      return kSignBitMask | sam;
+    }
+  }
+
+  // Given two numbers in the sign-and-magnitude representation,
+  // returns the distance between them as an unsigned number.
+  static Bits DistanceBetweenSignAndMagnitudeNumbers(const Bits &sam1,
+                                                     const Bits &sam2) {
+    const Bits biased1 = SignAndMagnitudeToBiased(sam1);
+    const Bits biased2 = SignAndMagnitudeToBiased(sam2);
+    return (biased1 >= biased2) ? (biased1 - biased2) : (biased2 - biased1);
+  }
+
+  FloatingPointUnion u_;
+};
+
+// We cannot use std::numeric_limits<T>::max() as it clashes with the max()
+// macro defined by <windows.h>.
+template <>
+inline float FloatingPoint<float>::Max() { return FLT_MAX; }
+template <>
+inline double FloatingPoint<double>::Max() { return DBL_MAX; }
+
+// Typedefs the instances of the FloatingPoint template class that we
+// care to use.
+typedef FloatingPoint<float> Float;
+typedef FloatingPoint<double> Double;
+
+// In order to catch the mistake of putting tests that use different
+// test fixture classes in the same test suite, we need to assign
+// unique IDs to fixture classes and compare them.  The TypeId type is
+// used to hold such IDs.  The user should treat TypeId as an opaque
+// type: the only operation allowed on TypeId values is to compare
+// them for equality using the == operator.
+typedef const void* TypeId;
+
+template <typename T>
+class TypeIdHelper {
+ public:
+  // dummy_ must not have a const type.  Otherwise an overly eager
+  // compiler (e.g. MSVC 7.1 & 8.0) may try to merge
+  // TypeIdHelper<T>::dummy_ for different Ts as an "optimization".
+  static bool dummy_;
+};
+
+template <typename T>
+bool TypeIdHelper<T>::dummy_ = false;
+
+// GetTypeId<T>() returns the ID of type T.  Different values will be
+// returned for different types.  Calling the function twice with the
+// same type argument is guaranteed to return the same ID.
+template <typename T>
+TypeId GetTypeId() {
+  // The compiler is required to allocate a different
+  // TypeIdHelper<T>::dummy_ variable for each T used to instantiate
+  // the template.  Therefore, the address of dummy_ is guaranteed to
+  // be unique.
+  return &(TypeIdHelper<T>::dummy_);
+}
+
+// Returns the type ID of ::testing::Test.  Always call this instead
+// of GetTypeId< ::testing::Test>() to get the type ID of
+// ::testing::Test, as the latter may give the wrong result due to a
+// suspected linker bug when compiling Google Test as a Mac OS X
+// framework.
+GTEST_API_ TypeId GetTestTypeId();
+
+// Defines the abstract factory interface that creates instances
+// of a Test object.
+class TestFactoryBase {
+ public:
+  virtual ~TestFactoryBase() {}
+
+  // Creates a test instance to run. The instance is both created and destroyed
+  // within TestInfoImpl::Run()
+  virtual Test* CreateTest() = 0;
+
+ protected:
+  TestFactoryBase() {}
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestFactoryBase);
+};
+
+// This class provides implementation of TeastFactoryBase interface.
+// It is used in TEST and TEST_F macros.
+template <class TestClass>
+class TestFactoryImpl : public TestFactoryBase {
+ public:
+  Test* CreateTest() override { return new TestClass; }
+};
+
+#if GTEST_OS_WINDOWS
+
+// Predicate-formatters for implementing the HRESULT checking macros
+// {ASSERT|EXPECT}_HRESULT_{SUCCEEDED|FAILED}
+// We pass a long instead of HRESULT to avoid causing an
+// include dependency for the HRESULT type.
+GTEST_API_ AssertionResult IsHRESULTSuccess(const char* expr,
+                                            long hr);  // NOLINT
+GTEST_API_ AssertionResult IsHRESULTFailure(const char* expr,
+                                            long hr);  // NOLINT
+
+#endif  // GTEST_OS_WINDOWS
+
+// Types of SetUpTestSuite() and TearDownTestSuite() functions.
+using SetUpTestSuiteFunc = void (*)();
+using TearDownTestSuiteFunc = void (*)();
+
+struct CodeLocation {
+  CodeLocation(const std::string& a_file, int a_line)
+      : file(a_file), line(a_line) {}
+
+  std::string file;
+  int line;
+};
+
+//  Helper to identify which setup function for TestCase / TestSuite to call.
+//  Only one function is allowed, either TestCase or TestSute but not both.
+
+// Utility functions to help SuiteApiResolver
+using SetUpTearDownSuiteFuncType = void (*)();
+
+inline SetUpTearDownSuiteFuncType GetNotDefaultOrNull(
+    SetUpTearDownSuiteFuncType a, SetUpTearDownSuiteFuncType def) {
+  return a == def ? nullptr : a;
+}
+
+template <typename T>
+//  Note that SuiteApiResolver inherits from T because
+//  SetUpTestSuite()/TearDownTestSuite() could be protected. Ths way
+//  SuiteApiResolver can access them.
+struct SuiteApiResolver : T {
+  // testing::Test is only forward declared at this point. So we make it a
+  // dependend class for the compiler to be OK with it.
+  using Test =
+      typename std::conditional<sizeof(T) != 0, ::testing::Test, void>::type;
+
+  static SetUpTearDownSuiteFuncType GetSetUpCaseOrSuite(const char* filename,
+                                                        int line_num) {
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+    SetUpTearDownSuiteFuncType test_case_fp =
+        GetNotDefaultOrNull(&T::SetUpTestCase, &Test::SetUpTestCase);
+    SetUpTearDownSuiteFuncType test_suite_fp =
+        GetNotDefaultOrNull(&T::SetUpTestSuite, &Test::SetUpTestSuite);
+
+    GTEST_CHECK_(!test_case_fp || !test_suite_fp)
+        << "Test can not provide both SetUpTestSuite and SetUpTestCase, please "
+           "make sure there is only one present at "
+        << filename << ":" << line_num;
+
+    return test_case_fp != nullptr ? test_case_fp : test_suite_fp;
+#else
+    (void)(filename);
+    (void)(line_num);
+    return &T::SetUpTestSuite;
+#endif
+  }
+
+  static SetUpTearDownSuiteFuncType GetTearDownCaseOrSuite(const char* filename,
+                                                           int line_num) {
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+    SetUpTearDownSuiteFuncType test_case_fp =
+        GetNotDefaultOrNull(&T::TearDownTestCase, &Test::TearDownTestCase);
+    SetUpTearDownSuiteFuncType test_suite_fp =
+        GetNotDefaultOrNull(&T::TearDownTestSuite, &Test::TearDownTestSuite);
+
+    GTEST_CHECK_(!test_case_fp || !test_suite_fp)
+        << "Test can not provide both TearDownTestSuite and TearDownTestCase,"
+           " please make sure there is only one present at"
+        << filename << ":" << line_num;
+
+    return test_case_fp != nullptr ? test_case_fp : test_suite_fp;
+#else
+    (void)(filename);
+    (void)(line_num);
+    return &T::TearDownTestSuite;
+#endif
+  }
+};
+
+// Creates a new TestInfo object and registers it with Google Test;
+// returns the created object.
+//
+// Arguments:
+//
+//   test_suite_name:  name of the test suite
+//   name:             name of the test
+//   type_param:       the name of the test's type parameter, or NULL if
+//                     this is not a typed or a type-parameterized test.
+//   value_param:      text representation of the test's value parameter,
+//                     or NULL if this is not a type-parameterized test.
+//   code_location:    code location where the test is defined
+//   fixture_class_id: ID of the test fixture class
+//   set_up_tc:        pointer to the function that sets up the test suite
+//   tear_down_tc:     pointer to the function that tears down the test suite
+//   factory:          pointer to the factory that creates a test object.
+//                     The newly created TestInfo instance will assume
+//                     ownership of the factory object.
+GTEST_API_ TestInfo* MakeAndRegisterTestInfo(
+    const char* test_suite_name, const char* name, const char* type_param,
+    const char* value_param, CodeLocation code_location,
+    TypeId fixture_class_id, SetUpTestSuiteFunc set_up_tc,
+    TearDownTestSuiteFunc tear_down_tc, TestFactoryBase* factory);
+
+// If *pstr starts with the given prefix, modifies *pstr to be right
+// past the prefix and returns true; otherwise leaves *pstr unchanged
+// and returns false.  None of pstr, *pstr, and prefix can be NULL.
+GTEST_API_ bool SkipPrefix(const char* prefix, const char** pstr);
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+// State of the definition of a type-parameterized test suite.
+class GTEST_API_ TypedTestSuitePState {
+ public:
+  TypedTestSuitePState() : registered_(false) {}
+
+  // Adds the given test name to defined_test_names_ and return true
+  // if the test suite hasn't been registered; otherwise aborts the
+  // program.
+  bool AddTestName(const char* file, int line, const char* case_name,
+                   const char* test_name) {
+    if (registered_) {
+      fprintf(stderr,
+              "%s Test %s must be defined before "
+              "REGISTER_TYPED_TEST_SUITE_P(%s, ...).\n",
+              FormatFileLocation(file, line).c_str(), test_name, case_name);
+      fflush(stderr);
+      posix::Abort();
+    }
+    registered_tests_.insert(
+        ::std::make_pair(test_name, CodeLocation(file, line)));
+    return true;
+  }
+
+  bool TestExists(const std::string& test_name) const {
+    return registered_tests_.count(test_name) > 0;
+  }
+
+  const CodeLocation& GetCodeLocation(const std::string& test_name) const {
+    RegisteredTestsMap::const_iterator it = registered_tests_.find(test_name);
+    GTEST_CHECK_(it != registered_tests_.end());
+    return it->second;
+  }
+
+  // Verifies that registered_tests match the test names in
+  // defined_test_names_; returns registered_tests if successful, or
+  // aborts the program otherwise.
+  const char* VerifyRegisteredTestNames(const char* test_suite_name,
+                                        const char* file, int line,
+                                        const char* registered_tests);
+
+ private:
+  typedef ::std::map<std::string, CodeLocation> RegisteredTestsMap;
+
+  bool registered_;
+  RegisteredTestsMap registered_tests_;
+};
+
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+using TypedTestCasePState = TypedTestSuitePState;
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+// Skips to the first non-space char after the first comma in 'str';
+// returns NULL if no comma is found in 'str'.
+inline const char* SkipComma(const char* str) {
+  const char* comma = strchr(str, ',');
+  if (comma == nullptr) {
+    return nullptr;
+  }
+  while (IsSpace(*(++comma))) {}
+  return comma;
+}
+
+// Returns the prefix of 'str' before the first comma in it; returns
+// the entire string if it contains no comma.
+inline std::string GetPrefixUntilComma(const char* str) {
+  const char* comma = strchr(str, ',');
+  return comma == nullptr ? str : std::string(str, comma);
+}
+
+// Splits a given string on a given delimiter, populating a given
+// vector with the fields.
+void SplitString(const ::std::string& str, char delimiter,
+                 ::std::vector< ::std::string>* dest);
+
+// The default argument to the template below for the case when the user does
+// not provide a name generator.
+struct DefaultNameGenerator {
+  template <typename T>
+  static std::string GetName(int i) {
+    return StreamableToString(i);
+  }
+};
+
+template <typename Provided = DefaultNameGenerator>
+struct NameGeneratorSelector {
+  typedef Provided type;
+};
+
+template <typename NameGenerator>
+void GenerateNamesRecursively(internal::None, std::vector<std::string>*, int) {}
+
+template <typename NameGenerator, typename Types>
+void GenerateNamesRecursively(Types, std::vector<std::string>* result, int i) {
+  result->push_back(NameGenerator::template GetName<typename Types::Head>(i));
+  GenerateNamesRecursively<NameGenerator>(typename Types::Tail(), result,
+                                          i + 1);
+}
+
+template <typename NameGenerator, typename Types>
+std::vector<std::string> GenerateNames() {
+  std::vector<std::string> result;
+  GenerateNamesRecursively<NameGenerator>(Types(), &result, 0);
+  return result;
+}
+
+// TypeParameterizedTest<Fixture, TestSel, Types>::Register()
+// registers a list of type-parameterized tests with Google Test.  The
+// return value is insignificant - we just need to return something
+// such that we can call this function in a namespace scope.
+//
+// Implementation note: The GTEST_TEMPLATE_ macro declares a template
+// template parameter.  It's defined in gtest-type-util.h.
+template <GTEST_TEMPLATE_ Fixture, class TestSel, typename Types>
+class TypeParameterizedTest {
+ public:
+  // 'index' is the index of the test in the type list 'Types'
+  // specified in INSTANTIATE_TYPED_TEST_SUITE_P(Prefix, TestSuite,
+  // Types).  Valid values for 'index' are [0, N - 1] where N is the
+  // length of Types.
+  static bool Register(const char* prefix, const CodeLocation& code_location,
+                       const char* case_name, const char* test_names, int index,
+                       const std::vector<std::string>& type_names =
+                           GenerateNames<DefaultNameGenerator, Types>()) {
+    typedef typename Types::Head Type;
+    typedef Fixture<Type> FixtureClass;
+    typedef typename GTEST_BIND_(TestSel, Type) TestClass;
+
+    // First, registers the first type-parameterized test in the type
+    // list.
+    MakeAndRegisterTestInfo(
+        (std::string(prefix) + (prefix[0] == '\0' ? "" : "/") + case_name +
+         "/" + type_names[static_cast<size_t>(index)])
+            .c_str(),
+        StripTrailingSpaces(GetPrefixUntilComma(test_names)).c_str(),
+        GetTypeName<Type>().c_str(),
+        nullptr,  // No value parameter.
+        code_location, GetTypeId<FixtureClass>(),
+        SuiteApiResolver<TestClass>::GetSetUpCaseOrSuite(
+            code_location.file.c_str(), code_location.line),
+        SuiteApiResolver<TestClass>::GetTearDownCaseOrSuite(
+            code_location.file.c_str(), code_location.line),
+        new TestFactoryImpl<TestClass>);
+
+    // Next, recurses (at compile time) with the tail of the type list.
+    return TypeParameterizedTest<Fixture, TestSel,
+                                 typename Types::Tail>::Register(prefix,
+                                                                 code_location,
+                                                                 case_name,
+                                                                 test_names,
+                                                                 index + 1,
+                                                                 type_names);
+  }
+};
+
+// The base case for the compile time recursion.
+template <GTEST_TEMPLATE_ Fixture, class TestSel>
+class TypeParameterizedTest<Fixture, TestSel, internal::None> {
+ public:
+  static bool Register(const char* /*prefix*/, const CodeLocation&,
+                       const char* /*case_name*/, const char* /*test_names*/,
+                       int /*index*/,
+                       const std::vector<std::string>& =
+                           std::vector<std::string>() /*type_names*/) {
+    return true;
+  }
+};
+
+GTEST_API_ void RegisterTypeParameterizedTestSuite(const char* test_suite_name,
+                                                   CodeLocation code_location);
+GTEST_API_ void RegisterTypeParameterizedTestSuiteInstantiation(
+    const char* case_name);
+
+// TypeParameterizedTestSuite<Fixture, Tests, Types>::Register()
+// registers *all combinations* of 'Tests' and 'Types' with Google
+// Test.  The return value is insignificant - we just need to return
+// something such that we can call this function in a namespace scope.
+template <GTEST_TEMPLATE_ Fixture, typename Tests, typename Types>
+class TypeParameterizedTestSuite {
+ public:
+  static bool Register(const char* prefix, CodeLocation code_location,
+                       const TypedTestSuitePState* state, const char* case_name,
+                       const char* test_names,
+                       const std::vector<std::string>& type_names =
+                           GenerateNames<DefaultNameGenerator, Types>()) {
+    RegisterTypeParameterizedTestSuiteInstantiation(case_name);
+    std::string test_name = StripTrailingSpaces(
+        GetPrefixUntilComma(test_names));
+    if (!state->TestExists(test_name)) {
+      fprintf(stderr, "Failed to get code location for test %s.%s at %s.",
+              case_name, test_name.c_str(),
+              FormatFileLocation(code_location.file.c_str(),
+                                 code_location.line).c_str());
+      fflush(stderr);
+      posix::Abort();
+    }
+    const CodeLocation& test_location = state->GetCodeLocation(test_name);
+
+    typedef typename Tests::Head Head;
+
+    // First, register the first test in 'Test' for each type in 'Types'.
+    TypeParameterizedTest<Fixture, Head, Types>::Register(
+        prefix, test_location, case_name, test_names, 0, type_names);
+
+    // Next, recurses (at compile time) with the tail of the test list.
+    return TypeParameterizedTestSuite<Fixture, typename Tests::Tail,
+                                      Types>::Register(prefix, code_location,
+                                                       state, case_name,
+                                                       SkipComma(test_names),
+                                                       type_names);
+  }
+};
+
+// The base case for the compile time recursion.
+template <GTEST_TEMPLATE_ Fixture, typename Types>
+class TypeParameterizedTestSuite<Fixture, internal::None, Types> {
+ public:
+  static bool Register(const char* /*prefix*/, const CodeLocation&,
+                       const TypedTestSuitePState* /*state*/,
+                       const char* /*case_name*/, const char* /*test_names*/,
+                       const std::vector<std::string>& =
+                           std::vector<std::string>() /*type_names*/) {
+    return true;
+  }
+};
+
+// Returns the current OS stack trace as an std::string.
+//
+// The maximum number of stack frames to be included is specified by
+// the gtest_stack_trace_depth flag.  The skip_count parameter
+// specifies the number of top frames to be skipped, which doesn't
+// count against the number of frames to be included.
+//
+// For example, if Foo() calls Bar(), which in turn calls
+// GetCurrentOsStackTraceExceptTop(..., 1), Foo() will be included in
+// the trace but Bar() and GetCurrentOsStackTraceExceptTop() won't.
+GTEST_API_ std::string GetCurrentOsStackTraceExceptTop(
+    UnitTest* unit_test, int skip_count);
+
+// Helpers for suppressing warnings on unreachable code or constant
+// condition.
+
+// Always returns true.
+GTEST_API_ bool AlwaysTrue();
+
+// Always returns false.
+inline bool AlwaysFalse() { return !AlwaysTrue(); }
+
+// Helper for suppressing false warning from Clang on a const char*
+// variable declared in a conditional expression always being NULL in
+// the else branch.
+struct GTEST_API_ ConstCharPtr {
+  ConstCharPtr(const char* str) : value(str) {}
+  operator bool() const { return true; }
+  const char* value;
+};
+
+// Helper for declaring std::string within 'if' statement
+// in pre C++17 build environment.
+struct TrueWithString {
+  TrueWithString() = default;
+  explicit TrueWithString(const char* str) : value(str) {}
+  explicit TrueWithString(const std::string& str) : value(str) {}
+  explicit operator bool() const { return true; }
+  std::string value;
+};
+
+// A simple Linear Congruential Generator for generating random
+// numbers with a uniform distribution.  Unlike rand() and srand(), it
+// doesn't use global state (and therefore can't interfere with user
+// code).  Unlike rand_r(), it's portable.  An LCG isn't very random,
+// but it's good enough for our purposes.
+class GTEST_API_ Random {
+ public:
+  static const uint32_t kMaxRange = 1u << 31;
+
+  explicit Random(uint32_t seed) : state_(seed) {}
+
+  void Reseed(uint32_t seed) { state_ = seed; }
+
+  // Generates a random number from [0, range).  Crashes if 'range' is
+  // 0 or greater than kMaxRange.
+  uint32_t Generate(uint32_t range);
+
+ private:
+  uint32_t state_;
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(Random);
+};
+
+// Turns const U&, U&, const U, and U all into U.
+#define GTEST_REMOVE_REFERENCE_AND_CONST_(T) \
+  typename std::remove_const<typename std::remove_reference<T>::type>::type
+
+// HasDebugStringAndShortDebugString<T>::value is a compile-time bool constant
+// that's true if and only if T has methods DebugString() and ShortDebugString()
+// that return std::string.
+template <typename T>
+class HasDebugStringAndShortDebugString {
+ private:
+  template <typename C>
+  static auto CheckDebugString(C*) -> typename std::is_same<
+      std::string, decltype(std::declval<const C>().DebugString())>::type;
+  template <typename>
+  static std::false_type CheckDebugString(...);
+
+  template <typename C>
+  static auto CheckShortDebugString(C*) -> typename std::is_same<
+      std::string, decltype(std::declval<const C>().ShortDebugString())>::type;
+  template <typename>
+  static std::false_type CheckShortDebugString(...);
+
+  using HasDebugStringType = decltype(CheckDebugString<T>(nullptr));
+  using HasShortDebugStringType = decltype(CheckShortDebugString<T>(nullptr));
+
+ public:
+  static constexpr bool value =
+      HasDebugStringType::value && HasShortDebugStringType::value;
+};
+
+template <typename T>
+constexpr bool HasDebugStringAndShortDebugString<T>::value;
+
+// When the compiler sees expression IsContainerTest<C>(0), if C is an
+// STL-style container class, the first overload of IsContainerTest
+// will be viable (since both C::iterator* and C::const_iterator* are
+// valid types and NULL can be implicitly converted to them).  It will
+// be picked over the second overload as 'int' is a perfect match for
+// the type of argument 0.  If C::iterator or C::const_iterator is not
+// a valid type, the first overload is not viable, and the second
+// overload will be picked.  Therefore, we can determine whether C is
+// a container class by checking the type of IsContainerTest<C>(0).
+// The value of the expression is insignificant.
+//
+// In C++11 mode we check the existence of a const_iterator and that an
+// iterator is properly implemented for the container.
+//
+// For pre-C++11 that we look for both C::iterator and C::const_iterator.
+// The reason is that C++ injects the name of a class as a member of the
+// class itself (e.g. you can refer to class iterator as either
+// 'iterator' or 'iterator::iterator').  If we look for C::iterator
+// only, for example, we would mistakenly think that a class named
+// iterator is an STL container.
+//
+// Also note that the simpler approach of overloading
+// IsContainerTest(typename C::const_iterator*) and
+// IsContainerTest(...) doesn't work with Visual Age C++ and Sun C++.
+typedef int IsContainer;
+template <class C,
+          class Iterator = decltype(::std::declval<const C&>().begin()),
+          class = decltype(::std::declval<const C&>().end()),
+          class = decltype(++::std::declval<Iterator&>()),
+          class = decltype(*::std::declval<Iterator>()),
+          class = typename C::const_iterator>
+IsContainer IsContainerTest(int /* dummy */) {
+  return 0;
+}
+
+typedef char IsNotContainer;
+template <class C>
+IsNotContainer IsContainerTest(long /* dummy */) { return '\0'; }
+
+// Trait to detect whether a type T is a hash table.
+// The heuristic used is that the type contains an inner type `hasher` and does
+// not contain an inner type `reverse_iterator`.
+// If the container is iterable in reverse, then order might actually matter.
+template <typename T>
+struct IsHashTable {
+ private:
+  template <typename U>
+  static char test(typename U::hasher*, typename U::reverse_iterator*);
+  template <typename U>
+  static int test(typename U::hasher*, ...);
+  template <typename U>
+  static char test(...);
+
+ public:
+  static const bool value = sizeof(test<T>(nullptr, nullptr)) == sizeof(int);
+};
+
+template <typename T>
+const bool IsHashTable<T>::value;
+
+template <typename C,
+          bool = sizeof(IsContainerTest<C>(0)) == sizeof(IsContainer)>
+struct IsRecursiveContainerImpl;
+
+template <typename C>
+struct IsRecursiveContainerImpl<C, false> : public std::false_type {};
+
+// Since the IsRecursiveContainerImpl depends on the IsContainerTest we need to
+// obey the same inconsistencies as the IsContainerTest, namely check if
+// something is a container is relying on only const_iterator in C++11 and
+// is relying on both const_iterator and iterator otherwise
+template <typename C>
+struct IsRecursiveContainerImpl<C, true> {
+  using value_type = decltype(*std::declval<typename C::const_iterator>());
+  using type =
+      std::is_same<typename std::remove_const<
+                       typename std::remove_reference<value_type>::type>::type,
+                   C>;
+};
+
+// IsRecursiveContainer<Type> is a unary compile-time predicate that
+// evaluates whether C is a recursive container type. A recursive container
+// type is a container type whose value_type is equal to the container type
+// itself. An example for a recursive container type is
+// boost::filesystem::path, whose iterator has a value_type that is equal to
+// boost::filesystem::path.
+template <typename C>
+struct IsRecursiveContainer : public IsRecursiveContainerImpl<C>::type {};
+
+// Utilities for native arrays.
+
+// ArrayEq() compares two k-dimensional native arrays using the
+// elements' operator==, where k can be any integer >= 0.  When k is
+// 0, ArrayEq() degenerates into comparing a single pair of values.
+
+template <typename T, typename U>
+bool ArrayEq(const T* lhs, size_t size, const U* rhs);
+
+// This generic version is used when k is 0.
+template <typename T, typename U>
+inline bool ArrayEq(const T& lhs, const U& rhs) { return lhs == rhs; }
+
+// This overload is used when k >= 1.
+template <typename T, typename U, size_t N>
+inline bool ArrayEq(const T(&lhs)[N], const U(&rhs)[N]) {
+  return internal::ArrayEq(lhs, N, rhs);
+}
+
+// This helper reduces code bloat.  If we instead put its logic inside
+// the previous ArrayEq() function, arrays with different sizes would
+// lead to different copies of the template code.
+template <typename T, typename U>
+bool ArrayEq(const T* lhs, size_t size, const U* rhs) {
+  for (size_t i = 0; i != size; i++) {
+    if (!internal::ArrayEq(lhs[i], rhs[i]))
+      return false;
+  }
+  return true;
+}
+
+// Finds the first element in the iterator range [begin, end) that
+// equals elem.  Element may be a native array type itself.
+template <typename Iter, typename Element>
+Iter ArrayAwareFind(Iter begin, Iter end, const Element& elem) {
+  for (Iter it = begin; it != end; ++it) {
+    if (internal::ArrayEq(*it, elem))
+      return it;
+  }
+  return end;
+}
+
+// CopyArray() copies a k-dimensional native array using the elements'
+// operator=, where k can be any integer >= 0.  When k is 0,
+// CopyArray() degenerates into copying a single value.
+
+template <typename T, typename U>
+void CopyArray(const T* from, size_t size, U* to);
+
+// This generic version is used when k is 0.
+template <typename T, typename U>
+inline void CopyArray(const T& from, U* to) { *to = from; }
+
+// This overload is used when k >= 1.
+template <typename T, typename U, size_t N>
+inline void CopyArray(const T(&from)[N], U(*to)[N]) {
+  internal::CopyArray(from, N, *to);
+}
+
+// This helper reduces code bloat.  If we instead put its logic inside
+// the previous CopyArray() function, arrays with different sizes
+// would lead to different copies of the template code.
+template <typename T, typename U>
+void CopyArray(const T* from, size_t size, U* to) {
+  for (size_t i = 0; i != size; i++) {
+    internal::CopyArray(from[i], to + i);
+  }
+}
+
+// The relation between an NativeArray object (see below) and the
+// native array it represents.
+// We use 2 different structs to allow non-copyable types to be used, as long
+// as RelationToSourceReference() is passed.
+struct RelationToSourceReference {};
+struct RelationToSourceCopy {};
+
+// Adapts a native array to a read-only STL-style container.  Instead
+// of the complete STL container concept, this adaptor only implements
+// members useful for Google Mock's container matchers.  New members
+// should be added as needed.  To simplify the implementation, we only
+// support Element being a raw type (i.e. having no top-level const or
+// reference modifier).  It's the client's responsibility to satisfy
+// this requirement.  Element can be an array type itself (hence
+// multi-dimensional arrays are supported).
+template <typename Element>
+class NativeArray {
+ public:
+  // STL-style container typedefs.
+  typedef Element value_type;
+  typedef Element* iterator;
+  typedef const Element* const_iterator;
+
+  // Constructs from a native array. References the source.
+  NativeArray(const Element* array, size_t count, RelationToSourceReference) {
+    InitRef(array, count);
+  }
+
+  // Constructs from a native array. Copies the source.
+  NativeArray(const Element* array, size_t count, RelationToSourceCopy) {
+    InitCopy(array, count);
+  }
+
+  // Copy constructor.
+  NativeArray(const NativeArray& rhs) {
+    (this->*rhs.clone_)(rhs.array_, rhs.size_);
+  }
+
+  ~NativeArray() {
+    if (clone_ != &NativeArray::InitRef)
+      delete[] array_;
+  }
+
+  // STL-style container methods.
+  size_t size() const { return size_; }
+  const_iterator begin() const { return array_; }
+  const_iterator end() const { return array_ + size_; }
+  bool operator==(const NativeArray& rhs) const {
+    return size() == rhs.size() &&
+        ArrayEq(begin(), size(), rhs.begin());
+  }
+
+ private:
+  static_assert(!std::is_const<Element>::value, "Type must not be const");
+  static_assert(!std::is_reference<Element>::value,
+                "Type must not be a reference");
+
+  // Initializes this object with a copy of the input.
+  void InitCopy(const Element* array, size_t a_size) {
+    Element* const copy = new Element[a_size];
+    CopyArray(array, a_size, copy);
+    array_ = copy;
+    size_ = a_size;
+    clone_ = &NativeArray::InitCopy;
+  }
+
+  // Initializes this object with a reference of the input.
+  void InitRef(const Element* array, size_t a_size) {
+    array_ = array;
+    size_ = a_size;
+    clone_ = &NativeArray::InitRef;
+  }
+
+  const Element* array_;
+  size_t size_;
+  void (NativeArray::*clone_)(const Element*, size_t);
+};
+
+// Backport of std::index_sequence.
+template <size_t... Is>
+struct IndexSequence {
+  using type = IndexSequence;
+};
+
+// Double the IndexSequence, and one if plus_one is true.
+template <bool plus_one, typename T, size_t sizeofT>
+struct DoubleSequence;
+template <size_t... I, size_t sizeofT>
+struct DoubleSequence<true, IndexSequence<I...>, sizeofT> {
+  using type = IndexSequence<I..., (sizeofT + I)..., 2 * sizeofT>;
+};
+template <size_t... I, size_t sizeofT>
+struct DoubleSequence<false, IndexSequence<I...>, sizeofT> {
+  using type = IndexSequence<I..., (sizeofT + I)...>;
+};
+
+// Backport of std::make_index_sequence.
+// It uses O(ln(N)) instantiation depth.
+template <size_t N>
+struct MakeIndexSequenceImpl
+    : DoubleSequence<N % 2 == 1, typename MakeIndexSequenceImpl<N / 2>::type,
+                     N / 2>::type {};
+
+template <>
+struct MakeIndexSequenceImpl<0> : IndexSequence<> {};
+
+template <size_t N>
+using MakeIndexSequence = typename MakeIndexSequenceImpl<N>::type;
+
+template <typename... T>
+using IndexSequenceFor = typename MakeIndexSequence<sizeof...(T)>::type;
+
+template <size_t>
+struct Ignore {
+  Ignore(...);  // NOLINT
+};
+
+template <typename>
+struct ElemFromListImpl;
+template <size_t... I>
+struct ElemFromListImpl<IndexSequence<I...>> {
+  // We make Ignore a template to solve a problem with MSVC.
+  // A non-template Ignore would work fine with `decltype(Ignore(I))...`, but
+  // MSVC doesn't understand how to deal with that pack expansion.
+  // Use `0 * I` to have a single instantiation of Ignore.
+  template <typename R>
+  static R Apply(Ignore<0 * I>..., R (*)(), ...);
+};
+
+template <size_t N, typename... T>
+struct ElemFromList {
+  using type =
+      decltype(ElemFromListImpl<typename MakeIndexSequence<N>::type>::Apply(
+          static_cast<T (*)()>(nullptr)...));
+};
+
+struct FlatTupleConstructTag {};
+
+template <typename... T>
+class FlatTuple;
+
+template <typename Derived, size_t I>
+struct FlatTupleElemBase;
+
+template <typename... T, size_t I>
+struct FlatTupleElemBase<FlatTuple<T...>, I> {
+  using value_type = typename ElemFromList<I, T...>::type;
+  FlatTupleElemBase() = default;
+  template <typename Arg>
+  explicit FlatTupleElemBase(FlatTupleConstructTag, Arg&& t)
+      : value(std::forward<Arg>(t)) {}
+  value_type value;
+};
+
+template <typename Derived, typename Idx>
+struct FlatTupleBase;
+
+template <size_t... Idx, typename... T>
+struct FlatTupleBase<FlatTuple<T...>, IndexSequence<Idx...>>
+    : FlatTupleElemBase<FlatTuple<T...>, Idx>... {
+  using Indices = IndexSequence<Idx...>;
+  FlatTupleBase() = default;
+  template <typename... Args>
+  explicit FlatTupleBase(FlatTupleConstructTag, Args&&... args)
+      : FlatTupleElemBase<FlatTuple<T...>, Idx>(FlatTupleConstructTag{},
+                                                std::forward<Args>(args))... {}
+
+  template <size_t I>
+  const typename ElemFromList<I, T...>::type& Get() const {
+    return FlatTupleElemBase<FlatTuple<T...>, I>::value;
+  }
+
+  template <size_t I>
+  typename ElemFromList<I, T...>::type& Get() {
+    return FlatTupleElemBase<FlatTuple<T...>, I>::value;
+  }
+
+  template <typename F>
+  auto Apply(F&& f) -> decltype(std::forward<F>(f)(this->Get<Idx>()...)) {
+    return std::forward<F>(f)(Get<Idx>()...);
+  }
+
+  template <typename F>
+  auto Apply(F&& f) const -> decltype(std::forward<F>(f)(this->Get<Idx>()...)) {
+    return std::forward<F>(f)(Get<Idx>()...);
+  }
+};
+
+// Analog to std::tuple but with different tradeoffs.
+// This class minimizes the template instantiation depth, thus allowing more
+// elements than std::tuple would. std::tuple has been seen to require an
+// instantiation depth of more than 10x the number of elements in some
+// implementations.
+// FlatTuple and ElemFromList are not recursive and have a fixed depth
+// regardless of T...
+// MakeIndexSequence, on the other hand, it is recursive but with an
+// instantiation depth of O(ln(N)).
+template <typename... T>
+class FlatTuple
+    : private FlatTupleBase<FlatTuple<T...>,
+                            typename MakeIndexSequence<sizeof...(T)>::type> {
+  using Indices = typename FlatTupleBase<
+      FlatTuple<T...>, typename MakeIndexSequence<sizeof...(T)>::type>::Indices;
+
+ public:
+  FlatTuple() = default;
+  template <typename... Args>
+  explicit FlatTuple(FlatTupleConstructTag tag, Args&&... args)
+      : FlatTuple::FlatTupleBase(tag, std::forward<Args>(args)...) {}
+
+  using FlatTuple::FlatTupleBase::Apply;
+  using FlatTuple::FlatTupleBase::Get;
+};
+
+// Utility functions to be called with static_assert to induce deprecation
+// warnings.
+GTEST_INTERNAL_DEPRECATED(
+    "INSTANTIATE_TEST_CASE_P is deprecated, please use "
+    "INSTANTIATE_TEST_SUITE_P")
+constexpr bool InstantiateTestCase_P_IsDeprecated() { return true; }
+
+GTEST_INTERNAL_DEPRECATED(
+    "TYPED_TEST_CASE_P is deprecated, please use "
+    "TYPED_TEST_SUITE_P")
+constexpr bool TypedTestCase_P_IsDeprecated() { return true; }
+
+GTEST_INTERNAL_DEPRECATED(
+    "TYPED_TEST_CASE is deprecated, please use "
+    "TYPED_TEST_SUITE")
+constexpr bool TypedTestCaseIsDeprecated() { return true; }
+
+GTEST_INTERNAL_DEPRECATED(
+    "REGISTER_TYPED_TEST_CASE_P is deprecated, please use "
+    "REGISTER_TYPED_TEST_SUITE_P")
+constexpr bool RegisterTypedTestCase_P_IsDeprecated() { return true; }
+
+GTEST_INTERNAL_DEPRECATED(
+    "INSTANTIATE_TYPED_TEST_CASE_P is deprecated, please use "
+    "INSTANTIATE_TYPED_TEST_SUITE_P")
+constexpr bool InstantiateTypedTestCase_P_IsDeprecated() { return true; }
+
+}  // namespace internal
+}  // namespace testing
+
+namespace std {
+// Some standard library implementations use `struct tuple_size` and some use
+// `class tuple_size`. Clang warns about the mismatch.
+// https://reviews.llvm.org/D55466
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wmismatched-tags"
+#endif
+template <typename... Ts>
+struct tuple_size<testing::internal::FlatTuple<Ts...>>
+    : std::integral_constant<size_t, sizeof...(Ts)> {};
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+}  // namespace std
+
+#define GTEST_MESSAGE_AT_(file, line, message, result_type) \
+  ::testing::internal::AssertHelper(result_type, file, line, message) \
+    = ::testing::Message()
+
+#define GTEST_MESSAGE_(message, result_type) \
+  GTEST_MESSAGE_AT_(__FILE__, __LINE__, message, result_type)
+
+#define GTEST_FATAL_FAILURE_(message) \
+  return GTEST_MESSAGE_(message, ::testing::TestPartResult::kFatalFailure)
+
+#define GTEST_NONFATAL_FAILURE_(message) \
+  GTEST_MESSAGE_(message, ::testing::TestPartResult::kNonFatalFailure)
+
+#define GTEST_SUCCESS_(message) \
+  GTEST_MESSAGE_(message, ::testing::TestPartResult::kSuccess)
+
+#define GTEST_SKIP_(message) \
+  return GTEST_MESSAGE_(message, ::testing::TestPartResult::kSkip)
+
+// Suppress MSVC warning 4072 (unreachable code) for the code following
+// statement if it returns or throws (or doesn't return or throw in some
+// situations).
+// NOTE: The "else" is important to keep this expansion to prevent a top-level
+// "else" from attaching to our "if".
+#define GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement) \
+  if (::testing::internal::AlwaysTrue()) {                        \
+    statement;                                                    \
+  } else                     /* NOLINT */                         \
+    static_assert(true, "")  // User must have a semicolon after expansion.
+
+#if GTEST_HAS_EXCEPTIONS
+
+namespace testing {
+namespace internal {
+
+class NeverThrown {
+ public:
+  const char* what() const noexcept {
+    return "this exception should never be thrown";
+  }
+};
+
+}  // namespace internal
+}  // namespace testing
+
+#if GTEST_HAS_RTTI
+
+#define GTEST_EXCEPTION_TYPE_(e) ::testing::internal::GetTypeName(typeid(e))
+
+#else  // GTEST_HAS_RTTI
+
+#define GTEST_EXCEPTION_TYPE_(e) \
+  std::string { "an std::exception-derived error" }
+
+#endif  // GTEST_HAS_RTTI
+
+#define GTEST_TEST_THROW_CATCH_STD_EXCEPTION_(statement, expected_exception)   \
+  catch (typename std::conditional<                                            \
+         std::is_same<typename std::remove_cv<typename std::remove_reference<  \
+                          expected_exception>::type>::type,                    \
+                      std::exception>::value,                                  \
+         const ::testing::internal::NeverThrown&, const std::exception&>::type \
+             e) {                                                              \
+    gtest_msg.value = "Expected: " #statement                                  \
+                      " throws an exception of type " #expected_exception      \
+                      ".\n  Actual: it throws ";                               \
+    gtest_msg.value += GTEST_EXCEPTION_TYPE_(e);                               \
+    gtest_msg.value += " with description \"";                                 \
+    gtest_msg.value += e.what();                                               \
+    gtest_msg.value += "\".";                                                  \
+    goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__);                \
+  }
+
+#else  // GTEST_HAS_EXCEPTIONS
+
+#define GTEST_TEST_THROW_CATCH_STD_EXCEPTION_(statement, expected_exception)
+
+#endif  // GTEST_HAS_EXCEPTIONS
+
+#define GTEST_TEST_THROW_(statement, expected_exception, fail)              \
+  GTEST_AMBIGUOUS_ELSE_BLOCKER_                                             \
+  if (::testing::internal::TrueWithString gtest_msg{}) {                    \
+    bool gtest_caught_expected = false;                                     \
+    try {                                                                   \
+      GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement);            \
+    } catch (expected_exception const&) {                                   \
+      gtest_caught_expected = true;                                         \
+    }                                                                       \
+    GTEST_TEST_THROW_CATCH_STD_EXCEPTION_(statement, expected_exception)    \
+    catch (...) {                                                           \
+      gtest_msg.value = "Expected: " #statement                             \
+                        " throws an exception of type " #expected_exception \
+                        ".\n  Actual: it throws a different type.";         \
+      goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__);           \
+    }                                                                       \
+    if (!gtest_caught_expected) {                                           \
+      gtest_msg.value = "Expected: " #statement                             \
+                        " throws an exception of type " #expected_exception \
+                        ".\n  Actual: it throws nothing.";                  \
+      goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__);           \
+    }                                                                       \
+  } else /*NOLINT*/                                                         \
+    GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__)                   \
+        : fail(gtest_msg.value.c_str())
+
+#if GTEST_HAS_EXCEPTIONS
+
+#define GTEST_TEST_NO_THROW_CATCH_STD_EXCEPTION_()                \
+  catch (std::exception const& e) {                               \
+    gtest_msg.value = "it throws ";                               \
+    gtest_msg.value += GTEST_EXCEPTION_TYPE_(e);                  \
+    gtest_msg.value += " with description \"";                    \
+    gtest_msg.value += e.what();                                  \
+    gtest_msg.value += "\".";                                     \
+    goto GTEST_CONCAT_TOKEN_(gtest_label_testnothrow_, __LINE__); \
+  }
+
+#else  // GTEST_HAS_EXCEPTIONS
+
+#define GTEST_TEST_NO_THROW_CATCH_STD_EXCEPTION_()
+
+#endif  // GTEST_HAS_EXCEPTIONS
+
+#define GTEST_TEST_NO_THROW_(statement, fail) \
+  GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
+  if (::testing::internal::TrueWithString gtest_msg{}) { \
+    try { \
+      GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
+    } \
+    GTEST_TEST_NO_THROW_CATCH_STD_EXCEPTION_() \
+    catch (...) { \
+      gtest_msg.value = "it throws."; \
+      goto GTEST_CONCAT_TOKEN_(gtest_label_testnothrow_, __LINE__); \
+    } \
+  } else \
+    GTEST_CONCAT_TOKEN_(gtest_label_testnothrow_, __LINE__): \
+      fail(("Expected: " #statement " doesn't throw an exception.\n" \
+            "  Actual: " + gtest_msg.value).c_str())
+
+#define GTEST_TEST_ANY_THROW_(statement, fail) \
+  GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
+  if (::testing::internal::AlwaysTrue()) { \
+    bool gtest_caught_any = false; \
+    try { \
+      GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
+    } \
+    catch (...) { \
+      gtest_caught_any = true; \
+    } \
+    if (!gtest_caught_any) { \
+      goto GTEST_CONCAT_TOKEN_(gtest_label_testanythrow_, __LINE__); \
+    } \
+  } else \
+    GTEST_CONCAT_TOKEN_(gtest_label_testanythrow_, __LINE__): \
+      fail("Expected: " #statement " throws an exception.\n" \
+           "  Actual: it doesn't.")
+
+
+// Implements Boolean test assertions such as EXPECT_TRUE. expression can be
+// either a boolean expression or an AssertionResult. text is a textual
+// representation of expression as it was passed into the EXPECT_TRUE.
+#define GTEST_TEST_BOOLEAN_(expression, text, actual, expected, fail) \
+  GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
+  if (const ::testing::AssertionResult gtest_ar_ = \
+      ::testing::AssertionResult(expression)) \
+    ; \
+  else \
+    fail(::testing::internal::GetBoolAssertionFailureMessage(\
+        gtest_ar_, text, #actual, #expected).c_str())
+
+#define GTEST_TEST_NO_FATAL_FAILURE_(statement, fail) \
+  GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
+  if (::testing::internal::AlwaysTrue()) { \
+    ::testing::internal::HasNewFatalFailureHelper gtest_fatal_failure_checker; \
+    GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
+    if (gtest_fatal_failure_checker.has_new_fatal_failure()) { \
+      goto GTEST_CONCAT_TOKEN_(gtest_label_testnofatal_, __LINE__); \
+    } \
+  } else \
+    GTEST_CONCAT_TOKEN_(gtest_label_testnofatal_, __LINE__): \
+      fail("Expected: " #statement " doesn't generate new fatal " \
+           "failures in the current thread.\n" \
+           "  Actual: it does.")
+
+// Expands to the name of the class that implements the given test.
+#define GTEST_TEST_CLASS_NAME_(test_suite_name, test_name) \
+  test_suite_name##_##test_name##_Test
+
+// Helper macro for defining tests.
+#define GTEST_TEST_(test_suite_name, test_name, parent_class, parent_id)      \
+  static_assert(sizeof(GTEST_STRINGIFY_(test_suite_name)) > 1,                \
+                "test_suite_name must not be empty");                         \
+  static_assert(sizeof(GTEST_STRINGIFY_(test_name)) > 1,                      \
+                "test_name must not be empty");                               \
+  class GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)                    \
+      : public parent_class {                                                 \
+   public:                                                                    \
+    GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)() = default;           \
+    ~GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)() override = default; \
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(GTEST_TEST_CLASS_NAME_(test_suite_name,   \
+                                                           test_name));       \
+    GTEST_DISALLOW_MOVE_AND_ASSIGN_(GTEST_TEST_CLASS_NAME_(test_suite_name,   \
+                                                           test_name));       \
+                                                                              \
+   private:                                                                   \
+    void TestBody() override;                                                 \
+    static ::testing::TestInfo* const test_info_ GTEST_ATTRIBUTE_UNUSED_;     \
+  };                                                                          \
+                                                                              \
+  ::testing::TestInfo* const GTEST_TEST_CLASS_NAME_(test_suite_name,          \
+                                                    test_name)::test_info_ =  \
+      ::testing::internal::MakeAndRegisterTestInfo(                           \
+          #test_suite_name, #test_name, nullptr, nullptr,                     \
+          ::testing::internal::CodeLocation(__FILE__, __LINE__), (parent_id), \
+          ::testing::internal::SuiteApiResolver<                              \
+              parent_class>::GetSetUpCaseOrSuite(__FILE__, __LINE__),         \
+          ::testing::internal::SuiteApiResolver<                              \
+              parent_class>::GetTearDownCaseOrSuite(__FILE__, __LINE__),      \
+          new ::testing::internal::TestFactoryImpl<GTEST_TEST_CLASS_NAME_(    \
+              test_suite_name, test_name)>);                                  \
+  void GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)::TestBody()
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_INTERNAL_H_
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// The Google C++ Testing and Mocking Framework (Google Test)
+//
+// This header file defines the public API for death tests.  It is
+// #included by gtest.h so a user doesn't need to include this
+// directly.
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_DEATH_TEST_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_DEATH_TEST_H_
+
+// Copyright 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// The Google C++ Testing and Mocking Framework (Google Test)
+//
+// This header file defines internal utilities needed for implementing
+// death tests.  They are subject to change without notice.
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_DEATH_TEST_INTERNAL_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_DEATH_TEST_INTERNAL_H_
+
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// The Google C++ Testing and Mocking Framework (Google Test)
+//
+// This file implements just enough of the matcher interface to allow
+// EXPECT_DEATH and friends to accept a matcher argument.
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_MATCHERS_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_MATCHERS_H_
+
+#include <atomic>
+#include <memory>
+#include <ostream>
+#include <string>
+#include <type_traits>
+
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Google Test - The Google C++ Testing and Mocking Framework
+//
+// This file implements a universal value printer that can print a
+// value of any type T:
+//
+//   void ::testing::internal::UniversalPrinter<T>::Print(value, ostream_ptr);
+//
+// A user can teach this function how to print a class type T by
+// defining either operator<<() or PrintTo() in the namespace that
+// defines T.  More specifically, the FIRST defined function in the
+// following list will be used (assuming T is defined in namespace
+// foo):
+//
+//   1. foo::PrintTo(const T&, ostream*)
+//   2. operator<<(ostream&, const T&) defined in either foo or the
+//      global namespace.
+//
+// However if T is an STL-style container then it is printed element-wise
+// unless foo::PrintTo(const T&, ostream*) is defined. Note that
+// operator<<() is ignored for container types.
+//
+// If none of the above is defined, it will print the debug string of
+// the value if it is a protocol buffer, or print the raw bytes in the
+// value otherwise.
+//
+// To aid debugging: when T is a reference type, the address of the
+// value is also printed; when T is a (const) char pointer, both the
+// pointer value and the NUL-terminated string it points to are
+// printed.
+//
+// We also provide some convenient wrappers:
+//
+//   // Prints a value to a string.  For a (const or not) char
+//   // pointer, the NUL-terminated string (but not the pointer) is
+//   // printed.
+//   std::string ::testing::PrintToString(const T& value);
+//
+//   // Prints a value tersely: for a reference type, the referenced
+//   // value (but not the address) is printed; for a (const or not) char
+//   // pointer, the NUL-terminated string (but not the pointer) is
+//   // printed.
+//   void ::testing::internal::UniversalTersePrint(const T& value, ostream*);
+//
+//   // Prints value using the type inferred by the compiler.  The difference
+//   // from UniversalTersePrint() is that this function prints both the
+//   // pointer and the NUL-terminated string for a (const or not) char pointer.
+//   void ::testing::internal::UniversalPrint(const T& value, ostream*);
+//
+//   // Prints the fields of a tuple tersely to a string vector, one
+//   // element for each field. Tuple support must be enabled in
+//   // gtest-port.h.
+//   std::vector<string> UniversalTersePrintTupleFieldsToStrings(
+//       const Tuple& value);
+//
+// Known limitation:
+//
+// The print primitives print the elements of an STL-style container
+// using the compiler-inferred type of *iter where iter is a
+// const_iterator of the container.  When const_iterator is an input
+// iterator but not a forward iterator, this inferred type may not
+// match value_type, and the print output may be incorrect.  In
+// practice, this is rarely a problem as for most containers
+// const_iterator is a forward iterator.  We'll fix this if there's an
+// actual need for it.  Note that this fix cannot rely on value_type
+// being defined as many user-defined container types don't have
+// value_type.
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_PRINTERS_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_PRINTERS_H_
+
+#include <functional>
+#include <memory>
+#include <ostream>  // NOLINT
+#include <sstream>
+#include <string>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+
+#if GTEST_HAS_RTTI
+#include <typeindex>
+#include <typeinfo>
+#endif  // GTEST_HAS_RTTI
+
+namespace testing {
+
+// Definitions in the internal* namespaces are subject to change without notice.
+// DO NOT USE THEM IN USER CODE!
+namespace internal {
+
+template <typename T>
+void UniversalPrint(const T& value, ::std::ostream* os);
+
+// Used to print an STL-style container when the user doesn't define
+// a PrintTo() for it.
+struct ContainerPrinter {
+  template <typename T,
+            typename = typename std::enable_if<
+                (sizeof(IsContainerTest<T>(0)) == sizeof(IsContainer)) &&
+                !IsRecursiveContainer<T>::value>::type>
+  static void PrintValue(const T& container, std::ostream* os) {
+    const size_t kMaxCount = 32;  // The maximum number of elements to print.
+    *os << '{';
+    size_t count = 0;
+    for (auto&& elem : container) {
+      if (count > 0) {
+        *os << ',';
+        if (count == kMaxCount) {  // Enough has been printed.
+          *os << " ...";
+          break;
+        }
+      }
+      *os << ' ';
+      // We cannot call PrintTo(elem, os) here as PrintTo() doesn't
+      // handle `elem` being a native array.
+      internal::UniversalPrint(elem, os);
+      ++count;
+    }
+
+    if (count > 0) {
+      *os << ' ';
+    }
+    *os << '}';
+  }
+};
+
+// Used to print a pointer that is neither a char pointer nor a member
+// pointer, when the user doesn't define PrintTo() for it.  (A member
+// variable pointer or member function pointer doesn't really point to
+// a location in the address space.  Their representation is
+// implementation-defined.  Therefore they will be printed as raw
+// bytes.)
+struct FunctionPointerPrinter {
+  template <typename T, typename = typename std::enable_if<
+                            std::is_function<T>::value>::type>
+  static void PrintValue(T* p, ::std::ostream* os) {
+    if (p == nullptr) {
+      *os << "NULL";
+    } else {
+      // T is a function type, so '*os << p' doesn't do what we want
+      // (it just prints p as bool).  We want to print p as a const
+      // void*.
+      *os << reinterpret_cast<const void*>(p);
+    }
+  }
+};
+
+struct PointerPrinter {
+  template <typename T>
+  static void PrintValue(T* p, ::std::ostream* os) {
+    if (p == nullptr) {
+      *os << "NULL";
+    } else {
+      // T is not a function type.  We just call << to print p,
+      // relying on ADL to pick up user-defined << for their pointer
+      // types, if any.
+      *os << p;
+    }
+  }
+};
+
+namespace internal_stream_operator_without_lexical_name_lookup {
+
+// The presence of an operator<< here will terminate lexical scope lookup
+// straight away (even though it cannot be a match because of its argument
+// types). Thus, the two operator<< calls in StreamPrinter will find only ADL
+// candidates.
+struct LookupBlocker {};
+void operator<<(LookupBlocker, LookupBlocker);
+
+struct StreamPrinter {
+  template <typename T,
+            // Don't accept member pointers here. We'd print them via implicit
+            // conversion to bool, which isn't useful.
+            typename = typename std::enable_if<
+                !std::is_member_pointer<T>::value>::type,
+            // Only accept types for which we can find a streaming operator via
+            // ADL (possibly involving implicit conversions).
+            typename = decltype(std::declval<std::ostream&>()
+                                << std::declval<const T&>())>
+  static void PrintValue(const T& value, ::std::ostream* os) {
+    // Call streaming operator found by ADL, possibly with implicit conversions
+    // of the arguments.
+    *os << value;
+  }
+};
+
+}  // namespace internal_stream_operator_without_lexical_name_lookup
+
+struct ProtobufPrinter {
+  // We print a protobuf using its ShortDebugString() when the string
+  // doesn't exceed this many characters; otherwise we print it using
+  // DebugString() for better readability.
+  static const size_t kProtobufOneLinerMaxLength = 50;
+
+  template <typename T,
+            typename = typename std::enable_if<
+                internal::HasDebugStringAndShortDebugString<T>::value>::type>
+  static void PrintValue(const T& value, ::std::ostream* os) {
+    std::string pretty_str = value.ShortDebugString();
+    if (pretty_str.length() > kProtobufOneLinerMaxLength) {
+      pretty_str = "\n" + value.DebugString();
+    }
+    *os << ("<" + pretty_str + ">");
+  }
+};
+
+struct ConvertibleToIntegerPrinter {
+  // Since T has no << operator or PrintTo() but can be implicitly
+  // converted to BiggestInt, we print it as a BiggestInt.
+  //
+  // Most likely T is an enum type (either named or unnamed), in which
+  // case printing it as an integer is the desired behavior.  In case
+  // T is not an enum, printing it as an integer is the best we can do
+  // given that it has no user-defined printer.
+  static void PrintValue(internal::BiggestInt value, ::std::ostream* os) {
+    *os << value;
+  }
+};
+
+struct ConvertibleToStringViewPrinter {
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  static void PrintValue(internal::StringView value, ::std::ostream* os) {
+    internal::UniversalPrint(value, os);
+  }
+#endif
+};
+
+
+// Prints the given number of bytes in the given object to the given
+// ostream.
+GTEST_API_ void PrintBytesInObjectTo(const unsigned char* obj_bytes,
+                                     size_t count,
+                                     ::std::ostream* os);
+struct RawBytesPrinter {
+  // SFINAE on `sizeof` to make sure we have a complete type.
+  template <typename T, size_t = sizeof(T)>
+  static void PrintValue(const T& value, ::std::ostream* os) {
+    PrintBytesInObjectTo(
+        static_cast<const unsigned char*>(
+            // Load bearing cast to void* to support iOS
+            reinterpret_cast<const void*>(std::addressof(value))),
+        sizeof(value), os);
+  }
+};
+
+struct FallbackPrinter {
+  template <typename T>
+  static void PrintValue(const T&, ::std::ostream* os) {
+    *os << "(incomplete type)";
+  }
+};
+
+// Try every printer in order and return the first one that works.
+template <typename T, typename E, typename Printer, typename... Printers>
+struct FindFirstPrinter : FindFirstPrinter<T, E, Printers...> {};
+
+template <typename T, typename Printer, typename... Printers>
+struct FindFirstPrinter<
+    T, decltype(Printer::PrintValue(std::declval<const T&>(), nullptr)),
+    Printer, Printers...> {
+  using type = Printer;
+};
+
+// Select the best printer in the following order:
+//  - Print containers (they have begin/end/etc).
+//  - Print function pointers.
+//  - Print object pointers.
+//  - Use the stream operator, if available.
+//  - Print protocol buffers.
+//  - Print types convertible to BiggestInt.
+//  - Print types convertible to StringView, if available.
+//  - Fallback to printing the raw bytes of the object.
+template <typename T>
+void PrintWithFallback(const T& value, ::std::ostream* os) {
+  using Printer = typename FindFirstPrinter<
+      T, void, ContainerPrinter, FunctionPointerPrinter, PointerPrinter,
+      internal_stream_operator_without_lexical_name_lookup::StreamPrinter,
+      ProtobufPrinter, ConvertibleToIntegerPrinter,
+      ConvertibleToStringViewPrinter, RawBytesPrinter, FallbackPrinter>::type;
+  Printer::PrintValue(value, os);
+}
+
+// FormatForComparison<ToPrint, OtherOperand>::Format(value) formats a
+// value of type ToPrint that is an operand of a comparison assertion
+// (e.g. ASSERT_EQ).  OtherOperand is the type of the other operand in
+// the comparison, and is used to help determine the best way to
+// format the value.  In particular, when the value is a C string
+// (char pointer) and the other operand is an STL string object, we
+// want to format the C string as a string, since we know it is
+// compared by value with the string object.  If the value is a char
+// pointer but the other operand is not an STL string object, we don't
+// know whether the pointer is supposed to point to a NUL-terminated
+// string, and thus want to print it as a pointer to be safe.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+
+// The default case.
+template <typename ToPrint, typename OtherOperand>
+class FormatForComparison {
+ public:
+  static ::std::string Format(const ToPrint& value) {
+    return ::testing::PrintToString(value);
+  }
+};
+
+// Array.
+template <typename ToPrint, size_t N, typename OtherOperand>
+class FormatForComparison<ToPrint[N], OtherOperand> {
+ public:
+  static ::std::string Format(const ToPrint* value) {
+    return FormatForComparison<const ToPrint*, OtherOperand>::Format(value);
+  }
+};
+
+// By default, print C string as pointers to be safe, as we don't know
+// whether they actually point to a NUL-terminated string.
+
+#define GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(CharType)                \
+  template <typename OtherOperand>                                      \
+  class FormatForComparison<CharType*, OtherOperand> {                  \
+   public:                                                              \
+    static ::std::string Format(CharType* value) {                      \
+      return ::testing::PrintToString(static_cast<const void*>(value)); \
+    }                                                                   \
+  }
+
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(wchar_t);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const wchar_t);
+#ifdef __cpp_char8_t
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char8_t);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char8_t);
+#endif
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char16_t);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char16_t);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char32_t);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char32_t);
+
+#undef GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_
+
+// If a C string is compared with an STL string object, we know it's meant
+// to point to a NUL-terminated string, and thus can print it as a string.
+
+#define GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(CharType, OtherStringType) \
+  template <>                                                           \
+  class FormatForComparison<CharType*, OtherStringType> {               \
+   public:                                                              \
+    static ::std::string Format(CharType* value) {                      \
+      return ::testing::PrintToString(value);                           \
+    }                                                                   \
+  }
+
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char, ::std::string);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char, ::std::string);
+#ifdef __cpp_char8_t
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char8_t, ::std::u8string);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char8_t, ::std::u8string);
+#endif
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char16_t, ::std::u16string);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char16_t, ::std::u16string);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char32_t, ::std::u32string);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char32_t, ::std::u32string);
+
+#if GTEST_HAS_STD_WSTRING
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(wchar_t, ::std::wstring);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const wchar_t, ::std::wstring);
+#endif
+
+#undef GTEST_IMPL_FORMAT_C_STRING_AS_STRING_
+
+// Formats a comparison assertion (e.g. ASSERT_EQ, EXPECT_LT, and etc)
+// operand to be used in a failure message.  The type (but not value)
+// of the other operand may affect the format.  This allows us to
+// print a char* as a raw pointer when it is compared against another
+// char* or void*, and print it as a C string when it is compared
+// against an std::string object, for example.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+template <typename T1, typename T2>
+std::string FormatForComparisonFailureMessage(
+    const T1& value, const T2& /* other_operand */) {
+  return FormatForComparison<T1, T2>::Format(value);
+}
+
+// UniversalPrinter<T>::Print(value, ostream_ptr) prints the given
+// value to the given ostream.  The caller must ensure that
+// 'ostream_ptr' is not NULL, or the behavior is undefined.
+//
+// We define UniversalPrinter as a class template (as opposed to a
+// function template), as we need to partially specialize it for
+// reference types, which cannot be done with function templates.
+template <typename T>
+class UniversalPrinter;
+
+// Prints the given value using the << operator if it has one;
+// otherwise prints the bytes in it.  This is what
+// UniversalPrinter<T>::Print() does when PrintTo() is not specialized
+// or overloaded for type T.
+//
+// A user can override this behavior for a class type Foo by defining
+// an overload of PrintTo() in the namespace where Foo is defined.  We
+// give the user this option as sometimes defining a << operator for
+// Foo is not desirable (e.g. the coding style may prevent doing it,
+// or there is already a << operator but it doesn't do what the user
+// wants).
+template <typename T>
+void PrintTo(const T& value, ::std::ostream* os) {
+  internal::PrintWithFallback(value, os);
+}
+
+// The following list of PrintTo() overloads tells
+// UniversalPrinter<T>::Print() how to print standard types (built-in
+// types, strings, plain arrays, and pointers).
+
+// Overloads for various char types.
+GTEST_API_ void PrintTo(unsigned char c, ::std::ostream* os);
+GTEST_API_ void PrintTo(signed char c, ::std::ostream* os);
+inline void PrintTo(char c, ::std::ostream* os) {
+  // When printing a plain char, we always treat it as unsigned.  This
+  // way, the output won't be affected by whether the compiler thinks
+  // char is signed or not.
+  PrintTo(static_cast<unsigned char>(c), os);
+}
+
+// Overloads for other simple built-in types.
+inline void PrintTo(bool x, ::std::ostream* os) {
+  *os << (x ? "true" : "false");
+}
+
+// Overload for wchar_t type.
+// Prints a wchar_t as a symbol if it is printable or as its internal
+// code otherwise and also as its decimal code (except for L'\0').
+// The L'\0' char is printed as "L'\\0'". The decimal code is printed
+// as signed integer when wchar_t is implemented by the compiler
+// as a signed type and is printed as an unsigned integer when wchar_t
+// is implemented as an unsigned type.
+GTEST_API_ void PrintTo(wchar_t wc, ::std::ostream* os);
+
+GTEST_API_ void PrintTo(char32_t c, ::std::ostream* os);
+inline void PrintTo(char16_t c, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<char32_t>(c), os);
+}
+#ifdef __cpp_char8_t
+inline void PrintTo(char8_t c, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<char32_t>(c), os);
+}
+#endif
+
+// Overloads for C strings.
+GTEST_API_ void PrintTo(const char* s, ::std::ostream* os);
+inline void PrintTo(char* s, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<const char*>(s), os);
+}
+
+// signed/unsigned char is often used for representing binary data, so
+// we print pointers to it as void* to be safe.
+inline void PrintTo(const signed char* s, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<const void*>(s), os);
+}
+inline void PrintTo(signed char* s, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<const void*>(s), os);
+}
+inline void PrintTo(const unsigned char* s, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<const void*>(s), os);
+}
+inline void PrintTo(unsigned char* s, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<const void*>(s), os);
+}
+#ifdef __cpp_char8_t
+// Overloads for u8 strings.
+void PrintTo(const char8_t* s, ::std::ostream* os);
+inline void PrintTo(char8_t* s, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<const char8_t*>(s), os);
+}
+#endif
+// Overloads for u16 strings.
+void PrintTo(const char16_t* s, ::std::ostream* os);
+inline void PrintTo(char16_t* s, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<const char16_t*>(s), os);
+}
+// Overloads for u32 strings.
+void PrintTo(const char32_t* s, ::std::ostream* os);
+inline void PrintTo(char32_t* s, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<const char32_t*>(s), os);
+}
+
+// MSVC can be configured to define wchar_t as a typedef of unsigned
+// short.  It defines _NATIVE_WCHAR_T_DEFINED when wchar_t is a native
+// type.  When wchar_t is a typedef, defining an overload for const
+// wchar_t* would cause unsigned short* be printed as a wide string,
+// possibly causing invalid memory accesses.
+#if !defined(_MSC_VER) || defined(_NATIVE_WCHAR_T_DEFINED)
+// Overloads for wide C strings
+GTEST_API_ void PrintTo(const wchar_t* s, ::std::ostream* os);
+inline void PrintTo(wchar_t* s, ::std::ostream* os) {
+  PrintTo(ImplicitCast_<const wchar_t*>(s), os);
+}
+#endif
+
+// Overload for C arrays.  Multi-dimensional arrays are printed
+// properly.
+
+// Prints the given number of elements in an array, without printing
+// the curly braces.
+template <typename T>
+void PrintRawArrayTo(const T a[], size_t count, ::std::ostream* os) {
+  UniversalPrint(a[0], os);
+  for (size_t i = 1; i != count; i++) {
+    *os << ", ";
+    UniversalPrint(a[i], os);
+  }
+}
+
+// Overloads for ::std::string.
+GTEST_API_ void PrintStringTo(const ::std::string&s, ::std::ostream* os);
+inline void PrintTo(const ::std::string& s, ::std::ostream* os) {
+  PrintStringTo(s, os);
+}
+
+// Overloads for ::std::u8string
+#ifdef __cpp_char8_t
+GTEST_API_ void PrintU8StringTo(const ::std::u8string& s, ::std::ostream* os);
+inline void PrintTo(const ::std::u8string& s, ::std::ostream* os) {
+  PrintU8StringTo(s, os);
+}
+#endif
+
+// Overloads for ::std::u16string
+GTEST_API_ void PrintU16StringTo(const ::std::u16string& s, ::std::ostream* os);
+inline void PrintTo(const ::std::u16string& s, ::std::ostream* os) {
+  PrintU16StringTo(s, os);
+}
+
+// Overloads for ::std::u32string
+GTEST_API_ void PrintU32StringTo(const ::std::u32string& s, ::std::ostream* os);
+inline void PrintTo(const ::std::u32string& s, ::std::ostream* os) {
+  PrintU32StringTo(s, os);
+}
+
+// Overloads for ::std::wstring.
+#if GTEST_HAS_STD_WSTRING
+GTEST_API_ void PrintWideStringTo(const ::std::wstring&s, ::std::ostream* os);
+inline void PrintTo(const ::std::wstring& s, ::std::ostream* os) {
+  PrintWideStringTo(s, os);
+}
+#endif  // GTEST_HAS_STD_WSTRING
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+// Overload for internal::StringView.
+inline void PrintTo(internal::StringView sp, ::std::ostream* os) {
+  PrintTo(::std::string(sp), os);
+}
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+inline void PrintTo(std::nullptr_t, ::std::ostream* os) { *os << "(nullptr)"; }
+
+template <typename T>
+void PrintTo(std::reference_wrapper<T> ref, ::std::ostream* os) {
+  UniversalPrinter<T&>::Print(ref.get(), os);
+}
+
+inline const void* VoidifyPointer(const void* p) { return p; }
+inline const void* VoidifyPointer(volatile const void* p) {
+  return const_cast<const void*>(p);
+}
+
+template <typename T, typename Ptr>
+void PrintSmartPointer(const Ptr& ptr, std::ostream* os, char) {
+  if (ptr == nullptr) {
+    *os << "(nullptr)";
+  } else {
+    // We can't print the value. Just print the pointer..
+    *os << "(" << (VoidifyPointer)(ptr.get()) << ")";
+  }
+}
+template <typename T, typename Ptr,
+          typename = typename std::enable_if<!std::is_void<T>::value &&
+                                             !std::is_array<T>::value>::type>
+void PrintSmartPointer(const Ptr& ptr, std::ostream* os, int) {
+  if (ptr == nullptr) {
+    *os << "(nullptr)";
+  } else {
+    *os << "(ptr = " << (VoidifyPointer)(ptr.get()) << ", value = ";
+    UniversalPrinter<T>::Print(*ptr, os);
+    *os << ")";
+  }
+}
+
+template <typename T, typename D>
+void PrintTo(const std::unique_ptr<T, D>& ptr, std::ostream* os) {
+  (PrintSmartPointer<T>)(ptr, os, 0);
+}
+
+template <typename T>
+void PrintTo(const std::shared_ptr<T>& ptr, std::ostream* os) {
+  (PrintSmartPointer<T>)(ptr, os, 0);
+}
+
+// Helper function for printing a tuple.  T must be instantiated with
+// a tuple type.
+template <typename T>
+void PrintTupleTo(const T&, std::integral_constant<size_t, 0>,
+                  ::std::ostream*) {}
+
+template <typename T, size_t I>
+void PrintTupleTo(const T& t, std::integral_constant<size_t, I>,
+                  ::std::ostream* os) {
+  PrintTupleTo(t, std::integral_constant<size_t, I - 1>(), os);
+  GTEST_INTENTIONAL_CONST_COND_PUSH_()
+  if (I > 1) {
+    GTEST_INTENTIONAL_CONST_COND_POP_()
+    *os << ", ";
+  }
+  UniversalPrinter<typename std::tuple_element<I - 1, T>::type>::Print(
+      std::get<I - 1>(t), os);
+}
+
+template <typename... Types>
+void PrintTo(const ::std::tuple<Types...>& t, ::std::ostream* os) {
+  *os << "(";
+  PrintTupleTo(t, std::integral_constant<size_t, sizeof...(Types)>(), os);
+  *os << ")";
+}
+
+// Overload for std::pair.
+template <typename T1, typename T2>
+void PrintTo(const ::std::pair<T1, T2>& value, ::std::ostream* os) {
+  *os << '(';
+  // We cannot use UniversalPrint(value.first, os) here, as T1 may be
+  // a reference type.  The same for printing value.second.
+  UniversalPrinter<T1>::Print(value.first, os);
+  *os << ", ";
+  UniversalPrinter<T2>::Print(value.second, os);
+  *os << ')';
+}
+
+#if GTEST_HAS_RTTI
+inline void PrintTo(const ::std::type_info& value, ::std::ostream* os) {
+  internal::PrintTo<::std::type_info>(value, os);
+  *os << " (\"" << value.name() << "\")";
+}
+
+inline void PrintTo(const ::std::type_index& value, ::std::ostream* os) {
+  internal::PrintTo<::std::type_index>(value, os);
+  *os << " (\"" << value.name() << "\")";
+}
+#endif  // GTEST_HAS_RTTI
+
+// Implements printing a non-reference type T by letting the compiler
+// pick the right overload of PrintTo() for T.
+template <typename T>
+class UniversalPrinter {
+ public:
+  // MSVC warns about adding const to a function type, so we want to
+  // disable the warning.
+  GTEST_DISABLE_MSC_WARNINGS_PUSH_(4180)
+
+  // Note: we deliberately don't call this PrintTo(), as that name
+  // conflicts with ::testing::internal::PrintTo in the body of the
+  // function.
+  static void Print(const T& value, ::std::ostream* os) {
+    // By default, ::testing::internal::PrintTo() is used for printing
+    // the value.
+    //
+    // Thanks to Koenig look-up, if T is a class and has its own
+    // PrintTo() function defined in its namespace, that function will
+    // be visible here.  Since it is more specific than the generic ones
+    // in ::testing::internal, it will be picked by the compiler in the
+    // following statement - exactly what we want.
+    PrintTo(value, os);
+  }
+
+  GTEST_DISABLE_MSC_WARNINGS_POP_()
+};
+
+// Remove any const-qualifiers before passing a type to UniversalPrinter.
+template <typename T>
+class UniversalPrinter<const T> : public UniversalPrinter<T> {};
+
+#if GTEST_INTERNAL_HAS_ANY
+
+// Printer for std::any / absl::any
+
+template <>
+class UniversalPrinter<Any> {
+ public:
+  static void Print(const Any& value, ::std::ostream* os) {
+    if (value.has_value()) {
+      *os << "value of type " << GetTypeName(value);
+    } else {
+      *os << "no value";
+    }
+  }
+
+ private:
+  static std::string GetTypeName(const Any& value) {
+#if GTEST_HAS_RTTI
+    return internal::GetTypeName(value.type());
+#else
+    static_cast<void>(value);  // possibly unused
+    return "<unknown_type>";
+#endif  // GTEST_HAS_RTTI
+  }
+};
+
+#endif  // GTEST_INTERNAL_HAS_ANY
+
+#if GTEST_INTERNAL_HAS_OPTIONAL
+
+// Printer for std::optional / absl::optional
+
+template <typename T>
+class UniversalPrinter<Optional<T>> {
+ public:
+  static void Print(const Optional<T>& value, ::std::ostream* os) {
+    *os << '(';
+    if (!value) {
+      *os << "nullopt";
+    } else {
+      UniversalPrint(*value, os);
+    }
+    *os << ')';
+  }
+};
+
+#endif  // GTEST_INTERNAL_HAS_OPTIONAL
+
+#if GTEST_INTERNAL_HAS_VARIANT
+
+// Printer for std::variant / absl::variant
+
+template <typename... T>
+class UniversalPrinter<Variant<T...>> {
+ public:
+  static void Print(const Variant<T...>& value, ::std::ostream* os) {
+    *os << '(';
+#if GTEST_HAS_ABSL
+    absl::visit(Visitor{os, value.index()}, value);
+#else
+    std::visit(Visitor{os, value.index()}, value);
+#endif  // GTEST_HAS_ABSL
+    *os << ')';
+  }
+
+ private:
+  struct Visitor {
+    template <typename U>
+    void operator()(const U& u) const {
+      *os << "'" << GetTypeName<U>() << "(index = " << index
+          << ")' with value ";
+      UniversalPrint(u, os);
+    }
+    ::std::ostream* os;
+    std::size_t index;
+  };
+};
+
+#endif  // GTEST_INTERNAL_HAS_VARIANT
+
+// UniversalPrintArray(begin, len, os) prints an array of 'len'
+// elements, starting at address 'begin'.
+template <typename T>
+void UniversalPrintArray(const T* begin, size_t len, ::std::ostream* os) {
+  if (len == 0) {
+    *os << "{}";
+  } else {
+    *os << "{ ";
+    const size_t kThreshold = 18;
+    const size_t kChunkSize = 8;
+    // If the array has more than kThreshold elements, we'll have to
+    // omit some details by printing only the first and the last
+    // kChunkSize elements.
+    if (len <= kThreshold) {
+      PrintRawArrayTo(begin, len, os);
+    } else {
+      PrintRawArrayTo(begin, kChunkSize, os);
+      *os << ", ..., ";
+      PrintRawArrayTo(begin + len - kChunkSize, kChunkSize, os);
+    }
+    *os << " }";
+  }
+}
+// This overload prints a (const) char array compactly.
+GTEST_API_ void UniversalPrintArray(
+    const char* begin, size_t len, ::std::ostream* os);
+
+#ifdef __cpp_char8_t
+// This overload prints a (const) char8_t array compactly.
+GTEST_API_ void UniversalPrintArray(const char8_t* begin, size_t len,
+                                    ::std::ostream* os);
+#endif
+
+// This overload prints a (const) char16_t array compactly.
+GTEST_API_ void UniversalPrintArray(const char16_t* begin, size_t len,
+                                    ::std::ostream* os);
+
+// This overload prints a (const) char32_t array compactly.
+GTEST_API_ void UniversalPrintArray(const char32_t* begin, size_t len,
+                                    ::std::ostream* os);
+
+// This overload prints a (const) wchar_t array compactly.
+GTEST_API_ void UniversalPrintArray(
+    const wchar_t* begin, size_t len, ::std::ostream* os);
+
+// Implements printing an array type T[N].
+template <typename T, size_t N>
+class UniversalPrinter<T[N]> {
+ public:
+  // Prints the given array, omitting some elements when there are too
+  // many.
+  static void Print(const T (&a)[N], ::std::ostream* os) {
+    UniversalPrintArray(a, N, os);
+  }
+};
+
+// Implements printing a reference type T&.
+template <typename T>
+class UniversalPrinter<T&> {
+ public:
+  // MSVC warns about adding const to a function type, so we want to
+  // disable the warning.
+  GTEST_DISABLE_MSC_WARNINGS_PUSH_(4180)
+
+  static void Print(const T& value, ::std::ostream* os) {
+    // Prints the address of the value.  We use reinterpret_cast here
+    // as static_cast doesn't compile when T is a function type.
+    *os << "@" << reinterpret_cast<const void*>(&value) << " ";
+
+    // Then prints the value itself.
+    UniversalPrint(value, os);
+  }
+
+  GTEST_DISABLE_MSC_WARNINGS_POP_()
+};
+
+// Prints a value tersely: for a reference type, the referenced value
+// (but not the address) is printed; for a (const) char pointer, the
+// NUL-terminated string (but not the pointer) is printed.
+
+template <typename T>
+class UniversalTersePrinter {
+ public:
+  static void Print(const T& value, ::std::ostream* os) {
+    UniversalPrint(value, os);
+  }
+};
+template <typename T>
+class UniversalTersePrinter<T&> {
+ public:
+  static void Print(const T& value, ::std::ostream* os) {
+    UniversalPrint(value, os);
+  }
+};
+template <typename T, size_t N>
+class UniversalTersePrinter<T[N]> {
+ public:
+  static void Print(const T (&value)[N], ::std::ostream* os) {
+    UniversalPrinter<T[N]>::Print(value, os);
+  }
+};
+template <>
+class UniversalTersePrinter<const char*> {
+ public:
+  static void Print(const char* str, ::std::ostream* os) {
+    if (str == nullptr) {
+      *os << "NULL";
+    } else {
+      UniversalPrint(std::string(str), os);
+    }
+  }
+};
+template <>
+class UniversalTersePrinter<char*> : public UniversalTersePrinter<const char*> {
+};
+
+#ifdef __cpp_char8_t
+template <>
+class UniversalTersePrinter<const char8_t*> {
+ public:
+  static void Print(const char8_t* str, ::std::ostream* os) {
+    if (str == nullptr) {
+      *os << "NULL";
+    } else {
+      UniversalPrint(::std::u8string(str), os);
+    }
+  }
+};
+template <>
+class UniversalTersePrinter<char8_t*>
+    : public UniversalTersePrinter<const char8_t*> {};
+#endif
+
+template <>
+class UniversalTersePrinter<const char16_t*> {
+ public:
+  static void Print(const char16_t* str, ::std::ostream* os) {
+    if (str == nullptr) {
+      *os << "NULL";
+    } else {
+      UniversalPrint(::std::u16string(str), os);
+    }
+  }
+};
+template <>
+class UniversalTersePrinter<char16_t*>
+    : public UniversalTersePrinter<const char16_t*> {};
+
+template <>
+class UniversalTersePrinter<const char32_t*> {
+ public:
+  static void Print(const char32_t* str, ::std::ostream* os) {
+    if (str == nullptr) {
+      *os << "NULL";
+    } else {
+      UniversalPrint(::std::u32string(str), os);
+    }
+  }
+};
+template <>
+class UniversalTersePrinter<char32_t*>
+    : public UniversalTersePrinter<const char32_t*> {};
+
+#if GTEST_HAS_STD_WSTRING
+template <>
+class UniversalTersePrinter<const wchar_t*> {
+ public:
+  static void Print(const wchar_t* str, ::std::ostream* os) {
+    if (str == nullptr) {
+      *os << "NULL";
+    } else {
+      UniversalPrint(::std::wstring(str), os);
+    }
+  }
+};
+#endif
+
+template <>
+class UniversalTersePrinter<wchar_t*> {
+ public:
+  static void Print(wchar_t* str, ::std::ostream* os) {
+    UniversalTersePrinter<const wchar_t*>::Print(str, os);
+  }
+};
+
+template <typename T>
+void UniversalTersePrint(const T& value, ::std::ostream* os) {
+  UniversalTersePrinter<T>::Print(value, os);
+}
+
+// Prints a value using the type inferred by the compiler.  The
+// difference between this and UniversalTersePrint() is that for a
+// (const) char pointer, this prints both the pointer and the
+// NUL-terminated string.
+template <typename T>
+void UniversalPrint(const T& value, ::std::ostream* os) {
+  // A workarond for the bug in VC++ 7.1 that prevents us from instantiating
+  // UniversalPrinter with T directly.
+  typedef T T1;
+  UniversalPrinter<T1>::Print(value, os);
+}
+
+typedef ::std::vector< ::std::string> Strings;
+
+  // Tersely prints the first N fields of a tuple to a string vector,
+  // one element for each field.
+template <typename Tuple>
+void TersePrintPrefixToStrings(const Tuple&, std::integral_constant<size_t, 0>,
+                               Strings*) {}
+template <typename Tuple, size_t I>
+void TersePrintPrefixToStrings(const Tuple& t,
+                               std::integral_constant<size_t, I>,
+                               Strings* strings) {
+  TersePrintPrefixToStrings(t, std::integral_constant<size_t, I - 1>(),
+                            strings);
+  ::std::stringstream ss;
+  UniversalTersePrint(std::get<I - 1>(t), &ss);
+  strings->push_back(ss.str());
+}
+
+// Prints the fields of a tuple tersely to a string vector, one
+// element for each field.  See the comment before
+// UniversalTersePrint() for how we define "tersely".
+template <typename Tuple>
+Strings UniversalTersePrintTupleFieldsToStrings(const Tuple& value) {
+  Strings result;
+  TersePrintPrefixToStrings(
+      value, std::integral_constant<size_t, std::tuple_size<Tuple>::value>(),
+      &result);
+  return result;
+}
+
+}  // namespace internal
+
+template <typename T>
+::std::string PrintToString(const T& value) {
+  ::std::stringstream ss;
+  internal::UniversalTersePrinter<T>::Print(value, &ss);
+  return ss.str();
+}
+
+}  // namespace testing
+
+// Include any custom printer added by the local installation.
+// We must include this header at the end to make sure it can use the
+// declarations from this file.
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// This file provides an injection point for custom printers in a local
+// installation of gTest.
+// It will be included from gtest-printers.h and the overrides in this file
+// will be visible to everyone.
+//
+// Injection point for custom user configurations. See README for details
+//
+// ** Custom implementation starts here **
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PRINTERS_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PRINTERS_H_
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PRINTERS_H_
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_PRINTERS_H_
+
+// MSVC warning C5046 is new as of VS2017 version 15.8.
+#if defined(_MSC_VER) && _MSC_VER >= 1915
+#define GTEST_MAYBE_5046_ 5046
+#else
+#define GTEST_MAYBE_5046_
+#endif
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(
+    4251 GTEST_MAYBE_5046_ /* class A needs to have dll-interface to be used by
+                              clients of class B */
+    /* Symbol involving type with internal linkage not defined */)
+
+namespace testing {
+
+// To implement a matcher Foo for type T, define:
+//   1. a class FooMatcherMatcher that implements the matcher interface:
+//     using is_gtest_matcher = void;
+//     bool MatchAndExplain(const T&, std::ostream*);
+//       (MatchResultListener* can also be used instead of std::ostream*)
+//     void DescribeTo(std::ostream*);
+//     void DescribeNegationTo(std::ostream*);
+//
+//   2. a factory function that creates a Matcher<T> object from a
+//      FooMatcherMatcher.
+
+class MatchResultListener {
+ public:
+  // Creates a listener object with the given underlying ostream.  The
+  // listener does not own the ostream, and does not dereference it
+  // in the constructor or destructor.
+  explicit MatchResultListener(::std::ostream* os) : stream_(os) {}
+  virtual ~MatchResultListener() = 0;  // Makes this class abstract.
+
+  // Streams x to the underlying ostream; does nothing if the ostream
+  // is NULL.
+  template <typename T>
+  MatchResultListener& operator<<(const T& x) {
+    if (stream_ != nullptr) *stream_ << x;
+    return *this;
+  }
+
+  // Returns the underlying ostream.
+  ::std::ostream* stream() { return stream_; }
+
+  // Returns true if and only if the listener is interested in an explanation
+  // of the match result.  A matcher's MatchAndExplain() method can use
+  // this information to avoid generating the explanation when no one
+  // intends to hear it.
+  bool IsInterested() const { return stream_ != nullptr; }
+
+ private:
+  ::std::ostream* const stream_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(MatchResultListener);
+};
+
+inline MatchResultListener::~MatchResultListener() {
+}
+
+// An instance of a subclass of this knows how to describe itself as a
+// matcher.
+class MatcherDescriberInterface {
+ public:
+  virtual ~MatcherDescriberInterface() {}
+
+  // Describes this matcher to an ostream.  The function should print
+  // a verb phrase that describes the property a value matching this
+  // matcher should have.  The subject of the verb phrase is the value
+  // being matched.  For example, the DescribeTo() method of the Gt(7)
+  // matcher prints "is greater than 7".
+  virtual void DescribeTo(::std::ostream* os) const = 0;
+
+  // Describes the negation of this matcher to an ostream.  For
+  // example, if the description of this matcher is "is greater than
+  // 7", the negated description could be "is not greater than 7".
+  // You are not required to override this when implementing
+  // MatcherInterface, but it is highly advised so that your matcher
+  // can produce good error messages.
+  virtual void DescribeNegationTo(::std::ostream* os) const {
+    *os << "not (";
+    DescribeTo(os);
+    *os << ")";
+  }
+};
+
+// The implementation of a matcher.
+template <typename T>
+class MatcherInterface : public MatcherDescriberInterface {
+ public:
+  // Returns true if and only if the matcher matches x; also explains the
+  // match result to 'listener' if necessary (see the next paragraph), in
+  // the form of a non-restrictive relative clause ("which ...",
+  // "whose ...", etc) that describes x.  For example, the
+  // MatchAndExplain() method of the Pointee(...) matcher should
+  // generate an explanation like "which points to ...".
+  //
+  // Implementations of MatchAndExplain() should add an explanation of
+  // the match result *if and only if* they can provide additional
+  // information that's not already present (or not obvious) in the
+  // print-out of x and the matcher's description.  Whether the match
+  // succeeds is not a factor in deciding whether an explanation is
+  // needed, as sometimes the caller needs to print a failure message
+  // when the match succeeds (e.g. when the matcher is used inside
+  // Not()).
+  //
+  // For example, a "has at least 10 elements" matcher should explain
+  // what the actual element count is, regardless of the match result,
+  // as it is useful information to the reader; on the other hand, an
+  // "is empty" matcher probably only needs to explain what the actual
+  // size is when the match fails, as it's redundant to say that the
+  // size is 0 when the value is already known to be empty.
+  //
+  // You should override this method when defining a new matcher.
+  //
+  // It's the responsibility of the caller (Google Test) to guarantee
+  // that 'listener' is not NULL.  This helps to simplify a matcher's
+  // implementation when it doesn't care about the performance, as it
+  // can talk to 'listener' without checking its validity first.
+  // However, in order to implement dummy listeners efficiently,
+  // listener->stream() may be NULL.
+  virtual bool MatchAndExplain(T x, MatchResultListener* listener) const = 0;
+
+  // Inherits these methods from MatcherDescriberInterface:
+  //   virtual void DescribeTo(::std::ostream* os) const = 0;
+  //   virtual void DescribeNegationTo(::std::ostream* os) const;
+};
+
+namespace internal {
+
+struct AnyEq {
+  template <typename A, typename B>
+  bool operator()(const A& a, const B& b) const { return a == b; }
+};
+struct AnyNe {
+  template <typename A, typename B>
+  bool operator()(const A& a, const B& b) const { return a != b; }
+};
+struct AnyLt {
+  template <typename A, typename B>
+  bool operator()(const A& a, const B& b) const { return a < b; }
+};
+struct AnyGt {
+  template <typename A, typename B>
+  bool operator()(const A& a, const B& b) const { return a > b; }
+};
+struct AnyLe {
+  template <typename A, typename B>
+  bool operator()(const A& a, const B& b) const { return a <= b; }
+};
+struct AnyGe {
+  template <typename A, typename B>
+  bool operator()(const A& a, const B& b) const { return a >= b; }
+};
+
+// A match result listener that ignores the explanation.
+class DummyMatchResultListener : public MatchResultListener {
+ public:
+  DummyMatchResultListener() : MatchResultListener(nullptr) {}
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(DummyMatchResultListener);
+};
+
+// A match result listener that forwards the explanation to a given
+// ostream.  The difference between this and MatchResultListener is
+// that the former is concrete.
+class StreamMatchResultListener : public MatchResultListener {
+ public:
+  explicit StreamMatchResultListener(::std::ostream* os)
+      : MatchResultListener(os) {}
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(StreamMatchResultListener);
+};
+
+struct SharedPayloadBase {
+  std::atomic<int> ref{1};
+  void Ref() { ref.fetch_add(1, std::memory_order_relaxed); }
+  bool Unref() { return ref.fetch_sub(1, std::memory_order_acq_rel) == 1; }
+};
+
+template <typename T>
+struct SharedPayload : SharedPayloadBase {
+  explicit SharedPayload(const T& v) : value(v) {}
+  explicit SharedPayload(T&& v) : value(std::move(v)) {}
+
+  static void Destroy(SharedPayloadBase* shared) {
+    delete static_cast<SharedPayload*>(shared);
+  }
+
+  T value;
+};
+
+template <typename T>
+using is_trivially_copy_constructible =
+#if defined(__GNUC__) && !defined(__clang__) && __GNUC__ < 5
+    std::has_trivial_copy_constructor<T>;
+#else
+    std::is_trivially_copy_constructible<T>;
+#endif
+
+// An internal class for implementing Matcher<T>, which will derive
+// from it.  We put functionalities common to all Matcher<T>
+// specializations here to avoid code duplication.
+template <typename T>
+class MatcherBase : private MatcherDescriberInterface {
+ public:
+  // Returns true if and only if the matcher matches x; also explains the
+  // match result to 'listener'.
+  bool MatchAndExplain(const T& x, MatchResultListener* listener) const {
+    GTEST_CHECK_(vtable_ != nullptr);
+    return vtable_->match_and_explain(*this, x, listener);
+  }
+
+  // Returns true if and only if this matcher matches x.
+  bool Matches(const T& x) const {
+    DummyMatchResultListener dummy;
+    return MatchAndExplain(x, &dummy);
+  }
+
+  // Describes this matcher to an ostream.
+  void DescribeTo(::std::ostream* os) const final {
+    GTEST_CHECK_(vtable_ != nullptr);
+    vtable_->describe(*this, os, false);
+  }
+
+  // Describes the negation of this matcher to an ostream.
+  void DescribeNegationTo(::std::ostream* os) const final {
+    GTEST_CHECK_(vtable_ != nullptr);
+    vtable_->describe(*this, os, true);
+  }
+
+  // Explains why x matches, or doesn't match, the matcher.
+  void ExplainMatchResultTo(const T& x, ::std::ostream* os) const {
+    StreamMatchResultListener listener(os);
+    MatchAndExplain(x, &listener);
+  }
+
+  // Returns the describer for this matcher object; retains ownership
+  // of the describer, which is only guaranteed to be alive when
+  // this matcher object is alive.
+  const MatcherDescriberInterface* GetDescriber() const {
+    if (vtable_ == nullptr) return nullptr;
+    return vtable_->get_describer(*this);
+  }
+
+ protected:
+  MatcherBase() : vtable_(nullptr) {}
+
+  // Constructs a matcher from its implementation.
+  template <typename U>
+  explicit MatcherBase(const MatcherInterface<U>* impl) {
+    Init(impl);
+  }
+
+  template <typename M, typename = typename std::remove_reference<
+                            M>::type::is_gtest_matcher>
+  MatcherBase(M&& m) {  // NOLINT
+    Init(std::forward<M>(m));
+  }
+
+  MatcherBase(const MatcherBase& other)
+      : vtable_(other.vtable_), buffer_(other.buffer_) {
+    if (IsShared()) buffer_.shared->Ref();
+  }
+
+  MatcherBase& operator=(const MatcherBase& other) {
+    if (this == &other) return *this;
+    Destroy();
+    vtable_ = other.vtable_;
+    buffer_ = other.buffer_;
+    if (IsShared()) buffer_.shared->Ref();
+    return *this;
+  }
+
+  MatcherBase(MatcherBase&& other)
+      : vtable_(other.vtable_), buffer_(other.buffer_) {
+    other.vtable_ = nullptr;
+  }
+
+  MatcherBase& operator=(MatcherBase&& other) {
+    if (this == &other) return *this;
+    Destroy();
+    vtable_ = other.vtable_;
+    buffer_ = other.buffer_;
+    other.vtable_ = nullptr;
+    return *this;
+  }
+
+  ~MatcherBase() override { Destroy(); }
+
+ private:
+  struct VTable {
+    bool (*match_and_explain)(const MatcherBase&, const T&,
+                              MatchResultListener*);
+    void (*describe)(const MatcherBase&, std::ostream*, bool negation);
+    // Returns the captured object if it implements the interface, otherwise
+    // returns the MatcherBase itself.
+    const MatcherDescriberInterface* (*get_describer)(const MatcherBase&);
+    // Called on shared instances when the reference count reaches 0.
+    void (*shared_destroy)(SharedPayloadBase*);
+  };
+
+  bool IsShared() const {
+    return vtable_ != nullptr && vtable_->shared_destroy != nullptr;
+  }
+
+  // If the implementation uses a listener, call that.
+  template <typename P>
+  static auto MatchAndExplainImpl(const MatcherBase& m, const T& value,
+                                  MatchResultListener* listener)
+      -> decltype(P::Get(m).MatchAndExplain(value, listener->stream())) {
+    return P::Get(m).MatchAndExplain(value, listener->stream());
+  }
+
+  template <typename P>
+  static auto MatchAndExplainImpl(const MatcherBase& m, const T& value,
+                                  MatchResultListener* listener)
+      -> decltype(P::Get(m).MatchAndExplain(value, listener)) {
+    return P::Get(m).MatchAndExplain(value, listener);
+  }
+
+  template <typename P>
+  static void DescribeImpl(const MatcherBase& m, std::ostream* os,
+                           bool negation) {
+    if (negation) {
+      P::Get(m).DescribeNegationTo(os);
+    } else {
+      P::Get(m).DescribeTo(os);
+    }
+  }
+
+  template <typename P>
+  static const MatcherDescriberInterface* GetDescriberImpl(
+      const MatcherBase& m) {
+    // If the impl is a MatcherDescriberInterface, then return it.
+    // Otherwise use MatcherBase itself.
+    // This allows us to implement the GetDescriber() function without support
+    // from the impl, but some users really want to get their impl back when
+    // they call GetDescriber().
+    // We use std::get on a tuple as a workaround of not having `if constexpr`.
+    return std::get<(
+        std::is_convertible<decltype(&P::Get(m)),
+                            const MatcherDescriberInterface*>::value
+            ? 1
+            : 0)>(std::make_tuple(&m, &P::Get(m)));
+  }
+
+  template <typename P>
+  const VTable* GetVTable() {
+    static constexpr VTable kVTable = {&MatchAndExplainImpl<P>,
+                                       &DescribeImpl<P>, &GetDescriberImpl<P>,
+                                       P::shared_destroy};
+    return &kVTable;
+  }
+
+  union Buffer {
+    // Add some types to give Buffer some common alignment/size use cases.
+    void* ptr;
+    double d;
+    int64_t i;
+    // And add one for the out-of-line cases.
+    SharedPayloadBase* shared;
+  };
+
+  void Destroy() {
+    if (IsShared() && buffer_.shared->Unref()) {
+      vtable_->shared_destroy(buffer_.shared);
+    }
+  }
+
+  template <typename M>
+  static constexpr bool IsInlined() {
+    return sizeof(M) <= sizeof(Buffer) && alignof(M) <= alignof(Buffer) &&
+           is_trivially_copy_constructible<M>::value &&
+           std::is_trivially_destructible<M>::value;
+  }
+
+  template <typename M, bool = MatcherBase::IsInlined<M>()>
+  struct ValuePolicy {
+    static const M& Get(const MatcherBase& m) {
+      // When inlined along with Init, need to be explicit to avoid violating
+      // strict aliasing rules.
+      const M *ptr = static_cast<const M*>(
+          static_cast<const void*>(&m.buffer_));
+      return *ptr;
+    }
+    static void Init(MatcherBase& m, M impl) {
+      ::new (static_cast<void*>(&m.buffer_)) M(impl);
+    }
+    static constexpr auto shared_destroy = nullptr;
+  };
+
+  template <typename M>
+  struct ValuePolicy<M, false> {
+    using Shared = SharedPayload<M>;
+    static const M& Get(const MatcherBase& m) {
+      return static_cast<Shared*>(m.buffer_.shared)->value;
+    }
+    template <typename Arg>
+    static void Init(MatcherBase& m, Arg&& arg) {
+      m.buffer_.shared = new Shared(std::forward<Arg>(arg));
+    }
+    static constexpr auto shared_destroy = &Shared::Destroy;
+  };
+
+  template <typename U, bool B>
+  struct ValuePolicy<const MatcherInterface<U>*, B> {
+    using M = const MatcherInterface<U>;
+    using Shared = SharedPayload<std::unique_ptr<M>>;
+    static const M& Get(const MatcherBase& m) {
+      return *static_cast<Shared*>(m.buffer_.shared)->value;
+    }
+    static void Init(MatcherBase& m, M* impl) {
+      m.buffer_.shared = new Shared(std::unique_ptr<M>(impl));
+    }
+
+    static constexpr auto shared_destroy = &Shared::Destroy;
+  };
+
+  template <typename M>
+  void Init(M&& m) {
+    using MM = typename std::decay<M>::type;
+    using Policy = ValuePolicy<MM>;
+    vtable_ = GetVTable<Policy>();
+    Policy::Init(*this, std::forward<M>(m));
+  }
+
+  const VTable* vtable_;
+  Buffer buffer_;
+};
+
+}  // namespace internal
+
+// A Matcher<T> is a copyable and IMMUTABLE (except by assignment)
+// object that can check whether a value of type T matches.  The
+// implementation of Matcher<T> is just a std::shared_ptr to const
+// MatcherInterface<T>.  Don't inherit from Matcher!
+template <typename T>
+class Matcher : public internal::MatcherBase<T> {
+ public:
+  // Constructs a null matcher.  Needed for storing Matcher objects in STL
+  // containers.  A default-constructed matcher is not yet initialized.  You
+  // cannot use it until a valid value has been assigned to it.
+  explicit Matcher() {}  // NOLINT
+
+  // Constructs a matcher from its implementation.
+  explicit Matcher(const MatcherInterface<const T&>* impl)
+      : internal::MatcherBase<T>(impl) {}
+
+  template <typename U>
+  explicit Matcher(
+      const MatcherInterface<U>* impl,
+      typename std::enable_if<!std::is_same<U, const U&>::value>::type* =
+          nullptr)
+      : internal::MatcherBase<T>(impl) {}
+
+  template <typename M, typename = typename std::remove_reference<
+                            M>::type::is_gtest_matcher>
+  Matcher(M&& m) : internal::MatcherBase<T>(std::forward<M>(m)) {}  // NOLINT
+
+  // Implicit constructor here allows people to write
+  // EXPECT_CALL(foo, Bar(5)) instead of EXPECT_CALL(foo, Bar(Eq(5))) sometimes
+  Matcher(T value);  // NOLINT
+};
+
+// The following two specializations allow the user to write str
+// instead of Eq(str) and "foo" instead of Eq("foo") when a std::string
+// matcher is expected.
+template <>
+class GTEST_API_ Matcher<const std::string&>
+    : public internal::MatcherBase<const std::string&> {
+ public:
+  Matcher() {}
+
+  explicit Matcher(const MatcherInterface<const std::string&>* impl)
+      : internal::MatcherBase<const std::string&>(impl) {}
+
+  template <typename M, typename = typename std::remove_reference<
+                            M>::type::is_gtest_matcher>
+  Matcher(M&& m)  // NOLINT
+      : internal::MatcherBase<const std::string&>(std::forward<M>(m)) {}
+
+  // Allows the user to write str instead of Eq(str) sometimes, where
+  // str is a std::string object.
+  Matcher(const std::string& s);  // NOLINT
+
+  // Allows the user to write "foo" instead of Eq("foo") sometimes.
+  Matcher(const char* s);  // NOLINT
+};
+
+template <>
+class GTEST_API_ Matcher<std::string>
+    : public internal::MatcherBase<std::string> {
+ public:
+  Matcher() {}
+
+  explicit Matcher(const MatcherInterface<const std::string&>* impl)
+      : internal::MatcherBase<std::string>(impl) {}
+  explicit Matcher(const MatcherInterface<std::string>* impl)
+      : internal::MatcherBase<std::string>(impl) {}
+
+  template <typename M, typename = typename std::remove_reference<
+                            M>::type::is_gtest_matcher>
+  Matcher(M&& m)  // NOLINT
+      : internal::MatcherBase<std::string>(std::forward<M>(m)) {}
+
+  // Allows the user to write str instead of Eq(str) sometimes, where
+  // str is a string object.
+  Matcher(const std::string& s);  // NOLINT
+
+  // Allows the user to write "foo" instead of Eq("foo") sometimes.
+  Matcher(const char* s);  // NOLINT
+};
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+// The following two specializations allow the user to write str
+// instead of Eq(str) and "foo" instead of Eq("foo") when a absl::string_view
+// matcher is expected.
+template <>
+class GTEST_API_ Matcher<const internal::StringView&>
+    : public internal::MatcherBase<const internal::StringView&> {
+ public:
+  Matcher() {}
+
+  explicit Matcher(const MatcherInterface<const internal::StringView&>* impl)
+      : internal::MatcherBase<const internal::StringView&>(impl) {}
+
+  template <typename M, typename = typename std::remove_reference<
+                            M>::type::is_gtest_matcher>
+  Matcher(M&& m)  // NOLINT
+      : internal::MatcherBase<const internal::StringView&>(std::forward<M>(m)) {
+  }
+
+  // Allows the user to write str instead of Eq(str) sometimes, where
+  // str is a std::string object.
+  Matcher(const std::string& s);  // NOLINT
+
+  // Allows the user to write "foo" instead of Eq("foo") sometimes.
+  Matcher(const char* s);  // NOLINT
+
+  // Allows the user to pass absl::string_views or std::string_views directly.
+  Matcher(internal::StringView s);  // NOLINT
+};
+
+template <>
+class GTEST_API_ Matcher<internal::StringView>
+    : public internal::MatcherBase<internal::StringView> {
+ public:
+  Matcher() {}
+
+  explicit Matcher(const MatcherInterface<const internal::StringView&>* impl)
+      : internal::MatcherBase<internal::StringView>(impl) {}
+  explicit Matcher(const MatcherInterface<internal::StringView>* impl)
+      : internal::MatcherBase<internal::StringView>(impl) {}
+
+  template <typename M, typename = typename std::remove_reference<
+                            M>::type::is_gtest_matcher>
+  Matcher(M&& m)  // NOLINT
+      : internal::MatcherBase<internal::StringView>(std::forward<M>(m)) {}
+
+  // Allows the user to write str instead of Eq(str) sometimes, where
+  // str is a std::string object.
+  Matcher(const std::string& s);  // NOLINT
+
+  // Allows the user to write "foo" instead of Eq("foo") sometimes.
+  Matcher(const char* s);  // NOLINT
+
+  // Allows the user to pass absl::string_views or std::string_views directly.
+  Matcher(internal::StringView s);  // NOLINT
+};
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+// Prints a matcher in a human-readable format.
+template <typename T>
+std::ostream& operator<<(std::ostream& os, const Matcher<T>& matcher) {
+  matcher.DescribeTo(&os);
+  return os;
+}
+
+// The PolymorphicMatcher class template makes it easy to implement a
+// polymorphic matcher (i.e. a matcher that can match values of more
+// than one type, e.g. Eq(n) and NotNull()).
+//
+// To define a polymorphic matcher, a user should provide an Impl
+// class that has a DescribeTo() method and a DescribeNegationTo()
+// method, and define a member function (or member function template)
+//
+//   bool MatchAndExplain(const Value& value,
+//                        MatchResultListener* listener) const;
+//
+// See the definition of NotNull() for a complete example.
+template <class Impl>
+class PolymorphicMatcher {
+ public:
+  explicit PolymorphicMatcher(const Impl& an_impl) : impl_(an_impl) {}
+
+  // Returns a mutable reference to the underlying matcher
+  // implementation object.
+  Impl& mutable_impl() { return impl_; }
+
+  // Returns an immutable reference to the underlying matcher
+  // implementation object.
+  const Impl& impl() const { return impl_; }
+
+  template <typename T>
+  operator Matcher<T>() const {
+    return Matcher<T>(new MonomorphicImpl<const T&>(impl_));
+  }
+
+ private:
+  template <typename T>
+  class MonomorphicImpl : public MatcherInterface<T> {
+   public:
+    explicit MonomorphicImpl(const Impl& impl) : impl_(impl) {}
+
+    void DescribeTo(::std::ostream* os) const override { impl_.DescribeTo(os); }
+
+    void DescribeNegationTo(::std::ostream* os) const override {
+      impl_.DescribeNegationTo(os);
+    }
+
+    bool MatchAndExplain(T x, MatchResultListener* listener) const override {
+      return impl_.MatchAndExplain(x, listener);
+    }
+
+   private:
+    const Impl impl_;
+  };
+
+  Impl impl_;
+};
+
+// Creates a matcher from its implementation.
+// DEPRECATED: Especially in the generic code, prefer:
+//   Matcher<T>(new MyMatcherImpl<const T&>(...));
+//
+// MakeMatcher may create a Matcher that accepts its argument by value, which
+// leads to unnecessary copies & lack of support for non-copyable types.
+template <typename T>
+inline Matcher<T> MakeMatcher(const MatcherInterface<T>* impl) {
+  return Matcher<T>(impl);
+}
+
+// Creates a polymorphic matcher from its implementation.  This is
+// easier to use than the PolymorphicMatcher<Impl> constructor as it
+// doesn't require you to explicitly write the template argument, e.g.
+//
+//   MakePolymorphicMatcher(foo);
+// vs
+//   PolymorphicMatcher<TypeOfFoo>(foo);
+template <class Impl>
+inline PolymorphicMatcher<Impl> MakePolymorphicMatcher(const Impl& impl) {
+  return PolymorphicMatcher<Impl>(impl);
+}
+
+namespace internal {
+// Implements a matcher that compares a given value with a
+// pre-supplied value using one of the ==, <=, <, etc, operators.  The
+// two values being compared don't have to have the same type.
+//
+// The matcher defined here is polymorphic (for example, Eq(5) can be
+// used to match an int, a short, a double, etc).  Therefore we use
+// a template type conversion operator in the implementation.
+//
+// The following template definition assumes that the Rhs parameter is
+// a "bare" type (i.e. neither 'const T' nor 'T&').
+template <typename D, typename Rhs, typename Op>
+class ComparisonBase {
+ public:
+  explicit ComparisonBase(const Rhs& rhs) : rhs_(rhs) {}
+
+  using is_gtest_matcher = void;
+
+  template <typename Lhs>
+  bool MatchAndExplain(const Lhs& lhs, std::ostream*) const {
+    return Op()(lhs, Unwrap(rhs_));
+  }
+  void DescribeTo(std::ostream* os) const {
+    *os << D::Desc() << " ";
+    UniversalPrint(Unwrap(rhs_), os);
+  }
+  void DescribeNegationTo(std::ostream* os) const {
+    *os << D::NegatedDesc() << " ";
+    UniversalPrint(Unwrap(rhs_), os);
+  }
+
+ private:
+  template <typename T>
+  static const T& Unwrap(const T& v) {
+    return v;
+  }
+  template <typename T>
+  static const T& Unwrap(std::reference_wrapper<T> v) {
+    return v;
+  }
+
+  Rhs rhs_;
+};
+
+template <typename Rhs>
+class EqMatcher : public ComparisonBase<EqMatcher<Rhs>, Rhs, AnyEq> {
+ public:
+  explicit EqMatcher(const Rhs& rhs)
+      : ComparisonBase<EqMatcher<Rhs>, Rhs, AnyEq>(rhs) { }
+  static const char* Desc() { return "is equal to"; }
+  static const char* NegatedDesc() { return "isn't equal to"; }
+};
+template <typename Rhs>
+class NeMatcher : public ComparisonBase<NeMatcher<Rhs>, Rhs, AnyNe> {
+ public:
+  explicit NeMatcher(const Rhs& rhs)
+      : ComparisonBase<NeMatcher<Rhs>, Rhs, AnyNe>(rhs) { }
+  static const char* Desc() { return "isn't equal to"; }
+  static const char* NegatedDesc() { return "is equal to"; }
+};
+template <typename Rhs>
+class LtMatcher : public ComparisonBase<LtMatcher<Rhs>, Rhs, AnyLt> {
+ public:
+  explicit LtMatcher(const Rhs& rhs)
+      : ComparisonBase<LtMatcher<Rhs>, Rhs, AnyLt>(rhs) { }
+  static const char* Desc() { return "is <"; }
+  static const char* NegatedDesc() { return "isn't <"; }
+};
+template <typename Rhs>
+class GtMatcher : public ComparisonBase<GtMatcher<Rhs>, Rhs, AnyGt> {
+ public:
+  explicit GtMatcher(const Rhs& rhs)
+      : ComparisonBase<GtMatcher<Rhs>, Rhs, AnyGt>(rhs) { }
+  static const char* Desc() { return "is >"; }
+  static const char* NegatedDesc() { return "isn't >"; }
+};
+template <typename Rhs>
+class LeMatcher : public ComparisonBase<LeMatcher<Rhs>, Rhs, AnyLe> {
+ public:
+  explicit LeMatcher(const Rhs& rhs)
+      : ComparisonBase<LeMatcher<Rhs>, Rhs, AnyLe>(rhs) { }
+  static const char* Desc() { return "is <="; }
+  static const char* NegatedDesc() { return "isn't <="; }
+};
+template <typename Rhs>
+class GeMatcher : public ComparisonBase<GeMatcher<Rhs>, Rhs, AnyGe> {
+ public:
+  explicit GeMatcher(const Rhs& rhs)
+      : ComparisonBase<GeMatcher<Rhs>, Rhs, AnyGe>(rhs) { }
+  static const char* Desc() { return "is >="; }
+  static const char* NegatedDesc() { return "isn't >="; }
+};
+
+template <typename T, typename = typename std::enable_if<
+                          std::is_constructible<std::string, T>::value>::type>
+using StringLike = T;
+
+// Implements polymorphic matchers MatchesRegex(regex) and
+// ContainsRegex(regex), which can be used as a Matcher<T> as long as
+// T can be converted to a string.
+class MatchesRegexMatcher {
+ public:
+  MatchesRegexMatcher(const RE* regex, bool full_match)
+      : regex_(regex), full_match_(full_match) {}
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  bool MatchAndExplain(const internal::StringView& s,
+                       MatchResultListener* listener) const {
+    return MatchAndExplain(std::string(s), listener);
+  }
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+  // Accepts pointer types, particularly:
+  //   const char*
+  //   char*
+  //   const wchar_t*
+  //   wchar_t*
+  template <typename CharType>
+  bool MatchAndExplain(CharType* s, MatchResultListener* listener) const {
+    return s != nullptr && MatchAndExplain(std::string(s), listener);
+  }
+
+  // Matches anything that can convert to std::string.
+  //
+  // This is a template, not just a plain function with const std::string&,
+  // because absl::string_view has some interfering non-explicit constructors.
+  template <class MatcheeStringType>
+  bool MatchAndExplain(const MatcheeStringType& s,
+                       MatchResultListener* /* listener */) const {
+    const std::string& s2(s);
+    return full_match_ ? RE::FullMatch(s2, *regex_)
+                       : RE::PartialMatch(s2, *regex_);
+  }
+
+  void DescribeTo(::std::ostream* os) const {
+    *os << (full_match_ ? "matches" : "contains") << " regular expression ";
+    UniversalPrinter<std::string>::Print(regex_->pattern(), os);
+  }
+
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "doesn't " << (full_match_ ? "match" : "contain")
+        << " regular expression ";
+    UniversalPrinter<std::string>::Print(regex_->pattern(), os);
+  }
+
+ private:
+  const std::shared_ptr<const RE> regex_;
+  const bool full_match_;
+};
+}  // namespace internal
+
+// Matches a string that fully matches regular expression 'regex'.
+// The matcher takes ownership of 'regex'.
+inline PolymorphicMatcher<internal::MatchesRegexMatcher> MatchesRegex(
+    const internal::RE* regex) {
+  return MakePolymorphicMatcher(internal::MatchesRegexMatcher(regex, true));
+}
+template <typename T = std::string>
+PolymorphicMatcher<internal::MatchesRegexMatcher> MatchesRegex(
+    const internal::StringLike<T>& regex) {
+  return MatchesRegex(new internal::RE(std::string(regex)));
+}
+
+// Matches a string that contains regular expression 'regex'.
+// The matcher takes ownership of 'regex'.
+inline PolymorphicMatcher<internal::MatchesRegexMatcher> ContainsRegex(
+    const internal::RE* regex) {
+  return MakePolymorphicMatcher(internal::MatchesRegexMatcher(regex, false));
+}
+template <typename T = std::string>
+PolymorphicMatcher<internal::MatchesRegexMatcher> ContainsRegex(
+    const internal::StringLike<T>& regex) {
+  return ContainsRegex(new internal::RE(std::string(regex)));
+}
+
+// Creates a polymorphic matcher that matches anything equal to x.
+// Note: if the parameter of Eq() were declared as const T&, Eq("foo")
+// wouldn't compile.
+template <typename T>
+inline internal::EqMatcher<T> Eq(T x) { return internal::EqMatcher<T>(x); }
+
+// Constructs a Matcher<T> from a 'value' of type T.  The constructed
+// matcher matches any value that's equal to 'value'.
+template <typename T>
+Matcher<T>::Matcher(T value) { *this = Eq(value); }
+
+// Creates a monomorphic matcher that matches anything with type Lhs
+// and equal to rhs.  A user may need to use this instead of Eq(...)
+// in order to resolve an overloading ambiguity.
+//
+// TypedEq<T>(x) is just a convenient short-hand for Matcher<T>(Eq(x))
+// or Matcher<T>(x), but more readable than the latter.
+//
+// We could define similar monomorphic matchers for other comparison
+// operations (e.g. TypedLt, TypedGe, and etc), but decided not to do
+// it yet as those are used much less than Eq() in practice.  A user
+// can always write Matcher<T>(Lt(5)) to be explicit about the type,
+// for example.
+template <typename Lhs, typename Rhs>
+inline Matcher<Lhs> TypedEq(const Rhs& rhs) { return Eq(rhs); }
+
+// Creates a polymorphic matcher that matches anything >= x.
+template <typename Rhs>
+inline internal::GeMatcher<Rhs> Ge(Rhs x) {
+  return internal::GeMatcher<Rhs>(x);
+}
+
+// Creates a polymorphic matcher that matches anything > x.
+template <typename Rhs>
+inline internal::GtMatcher<Rhs> Gt(Rhs x) {
+  return internal::GtMatcher<Rhs>(x);
+}
+
+// Creates a polymorphic matcher that matches anything <= x.
+template <typename Rhs>
+inline internal::LeMatcher<Rhs> Le(Rhs x) {
+  return internal::LeMatcher<Rhs>(x);
+}
+
+// Creates a polymorphic matcher that matches anything < x.
+template <typename Rhs>
+inline internal::LtMatcher<Rhs> Lt(Rhs x) {
+  return internal::LtMatcher<Rhs>(x);
+}
+
+// Creates a polymorphic matcher that matches anything != x.
+template <typename Rhs>
+inline internal::NeMatcher<Rhs> Ne(Rhs x) {
+  return internal::NeMatcher<Rhs>(x);
+}
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251 5046
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_MATCHERS_H_
+
+#include <stdio.h>
+#include <memory>
+
+namespace testing {
+namespace internal {
+
+GTEST_DECLARE_string_(internal_run_death_test);
+
+// Names of the flags (needed for parsing Google Test flags).
+const char kDeathTestStyleFlag[] = "death_test_style";
+const char kDeathTestUseFork[] = "death_test_use_fork";
+const char kInternalRunDeathTestFlag[] = "internal_run_death_test";
+
+#if GTEST_HAS_DEATH_TEST
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+// DeathTest is a class that hides much of the complexity of the
+// GTEST_DEATH_TEST_ macro.  It is abstract; its static Create method
+// returns a concrete class that depends on the prevailing death test
+// style, as defined by the --gtest_death_test_style and/or
+// --gtest_internal_run_death_test flags.
+
+// In describing the results of death tests, these terms are used with
+// the corresponding definitions:
+//
+// exit status:  The integer exit information in the format specified
+//               by wait(2)
+// exit code:    The integer code passed to exit(3), _exit(2), or
+//               returned from main()
+class GTEST_API_ DeathTest {
+ public:
+  // Create returns false if there was an error determining the
+  // appropriate action to take for the current death test; for example,
+  // if the gtest_death_test_style flag is set to an invalid value.
+  // The LastMessage method will return a more detailed message in that
+  // case.  Otherwise, the DeathTest pointer pointed to by the "test"
+  // argument is set.  If the death test should be skipped, the pointer
+  // is set to NULL; otherwise, it is set to the address of a new concrete
+  // DeathTest object that controls the execution of the current test.
+  static bool Create(const char* statement, Matcher<const std::string&> matcher,
+                     const char* file, int line, DeathTest** test);
+  DeathTest();
+  virtual ~DeathTest() { }
+
+  // A helper class that aborts a death test when it's deleted.
+  class ReturnSentinel {
+   public:
+    explicit ReturnSentinel(DeathTest* test) : test_(test) { }
+    ~ReturnSentinel() { test_->Abort(TEST_ENCOUNTERED_RETURN_STATEMENT); }
+   private:
+    DeathTest* const test_;
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(ReturnSentinel);
+  } GTEST_ATTRIBUTE_UNUSED_;
+
+  // An enumeration of possible roles that may be taken when a death
+  // test is encountered.  EXECUTE means that the death test logic should
+  // be executed immediately.  OVERSEE means that the program should prepare
+  // the appropriate environment for a child process to execute the death
+  // test, then wait for it to complete.
+  enum TestRole { OVERSEE_TEST, EXECUTE_TEST };
+
+  // An enumeration of the three reasons that a test might be aborted.
+  enum AbortReason {
+    TEST_ENCOUNTERED_RETURN_STATEMENT,
+    TEST_THREW_EXCEPTION,
+    TEST_DID_NOT_DIE
+  };
+
+  // Assumes one of the above roles.
+  virtual TestRole AssumeRole() = 0;
+
+  // Waits for the death test to finish and returns its status.
+  virtual int Wait() = 0;
+
+  // Returns true if the death test passed; that is, the test process
+  // exited during the test, its exit status matches a user-supplied
+  // predicate, and its stderr output matches a user-supplied regular
+  // expression.
+  // The user-supplied predicate may be a macro expression rather
+  // than a function pointer or functor, or else Wait and Passed could
+  // be combined.
+  virtual bool Passed(bool exit_status_ok) = 0;
+
+  // Signals that the death test did not die as expected.
+  virtual void Abort(AbortReason reason) = 0;
+
+  // Returns a human-readable outcome message regarding the outcome of
+  // the last death test.
+  static const char* LastMessage();
+
+  static void set_last_death_test_message(const std::string& message);
+
+ private:
+  // A string containing a description of the outcome of the last death test.
+  static std::string last_death_test_message_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(DeathTest);
+};
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+// Factory interface for death tests.  May be mocked out for testing.
+class DeathTestFactory {
+ public:
+  virtual ~DeathTestFactory() { }
+  virtual bool Create(const char* statement,
+                      Matcher<const std::string&> matcher, const char* file,
+                      int line, DeathTest** test) = 0;
+};
+
+// A concrete DeathTestFactory implementation for normal use.
+class DefaultDeathTestFactory : public DeathTestFactory {
+ public:
+  bool Create(const char* statement, Matcher<const std::string&> matcher,
+              const char* file, int line, DeathTest** test) override;
+};
+
+// Returns true if exit_status describes a process that was terminated
+// by a signal, or exited normally with a nonzero exit code.
+GTEST_API_ bool ExitedUnsuccessfully(int exit_status);
+
+// A string passed to EXPECT_DEATH (etc.) is caught by one of these overloads
+// and interpreted as a regex (rather than an Eq matcher) for legacy
+// compatibility.
+inline Matcher<const ::std::string&> MakeDeathTestMatcher(
+    ::testing::internal::RE regex) {
+  return ContainsRegex(regex.pattern());
+}
+inline Matcher<const ::std::string&> MakeDeathTestMatcher(const char* regex) {
+  return ContainsRegex(regex);
+}
+inline Matcher<const ::std::string&> MakeDeathTestMatcher(
+    const ::std::string& regex) {
+  return ContainsRegex(regex);
+}
+
+// If a Matcher<const ::std::string&> is passed to EXPECT_DEATH (etc.), it's
+// used directly.
+inline Matcher<const ::std::string&> MakeDeathTestMatcher(
+    Matcher<const ::std::string&> matcher) {
+  return matcher;
+}
+
+// Traps C++ exceptions escaping statement and reports them as test
+// failures. Note that trapping SEH exceptions is not implemented here.
+# if GTEST_HAS_EXCEPTIONS
+#  define GTEST_EXECUTE_DEATH_TEST_STATEMENT_(statement, death_test) \
+  try { \
+    GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
+  } catch (const ::std::exception& gtest_exception) { \
+    fprintf(\
+        stderr, \
+        "\n%s: Caught std::exception-derived exception escaping the " \
+        "death test statement. Exception message: %s\n", \
+        ::testing::internal::FormatFileLocation(__FILE__, __LINE__).c_str(), \
+        gtest_exception.what()); \
+    fflush(stderr); \
+    death_test->Abort(::testing::internal::DeathTest::TEST_THREW_EXCEPTION); \
+  } catch (...) { \
+    death_test->Abort(::testing::internal::DeathTest::TEST_THREW_EXCEPTION); \
+  }
+
+# else
+#  define GTEST_EXECUTE_DEATH_TEST_STATEMENT_(statement, death_test) \
+  GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement)
+
+# endif
+
+// This macro is for implementing ASSERT_DEATH*, EXPECT_DEATH*,
+// ASSERT_EXIT*, and EXPECT_EXIT*.
+#define GTEST_DEATH_TEST_(statement, predicate, regex_or_matcher, fail)        \
+  GTEST_AMBIGUOUS_ELSE_BLOCKER_                                                \
+  if (::testing::internal::AlwaysTrue()) {                                     \
+    ::testing::internal::DeathTest* gtest_dt;                                  \
+    if (!::testing::internal::DeathTest::Create(                               \
+            #statement,                                                        \
+            ::testing::internal::MakeDeathTestMatcher(regex_or_matcher),       \
+            __FILE__, __LINE__, &gtest_dt)) {                                  \
+      goto GTEST_CONCAT_TOKEN_(gtest_label_, __LINE__);                        \
+    }                                                                          \
+    if (gtest_dt != nullptr) {                                                 \
+      std::unique_ptr< ::testing::internal::DeathTest> gtest_dt_ptr(gtest_dt); \
+      switch (gtest_dt->AssumeRole()) {                                        \
+        case ::testing::internal::DeathTest::OVERSEE_TEST:                     \
+          if (!gtest_dt->Passed(predicate(gtest_dt->Wait()))) {                \
+            goto GTEST_CONCAT_TOKEN_(gtest_label_, __LINE__);                  \
+          }                                                                    \
+          break;                                                               \
+        case ::testing::internal::DeathTest::EXECUTE_TEST: {                   \
+          ::testing::internal::DeathTest::ReturnSentinel gtest_sentinel(       \
+              gtest_dt);                                                       \
+          GTEST_EXECUTE_DEATH_TEST_STATEMENT_(statement, gtest_dt);            \
+          gtest_dt->Abort(::testing::internal::DeathTest::TEST_DID_NOT_DIE);   \
+          break;                                                               \
+        }                                                                      \
+        default:                                                               \
+          break;                                                               \
+      }                                                                        \
+    }                                                                          \
+  } else                                                                       \
+    GTEST_CONCAT_TOKEN_(gtest_label_, __LINE__)                                \
+        : fail(::testing::internal::DeathTest::LastMessage())
+// The symbol "fail" here expands to something into which a message
+// can be streamed.
+
+// This macro is for implementing ASSERT/EXPECT_DEBUG_DEATH when compiled in
+// NDEBUG mode. In this case we need the statements to be executed and the macro
+// must accept a streamed message even though the message is never printed.
+// The regex object is not evaluated, but it is used to prevent "unused"
+// warnings and to avoid an expression that doesn't compile in debug mode.
+#define GTEST_EXECUTE_STATEMENT_(statement, regex_or_matcher)    \
+  GTEST_AMBIGUOUS_ELSE_BLOCKER_                                  \
+  if (::testing::internal::AlwaysTrue()) {                       \
+    GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement);   \
+  } else if (!::testing::internal::AlwaysTrue()) {               \
+    ::testing::internal::MakeDeathTestMatcher(regex_or_matcher); \
+  } else                                                         \
+    ::testing::Message()
+
+// A class representing the parsed contents of the
+// --gtest_internal_run_death_test flag, as it existed when
+// RUN_ALL_TESTS was called.
+class InternalRunDeathTestFlag {
+ public:
+  InternalRunDeathTestFlag(const std::string& a_file,
+                           int a_line,
+                           int an_index,
+                           int a_write_fd)
+      : file_(a_file), line_(a_line), index_(an_index),
+        write_fd_(a_write_fd) {}
+
+  ~InternalRunDeathTestFlag() {
+    if (write_fd_ >= 0)
+      posix::Close(write_fd_);
+  }
+
+  const std::string& file() const { return file_; }
+  int line() const { return line_; }
+  int index() const { return index_; }
+  int write_fd() const { return write_fd_; }
+
+ private:
+  std::string file_;
+  int line_;
+  int index_;
+  int write_fd_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(InternalRunDeathTestFlag);
+};
+
+// Returns a newly created InternalRunDeathTestFlag object with fields
+// initialized from the GTEST_FLAG(internal_run_death_test) flag if
+// the flag is specified; otherwise returns NULL.
+InternalRunDeathTestFlag* ParseInternalRunDeathTestFlag();
+
+#endif  // GTEST_HAS_DEATH_TEST
+
+}  // namespace internal
+}  // namespace testing
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_DEATH_TEST_INTERNAL_H_
+
+namespace testing {
+
+// This flag controls the style of death tests.  Valid values are "threadsafe",
+// meaning that the death test child process will re-execute the test binary
+// from the start, running only a single death test, or "fast",
+// meaning that the child process will execute the test logic immediately
+// after forking.
+GTEST_DECLARE_string_(death_test_style);
+
+#if GTEST_HAS_DEATH_TEST
+
+namespace internal {
+
+// Returns a Boolean value indicating whether the caller is currently
+// executing in the context of the death test child process.  Tools such as
+// Valgrind heap checkers may need this to modify their behavior in death
+// tests.  IMPORTANT: This is an internal utility.  Using it may break the
+// implementation of death tests.  User code MUST NOT use it.
+GTEST_API_ bool InDeathTestChild();
+
+}  // namespace internal
+
+// The following macros are useful for writing death tests.
+
+// Here's what happens when an ASSERT_DEATH* or EXPECT_DEATH* is
+// executed:
+//
+//   1. It generates a warning if there is more than one active
+//   thread.  This is because it's safe to fork() or clone() only
+//   when there is a single thread.
+//
+//   2. The parent process clone()s a sub-process and runs the death
+//   test in it; the sub-process exits with code 0 at the end of the
+//   death test, if it hasn't exited already.
+//
+//   3. The parent process waits for the sub-process to terminate.
+//
+//   4. The parent process checks the exit code and error message of
+//   the sub-process.
+//
+// Examples:
+//
+//   ASSERT_DEATH(server.SendMessage(56, "Hello"), "Invalid port number");
+//   for (int i = 0; i < 5; i++) {
+//     EXPECT_DEATH(server.ProcessRequest(i),
+//                  "Invalid request .* in ProcessRequest()")
+//                  << "Failed to die on request " << i;
+//   }
+//
+//   ASSERT_EXIT(server.ExitNow(), ::testing::ExitedWithCode(0), "Exiting");
+//
+//   bool KilledBySIGHUP(int exit_code) {
+//     return WIFSIGNALED(exit_code) && WTERMSIG(exit_code) == SIGHUP;
+//   }
+//
+//   ASSERT_EXIT(client.HangUpServer(), KilledBySIGHUP, "Hanging up!");
+//
+// On the regular expressions used in death tests:
+//
+//   GOOGLETEST_CM0005 DO NOT DELETE
+//   On POSIX-compliant systems (*nix), we use the <regex.h> library,
+//   which uses the POSIX extended regex syntax.
+//
+//   On other platforms (e.g. Windows or Mac), we only support a simple regex
+//   syntax implemented as part of Google Test.  This limited
+//   implementation should be enough most of the time when writing
+//   death tests; though it lacks many features you can find in PCRE
+//   or POSIX extended regex syntax.  For example, we don't support
+//   union ("x|y"), grouping ("(xy)"), brackets ("[xy]"), and
+//   repetition count ("x{5,7}"), among others.
+//
+//   Below is the syntax that we do support.  We chose it to be a
+//   subset of both PCRE and POSIX extended regex, so it's easy to
+//   learn wherever you come from.  In the following: 'A' denotes a
+//   literal character, period (.), or a single \\ escape sequence;
+//   'x' and 'y' denote regular expressions; 'm' and 'n' are for
+//   natural numbers.
+//
+//     c     matches any literal character c
+//     \\d   matches any decimal digit
+//     \\D   matches any character that's not a decimal digit
+//     \\f   matches \f
+//     \\n   matches \n
+//     \\r   matches \r
+//     \\s   matches any ASCII whitespace, including \n
+//     \\S   matches any character that's not a whitespace
+//     \\t   matches \t
+//     \\v   matches \v
+//     \\w   matches any letter, _, or decimal digit
+//     \\W   matches any character that \\w doesn't match
+//     \\c   matches any literal character c, which must be a punctuation
+//     .     matches any single character except \n
+//     A?    matches 0 or 1 occurrences of A
+//     A*    matches 0 or many occurrences of A
+//     A+    matches 1 or many occurrences of A
+//     ^     matches the beginning of a string (not that of each line)
+//     $     matches the end of a string (not that of each line)
+//     xy    matches x followed by y
+//
+//   If you accidentally use PCRE or POSIX extended regex features
+//   not implemented by us, you will get a run-time failure.  In that
+//   case, please try to rewrite your regular expression within the
+//   above syntax.
+//
+//   This implementation is *not* meant to be as highly tuned or robust
+//   as a compiled regex library, but should perform well enough for a
+//   death test, which already incurs significant overhead by launching
+//   a child process.
+//
+// Known caveats:
+//
+//   A "threadsafe" style death test obtains the path to the test
+//   program from argv[0] and re-executes it in the sub-process.  For
+//   simplicity, the current implementation doesn't search the PATH
+//   when launching the sub-process.  This means that the user must
+//   invoke the test program via a path that contains at least one
+//   path separator (e.g. path/to/foo_test and
+//   /absolute/path/to/bar_test are fine, but foo_test is not).  This
+//   is rarely a problem as people usually don't put the test binary
+//   directory in PATH.
+//
+
+// Asserts that a given statement causes the program to exit, with an
+// integer exit status that satisfies predicate, and emitting error output
+// that matches regex.
+# define ASSERT_EXIT(statement, predicate, regex) \
+    GTEST_DEATH_TEST_(statement, predicate, regex, GTEST_FATAL_FAILURE_)
+
+// Like ASSERT_EXIT, but continues on to successive tests in the
+// test suite, if any:
+# define EXPECT_EXIT(statement, predicate, regex) \
+    GTEST_DEATH_TEST_(statement, predicate, regex, GTEST_NONFATAL_FAILURE_)
+
+// Asserts that a given statement causes the program to exit, either by
+// explicitly exiting with a nonzero exit code or being killed by a
+// signal, and emitting error output that matches regex.
+# define ASSERT_DEATH(statement, regex) \
+    ASSERT_EXIT(statement, ::testing::internal::ExitedUnsuccessfully, regex)
+
+// Like ASSERT_DEATH, but continues on to successive tests in the
+// test suite, if any:
+# define EXPECT_DEATH(statement, regex) \
+    EXPECT_EXIT(statement, ::testing::internal::ExitedUnsuccessfully, regex)
+
+// Two predicate classes that can be used in {ASSERT,EXPECT}_EXIT*:
+
+// Tests that an exit code describes a normal exit with a given exit code.
+class GTEST_API_ ExitedWithCode {
+ public:
+  explicit ExitedWithCode(int exit_code);
+  ExitedWithCode(const ExitedWithCode&) = default;
+  void operator=(const ExitedWithCode& other) = delete;
+  bool operator()(int exit_status) const;
+ private:
+  const int exit_code_;
+};
+
+# if !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA
+// Tests that an exit code describes an exit due to termination by a
+// given signal.
+// GOOGLETEST_CM0006 DO NOT DELETE
+class GTEST_API_ KilledBySignal {
+ public:
+  explicit KilledBySignal(int signum);
+  bool operator()(int exit_status) const;
+ private:
+  const int signum_;
+};
+# endif  // !GTEST_OS_WINDOWS
+
+// EXPECT_DEBUG_DEATH asserts that the given statements die in debug mode.
+// The death testing framework causes this to have interesting semantics,
+// since the sideeffects of the call are only visible in opt mode, and not
+// in debug mode.
+//
+// In practice, this can be used to test functions that utilize the
+// LOG(DFATAL) macro using the following style:
+//
+// int DieInDebugOr12(int* sideeffect) {
+//   if (sideeffect) {
+//     *sideeffect = 12;
+//   }
+//   LOG(DFATAL) << "death";
+//   return 12;
+// }
+//
+// TEST(TestSuite, TestDieOr12WorksInDgbAndOpt) {
+//   int sideeffect = 0;
+//   // Only asserts in dbg.
+//   EXPECT_DEBUG_DEATH(DieInDebugOr12(&sideeffect), "death");
+//
+// #ifdef NDEBUG
+//   // opt-mode has sideeffect visible.
+//   EXPECT_EQ(12, sideeffect);
+// #else
+//   // dbg-mode no visible sideeffect.
+//   EXPECT_EQ(0, sideeffect);
+// #endif
+// }
+//
+// This will assert that DieInDebugReturn12InOpt() crashes in debug
+// mode, usually due to a DCHECK or LOG(DFATAL), but returns the
+// appropriate fallback value (12 in this case) in opt mode. If you
+// need to test that a function has appropriate side-effects in opt
+// mode, include assertions against the side-effects.  A general
+// pattern for this is:
+//
+// EXPECT_DEBUG_DEATH({
+//   // Side-effects here will have an effect after this statement in
+//   // opt mode, but none in debug mode.
+//   EXPECT_EQ(12, DieInDebugOr12(&sideeffect));
+// }, "death");
+//
+# ifdef NDEBUG
+
+#  define EXPECT_DEBUG_DEATH(statement, regex) \
+  GTEST_EXECUTE_STATEMENT_(statement, regex)
+
+#  define ASSERT_DEBUG_DEATH(statement, regex) \
+  GTEST_EXECUTE_STATEMENT_(statement, regex)
+
+# else
+
+#  define EXPECT_DEBUG_DEATH(statement, regex) \
+  EXPECT_DEATH(statement, regex)
+
+#  define ASSERT_DEBUG_DEATH(statement, regex) \
+  ASSERT_DEATH(statement, regex)
+
+# endif  // NDEBUG for EXPECT_DEBUG_DEATH
+#endif  // GTEST_HAS_DEATH_TEST
+
+// This macro is used for implementing macros such as
+// EXPECT_DEATH_IF_SUPPORTED and ASSERT_DEATH_IF_SUPPORTED on systems where
+// death tests are not supported. Those macros must compile on such systems
+// if and only if EXPECT_DEATH and ASSERT_DEATH compile with the same parameters
+// on systems that support death tests. This allows one to write such a macro on
+// a system that does not support death tests and be sure that it will compile
+// on a death-test supporting system. It is exposed publicly so that systems
+// that have death-tests with stricter requirements than GTEST_HAS_DEATH_TEST
+// can write their own equivalent of EXPECT_DEATH_IF_SUPPORTED and
+// ASSERT_DEATH_IF_SUPPORTED.
+//
+// Parameters:
+//   statement -  A statement that a macro such as EXPECT_DEATH would test
+//                for program termination. This macro has to make sure this
+//                statement is compiled but not executed, to ensure that
+//                EXPECT_DEATH_IF_SUPPORTED compiles with a certain
+//                parameter if and only if EXPECT_DEATH compiles with it.
+//   regex     -  A regex that a macro such as EXPECT_DEATH would use to test
+//                the output of statement.  This parameter has to be
+//                compiled but not evaluated by this macro, to ensure that
+//                this macro only accepts expressions that a macro such as
+//                EXPECT_DEATH would accept.
+//   terminator - Must be an empty statement for EXPECT_DEATH_IF_SUPPORTED
+//                and a return statement for ASSERT_DEATH_IF_SUPPORTED.
+//                This ensures that ASSERT_DEATH_IF_SUPPORTED will not
+//                compile inside functions where ASSERT_DEATH doesn't
+//                compile.
+//
+//  The branch that has an always false condition is used to ensure that
+//  statement and regex are compiled (and thus syntactically correct) but
+//  never executed. The unreachable code macro protects the terminator
+//  statement from generating an 'unreachable code' warning in case
+//  statement unconditionally returns or throws. The Message constructor at
+//  the end allows the syntax of streaming additional messages into the
+//  macro, for compilational compatibility with EXPECT_DEATH/ASSERT_DEATH.
+# define GTEST_UNSUPPORTED_DEATH_TEST(statement, regex, terminator) \
+    GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
+    if (::testing::internal::AlwaysTrue()) { \
+      GTEST_LOG_(WARNING) \
+          << "Death tests are not supported on this platform.\n" \
+          << "Statement '" #statement "' cannot be verified."; \
+    } else if (::testing::internal::AlwaysFalse()) { \
+      ::testing::internal::RE::PartialMatch(".*", (regex)); \
+      GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
+      terminator; \
+    } else \
+      ::testing::Message()
+
+// EXPECT_DEATH_IF_SUPPORTED(statement, regex) and
+// ASSERT_DEATH_IF_SUPPORTED(statement, regex) expand to real death tests if
+// death tests are supported; otherwise they just issue a warning.  This is
+// useful when you are combining death test assertions with normal test
+// assertions in one test.
+#if GTEST_HAS_DEATH_TEST
+# define EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
+    EXPECT_DEATH(statement, regex)
+# define ASSERT_DEATH_IF_SUPPORTED(statement, regex) \
+    ASSERT_DEATH(statement, regex)
+#else
+# define EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
+    GTEST_UNSUPPORTED_DEATH_TEST(statement, regex, )
+# define ASSERT_DEATH_IF_SUPPORTED(statement, regex) \
+    GTEST_UNSUPPORTED_DEATH_TEST(statement, regex, return)
+#endif
+
+}  // namespace testing
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_DEATH_TEST_H_
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Macros and functions for implementing parameterized tests
+// in Google C++ Testing and Mocking Framework (Google Test)
+//
+// GOOGLETEST_CM0001 DO NOT DELETE
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_PARAM_TEST_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_PARAM_TEST_H_
+
+// Value-parameterized tests allow you to test your code with different
+// parameters without writing multiple copies of the same test.
+//
+// Here is how you use value-parameterized tests:
+
+#if 0
+
+// To write value-parameterized tests, first you should define a fixture
+// class. It is usually derived from testing::TestWithParam<T> (see below for
+// another inheritance scheme that's sometimes useful in more complicated
+// class hierarchies), where the type of your parameter values.
+// TestWithParam<T> is itself derived from testing::Test. T can be any
+// copyable type. If it's a raw pointer, you are responsible for managing the
+// lifespan of the pointed values.
+
+class FooTest : public ::testing::TestWithParam<const char*> {
+  // You can implement all the usual class fixture members here.
+};
+
+// Then, use the TEST_P macro to define as many parameterized tests
+// for this fixture as you want. The _P suffix is for "parameterized"
+// or "pattern", whichever you prefer to think.
+
+TEST_P(FooTest, DoesBlah) {
+  // Inside a test, access the test parameter with the GetParam() method
+  // of the TestWithParam<T> class:
+  EXPECT_TRUE(foo.Blah(GetParam()));
+  ...
+}
+
+TEST_P(FooTest, HasBlahBlah) {
+  ...
+}
+
+// Finally, you can use INSTANTIATE_TEST_SUITE_P to instantiate the test
+// case with any set of parameters you want. Google Test defines a number
+// of functions for generating test parameters. They return what we call
+// (surprise!) parameter generators. Here is a summary of them, which
+// are all in the testing namespace:
+//
+//
+//  Range(begin, end [, step]) - Yields values {begin, begin+step,
+//                               begin+step+step, ...}. The values do not
+//                               include end. step defaults to 1.
+//  Values(v1, v2, ..., vN)    - Yields values {v1, v2, ..., vN}.
+//  ValuesIn(container)        - Yields values from a C-style array, an STL
+//  ValuesIn(begin,end)          container, or an iterator range [begin, end).
+//  Bool()                     - Yields sequence {false, true}.
+//  Combine(g1, g2, ..., gN)   - Yields all combinations (the Cartesian product
+//                               for the math savvy) of the values generated
+//                               by the N generators.
+//
+// For more details, see comments at the definitions of these functions below
+// in this file.
+//
+// The following statement will instantiate tests from the FooTest test suite
+// each with parameter values "meeny", "miny", and "moe".
+
+INSTANTIATE_TEST_SUITE_P(InstantiationName,
+                         FooTest,
+                         Values("meeny", "miny", "moe"));
+
+// To distinguish different instances of the pattern, (yes, you
+// can instantiate it more than once) the first argument to the
+// INSTANTIATE_TEST_SUITE_P macro is a prefix that will be added to the
+// actual test suite name. Remember to pick unique prefixes for different
+// instantiations. The tests from the instantiation above will have
+// these names:
+//
+//    * InstantiationName/FooTest.DoesBlah/0 for "meeny"
+//    * InstantiationName/FooTest.DoesBlah/1 for "miny"
+//    * InstantiationName/FooTest.DoesBlah/2 for "moe"
+//    * InstantiationName/FooTest.HasBlahBlah/0 for "meeny"
+//    * InstantiationName/FooTest.HasBlahBlah/1 for "miny"
+//    * InstantiationName/FooTest.HasBlahBlah/2 for "moe"
+//
+// You can use these names in --gtest_filter.
+//
+// This statement will instantiate all tests from FooTest again, each
+// with parameter values "cat" and "dog":
+
+const char* pets[] = {"cat", "dog"};
+INSTANTIATE_TEST_SUITE_P(AnotherInstantiationName, FooTest, ValuesIn(pets));
+
+// The tests from the instantiation above will have these names:
+//
+//    * AnotherInstantiationName/FooTest.DoesBlah/0 for "cat"
+//    * AnotherInstantiationName/FooTest.DoesBlah/1 for "dog"
+//    * AnotherInstantiationName/FooTest.HasBlahBlah/0 for "cat"
+//    * AnotherInstantiationName/FooTest.HasBlahBlah/1 for "dog"
+//
+// Please note that INSTANTIATE_TEST_SUITE_P will instantiate all tests
+// in the given test suite, whether their definitions come before or
+// AFTER the INSTANTIATE_TEST_SUITE_P statement.
+//
+// Please also note that generator expressions (including parameters to the
+// generators) are evaluated in InitGoogleTest(), after main() has started.
+// This allows the user on one hand, to adjust generator parameters in order
+// to dynamically determine a set of tests to run and on the other hand,
+// give the user a chance to inspect the generated tests with Google Test
+// reflection API before RUN_ALL_TESTS() is executed.
+//
+// You can see samples/sample7_unittest.cc and samples/sample8_unittest.cc
+// for more examples.
+//
+// In the future, we plan to publish the API for defining new parameter
+// generators. But for now this interface remains part of the internal
+// implementation and is subject to change.
+//
+//
+// A parameterized test fixture must be derived from testing::Test and from
+// testing::WithParamInterface<T>, where T is the type of the parameter
+// values. Inheriting from TestWithParam<T> satisfies that requirement because
+// TestWithParam<T> inherits from both Test and WithParamInterface. In more
+// complicated hierarchies, however, it is occasionally useful to inherit
+// separately from Test and WithParamInterface. For example:
+
+class BaseTest : public ::testing::Test {
+  // You can inherit all the usual members for a non-parameterized test
+  // fixture here.
+};
+
+class DerivedTest : public BaseTest, public ::testing::WithParamInterface<int> {
+  // The usual test fixture members go here too.
+};
+
+TEST_F(BaseTest, HasFoo) {
+  // This is an ordinary non-parameterized test.
+}
+
+TEST_P(DerivedTest, DoesBlah) {
+  // GetParam works just the same here as if you inherit from TestWithParam.
+  EXPECT_TRUE(foo.Blah(GetParam()));
+}
+
+#endif  // 0
+
+#include <iterator>
+#include <utility>
+
+// Copyright 2008 Google Inc.
+// All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Type and function utilities for implementing parameterized tests.
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PARAM_UTIL_H_
+#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PARAM_UTIL_H_
+
+#include <ctype.h>
+
+#include <cassert>
+#include <iterator>
+#include <memory>
+#include <set>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_TEST_PART_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_TEST_PART_H_
+
+#include <iosfwd>
+#include <vector>
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+namespace testing {
+
+// A copyable object representing the result of a test part (i.e. an
+// assertion or an explicit FAIL(), ADD_FAILURE(), or SUCCESS()).
+//
+// Don't inherit from TestPartResult as its destructor is not virtual.
+class GTEST_API_ TestPartResult {
+ public:
+  // The possible outcomes of a test part (i.e. an assertion or an
+  // explicit SUCCEED(), FAIL(), or ADD_FAILURE()).
+  enum Type {
+    kSuccess,          // Succeeded.
+    kNonFatalFailure,  // Failed but the test can continue.
+    kFatalFailure,     // Failed and the test should be terminated.
+    kSkip              // Skipped.
+  };
+
+  // C'tor.  TestPartResult does NOT have a default constructor.
+  // Always use this constructor (with parameters) to create a
+  // TestPartResult object.
+  TestPartResult(Type a_type, const char* a_file_name, int a_line_number,
+                 const char* a_message)
+      : type_(a_type),
+        file_name_(a_file_name == nullptr ? "" : a_file_name),
+        line_number_(a_line_number),
+        summary_(ExtractSummary(a_message)),
+        message_(a_message) {}
+
+  // Gets the outcome of the test part.
+  Type type() const { return type_; }
+
+  // Gets the name of the source file where the test part took place, or
+  // NULL if it's unknown.
+  const char* file_name() const {
+    return file_name_.empty() ? nullptr : file_name_.c_str();
+  }
+
+  // Gets the line in the source file where the test part took place,
+  // or -1 if it's unknown.
+  int line_number() const { return line_number_; }
+
+  // Gets the summary of the failure message.
+  const char* summary() const { return summary_.c_str(); }
+
+  // Gets the message associated with the test part.
+  const char* message() const { return message_.c_str(); }
+
+  // Returns true if and only if the test part was skipped.
+  bool skipped() const { return type_ == kSkip; }
+
+  // Returns true if and only if the test part passed.
+  bool passed() const { return type_ == kSuccess; }
+
+  // Returns true if and only if the test part non-fatally failed.
+  bool nonfatally_failed() const { return type_ == kNonFatalFailure; }
+
+  // Returns true if and only if the test part fatally failed.
+  bool fatally_failed() const { return type_ == kFatalFailure; }
+
+  // Returns true if and only if the test part failed.
+  bool failed() const { return fatally_failed() || nonfatally_failed(); }
+
+ private:
+  Type type_;
+
+  // Gets the summary of the failure message by omitting the stack
+  // trace in it.
+  static std::string ExtractSummary(const char* message);
+
+  // The name of the source file where the test part took place, or
+  // "" if the source file is unknown.
+  std::string file_name_;
+  // The line in the source file where the test part took place, or -1
+  // if the line number is unknown.
+  int line_number_;
+  std::string summary_;  // The test failure summary.
+  std::string message_;  // The test failure message.
+};
+
+// Prints a TestPartResult object.
+std::ostream& operator<<(std::ostream& os, const TestPartResult& result);
+
+// An array of TestPartResult objects.
+//
+// Don't inherit from TestPartResultArray as its destructor is not
+// virtual.
+class GTEST_API_ TestPartResultArray {
+ public:
+  TestPartResultArray() {}
+
+  // Appends the given TestPartResult to the array.
+  void Append(const TestPartResult& result);
+
+  // Returns the TestPartResult at the given index (0-based).
+  const TestPartResult& GetTestPartResult(int index) const;
+
+  // Returns the number of TestPartResult objects in the array.
+  int size() const;
+
+ private:
+  std::vector<TestPartResult> array_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestPartResultArray);
+};
+
+// This interface knows how to report a test part result.
+class GTEST_API_ TestPartResultReporterInterface {
+ public:
+  virtual ~TestPartResultReporterInterface() {}
+
+  virtual void ReportTestPartResult(const TestPartResult& result) = 0;
+};
+
+namespace internal {
+
+// This helper class is used by {ASSERT|EXPECT}_NO_FATAL_FAILURE to check if a
+// statement generates new fatal failures. To do so it registers itself as the
+// current test part result reporter. Besides checking if fatal failures were
+// reported, it only delegates the reporting to the former result reporter.
+// The original result reporter is restored in the destructor.
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+class GTEST_API_ HasNewFatalFailureHelper
+    : public TestPartResultReporterInterface {
+ public:
+  HasNewFatalFailureHelper();
+  ~HasNewFatalFailureHelper() override;
+  void ReportTestPartResult(const TestPartResult& result) override;
+  bool has_new_fatal_failure() const { return has_new_fatal_failure_; }
+ private:
+  bool has_new_fatal_failure_;
+  TestPartResultReporterInterface* original_reporter_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(HasNewFatalFailureHelper);
+};
+
+}  // namespace internal
+
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_TEST_PART_H_
+
+namespace testing {
+// Input to a parameterized test name generator, describing a test parameter.
+// Consists of the parameter value and the integer parameter index.
+template <class ParamType>
+struct TestParamInfo {
+  TestParamInfo(const ParamType& a_param, size_t an_index) :
+    param(a_param),
+    index(an_index) {}
+  ParamType param;
+  size_t index;
+};
+
+// A builtin parameterized test name generator which returns the result of
+// testing::PrintToString.
+struct PrintToStringParamName {
+  template <class ParamType>
+  std::string operator()(const TestParamInfo<ParamType>& info) const {
+    return PrintToString(info.param);
+  }
+};
+
+namespace internal {
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+// Utility Functions
+
+// Outputs a message explaining invalid registration of different
+// fixture class for the same test suite. This may happen when
+// TEST_P macro is used to define two tests with the same name
+// but in different namespaces.
+GTEST_API_ void ReportInvalidTestSuiteType(const char* test_suite_name,
+                                           CodeLocation code_location);
+
+template <typename> class ParamGeneratorInterface;
+template <typename> class ParamGenerator;
+
+// Interface for iterating over elements provided by an implementation
+// of ParamGeneratorInterface<T>.
+template <typename T>
+class ParamIteratorInterface {
+ public:
+  virtual ~ParamIteratorInterface() {}
+  // A pointer to the base generator instance.
+  // Used only for the purposes of iterator comparison
+  // to make sure that two iterators belong to the same generator.
+  virtual const ParamGeneratorInterface<T>* BaseGenerator() const = 0;
+  // Advances iterator to point to the next element
+  // provided by the generator. The caller is responsible
+  // for not calling Advance() on an iterator equal to
+  // BaseGenerator()->End().
+  virtual void Advance() = 0;
+  // Clones the iterator object. Used for implementing copy semantics
+  // of ParamIterator<T>.
+  virtual ParamIteratorInterface* Clone() const = 0;
+  // Dereferences the current iterator and provides (read-only) access
+  // to the pointed value. It is the caller's responsibility not to call
+  // Current() on an iterator equal to BaseGenerator()->End().
+  // Used for implementing ParamGenerator<T>::operator*().
+  virtual const T* Current() const = 0;
+  // Determines whether the given iterator and other point to the same
+  // element in the sequence generated by the generator.
+  // Used for implementing ParamGenerator<T>::operator==().
+  virtual bool Equals(const ParamIteratorInterface& other) const = 0;
+};
+
+// Class iterating over elements provided by an implementation of
+// ParamGeneratorInterface<T>. It wraps ParamIteratorInterface<T>
+// and implements the const forward iterator concept.
+template <typename T>
+class ParamIterator {
+ public:
+  typedef T value_type;
+  typedef const T& reference;
+  typedef ptrdiff_t difference_type;
+
+  // ParamIterator assumes ownership of the impl_ pointer.
+  ParamIterator(const ParamIterator& other) : impl_(other.impl_->Clone()) {}
+  ParamIterator& operator=(const ParamIterator& other) {
+    if (this != &other)
+      impl_.reset(other.impl_->Clone());
+    return *this;
+  }
+
+  const T& operator*() const { return *impl_->Current(); }
+  const T* operator->() const { return impl_->Current(); }
+  // Prefix version of operator++.
+  ParamIterator& operator++() {
+    impl_->Advance();
+    return *this;
+  }
+  // Postfix version of operator++.
+  ParamIterator operator++(int /*unused*/) {
+    ParamIteratorInterface<T>* clone = impl_->Clone();
+    impl_->Advance();
+    return ParamIterator(clone);
+  }
+  bool operator==(const ParamIterator& other) const {
+    return impl_.get() == other.impl_.get() || impl_->Equals(*other.impl_);
+  }
+  bool operator!=(const ParamIterator& other) const {
+    return !(*this == other);
+  }
+
+ private:
+  friend class ParamGenerator<T>;
+  explicit ParamIterator(ParamIteratorInterface<T>* impl) : impl_(impl) {}
+  std::unique_ptr<ParamIteratorInterface<T> > impl_;
+};
+
+// ParamGeneratorInterface<T> is the binary interface to access generators
+// defined in other translation units.
+template <typename T>
+class ParamGeneratorInterface {
+ public:
+  typedef T ParamType;
+
+  virtual ~ParamGeneratorInterface() {}
+
+  // Generator interface definition
+  virtual ParamIteratorInterface<T>* Begin() const = 0;
+  virtual ParamIteratorInterface<T>* End() const = 0;
+};
+
+// Wraps ParamGeneratorInterface<T> and provides general generator syntax
+// compatible with the STL Container concept.
+// This class implements copy initialization semantics and the contained
+// ParamGeneratorInterface<T> instance is shared among all copies
+// of the original object. This is possible because that instance is immutable.
+template<typename T>
+class ParamGenerator {
+ public:
+  typedef ParamIterator<T> iterator;
+
+  explicit ParamGenerator(ParamGeneratorInterface<T>* impl) : impl_(impl) {}
+  ParamGenerator(const ParamGenerator& other) : impl_(other.impl_) {}
+
+  ParamGenerator& operator=(const ParamGenerator& other) {
+    impl_ = other.impl_;
+    return *this;
+  }
+
+  iterator begin() const { return iterator(impl_->Begin()); }
+  iterator end() const { return iterator(impl_->End()); }
+
+ private:
+  std::shared_ptr<const ParamGeneratorInterface<T> > impl_;
+};
+
+// Generates values from a range of two comparable values. Can be used to
+// generate sequences of user-defined types that implement operator+() and
+// operator<().
+// This class is used in the Range() function.
+template <typename T, typename IncrementT>
+class RangeGenerator : public ParamGeneratorInterface<T> {
+ public:
+  RangeGenerator(T begin, T end, IncrementT step)
+      : begin_(begin), end_(end),
+        step_(step), end_index_(CalculateEndIndex(begin, end, step)) {}
+  ~RangeGenerator() override {}
+
+  ParamIteratorInterface<T>* Begin() const override {
+    return new Iterator(this, begin_, 0, step_);
+  }
+  ParamIteratorInterface<T>* End() const override {
+    return new Iterator(this, end_, end_index_, step_);
+  }
+
+ private:
+  class Iterator : public ParamIteratorInterface<T> {
+   public:
+    Iterator(const ParamGeneratorInterface<T>* base, T value, int index,
+             IncrementT step)
+        : base_(base), value_(value), index_(index), step_(step) {}
+    ~Iterator() override {}
+
+    const ParamGeneratorInterface<T>* BaseGenerator() const override {
+      return base_;
+    }
+    void Advance() override {
+      value_ = static_cast<T>(value_ + step_);
+      index_++;
+    }
+    ParamIteratorInterface<T>* Clone() const override {
+      return new Iterator(*this);
+    }
+    const T* Current() const override { return &value_; }
+    bool Equals(const ParamIteratorInterface<T>& other) const override {
+      // Having the same base generator guarantees that the other
+      // iterator is of the same type and we can downcast.
+      GTEST_CHECK_(BaseGenerator() == other.BaseGenerator())
+          << "The program attempted to compare iterators "
+          << "from different generators." << std::endl;
+      const int other_index =
+          CheckedDowncastToActualType<const Iterator>(&other)->index_;
+      return index_ == other_index;
+    }
+
+   private:
+    Iterator(const Iterator& other)
+        : ParamIteratorInterface<T>(),
+          base_(other.base_), value_(other.value_), index_(other.index_),
+          step_(other.step_) {}
+
+    // No implementation - assignment is unsupported.
+    void operator=(const Iterator& other);
+
+    const ParamGeneratorInterface<T>* const base_;
+    T value_;
+    int index_;
+    const IncrementT step_;
+  };  // class RangeGenerator::Iterator
+
+  static int CalculateEndIndex(const T& begin,
+                               const T& end,
+                               const IncrementT& step) {
+    int end_index = 0;
+    for (T i = begin; i < end; i = static_cast<T>(i + step))
+      end_index++;
+    return end_index;
+  }
+
+  // No implementation - assignment is unsupported.
+  void operator=(const RangeGenerator& other);
+
+  const T begin_;
+  const T end_;
+  const IncrementT step_;
+  // The index for the end() iterator. All the elements in the generated
+  // sequence are indexed (0-based) to aid iterator comparison.
+  const int end_index_;
+};  // class RangeGenerator
+
+
+// Generates values from a pair of STL-style iterators. Used in the
+// ValuesIn() function. The elements are copied from the source range
+// since the source can be located on the stack, and the generator
+// is likely to persist beyond that stack frame.
+template <typename T>
+class ValuesInIteratorRangeGenerator : public ParamGeneratorInterface<T> {
+ public:
+  template <typename ForwardIterator>
+  ValuesInIteratorRangeGenerator(ForwardIterator begin, ForwardIterator end)
+      : container_(begin, end) {}
+  ~ValuesInIteratorRangeGenerator() override {}
+
+  ParamIteratorInterface<T>* Begin() const override {
+    return new Iterator(this, container_.begin());
+  }
+  ParamIteratorInterface<T>* End() const override {
+    return new Iterator(this, container_.end());
+  }
+
+ private:
+  typedef typename ::std::vector<T> ContainerType;
+
+  class Iterator : public ParamIteratorInterface<T> {
+   public:
+    Iterator(const ParamGeneratorInterface<T>* base,
+             typename ContainerType::const_iterator iterator)
+        : base_(base), iterator_(iterator) {}
+    ~Iterator() override {}
+
+    const ParamGeneratorInterface<T>* BaseGenerator() const override {
+      return base_;
+    }
+    void Advance() override {
+      ++iterator_;
+      value_.reset();
+    }
+    ParamIteratorInterface<T>* Clone() const override {
+      return new Iterator(*this);
+    }
+    // We need to use cached value referenced by iterator_ because *iterator_
+    // can return a temporary object (and of type other then T), so just
+    // having "return &*iterator_;" doesn't work.
+    // value_ is updated here and not in Advance() because Advance()
+    // can advance iterator_ beyond the end of the range, and we cannot
+    // detect that fact. The client code, on the other hand, is
+    // responsible for not calling Current() on an out-of-range iterator.
+    const T* Current() const override {
+      if (value_.get() == nullptr) value_.reset(new T(*iterator_));
+      return value_.get();
+    }
+    bool Equals(const ParamIteratorInterface<T>& other) const override {
+      // Having the same base generator guarantees that the other
+      // iterator is of the same type and we can downcast.
+      GTEST_CHECK_(BaseGenerator() == other.BaseGenerator())
+          << "The program attempted to compare iterators "
+          << "from different generators." << std::endl;
+      return iterator_ ==
+          CheckedDowncastToActualType<const Iterator>(&other)->iterator_;
+    }
+
+   private:
+    Iterator(const Iterator& other)
+          // The explicit constructor call suppresses a false warning
+          // emitted by gcc when supplied with the -Wextra option.
+        : ParamIteratorInterface<T>(),
+          base_(other.base_),
+          iterator_(other.iterator_) {}
+
+    const ParamGeneratorInterface<T>* const base_;
+    typename ContainerType::const_iterator iterator_;
+    // A cached value of *iterator_. We keep it here to allow access by
+    // pointer in the wrapping iterator's operator->().
+    // value_ needs to be mutable to be accessed in Current().
+    // Use of std::unique_ptr helps manage cached value's lifetime,
+    // which is bound by the lifespan of the iterator itself.
+    mutable std::unique_ptr<const T> value_;
+  };  // class ValuesInIteratorRangeGenerator::Iterator
+
+  // No implementation - assignment is unsupported.
+  void operator=(const ValuesInIteratorRangeGenerator& other);
+
+  const ContainerType container_;
+};  // class ValuesInIteratorRangeGenerator
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// Default parameterized test name generator, returns a string containing the
+// integer test parameter index.
+template <class ParamType>
+std::string DefaultParamName(const TestParamInfo<ParamType>& info) {
+  Message name_stream;
+  name_stream << info.index;
+  return name_stream.GetString();
+}
+
+template <typename T = int>
+void TestNotEmpty() {
+  static_assert(sizeof(T) == 0, "Empty arguments are not allowed.");
+}
+template <typename T = int>
+void TestNotEmpty(const T&) {}
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// Stores a parameter value and later creates tests parameterized with that
+// value.
+template <class TestClass>
+class ParameterizedTestFactory : public TestFactoryBase {
+ public:
+  typedef typename TestClass::ParamType ParamType;
+  explicit ParameterizedTestFactory(ParamType parameter) :
+      parameter_(parameter) {}
+  Test* CreateTest() override {
+    TestClass::SetParam(&parameter_);
+    return new TestClass();
+  }
+
+ private:
+  const ParamType parameter_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ParameterizedTestFactory);
+};
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// TestMetaFactoryBase is a base class for meta-factories that create
+// test factories for passing into MakeAndRegisterTestInfo function.
+template <class ParamType>
+class TestMetaFactoryBase {
+ public:
+  virtual ~TestMetaFactoryBase() {}
+
+  virtual TestFactoryBase* CreateTestFactory(ParamType parameter) = 0;
+};
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// TestMetaFactory creates test factories for passing into
+// MakeAndRegisterTestInfo function. Since MakeAndRegisterTestInfo receives
+// ownership of test factory pointer, same factory object cannot be passed
+// into that method twice. But ParameterizedTestSuiteInfo is going to call
+// it for each Test/Parameter value combination. Thus it needs meta factory
+// creator class.
+template <class TestSuite>
+class TestMetaFactory
+    : public TestMetaFactoryBase<typename TestSuite::ParamType> {
+ public:
+  using ParamType = typename TestSuite::ParamType;
+
+  TestMetaFactory() {}
+
+  TestFactoryBase* CreateTestFactory(ParamType parameter) override {
+    return new ParameterizedTestFactory<TestSuite>(parameter);
+  }
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestMetaFactory);
+};
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// ParameterizedTestSuiteInfoBase is a generic interface
+// to ParameterizedTestSuiteInfo classes. ParameterizedTestSuiteInfoBase
+// accumulates test information provided by TEST_P macro invocations
+// and generators provided by INSTANTIATE_TEST_SUITE_P macro invocations
+// and uses that information to register all resulting test instances
+// in RegisterTests method. The ParameterizeTestSuiteRegistry class holds
+// a collection of pointers to the ParameterizedTestSuiteInfo objects
+// and calls RegisterTests() on each of them when asked.
+class ParameterizedTestSuiteInfoBase {
+ public:
+  virtual ~ParameterizedTestSuiteInfoBase() {}
+
+  // Base part of test suite name for display purposes.
+  virtual const std::string& GetTestSuiteName() const = 0;
+  // Test suite id to verify identity.
+  virtual TypeId GetTestSuiteTypeId() const = 0;
+  // UnitTest class invokes this method to register tests in this
+  // test suite right before running them in RUN_ALL_TESTS macro.
+  // This method should not be called more than once on any single
+  // instance of a ParameterizedTestSuiteInfoBase derived class.
+  virtual void RegisterTests() = 0;
+
+ protected:
+  ParameterizedTestSuiteInfoBase() {}
+
+ private:
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ParameterizedTestSuiteInfoBase);
+};
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// Report a the name of a test_suit as safe to ignore
+// as the side effect of construction of this type.
+struct MarkAsIgnored {
+  explicit MarkAsIgnored(const char* test_suite);
+};
+
+GTEST_API_ void InsertSyntheticTestCase(const std::string& name,
+                                        CodeLocation location, bool has_test_p);
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// ParameterizedTestSuiteInfo accumulates tests obtained from TEST_P
+// macro invocations for a particular test suite and generators
+// obtained from INSTANTIATE_TEST_SUITE_P macro invocations for that
+// test suite. It registers tests with all values generated by all
+// generators when asked.
+template <class TestSuite>
+class ParameterizedTestSuiteInfo : public ParameterizedTestSuiteInfoBase {
+ public:
+  // ParamType and GeneratorCreationFunc are private types but are required
+  // for declarations of public methods AddTestPattern() and
+  // AddTestSuiteInstantiation().
+  using ParamType = typename TestSuite::ParamType;
+  // A function that returns an instance of appropriate generator type.
+  typedef ParamGenerator<ParamType>(GeneratorCreationFunc)();
+  using ParamNameGeneratorFunc = std::string(const TestParamInfo<ParamType>&);
+
+  explicit ParameterizedTestSuiteInfo(const char* name,
+                                      CodeLocation code_location)
+      : test_suite_name_(name), code_location_(code_location) {}
+
+  // Test suite base name for display purposes.
+  const std::string& GetTestSuiteName() const override {
+    return test_suite_name_;
+  }
+  // Test suite id to verify identity.
+  TypeId GetTestSuiteTypeId() const override { return GetTypeId<TestSuite>(); }
+  // TEST_P macro uses AddTestPattern() to record information
+  // about a single test in a LocalTestInfo structure.
+  // test_suite_name is the base name of the test suite (without invocation
+  // prefix). test_base_name is the name of an individual test without
+  // parameter index. For the test SequenceA/FooTest.DoBar/1 FooTest is
+  // test suite base name and DoBar is test base name.
+  void AddTestPattern(const char* test_suite_name, const char* test_base_name,
+                      TestMetaFactoryBase<ParamType>* meta_factory,
+                      CodeLocation code_location) {
+    tests_.push_back(std::shared_ptr<TestInfo>(new TestInfo(
+        test_suite_name, test_base_name, meta_factory, code_location)));
+  }
+  // INSTANTIATE_TEST_SUITE_P macro uses AddGenerator() to record information
+  // about a generator.
+  int AddTestSuiteInstantiation(const std::string& instantiation_name,
+                                GeneratorCreationFunc* func,
+                                ParamNameGeneratorFunc* name_func,
+                                const char* file, int line) {
+    instantiations_.push_back(
+        InstantiationInfo(instantiation_name, func, name_func, file, line));
+    return 0;  // Return value used only to run this method in namespace scope.
+  }
+  // UnitTest class invokes this method to register tests in this test suite
+  // right before running tests in RUN_ALL_TESTS macro.
+  // This method should not be called more than once on any single
+  // instance of a ParameterizedTestSuiteInfoBase derived class.
+  // UnitTest has a guard to prevent from calling this method more than once.
+  void RegisterTests() override {
+    bool generated_instantiations = false;
+
+    for (typename TestInfoContainer::iterator test_it = tests_.begin();
+         test_it != tests_.end(); ++test_it) {
+      std::shared_ptr<TestInfo> test_info = *test_it;
+      for (typename InstantiationContainer::iterator gen_it =
+               instantiations_.begin(); gen_it != instantiations_.end();
+               ++gen_it) {
+        const std::string& instantiation_name = gen_it->name;
+        ParamGenerator<ParamType> generator((*gen_it->generator)());
+        ParamNameGeneratorFunc* name_func = gen_it->name_func;
+        const char* file = gen_it->file;
+        int line = gen_it->line;
+
+        std::string test_suite_name;
+        if ( !instantiation_name.empty() )
+          test_suite_name = instantiation_name + "/";
+        test_suite_name += test_info->test_suite_base_name;
+
+        size_t i = 0;
+        std::set<std::string> test_param_names;
+        for (typename ParamGenerator<ParamType>::iterator param_it =
+                 generator.begin();
+             param_it != generator.end(); ++param_it, ++i) {
+          generated_instantiations = true;
+
+          Message test_name_stream;
+
+          std::string param_name = name_func(
+              TestParamInfo<ParamType>(*param_it, i));
+
+          GTEST_CHECK_(IsValidParamName(param_name))
+              << "Parameterized test name '" << param_name
+              << "' is invalid, in " << file
+              << " line " << line << std::endl;
+
+          GTEST_CHECK_(test_param_names.count(param_name) == 0)
+              << "Duplicate parameterized test name '" << param_name
+              << "', in " << file << " line " << line << std::endl;
+
+          test_param_names.insert(param_name);
+
+          if (!test_info->test_base_name.empty()) {
+            test_name_stream << test_info->test_base_name << "/";
+          }
+          test_name_stream << param_name;
+          MakeAndRegisterTestInfo(
+              test_suite_name.c_str(), test_name_stream.GetString().c_str(),
+              nullptr,  // No type parameter.
+              PrintToString(*param_it).c_str(), test_info->code_location,
+              GetTestSuiteTypeId(),
+              SuiteApiResolver<TestSuite>::GetSetUpCaseOrSuite(file, line),
+              SuiteApiResolver<TestSuite>::GetTearDownCaseOrSuite(file, line),
+              test_info->test_meta_factory->CreateTestFactory(*param_it));
+        }  // for param_it
+      }  // for gen_it
+    }  // for test_it
+
+    if (!generated_instantiations) {
+      // There are no generaotrs, or they all generate nothing ...
+      InsertSyntheticTestCase(GetTestSuiteName(), code_location_,
+                              !tests_.empty());
+    }
+  }    // RegisterTests
+
+ private:
+  // LocalTestInfo structure keeps information about a single test registered
+  // with TEST_P macro.
+  struct TestInfo {
+    TestInfo(const char* a_test_suite_base_name, const char* a_test_base_name,
+             TestMetaFactoryBase<ParamType>* a_test_meta_factory,
+             CodeLocation a_code_location)
+        : test_suite_base_name(a_test_suite_base_name),
+          test_base_name(a_test_base_name),
+          test_meta_factory(a_test_meta_factory),
+          code_location(a_code_location) {}
+
+    const std::string test_suite_base_name;
+    const std::string test_base_name;
+    const std::unique_ptr<TestMetaFactoryBase<ParamType> > test_meta_factory;
+    const CodeLocation code_location;
+  };
+  using TestInfoContainer = ::std::vector<std::shared_ptr<TestInfo> >;
+  // Records data received from INSTANTIATE_TEST_SUITE_P macros:
+  //  <Instantiation name, Sequence generator creation function,
+  //     Name generator function, Source file, Source line>
+  struct InstantiationInfo {
+      InstantiationInfo(const std::string &name_in,
+                        GeneratorCreationFunc* generator_in,
+                        ParamNameGeneratorFunc* name_func_in,
+                        const char* file_in,
+                        int line_in)
+          : name(name_in),
+            generator(generator_in),
+            name_func(name_func_in),
+            file(file_in),
+            line(line_in) {}
+
+      std::string name;
+      GeneratorCreationFunc* generator;
+      ParamNameGeneratorFunc* name_func;
+      const char* file;
+      int line;
+  };
+  typedef ::std::vector<InstantiationInfo> InstantiationContainer;
+
+  static bool IsValidParamName(const std::string& name) {
+    // Check for empty string
+    if (name.empty())
+      return false;
+
+    // Check for invalid characters
+    for (std::string::size_type index = 0; index < name.size(); ++index) {
+      if (!isalnum(name[index]) && name[index] != '_')
+        return false;
+    }
+
+    return true;
+  }
+
+  const std::string test_suite_name_;
+  CodeLocation code_location_;
+  TestInfoContainer tests_;
+  InstantiationContainer instantiations_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ParameterizedTestSuiteInfo);
+};  // class ParameterizedTestSuiteInfo
+
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+template <class TestCase>
+using ParameterizedTestCaseInfo = ParameterizedTestSuiteInfo<TestCase>;
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// ParameterizedTestSuiteRegistry contains a map of
+// ParameterizedTestSuiteInfoBase classes accessed by test suite names. TEST_P
+// and INSTANTIATE_TEST_SUITE_P macros use it to locate their corresponding
+// ParameterizedTestSuiteInfo descriptors.
+class ParameterizedTestSuiteRegistry {
+ public:
+  ParameterizedTestSuiteRegistry() {}
+  ~ParameterizedTestSuiteRegistry() {
+    for (auto& test_suite_info : test_suite_infos_) {
+      delete test_suite_info;
+    }
+  }
+
+  // Looks up or creates and returns a structure containing information about
+  // tests and instantiations of a particular test suite.
+  template <class TestSuite>
+  ParameterizedTestSuiteInfo<TestSuite>* GetTestSuitePatternHolder(
+      const char* test_suite_name, CodeLocation code_location) {
+    ParameterizedTestSuiteInfo<TestSuite>* typed_test_info = nullptr;
+    for (auto& test_suite_info : test_suite_infos_) {
+      if (test_suite_info->GetTestSuiteName() == test_suite_name) {
+        if (test_suite_info->GetTestSuiteTypeId() != GetTypeId<TestSuite>()) {
+          // Complain about incorrect usage of Google Test facilities
+          // and terminate the program since we cannot guaranty correct
+          // test suite setup and tear-down in this case.
+          ReportInvalidTestSuiteType(test_suite_name, code_location);
+          posix::Abort();
+        } else {
+          // At this point we are sure that the object we found is of the same
+          // type we are looking for, so we downcast it to that type
+          // without further checks.
+          typed_test_info = CheckedDowncastToActualType<
+              ParameterizedTestSuiteInfo<TestSuite> >(test_suite_info);
+        }
+        break;
+      }
+    }
+    if (typed_test_info == nullptr) {
+      typed_test_info = new ParameterizedTestSuiteInfo<TestSuite>(
+          test_suite_name, code_location);
+      test_suite_infos_.push_back(typed_test_info);
+    }
+    return typed_test_info;
+  }
+  void RegisterTests() {
+    for (auto& test_suite_info : test_suite_infos_) {
+      test_suite_info->RegisterTests();
+    }
+  }
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  template <class TestCase>
+  ParameterizedTestCaseInfo<TestCase>* GetTestCasePatternHolder(
+      const char* test_case_name, CodeLocation code_location) {
+    return GetTestSuitePatternHolder<TestCase>(test_case_name, code_location);
+  }
+
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+ private:
+  using TestSuiteInfoContainer = ::std::vector<ParameterizedTestSuiteInfoBase*>;
+
+  TestSuiteInfoContainer test_suite_infos_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ParameterizedTestSuiteRegistry);
+};
+
+// Keep track of what type-parameterized test suite are defined and
+// where as well as which are intatiated. This allows susequently
+// identifying suits that are defined but never used.
+class TypeParameterizedTestSuiteRegistry {
+ public:
+  // Add a suite definition
+  void RegisterTestSuite(const char* test_suite_name,
+                         CodeLocation code_location);
+
+  // Add an instantiation of a suit.
+  void RegisterInstantiation(const char* test_suite_name);
+
+  // For each suit repored as defined but not reported as instantiation,
+  // emit a test that reports that fact (configurably, as an error).
+  void CheckForInstantiations();
+
+ private:
+  struct TypeParameterizedTestSuiteInfo {
+    explicit TypeParameterizedTestSuiteInfo(CodeLocation c)
+        : code_location(c), instantiated(false) {}
+
+    CodeLocation code_location;
+    bool instantiated;
+  };
+
+  std::map<std::string, TypeParameterizedTestSuiteInfo> suites_;
+};
+
+}  // namespace internal
+
+// Forward declarations of ValuesIn(), which is implemented in
+// include/gtest/gtest-param-test.h.
+template <class Container>
+internal::ParamGenerator<typename Container::value_type> ValuesIn(
+    const Container& container);
+
+namespace internal {
+// Used in the Values() function to provide polymorphic capabilities.
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4100)
+#endif
+
+template <typename... Ts>
+class ValueArray {
+ public:
+  explicit ValueArray(Ts... v) : v_(FlatTupleConstructTag{}, std::move(v)...) {}
+
+  template <typename T>
+  operator ParamGenerator<T>() const {  // NOLINT
+    return ValuesIn(MakeVector<T>(MakeIndexSequence<sizeof...(Ts)>()));
+  }
+
+ private:
+  template <typename T, size_t... I>
+  std::vector<T> MakeVector(IndexSequence<I...>) const {
+    return std::vector<T>{static_cast<T>(v_.template Get<I>())...};
+  }
+
+  FlatTuple<Ts...> v_;
+};
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+template <typename... T>
+class CartesianProductGenerator
+    : public ParamGeneratorInterface<::std::tuple<T...>> {
+ public:
+  typedef ::std::tuple<T...> ParamType;
+
+  CartesianProductGenerator(const std::tuple<ParamGenerator<T>...>& g)
+      : generators_(g) {}
+  ~CartesianProductGenerator() override {}
+
+  ParamIteratorInterface<ParamType>* Begin() const override {
+    return new Iterator(this, generators_, false);
+  }
+  ParamIteratorInterface<ParamType>* End() const override {
+    return new Iterator(this, generators_, true);
+  }
+
+ private:
+  template <class I>
+  class IteratorImpl;
+  template <size_t... I>
+  class IteratorImpl<IndexSequence<I...>>
+      : public ParamIteratorInterface<ParamType> {
+   public:
+    IteratorImpl(const ParamGeneratorInterface<ParamType>* base,
+             const std::tuple<ParamGenerator<T>...>& generators, bool is_end)
+        : base_(base),
+          begin_(std::get<I>(generators).begin()...),
+          end_(std::get<I>(generators).end()...),
+          current_(is_end ? end_ : begin_) {
+      ComputeCurrentValue();
+    }
+    ~IteratorImpl() override {}
+
+    const ParamGeneratorInterface<ParamType>* BaseGenerator() const override {
+      return base_;
+    }
+    // Advance should not be called on beyond-of-range iterators
+    // so no component iterators must be beyond end of range, either.
+    void Advance() override {
+      assert(!AtEnd());
+      // Advance the last iterator.
+      ++std::get<sizeof...(T) - 1>(current_);
+      // if that reaches end, propagate that up.
+      AdvanceIfEnd<sizeof...(T) - 1>();
+      ComputeCurrentValue();
+    }
+    ParamIteratorInterface<ParamType>* Clone() const override {
+      return new IteratorImpl(*this);
+    }
+
+    const ParamType* Current() const override { return current_value_.get(); }
+
+    bool Equals(const ParamIteratorInterface<ParamType>& other) const override {
+      // Having the same base generator guarantees that the other
+      // iterator is of the same type and we can downcast.
+      GTEST_CHECK_(BaseGenerator() == other.BaseGenerator())
+          << "The program attempted to compare iterators "
+          << "from different generators." << std::endl;
+      const IteratorImpl* typed_other =
+          CheckedDowncastToActualType<const IteratorImpl>(&other);
+
+      // We must report iterators equal if they both point beyond their
+      // respective ranges. That can happen in a variety of fashions,
+      // so we have to consult AtEnd().
+      if (AtEnd() && typed_other->AtEnd()) return true;
+
+      bool same = true;
+      bool dummy[] = {
+          (same = same && std::get<I>(current_) ==
+                              std::get<I>(typed_other->current_))...};
+      (void)dummy;
+      return same;
+    }
+
+   private:
+    template <size_t ThisI>
+    void AdvanceIfEnd() {
+      if (std::get<ThisI>(current_) != std::get<ThisI>(end_)) return;
+
+      bool last = ThisI == 0;
+      if (last) {
+        // We are done. Nothing else to propagate.
+        return;
+      }
+
+      constexpr size_t NextI = ThisI - (ThisI != 0);
+      std::get<ThisI>(current_) = std::get<ThisI>(begin_);
+      ++std::get<NextI>(current_);
+      AdvanceIfEnd<NextI>();
+    }
+
+    void ComputeCurrentValue() {
+      if (!AtEnd())
+        current_value_ = std::make_shared<ParamType>(*std::get<I>(current_)...);
+    }
+    bool AtEnd() const {
+      bool at_end = false;
+      bool dummy[] = {
+          (at_end = at_end || std::get<I>(current_) == std::get<I>(end_))...};
+      (void)dummy;
+      return at_end;
+    }
+
+    const ParamGeneratorInterface<ParamType>* const base_;
+    std::tuple<typename ParamGenerator<T>::iterator...> begin_;
+    std::tuple<typename ParamGenerator<T>::iterator...> end_;
+    std::tuple<typename ParamGenerator<T>::iterator...> current_;
+    std::shared_ptr<ParamType> current_value_;
+  };
+
+  using Iterator = IteratorImpl<typename MakeIndexSequence<sizeof...(T)>::type>;
+
+  std::tuple<ParamGenerator<T>...> generators_;
+};
+
+template <class... Gen>
+class CartesianProductHolder {
+ public:
+  CartesianProductHolder(const Gen&... g) : generators_(g...) {}
+  template <typename... T>
+  operator ParamGenerator<::std::tuple<T...>>() const {
+    return ParamGenerator<::std::tuple<T...>>(
+        new CartesianProductGenerator<T...>(generators_));
+  }
+
+ private:
+  std::tuple<Gen...> generators_;
+};
+
+}  // namespace internal
+}  // namespace testing
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PARAM_UTIL_H_
+
+namespace testing {
+
+// Functions producing parameter generators.
+//
+// Google Test uses these generators to produce parameters for value-
+// parameterized tests. When a parameterized test suite is instantiated
+// with a particular generator, Google Test creates and runs tests
+// for each element in the sequence produced by the generator.
+//
+// In the following sample, tests from test suite FooTest are instantiated
+// each three times with parameter values 3, 5, and 8:
+//
+// class FooTest : public TestWithParam<int> { ... };
+//
+// TEST_P(FooTest, TestThis) {
+// }
+// TEST_P(FooTest, TestThat) {
+// }
+// INSTANTIATE_TEST_SUITE_P(TestSequence, FooTest, Values(3, 5, 8));
+//
+
+// Range() returns generators providing sequences of values in a range.
+//
+// Synopsis:
+// Range(start, end)
+//   - returns a generator producing a sequence of values {start, start+1,
+//     start+2, ..., }.
+// Range(start, end, step)
+//   - returns a generator producing a sequence of values {start, start+step,
+//     start+step+step, ..., }.
+// Notes:
+//   * The generated sequences never include end. For example, Range(1, 5)
+//     returns a generator producing a sequence {1, 2, 3, 4}. Range(1, 9, 2)
+//     returns a generator producing {1, 3, 5, 7}.
+//   * start and end must have the same type. That type may be any integral or
+//     floating-point type or a user defined type satisfying these conditions:
+//     * It must be assignable (have operator=() defined).
+//     * It must have operator+() (operator+(int-compatible type) for
+//       two-operand version).
+//     * It must have operator<() defined.
+//     Elements in the resulting sequences will also have that type.
+//   * Condition start < end must be satisfied in order for resulting sequences
+//     to contain any elements.
+//
+template <typename T, typename IncrementT>
+internal::ParamGenerator<T> Range(T start, T end, IncrementT step) {
+  return internal::ParamGenerator<T>(
+      new internal::RangeGenerator<T, IncrementT>(start, end, step));
+}
+
+template <typename T>
+internal::ParamGenerator<T> Range(T start, T end) {
+  return Range(start, end, 1);
+}
+
+// ValuesIn() function allows generation of tests with parameters coming from
+// a container.
+//
+// Synopsis:
+// ValuesIn(const T (&array)[N])
+//   - returns a generator producing sequences with elements from
+//     a C-style array.
+// ValuesIn(const Container& container)
+//   - returns a generator producing sequences with elements from
+//     an STL-style container.
+// ValuesIn(Iterator begin, Iterator end)
+//   - returns a generator producing sequences with elements from
+//     a range [begin, end) defined by a pair of STL-style iterators. These
+//     iterators can also be plain C pointers.
+//
+// Please note that ValuesIn copies the values from the containers
+// passed in and keeps them to generate tests in RUN_ALL_TESTS().
+//
+// Examples:
+//
+// This instantiates tests from test suite StringTest
+// each with C-string values of "foo", "bar", and "baz":
+//
+// const char* strings[] = {"foo", "bar", "baz"};
+// INSTANTIATE_TEST_SUITE_P(StringSequence, StringTest, ValuesIn(strings));
+//
+// This instantiates tests from test suite StlStringTest
+// each with STL strings with values "a" and "b":
+//
+// ::std::vector< ::std::string> GetParameterStrings() {
+//   ::std::vector< ::std::string> v;
+//   v.push_back("a");
+//   v.push_back("b");
+//   return v;
+// }
+//
+// INSTANTIATE_TEST_SUITE_P(CharSequence,
+//                          StlStringTest,
+//                          ValuesIn(GetParameterStrings()));
+//
+//
+// This will also instantiate tests from CharTest
+// each with parameter values 'a' and 'b':
+//
+// ::std::list<char> GetParameterChars() {
+//   ::std::list<char> list;
+//   list.push_back('a');
+//   list.push_back('b');
+//   return list;
+// }
+// ::std::list<char> l = GetParameterChars();
+// INSTANTIATE_TEST_SUITE_P(CharSequence2,
+//                          CharTest,
+//                          ValuesIn(l.begin(), l.end()));
+//
+template <typename ForwardIterator>
+internal::ParamGenerator<
+    typename std::iterator_traits<ForwardIterator>::value_type>
+ValuesIn(ForwardIterator begin, ForwardIterator end) {
+  typedef typename std::iterator_traits<ForwardIterator>::value_type ParamType;
+  return internal::ParamGenerator<ParamType>(
+      new internal::ValuesInIteratorRangeGenerator<ParamType>(begin, end));
+}
+
+template <typename T, size_t N>
+internal::ParamGenerator<T> ValuesIn(const T (&array)[N]) {
+  return ValuesIn(array, array + N);
+}
+
+template <class Container>
+internal::ParamGenerator<typename Container::value_type> ValuesIn(
+    const Container& container) {
+  return ValuesIn(container.begin(), container.end());
+}
+
+// Values() allows generating tests from explicitly specified list of
+// parameters.
+//
+// Synopsis:
+// Values(T v1, T v2, ..., T vN)
+//   - returns a generator producing sequences with elements v1, v2, ..., vN.
+//
+// For example, this instantiates tests from test suite BarTest each
+// with values "one", "two", and "three":
+//
+// INSTANTIATE_TEST_SUITE_P(NumSequence,
+//                          BarTest,
+//                          Values("one", "two", "three"));
+//
+// This instantiates tests from test suite BazTest each with values 1, 2, 3.5.
+// The exact type of values will depend on the type of parameter in BazTest.
+//
+// INSTANTIATE_TEST_SUITE_P(FloatingNumbers, BazTest, Values(1, 2, 3.5));
+//
+//
+template <typename... T>
+internal::ValueArray<T...> Values(T... v) {
+  return internal::ValueArray<T...>(std::move(v)...);
+}
+
+// Bool() allows generating tests with parameters in a set of (false, true).
+//
+// Synopsis:
+// Bool()
+//   - returns a generator producing sequences with elements {false, true}.
+//
+// It is useful when testing code that depends on Boolean flags. Combinations
+// of multiple flags can be tested when several Bool()'s are combined using
+// Combine() function.
+//
+// In the following example all tests in the test suite FlagDependentTest
+// will be instantiated twice with parameters false and true.
+//
+// class FlagDependentTest : public testing::TestWithParam<bool> {
+//   virtual void SetUp() {
+//     external_flag = GetParam();
+//   }
+// }
+// INSTANTIATE_TEST_SUITE_P(BoolSequence, FlagDependentTest, Bool());
+//
+inline internal::ParamGenerator<bool> Bool() {
+  return Values(false, true);
+}
+
+// Combine() allows the user to combine two or more sequences to produce
+// values of a Cartesian product of those sequences' elements.
+//
+// Synopsis:
+// Combine(gen1, gen2, ..., genN)
+//   - returns a generator producing sequences with elements coming from
+//     the Cartesian product of elements from the sequences generated by
+//     gen1, gen2, ..., genN. The sequence elements will have a type of
+//     std::tuple<T1, T2, ..., TN> where T1, T2, ..., TN are the types
+//     of elements from sequences produces by gen1, gen2, ..., genN.
+//
+// Example:
+//
+// This will instantiate tests in test suite AnimalTest each one with
+// the parameter values tuple("cat", BLACK), tuple("cat", WHITE),
+// tuple("dog", BLACK), and tuple("dog", WHITE):
+//
+// enum Color { BLACK, GRAY, WHITE };
+// class AnimalTest
+//     : public testing::TestWithParam<std::tuple<const char*, Color> > {...};
+//
+// TEST_P(AnimalTest, AnimalLooksNice) {...}
+//
+// INSTANTIATE_TEST_SUITE_P(AnimalVariations, AnimalTest,
+//                          Combine(Values("cat", "dog"),
+//                                  Values(BLACK, WHITE)));
+//
+// This will instantiate tests in FlagDependentTest with all variations of two
+// Boolean flags:
+//
+// class FlagDependentTest
+//     : public testing::TestWithParam<std::tuple<bool, bool> > {
+//   virtual void SetUp() {
+//     // Assigns external_flag_1 and external_flag_2 values from the tuple.
+//     std::tie(external_flag_1, external_flag_2) = GetParam();
+//   }
+// };
+//
+// TEST_P(FlagDependentTest, TestFeature1) {
+//   // Test your code using external_flag_1 and external_flag_2 here.
+// }
+// INSTANTIATE_TEST_SUITE_P(TwoBoolSequence, FlagDependentTest,
+//                          Combine(Bool(), Bool()));
+//
+template <typename... Generator>
+internal::CartesianProductHolder<Generator...> Combine(const Generator&... g) {
+  return internal::CartesianProductHolder<Generator...>(g...);
+}
+
+#define TEST_P(test_suite_name, test_name)                                     \
+  class GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)                     \
+      : public test_suite_name {                                               \
+   public:                                                                     \
+    GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)() {}                    \
+    void TestBody() override;                                                  \
+                                                                               \
+   private:                                                                    \
+    static int AddToRegistry() {                                               \
+      ::testing::UnitTest::GetInstance()                                       \
+          ->parameterized_test_registry()                                      \
+          .GetTestSuitePatternHolder<test_suite_name>(                         \
+              GTEST_STRINGIFY_(test_suite_name),                               \
+              ::testing::internal::CodeLocation(__FILE__, __LINE__))           \
+          ->AddTestPattern(                                                    \
+              GTEST_STRINGIFY_(test_suite_name), GTEST_STRINGIFY_(test_name),  \
+              new ::testing::internal::TestMetaFactory<GTEST_TEST_CLASS_NAME_( \
+                  test_suite_name, test_name)>(),                              \
+              ::testing::internal::CodeLocation(__FILE__, __LINE__));          \
+      return 0;                                                                \
+    }                                                                          \
+    static int gtest_registering_dummy_ GTEST_ATTRIBUTE_UNUSED_;               \
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(GTEST_TEST_CLASS_NAME_(test_suite_name,    \
+                                                           test_name));        \
+  };                                                                           \
+  int GTEST_TEST_CLASS_NAME_(test_suite_name,                                  \
+                             test_name)::gtest_registering_dummy_ =            \
+      GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)::AddToRegistry();     \
+  void GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)::TestBody()
+
+// The last argument to INSTANTIATE_TEST_SUITE_P allows the user to specify
+// generator and an optional function or functor that generates custom test name
+// suffixes based on the test parameters. Such a function or functor should
+// accept one argument of type testing::TestParamInfo<class ParamType>, and
+// return std::string.
+//
+// testing::PrintToStringParamName is a builtin test suffix generator that
+// returns the value of testing::PrintToString(GetParam()).
+//
+// Note: test names must be non-empty, unique, and may only contain ASCII
+// alphanumeric characters or underscore. Because PrintToString adds quotes
+// to std::string and C strings, it won't work for these types.
+
+#define GTEST_EXPAND_(arg) arg
+#define GTEST_GET_FIRST_(first, ...) first
+#define GTEST_GET_SECOND_(first, second, ...) second
+
+#define INSTANTIATE_TEST_SUITE_P(prefix, test_suite_name, ...)                \
+  static ::testing::internal::ParamGenerator<test_suite_name::ParamType>      \
+      gtest_##prefix##test_suite_name##_EvalGenerator_() {                    \
+    return GTEST_EXPAND_(GTEST_GET_FIRST_(__VA_ARGS__, DUMMY_PARAM_));        \
+  }                                                                           \
+  static ::std::string gtest_##prefix##test_suite_name##_EvalGenerateName_(   \
+      const ::testing::TestParamInfo<test_suite_name::ParamType>& info) {     \
+    if (::testing::internal::AlwaysFalse()) {                                 \
+      ::testing::internal::TestNotEmpty(GTEST_EXPAND_(GTEST_GET_SECOND_(      \
+          __VA_ARGS__,                                                        \
+          ::testing::internal::DefaultParamName<test_suite_name::ParamType>,  \
+          DUMMY_PARAM_)));                                                    \
+      auto t = std::make_tuple(__VA_ARGS__);                                  \
+      static_assert(std::tuple_size<decltype(t)>::value <= 2,                 \
+                    "Too Many Args!");                                        \
+    }                                                                         \
+    return ((GTEST_EXPAND_(GTEST_GET_SECOND_(                                 \
+        __VA_ARGS__,                                                          \
+        ::testing::internal::DefaultParamName<test_suite_name::ParamType>,    \
+        DUMMY_PARAM_))))(info);                                               \
+  }                                                                           \
+  static int gtest_##prefix##test_suite_name##_dummy_                         \
+      GTEST_ATTRIBUTE_UNUSED_ =                                               \
+          ::testing::UnitTest::GetInstance()                                  \
+              ->parameterized_test_registry()                                 \
+              .GetTestSuitePatternHolder<test_suite_name>(                    \
+                  GTEST_STRINGIFY_(test_suite_name),                          \
+                  ::testing::internal::CodeLocation(__FILE__, __LINE__))      \
+              ->AddTestSuiteInstantiation(                                    \
+                  GTEST_STRINGIFY_(prefix),                                   \
+                  &gtest_##prefix##test_suite_name##_EvalGenerator_,          \
+                  &gtest_##prefix##test_suite_name##_EvalGenerateName_,       \
+                  __FILE__, __LINE__)
+
+
+// Allow Marking a Parameterized test class as not needing to be instantiated.
+#define GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(T)                   \
+  namespace gtest_do_not_use_outside_namespace_scope {}                   \
+  static const ::testing::internal::MarkAsIgnored gtest_allow_ignore_##T( \
+      GTEST_STRINGIFY_(T))
+
+// Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+#define INSTANTIATE_TEST_CASE_P                                            \
+  static_assert(::testing::internal::InstantiateTestCase_P_IsDeprecated(), \
+                "");                                                       \
+  INSTANTIATE_TEST_SUITE_P
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+}  // namespace testing
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_PARAM_TEST_H_
+// Copyright 2006, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//
+// Google C++ Testing and Mocking Framework definitions useful in production code.
+// GOOGLETEST_CM0003 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_PROD_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_PROD_H_
+
+// When you need to test the private or protected members of a class,
+// use the FRIEND_TEST macro to declare your tests as friends of the
+// class.  For example:
+//
+// class MyClass {
+//  private:
+//   void PrivateMethod();
+//   FRIEND_TEST(MyClassTest, PrivateMethodWorks);
+// };
+//
+// class MyClassTest : public testing::Test {
+//   // ...
+// };
+//
+// TEST_F(MyClassTest, PrivateMethodWorks) {
+//   // Can call MyClass::PrivateMethod() here.
+// }
+//
+// Note: The test class must be in the same namespace as the class being tested.
+// For example, putting MyClassTest in an anonymous namespace will not work.
+
+#define FRIEND_TEST(test_case_name, test_name)\
+friend class test_case_name##_##test_name##_Test
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_PROD_H_
+// Copyright 2008 Google Inc.
+// All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_TYPED_TEST_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_TYPED_TEST_H_
+
+// This header implements typed tests and type-parameterized tests.
+
+// Typed (aka type-driven) tests repeat the same test for types in a
+// list.  You must know which types you want to test with when writing
+// typed tests. Here's how you do it:
+
+#if 0
+
+// First, define a fixture class template.  It should be parameterized
+// by a type.  Remember to derive it from testing::Test.
+template <typename T>
+class FooTest : public testing::Test {
+ public:
+  ...
+  typedef std::list<T> List;
+  static T shared_;
+  T value_;
+};
+
+// Next, associate a list of types with the test suite, which will be
+// repeated for each type in the list.  The typedef is necessary for
+// the macro to parse correctly.
+typedef testing::Types<char, int, unsigned int> MyTypes;
+TYPED_TEST_SUITE(FooTest, MyTypes);
+
+// If the type list contains only one type, you can write that type
+// directly without Types<...>:
+//   TYPED_TEST_SUITE(FooTest, int);
+
+// Then, use TYPED_TEST() instead of TEST_F() to define as many typed
+// tests for this test suite as you want.
+TYPED_TEST(FooTest, DoesBlah) {
+  // Inside a test, refer to the special name TypeParam to get the type
+  // parameter.  Since we are inside a derived class template, C++ requires
+  // us to visit the members of FooTest via 'this'.
+  TypeParam n = this->value_;
+
+  // To visit static members of the fixture, add the TestFixture::
+  // prefix.
+  n += TestFixture::shared_;
+
+  // To refer to typedefs in the fixture, add the "typename
+  // TestFixture::" prefix.
+  typename TestFixture::List values;
+  values.push_back(n);
+  ...
+}
+
+TYPED_TEST(FooTest, HasPropertyA) { ... }
+
+// TYPED_TEST_SUITE takes an optional third argument which allows to specify a
+// class that generates custom test name suffixes based on the type. This should
+// be a class which has a static template function GetName(int index) returning
+// a string for each type. The provided integer index equals the index of the
+// type in the provided type list. In many cases the index can be ignored.
+//
+// For example:
+//   class MyTypeNames {
+//    public:
+//     template <typename T>
+//     static std::string GetName(int) {
+//       if (std::is_same<T, char>()) return "char";
+//       if (std::is_same<T, int>()) return "int";
+//       if (std::is_same<T, unsigned int>()) return "unsignedInt";
+//     }
+//   };
+//   TYPED_TEST_SUITE(FooTest, MyTypes, MyTypeNames);
+
+#endif  // 0
+
+// Type-parameterized tests are abstract test patterns parameterized
+// by a type.  Compared with typed tests, type-parameterized tests
+// allow you to define the test pattern without knowing what the type
+// parameters are.  The defined pattern can be instantiated with
+// different types any number of times, in any number of translation
+// units.
+//
+// If you are designing an interface or concept, you can define a
+// suite of type-parameterized tests to verify properties that any
+// valid implementation of the interface/concept should have.  Then,
+// each implementation can easily instantiate the test suite to verify
+// that it conforms to the requirements, without having to write
+// similar tests repeatedly.  Here's an example:
+
+#if 0
+
+// First, define a fixture class template.  It should be parameterized
+// by a type.  Remember to derive it from testing::Test.
+template <typename T>
+class FooTest : public testing::Test {
+  ...
+};
+
+// Next, declare that you will define a type-parameterized test suite
+// (the _P suffix is for "parameterized" or "pattern", whichever you
+// prefer):
+TYPED_TEST_SUITE_P(FooTest);
+
+// Then, use TYPED_TEST_P() to define as many type-parameterized tests
+// for this type-parameterized test suite as you want.
+TYPED_TEST_P(FooTest, DoesBlah) {
+  // Inside a test, refer to TypeParam to get the type parameter.
+  TypeParam n = 0;
+  ...
+}
+
+TYPED_TEST_P(FooTest, HasPropertyA) { ... }
+
+// Now the tricky part: you need to register all test patterns before
+// you can instantiate them.  The first argument of the macro is the
+// test suite name; the rest are the names of the tests in this test
+// case.
+REGISTER_TYPED_TEST_SUITE_P(FooTest,
+                            DoesBlah, HasPropertyA);
+
+// Finally, you are free to instantiate the pattern with the types you
+// want.  If you put the above code in a header file, you can #include
+// it in multiple C++ source files and instantiate it multiple times.
+//
+// To distinguish different instances of the pattern, the first
+// argument to the INSTANTIATE_* macro is a prefix that will be added
+// to the actual test suite name.  Remember to pick unique prefixes for
+// different instances.
+typedef testing::Types<char, int, unsigned int> MyTypes;
+INSTANTIATE_TYPED_TEST_SUITE_P(My, FooTest, MyTypes);
+
+// If the type list contains only one type, you can write that type
+// directly without Types<...>:
+//   INSTANTIATE_TYPED_TEST_SUITE_P(My, FooTest, int);
+//
+// Similar to the optional argument of TYPED_TEST_SUITE above,
+// INSTANTIATE_TEST_SUITE_P takes an optional fourth argument which allows to
+// generate custom names.
+//   INSTANTIATE_TYPED_TEST_SUITE_P(My, FooTest, MyTypes, MyTypeNames);
+
+#endif  // 0
+
+
+// Implements typed tests.
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// Expands to the name of the typedef for the type parameters of the
+// given test suite.
+#define GTEST_TYPE_PARAMS_(TestSuiteName) gtest_type_params_##TestSuiteName##_
+
+// Expands to the name of the typedef for the NameGenerator, responsible for
+// creating the suffixes of the name.
+#define GTEST_NAME_GENERATOR_(TestSuiteName) \
+  gtest_type_params_##TestSuiteName##_NameGenerator
+
+#define TYPED_TEST_SUITE(CaseName, Types, ...)                          \
+  typedef ::testing::internal::GenerateTypeList<Types>::type            \
+      GTEST_TYPE_PARAMS_(CaseName);                                     \
+  typedef ::testing::internal::NameGeneratorSelector<__VA_ARGS__>::type \
+      GTEST_NAME_GENERATOR_(CaseName)
+
+#define TYPED_TEST(CaseName, TestName)                                        \
+  static_assert(sizeof(GTEST_STRINGIFY_(TestName)) > 1,                       \
+                "test-name must not be empty");                               \
+  template <typename gtest_TypeParam_>                                        \
+  class GTEST_TEST_CLASS_NAME_(CaseName, TestName)                            \
+      : public CaseName<gtest_TypeParam_> {                                   \
+   private:                                                                   \
+    typedef CaseName<gtest_TypeParam_> TestFixture;                           \
+    typedef gtest_TypeParam_ TypeParam;                                       \
+    void TestBody() override;                                                 \
+  };                                                                          \
+  static bool gtest_##CaseName##_##TestName##_registered_                     \
+      GTEST_ATTRIBUTE_UNUSED_ = ::testing::internal::TypeParameterizedTest<   \
+          CaseName,                                                           \
+          ::testing::internal::TemplateSel<GTEST_TEST_CLASS_NAME_(CaseName,   \
+                                                                  TestName)>, \
+          GTEST_TYPE_PARAMS_(                                                 \
+              CaseName)>::Register("",                                        \
+                                   ::testing::internal::CodeLocation(         \
+                                       __FILE__, __LINE__),                   \
+                                   GTEST_STRINGIFY_(CaseName),                \
+                                   GTEST_STRINGIFY_(TestName), 0,             \
+                                   ::testing::internal::GenerateNames<        \
+                                       GTEST_NAME_GENERATOR_(CaseName),       \
+                                       GTEST_TYPE_PARAMS_(CaseName)>());      \
+  template <typename gtest_TypeParam_>                                        \
+  void GTEST_TEST_CLASS_NAME_(CaseName,                                       \
+                              TestName)<gtest_TypeParam_>::TestBody()
+
+// Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+#define TYPED_TEST_CASE                                                \
+  static_assert(::testing::internal::TypedTestCaseIsDeprecated(), ""); \
+  TYPED_TEST_SUITE
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+// Implements type-parameterized tests.
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// Expands to the namespace name that the type-parameterized tests for
+// the given type-parameterized test suite are defined in.  The exact
+// name of the namespace is subject to change without notice.
+#define GTEST_SUITE_NAMESPACE_(TestSuiteName) gtest_suite_##TestSuiteName##_
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+//
+// Expands to the name of the variable used to remember the names of
+// the defined tests in the given test suite.
+#define GTEST_TYPED_TEST_SUITE_P_STATE_(TestSuiteName) \
+  gtest_typed_test_suite_p_state_##TestSuiteName##_
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE DIRECTLY.
+//
+// Expands to the name of the variable used to remember the names of
+// the registered tests in the given test suite.
+#define GTEST_REGISTERED_TEST_NAMES_(TestSuiteName) \
+  gtest_registered_test_names_##TestSuiteName##_
+
+// The variables defined in the type-parameterized test macros are
+// static as typically these macros are used in a .h file that can be
+// #included in multiple translation units linked together.
+#define TYPED_TEST_SUITE_P(SuiteName)              \
+  static ::testing::internal::TypedTestSuitePState \
+      GTEST_TYPED_TEST_SUITE_P_STATE_(SuiteName)
+
+// Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+#define TYPED_TEST_CASE_P                                                 \
+  static_assert(::testing::internal::TypedTestCase_P_IsDeprecated(), ""); \
+  TYPED_TEST_SUITE_P
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+#define TYPED_TEST_P(SuiteName, TestName)                             \
+  namespace GTEST_SUITE_NAMESPACE_(SuiteName) {                       \
+    template <typename gtest_TypeParam_>                              \
+    class TestName : public SuiteName<gtest_TypeParam_> {             \
+     private:                                                         \
+      typedef SuiteName<gtest_TypeParam_> TestFixture;                \
+      typedef gtest_TypeParam_ TypeParam;                             \
+      void TestBody() override;                                       \
+    };                                                                \
+    static bool gtest_##TestName##_defined_ GTEST_ATTRIBUTE_UNUSED_ = \
+        GTEST_TYPED_TEST_SUITE_P_STATE_(SuiteName).AddTestName(       \
+            __FILE__, __LINE__, GTEST_STRINGIFY_(SuiteName),          \
+            GTEST_STRINGIFY_(TestName));                              \
+  }                                                                   \
+  template <typename gtest_TypeParam_>                                \
+  void GTEST_SUITE_NAMESPACE_(                                        \
+      SuiteName)::TestName<gtest_TypeParam_>::TestBody()
+
+// Note: this won't work correctly if the trailing arguments are macros.
+#define REGISTER_TYPED_TEST_SUITE_P(SuiteName, ...)                         \
+  namespace GTEST_SUITE_NAMESPACE_(SuiteName) {                             \
+    typedef ::testing::internal::Templates<__VA_ARGS__> gtest_AllTests_;    \
+  }                                                                         \
+  static const char* const GTEST_REGISTERED_TEST_NAMES_(                    \
+      SuiteName) GTEST_ATTRIBUTE_UNUSED_ =                                  \
+      GTEST_TYPED_TEST_SUITE_P_STATE_(SuiteName).VerifyRegisteredTestNames( \
+          GTEST_STRINGIFY_(SuiteName), __FILE__, __LINE__, #__VA_ARGS__)
+
+// Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+#define REGISTER_TYPED_TEST_CASE_P                                           \
+  static_assert(::testing::internal::RegisterTypedTestCase_P_IsDeprecated(), \
+                "");                                                         \
+  REGISTER_TYPED_TEST_SUITE_P
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+#define INSTANTIATE_TYPED_TEST_SUITE_P(Prefix, SuiteName, Types, ...)       \
+  static_assert(sizeof(GTEST_STRINGIFY_(Prefix)) > 1,                       \
+                "test-suit-prefix must not be empty");                      \
+  static bool gtest_##Prefix##_##SuiteName GTEST_ATTRIBUTE_UNUSED_ =        \
+      ::testing::internal::TypeParameterizedTestSuite<                      \
+          SuiteName, GTEST_SUITE_NAMESPACE_(SuiteName)::gtest_AllTests_,    \
+          ::testing::internal::GenerateTypeList<Types>::type>::             \
+          Register(GTEST_STRINGIFY_(Prefix),                                \
+                   ::testing::internal::CodeLocation(__FILE__, __LINE__),   \
+                   &GTEST_TYPED_TEST_SUITE_P_STATE_(SuiteName),             \
+                   GTEST_STRINGIFY_(SuiteName),                             \
+                   GTEST_REGISTERED_TEST_NAMES_(SuiteName),                 \
+                   ::testing::internal::GenerateNames<                      \
+                       ::testing::internal::NameGeneratorSelector<          \
+                           __VA_ARGS__>::type,                              \
+                       ::testing::internal::GenerateTypeList<Types>::type>())
+
+// Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+#define INSTANTIATE_TYPED_TEST_CASE_P                                      \
+  static_assert(                                                           \
+      ::testing::internal::InstantiateTypedTestCase_P_IsDeprecated(), ""); \
+  INSTANTIATE_TYPED_TEST_SUITE_P
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_TYPED_TEST_H_
+
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
+/* class A needs to have dll-interface to be used by clients of class B */)
+
+namespace testing {
+
+// Silence C4100 (unreferenced formal parameter) and 4805
+// unsafe mix of type 'const int' and type 'const bool'
+#ifdef _MSC_VER
+# pragma warning(push)
+# pragma warning(disable:4805)
+# pragma warning(disable:4100)
+#endif
+
+
+// Declares the flags.
+
+// This flag temporary enables the disabled tests.
+GTEST_DECLARE_bool_(also_run_disabled_tests);
+
+// This flag brings the debugger on an assertion failure.
+GTEST_DECLARE_bool_(break_on_failure);
+
+// This flag controls whether Google Test catches all test-thrown exceptions
+// and logs them as failures.
+GTEST_DECLARE_bool_(catch_exceptions);
+
+// This flag enables using colors in terminal output. Available values are
+// "yes" to enable colors, "no" (disable colors), or "auto" (the default)
+// to let Google Test decide.
+GTEST_DECLARE_string_(color);
+
+// This flag controls whether the test runner should continue execution past
+// first failure.
+GTEST_DECLARE_bool_(fail_fast);
+
+// This flag sets up the filter to select by name using a glob pattern
+// the tests to run. If the filter is not given all tests are executed.
+GTEST_DECLARE_string_(filter);
+
+// This flag controls whether Google Test installs a signal handler that dumps
+// debugging information when fatal signals are raised.
+GTEST_DECLARE_bool_(install_failure_signal_handler);
+
+// This flag causes the Google Test to list tests. None of the tests listed
+// are actually run if the flag is provided.
+GTEST_DECLARE_bool_(list_tests);
+
+// This flag controls whether Google Test emits a detailed XML report to a file
+// in addition to its normal textual output.
+GTEST_DECLARE_string_(output);
+
+// This flags control whether Google Test prints only test failures.
+GTEST_DECLARE_bool_(brief);
+
+// This flags control whether Google Test prints the elapsed time for each
+// test.
+GTEST_DECLARE_bool_(print_time);
+
+// This flags control whether Google Test prints UTF8 characters as text.
+GTEST_DECLARE_bool_(print_utf8);
+
+// This flag specifies the random number seed.
+GTEST_DECLARE_int32_(random_seed);
+
+// This flag sets how many times the tests are repeated. The default value
+// is 1. If the value is -1 the tests are repeating forever.
+GTEST_DECLARE_int32_(repeat);
+
+// This flag controls whether Google Test includes Google Test internal
+// stack frames in failure stack traces.
+GTEST_DECLARE_bool_(show_internal_stack_frames);
+
+// When this flag is specified, tests' order is randomized on every iteration.
+GTEST_DECLARE_bool_(shuffle);
+
+// This flag specifies the maximum number of stack frames to be
+// printed in a failure message.
+GTEST_DECLARE_int32_(stack_trace_depth);
+
+// When this flag is specified, a failed assertion will throw an
+// exception if exceptions are enabled, or exit the program with a
+// non-zero code otherwise. For use with an external test framework.
+GTEST_DECLARE_bool_(throw_on_failure);
+
+// When this flag is set with a "host:port" string, on supported
+// platforms test results are streamed to the specified port on
+// the specified host machine.
+GTEST_DECLARE_string_(stream_result_to);
+
+#if GTEST_USE_OWN_FLAGFILE_FLAG_
+GTEST_DECLARE_string_(flagfile);
+#endif  // GTEST_USE_OWN_FLAGFILE_FLAG_
+
+// The upper limit for valid stack trace depths.
+const int kMaxStackTraceDepth = 100;
+
+namespace internal {
+
+class AssertHelper;
+class DefaultGlobalTestPartResultReporter;
+class ExecDeathTest;
+class NoExecDeathTest;
+class FinalSuccessChecker;
+class GTestFlagSaver;
+class StreamingListenerTest;
+class TestResultAccessor;
+class TestEventListenersAccessor;
+class TestEventRepeater;
+class UnitTestRecordPropertyTestHelper;
+class WindowsDeathTest;
+class FuchsiaDeathTest;
+class UnitTestImpl* GetUnitTestImpl();
+void ReportFailureInUnknownLocation(TestPartResult::Type result_type,
+                                    const std::string& message);
+std::set<std::string>* GetIgnoredParameterizedTestSuites();
+
+}  // namespace internal
+
+// The friend relationship of some of these classes is cyclic.
+// If we don't forward declare them the compiler might confuse the classes
+// in friendship clauses with same named classes on the scope.
+class Test;
+class TestSuite;
+
+// Old API is still available but deprecated
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+using TestCase = TestSuite;
+#endif
+class TestInfo;
+class UnitTest;
+
+// A class for indicating whether an assertion was successful.  When
+// the assertion wasn't successful, the AssertionResult object
+// remembers a non-empty message that describes how it failed.
+//
+// To create an instance of this class, use one of the factory functions
+// (AssertionSuccess() and AssertionFailure()).
+//
+// This class is useful for two purposes:
+//   1. Defining predicate functions to be used with Boolean test assertions
+//      EXPECT_TRUE/EXPECT_FALSE and their ASSERT_ counterparts
+//   2. Defining predicate-format functions to be
+//      used with predicate assertions (ASSERT_PRED_FORMAT*, etc).
+//
+// For example, if you define IsEven predicate:
+//
+//   testing::AssertionResult IsEven(int n) {
+//     if ((n % 2) == 0)
+//       return testing::AssertionSuccess();
+//     else
+//       return testing::AssertionFailure() << n << " is odd";
+//   }
+//
+// Then the failed expectation EXPECT_TRUE(IsEven(Fib(5)))
+// will print the message
+//
+//   Value of: IsEven(Fib(5))
+//     Actual: false (5 is odd)
+//   Expected: true
+//
+// instead of a more opaque
+//
+//   Value of: IsEven(Fib(5))
+//     Actual: false
+//   Expected: true
+//
+// in case IsEven is a simple Boolean predicate.
+//
+// If you expect your predicate to be reused and want to support informative
+// messages in EXPECT_FALSE and ASSERT_FALSE (negative assertions show up
+// about half as often as positive ones in our tests), supply messages for
+// both success and failure cases:
+//
+//   testing::AssertionResult IsEven(int n) {
+//     if ((n % 2) == 0)
+//       return testing::AssertionSuccess() << n << " is even";
+//     else
+//       return testing::AssertionFailure() << n << " is odd";
+//   }
+//
+// Then a statement EXPECT_FALSE(IsEven(Fib(6))) will print
+//
+//   Value of: IsEven(Fib(6))
+//     Actual: true (8 is even)
+//   Expected: false
+//
+// NB: Predicates that support negative Boolean assertions have reduced
+// performance in positive ones so be careful not to use them in tests
+// that have lots (tens of thousands) of positive Boolean assertions.
+//
+// To use this class with EXPECT_PRED_FORMAT assertions such as:
+//
+//   // Verifies that Foo() returns an even number.
+//   EXPECT_PRED_FORMAT1(IsEven, Foo());
+//
+// you need to define:
+//
+//   testing::AssertionResult IsEven(const char* expr, int n) {
+//     if ((n % 2) == 0)
+//       return testing::AssertionSuccess();
+//     else
+//       return testing::AssertionFailure()
+//         << "Expected: " << expr << " is even\n  Actual: it's " << n;
+//   }
+//
+// If Foo() returns 5, you will see the following message:
+//
+//   Expected: Foo() is even
+//     Actual: it's 5
+//
+class GTEST_API_ AssertionResult {
+ public:
+  // Copy constructor.
+  // Used in EXPECT_TRUE/FALSE(assertion_result).
+  AssertionResult(const AssertionResult& other);
+
+// C4800 is a level 3 warning in Visual Studio 2015 and earlier.
+// This warning is not emitted in Visual Studio 2017.
+// This warning is off by default starting in Visual Studio 2019 but can be
+// enabled with command-line options.
+#if defined(_MSC_VER) && (_MSC_VER < 1910 || _MSC_VER >= 1920)
+  GTEST_DISABLE_MSC_WARNINGS_PUSH_(4800 /* forcing value to bool */)
+#endif
+
+  // Used in the EXPECT_TRUE/FALSE(bool_expression).
+  //
+  // T must be contextually convertible to bool.
+  //
+  // The second parameter prevents this overload from being considered if
+  // the argument is implicitly convertible to AssertionResult. In that case
+  // we want AssertionResult's copy constructor to be used.
+  template <typename T>
+  explicit AssertionResult(
+      const T& success,
+      typename std::enable_if<
+          !std::is_convertible<T, AssertionResult>::value>::type*
+      /*enabler*/
+      = nullptr)
+      : success_(success) {}
+
+#if defined(_MSC_VER) && (_MSC_VER < 1910 || _MSC_VER >= 1920)
+  GTEST_DISABLE_MSC_WARNINGS_POP_()
+#endif
+
+  // Assignment operator.
+  AssertionResult& operator=(AssertionResult other) {
+    swap(other);
+    return *this;
+  }
+
+  // Returns true if and only if the assertion succeeded.
+  operator bool() const { return success_; }  // NOLINT
+
+  // Returns the assertion's negation. Used with EXPECT/ASSERT_FALSE.
+  AssertionResult operator!() const;
+
+  // Returns the text streamed into this AssertionResult. Test assertions
+  // use it when they fail (i.e., the predicate's outcome doesn't match the
+  // assertion's expectation). When nothing has been streamed into the
+  // object, returns an empty string.
+  const char* message() const {
+    return message_.get() != nullptr ? message_->c_str() : "";
+  }
+  // Deprecated; please use message() instead.
+  const char* failure_message() const { return message(); }
+
+  // Streams a custom failure message into this object.
+  template <typename T> AssertionResult& operator<<(const T& value) {
+    AppendMessage(Message() << value);
+    return *this;
+  }
+
+  // Allows streaming basic output manipulators such as endl or flush into
+  // this object.
+  AssertionResult& operator<<(
+      ::std::ostream& (*basic_manipulator)(::std::ostream& stream)) {
+    AppendMessage(Message() << basic_manipulator);
+    return *this;
+  }
+
+ private:
+  // Appends the contents of message to message_.
+  void AppendMessage(const Message& a_message) {
+    if (message_.get() == nullptr) message_.reset(new ::std::string);
+    message_->append(a_message.GetString().c_str());
+  }
+
+  // Swap the contents of this AssertionResult with other.
+  void swap(AssertionResult& other);
+
+  // Stores result of the assertion predicate.
+  bool success_;
+  // Stores the message describing the condition in case the expectation
+  // construct is not satisfied with the predicate's outcome.
+  // Referenced via a pointer to avoid taking too much stack frame space
+  // with test assertions.
+  std::unique_ptr< ::std::string> message_;
+};
+
+// Makes a successful assertion result.
+GTEST_API_ AssertionResult AssertionSuccess();
+
+// Makes a failed assertion result.
+GTEST_API_ AssertionResult AssertionFailure();
+
+// Makes a failed assertion result with the given failure message.
+// Deprecated; use AssertionFailure() << msg.
+GTEST_API_ AssertionResult AssertionFailure(const Message& msg);
+
+}  // namespace testing
+
+// Includes the auto-generated header that implements a family of generic
+// predicate assertion macros. This include comes late because it relies on
+// APIs declared above.
+// Copyright 2006, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This file is AUTOMATICALLY GENERATED on 01/02/2019 by command
+// 'gen_gtest_pred_impl.py 5'.  DO NOT EDIT BY HAND!
+//
+// Implements a family of generic predicate assertion macros.
+// GOOGLETEST_CM0001 DO NOT DELETE
+
+#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_PRED_IMPL_H_
+#define GOOGLETEST_INCLUDE_GTEST_GTEST_PRED_IMPL_H_
+
+
+namespace testing {
+
+// This header implements a family of generic predicate assertion
+// macros:
+//
+//   ASSERT_PRED_FORMAT1(pred_format, v1)
+//   ASSERT_PRED_FORMAT2(pred_format, v1, v2)
+//   ...
+//
+// where pred_format is a function or functor that takes n (in the
+// case of ASSERT_PRED_FORMATn) values and their source expression
+// text, and returns a testing::AssertionResult.  See the definition
+// of ASSERT_EQ in gtest.h for an example.
+//
+// If you don't care about formatting, you can use the more
+// restrictive version:
+//
+//   ASSERT_PRED1(pred, v1)
+//   ASSERT_PRED2(pred, v1, v2)
+//   ...
+//
+// where pred is an n-ary function or functor that returns bool,
+// and the values v1, v2, ..., must support the << operator for
+// streaming to std::ostream.
+//
+// We also define the EXPECT_* variations.
+//
+// For now we only support predicates whose arity is at most 5.
+// Please email googletestframework@googlegroups.com if you need
+// support for higher arities.
+
+// GTEST_ASSERT_ is the basic statement to which all of the assertions
+// in this file reduce.  Don't use this in your code.
+
+#define GTEST_ASSERT_(expression, on_failure) \
+  GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
+  if (const ::testing::AssertionResult gtest_ar = (expression)) \
+    ; \
+  else \
+    on_failure(gtest_ar.failure_message())
+
+
+// Helper function for implementing {EXPECT|ASSERT}_PRED1.  Don't use
+// this in your code.
+template <typename Pred,
+          typename T1>
+AssertionResult AssertPred1Helper(const char* pred_text,
+                                  const char* e1,
+                                  Pred pred,
+                                  const T1& v1) {
+  if (pred(v1)) return AssertionSuccess();
+
+  return AssertionFailure()
+         << pred_text << "(" << e1 << ") evaluates to false, where"
+         << "\n"
+         << e1 << " evaluates to " << ::testing::PrintToString(v1);
+}
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED_FORMAT1.
+// Don't use this in your code.
+#define GTEST_PRED_FORMAT1_(pred_format, v1, on_failure)\
+  GTEST_ASSERT_(pred_format(#v1, v1), \
+                on_failure)
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED1.  Don't use
+// this in your code.
+#define GTEST_PRED1_(pred, v1, on_failure)\
+  GTEST_ASSERT_(::testing::AssertPred1Helper(#pred, \
+                                             #v1, \
+                                             pred, \
+                                             v1), on_failure)
+
+// Unary predicate assertion macros.
+#define EXPECT_PRED_FORMAT1(pred_format, v1) \
+  GTEST_PRED_FORMAT1_(pred_format, v1, GTEST_NONFATAL_FAILURE_)
+#define EXPECT_PRED1(pred, v1) \
+  GTEST_PRED1_(pred, v1, GTEST_NONFATAL_FAILURE_)
+#define ASSERT_PRED_FORMAT1(pred_format, v1) \
+  GTEST_PRED_FORMAT1_(pred_format, v1, GTEST_FATAL_FAILURE_)
+#define ASSERT_PRED1(pred, v1) \
+  GTEST_PRED1_(pred, v1, GTEST_FATAL_FAILURE_)
+
+
+
+// Helper function for implementing {EXPECT|ASSERT}_PRED2.  Don't use
+// this in your code.
+template <typename Pred,
+          typename T1,
+          typename T2>
+AssertionResult AssertPred2Helper(const char* pred_text,
+                                  const char* e1,
+                                  const char* e2,
+                                  Pred pred,
+                                  const T1& v1,
+                                  const T2& v2) {
+  if (pred(v1, v2)) return AssertionSuccess();
+
+  return AssertionFailure()
+         << pred_text << "(" << e1 << ", " << e2
+         << ") evaluates to false, where"
+         << "\n"
+         << e1 << " evaluates to " << ::testing::PrintToString(v1) << "\n"
+         << e2 << " evaluates to " << ::testing::PrintToString(v2);
+}
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED_FORMAT2.
+// Don't use this in your code.
+#define GTEST_PRED_FORMAT2_(pred_format, v1, v2, on_failure)\
+  GTEST_ASSERT_(pred_format(#v1, #v2, v1, v2), \
+                on_failure)
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED2.  Don't use
+// this in your code.
+#define GTEST_PRED2_(pred, v1, v2, on_failure)\
+  GTEST_ASSERT_(::testing::AssertPred2Helper(#pred, \
+                                             #v1, \
+                                             #v2, \
+                                             pred, \
+                                             v1, \
+                                             v2), on_failure)
+
+// Binary predicate assertion macros.
+#define EXPECT_PRED_FORMAT2(pred_format, v1, v2) \
+  GTEST_PRED_FORMAT2_(pred_format, v1, v2, GTEST_NONFATAL_FAILURE_)
+#define EXPECT_PRED2(pred, v1, v2) \
+  GTEST_PRED2_(pred, v1, v2, GTEST_NONFATAL_FAILURE_)
+#define ASSERT_PRED_FORMAT2(pred_format, v1, v2) \
+  GTEST_PRED_FORMAT2_(pred_format, v1, v2, GTEST_FATAL_FAILURE_)
+#define ASSERT_PRED2(pred, v1, v2) \
+  GTEST_PRED2_(pred, v1, v2, GTEST_FATAL_FAILURE_)
+
+
+
+// Helper function for implementing {EXPECT|ASSERT}_PRED3.  Don't use
+// this in your code.
+template <typename Pred,
+          typename T1,
+          typename T2,
+          typename T3>
+AssertionResult AssertPred3Helper(const char* pred_text,
+                                  const char* e1,
+                                  const char* e2,
+                                  const char* e3,
+                                  Pred pred,
+                                  const T1& v1,
+                                  const T2& v2,
+                                  const T3& v3) {
+  if (pred(v1, v2, v3)) return AssertionSuccess();
+
+  return AssertionFailure()
+         << pred_text << "(" << e1 << ", " << e2 << ", " << e3
+         << ") evaluates to false, where"
+         << "\n"
+         << e1 << " evaluates to " << ::testing::PrintToString(v1) << "\n"
+         << e2 << " evaluates to " << ::testing::PrintToString(v2) << "\n"
+         << e3 << " evaluates to " << ::testing::PrintToString(v3);
+}
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED_FORMAT3.
+// Don't use this in your code.
+#define GTEST_PRED_FORMAT3_(pred_format, v1, v2, v3, on_failure)\
+  GTEST_ASSERT_(pred_format(#v1, #v2, #v3, v1, v2, v3), \
+                on_failure)
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED3.  Don't use
+// this in your code.
+#define GTEST_PRED3_(pred, v1, v2, v3, on_failure)\
+  GTEST_ASSERT_(::testing::AssertPred3Helper(#pred, \
+                                             #v1, \
+                                             #v2, \
+                                             #v3, \
+                                             pred, \
+                                             v1, \
+                                             v2, \
+                                             v3), on_failure)
+
+// Ternary predicate assertion macros.
+#define EXPECT_PRED_FORMAT3(pred_format, v1, v2, v3) \
+  GTEST_PRED_FORMAT3_(pred_format, v1, v2, v3, GTEST_NONFATAL_FAILURE_)
+#define EXPECT_PRED3(pred, v1, v2, v3) \
+  GTEST_PRED3_(pred, v1, v2, v3, GTEST_NONFATAL_FAILURE_)
+#define ASSERT_PRED_FORMAT3(pred_format, v1, v2, v3) \
+  GTEST_PRED_FORMAT3_(pred_format, v1, v2, v3, GTEST_FATAL_FAILURE_)
+#define ASSERT_PRED3(pred, v1, v2, v3) \
+  GTEST_PRED3_(pred, v1, v2, v3, GTEST_FATAL_FAILURE_)
+
+
+
+// Helper function for implementing {EXPECT|ASSERT}_PRED4.  Don't use
+// this in your code.
+template <typename Pred,
+          typename T1,
+          typename T2,
+          typename T3,
+          typename T4>
+AssertionResult AssertPred4Helper(const char* pred_text,
+                                  const char* e1,
+                                  const char* e2,
+                                  const char* e3,
+                                  const char* e4,
+                                  Pred pred,
+                                  const T1& v1,
+                                  const T2& v2,
+                                  const T3& v3,
+                                  const T4& v4) {
+  if (pred(v1, v2, v3, v4)) return AssertionSuccess();
+
+  return AssertionFailure()
+         << pred_text << "(" << e1 << ", " << e2 << ", " << e3 << ", " << e4
+         << ") evaluates to false, where"
+         << "\n"
+         << e1 << " evaluates to " << ::testing::PrintToString(v1) << "\n"
+         << e2 << " evaluates to " << ::testing::PrintToString(v2) << "\n"
+         << e3 << " evaluates to " << ::testing::PrintToString(v3) << "\n"
+         << e4 << " evaluates to " << ::testing::PrintToString(v4);
+}
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED_FORMAT4.
+// Don't use this in your code.
+#define GTEST_PRED_FORMAT4_(pred_format, v1, v2, v3, v4, on_failure)\
+  GTEST_ASSERT_(pred_format(#v1, #v2, #v3, #v4, v1, v2, v3, v4), \
+                on_failure)
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED4.  Don't use
+// this in your code.
+#define GTEST_PRED4_(pred, v1, v2, v3, v4, on_failure)\
+  GTEST_ASSERT_(::testing::AssertPred4Helper(#pred, \
+                                             #v1, \
+                                             #v2, \
+                                             #v3, \
+                                             #v4, \
+                                             pred, \
+                                             v1, \
+                                             v2, \
+                                             v3, \
+                                             v4), on_failure)
+
+// 4-ary predicate assertion macros.
+#define EXPECT_PRED_FORMAT4(pred_format, v1, v2, v3, v4) \
+  GTEST_PRED_FORMAT4_(pred_format, v1, v2, v3, v4, GTEST_NONFATAL_FAILURE_)
+#define EXPECT_PRED4(pred, v1, v2, v3, v4) \
+  GTEST_PRED4_(pred, v1, v2, v3, v4, GTEST_NONFATAL_FAILURE_)
+#define ASSERT_PRED_FORMAT4(pred_format, v1, v2, v3, v4) \
+  GTEST_PRED_FORMAT4_(pred_format, v1, v2, v3, v4, GTEST_FATAL_FAILURE_)
+#define ASSERT_PRED4(pred, v1, v2, v3, v4) \
+  GTEST_PRED4_(pred, v1, v2, v3, v4, GTEST_FATAL_FAILURE_)
+
+
+
+// Helper function for implementing {EXPECT|ASSERT}_PRED5.  Don't use
+// this in your code.
+template <typename Pred,
+          typename T1,
+          typename T2,
+          typename T3,
+          typename T4,
+          typename T5>
+AssertionResult AssertPred5Helper(const char* pred_text,
+                                  const char* e1,
+                                  const char* e2,
+                                  const char* e3,
+                                  const char* e4,
+                                  const char* e5,
+                                  Pred pred,
+                                  const T1& v1,
+                                  const T2& v2,
+                                  const T3& v3,
+                                  const T4& v4,
+                                  const T5& v5) {
+  if (pred(v1, v2, v3, v4, v5)) return AssertionSuccess();
+
+  return AssertionFailure()
+         << pred_text << "(" << e1 << ", " << e2 << ", " << e3 << ", " << e4
+         << ", " << e5 << ") evaluates to false, where"
+         << "\n"
+         << e1 << " evaluates to " << ::testing::PrintToString(v1) << "\n"
+         << e2 << " evaluates to " << ::testing::PrintToString(v2) << "\n"
+         << e3 << " evaluates to " << ::testing::PrintToString(v3) << "\n"
+         << e4 << " evaluates to " << ::testing::PrintToString(v4) << "\n"
+         << e5 << " evaluates to " << ::testing::PrintToString(v5);
+}
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED_FORMAT5.
+// Don't use this in your code.
+#define GTEST_PRED_FORMAT5_(pred_format, v1, v2, v3, v4, v5, on_failure)\
+  GTEST_ASSERT_(pred_format(#v1, #v2, #v3, #v4, #v5, v1, v2, v3, v4, v5), \
+                on_failure)
+
+// Internal macro for implementing {EXPECT|ASSERT}_PRED5.  Don't use
+// this in your code.
+#define GTEST_PRED5_(pred, v1, v2, v3, v4, v5, on_failure)\
+  GTEST_ASSERT_(::testing::AssertPred5Helper(#pred, \
+                                             #v1, \
+                                             #v2, \
+                                             #v3, \
+                                             #v4, \
+                                             #v5, \
+                                             pred, \
+                                             v1, \
+                                             v2, \
+                                             v3, \
+                                             v4, \
+                                             v5), on_failure)
+
+// 5-ary predicate assertion macros.
+#define EXPECT_PRED_FORMAT5(pred_format, v1, v2, v3, v4, v5) \
+  GTEST_PRED_FORMAT5_(pred_format, v1, v2, v3, v4, v5, GTEST_NONFATAL_FAILURE_)
+#define EXPECT_PRED5(pred, v1, v2, v3, v4, v5) \
+  GTEST_PRED5_(pred, v1, v2, v3, v4, v5, GTEST_NONFATAL_FAILURE_)
+#define ASSERT_PRED_FORMAT5(pred_format, v1, v2, v3, v4, v5) \
+  GTEST_PRED_FORMAT5_(pred_format, v1, v2, v3, v4, v5, GTEST_FATAL_FAILURE_)
+#define ASSERT_PRED5(pred, v1, v2, v3, v4, v5) \
+  GTEST_PRED5_(pred, v1, v2, v3, v4, v5, GTEST_FATAL_FAILURE_)
+
+
+
+}  // namespace testing
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_PRED_IMPL_H_
+
+namespace testing {
+
+// The abstract class that all tests inherit from.
+//
+// In Google Test, a unit test program contains one or many TestSuites, and
+// each TestSuite contains one or many Tests.
+//
+// When you define a test using the TEST macro, you don't need to
+// explicitly derive from Test - the TEST macro automatically does
+// this for you.
+//
+// The only time you derive from Test is when defining a test fixture
+// to be used in a TEST_F.  For example:
+//
+//   class FooTest : public testing::Test {
+//    protected:
+//     void SetUp() override { ... }
+//     void TearDown() override { ... }
+//     ...
+//   };
+//
+//   TEST_F(FooTest, Bar) { ... }
+//   TEST_F(FooTest, Baz) { ... }
+//
+// Test is not copyable.
+class GTEST_API_ Test {
+ public:
+  friend class TestInfo;
+
+  // The d'tor is virtual as we intend to inherit from Test.
+  virtual ~Test();
+
+  // Sets up the stuff shared by all tests in this test suite.
+  //
+  // Google Test will call Foo::SetUpTestSuite() before running the first
+  // test in test suite Foo.  Hence a sub-class can define its own
+  // SetUpTestSuite() method to shadow the one defined in the super
+  // class.
+  static void SetUpTestSuite() {}
+
+  // Tears down the stuff shared by all tests in this test suite.
+  //
+  // Google Test will call Foo::TearDownTestSuite() after running the last
+  // test in test suite Foo.  Hence a sub-class can define its own
+  // TearDownTestSuite() method to shadow the one defined in the super
+  // class.
+  static void TearDownTestSuite() {}
+
+  // Legacy API is deprecated but still available. Use SetUpTestSuite and
+  // TearDownTestSuite instead.
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  static void TearDownTestCase() {}
+  static void SetUpTestCase() {}
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  // Returns true if and only if the current test has a fatal failure.
+  static bool HasFatalFailure();
+
+  // Returns true if and only if the current test has a non-fatal failure.
+  static bool HasNonfatalFailure();
+
+  // Returns true if and only if the current test was skipped.
+  static bool IsSkipped();
+
+  // Returns true if and only if the current test has a (either fatal or
+  // non-fatal) failure.
+  static bool HasFailure() { return HasFatalFailure() || HasNonfatalFailure(); }
+
+  // Logs a property for the current test, test suite, or for the entire
+  // invocation of the test program when used outside of the context of a
+  // test suite.  Only the last value for a given key is remembered.  These
+  // are public static so they can be called from utility functions that are
+  // not members of the test fixture.  Calls to RecordProperty made during
+  // lifespan of the test (from the moment its constructor starts to the
+  // moment its destructor finishes) will be output in XML as attributes of
+  // the <testcase> element.  Properties recorded from fixture's
+  // SetUpTestSuite or TearDownTestSuite are logged as attributes of the
+  // corresponding <testsuite> element.  Calls to RecordProperty made in the
+  // global context (before or after invocation of RUN_ALL_TESTS and from
+  // SetUp/TearDown method of Environment objects registered with Google
+  // Test) will be output as attributes of the <testsuites> element.
+  static void RecordProperty(const std::string& key, const std::string& value);
+  static void RecordProperty(const std::string& key, int value);
+
+ protected:
+  // Creates a Test object.
+  Test();
+
+  // Sets up the test fixture.
+  virtual void SetUp();
+
+  // Tears down the test fixture.
+  virtual void TearDown();
+
+ private:
+  // Returns true if and only if the current test has the same fixture class
+  // as the first test in the current test suite.
+  static bool HasSameFixtureClass();
+
+  // Runs the test after the test fixture has been set up.
+  //
+  // A sub-class must implement this to define the test logic.
+  //
+  // DO NOT OVERRIDE THIS FUNCTION DIRECTLY IN A USER PROGRAM.
+  // Instead, use the TEST or TEST_F macro.
+  virtual void TestBody() = 0;
+
+  // Sets up, executes, and tears down the test.
+  void Run();
+
+  // Deletes self.  We deliberately pick an unusual name for this
+  // internal method to avoid clashing with names used in user TESTs.
+  void DeleteSelf_() { delete this; }
+
+  const std::unique_ptr<GTEST_FLAG_SAVER_> gtest_flag_saver_;
+
+  // Often a user misspells SetUp() as Setup() and spends a long time
+  // wondering why it is never called by Google Test.  The declaration of
+  // the following method is solely for catching such an error at
+  // compile time:
+  //
+  //   - The return type is deliberately chosen to be not void, so it
+  //   will be a conflict if void Setup() is declared in the user's
+  //   test fixture.
+  //
+  //   - This method is private, so it will be another compiler error
+  //   if the method is called from the user's test fixture.
+  //
+  // DO NOT OVERRIDE THIS FUNCTION.
+  //
+  // If you see an error about overriding the following function or
+  // about it being private, you have mis-spelled SetUp() as Setup().
+  struct Setup_should_be_spelled_SetUp {};
+  virtual Setup_should_be_spelled_SetUp* Setup() { return nullptr; }
+
+  // We disallow copying Tests.
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(Test);
+};
+
+typedef internal::TimeInMillis TimeInMillis;
+
+// A copyable object representing a user specified test property which can be
+// output as a key/value string pair.
+//
+// Don't inherit from TestProperty as its destructor is not virtual.
+class TestProperty {
+ public:
+  // C'tor.  TestProperty does NOT have a default constructor.
+  // Always use this constructor (with parameters) to create a
+  // TestProperty object.
+  TestProperty(const std::string& a_key, const std::string& a_value) :
+    key_(a_key), value_(a_value) {
+  }
+
+  // Gets the user supplied key.
+  const char* key() const {
+    return key_.c_str();
+  }
+
+  // Gets the user supplied value.
+  const char* value() const {
+    return value_.c_str();
+  }
+
+  // Sets a new value, overriding the one supplied in the constructor.
+  void SetValue(const std::string& new_value) {
+    value_ = new_value;
+  }
+
+ private:
+  // The key supplied by the user.
+  std::string key_;
+  // The value supplied by the user.
+  std::string value_;
+};
+
+// The result of a single Test.  This includes a list of
+// TestPartResults, a list of TestProperties, a count of how many
+// death tests there are in the Test, and how much time it took to run
+// the Test.
+//
+// TestResult is not copyable.
+class GTEST_API_ TestResult {
+ public:
+  // Creates an empty TestResult.
+  TestResult();
+
+  // D'tor.  Do not inherit from TestResult.
+  ~TestResult();
+
+  // Gets the number of all test parts.  This is the sum of the number
+  // of successful test parts and the number of failed test parts.
+  int total_part_count() const;
+
+  // Returns the number of the test properties.
+  int test_property_count() const;
+
+  // Returns true if and only if the test passed (i.e. no test part failed).
+  bool Passed() const { return !Skipped() && !Failed(); }
+
+  // Returns true if and only if the test was skipped.
+  bool Skipped() const;
+
+  // Returns true if and only if the test failed.
+  bool Failed() const;
+
+  // Returns true if and only if the test fatally failed.
+  bool HasFatalFailure() const;
+
+  // Returns true if and only if the test has a non-fatal failure.
+  bool HasNonfatalFailure() const;
+
+  // Returns the elapsed time, in milliseconds.
+  TimeInMillis elapsed_time() const { return elapsed_time_; }
+
+  // Gets the time of the test case start, in ms from the start of the
+  // UNIX epoch.
+  TimeInMillis start_timestamp() const { return start_timestamp_; }
+
+  // Returns the i-th test part result among all the results. i can range from 0
+  // to total_part_count() - 1. If i is not in that range, aborts the program.
+  const TestPartResult& GetTestPartResult(int i) const;
+
+  // Returns the i-th test property. i can range from 0 to
+  // test_property_count() - 1. If i is not in that range, aborts the
+  // program.
+  const TestProperty& GetTestProperty(int i) const;
+
+ private:
+  friend class TestInfo;
+  friend class TestSuite;
+  friend class UnitTest;
+  friend class internal::DefaultGlobalTestPartResultReporter;
+  friend class internal::ExecDeathTest;
+  friend class internal::TestResultAccessor;
+  friend class internal::UnitTestImpl;
+  friend class internal::WindowsDeathTest;
+  friend class internal::FuchsiaDeathTest;
+
+  // Gets the vector of TestPartResults.
+  const std::vector<TestPartResult>& test_part_results() const {
+    return test_part_results_;
+  }
+
+  // Gets the vector of TestProperties.
+  const std::vector<TestProperty>& test_properties() const {
+    return test_properties_;
+  }
+
+  // Sets the start time.
+  void set_start_timestamp(TimeInMillis start) { start_timestamp_ = start; }
+
+  // Sets the elapsed time.
+  void set_elapsed_time(TimeInMillis elapsed) { elapsed_time_ = elapsed; }
+
+  // Adds a test property to the list. The property is validated and may add
+  // a non-fatal failure if invalid (e.g., if it conflicts with reserved
+  // key names). If a property is already recorded for the same key, the
+  // value will be updated, rather than storing multiple values for the same
+  // key.  xml_element specifies the element for which the property is being
+  // recorded and is used for validation.
+  void RecordProperty(const std::string& xml_element,
+                      const TestProperty& test_property);
+
+  // Adds a failure if the key is a reserved attribute of Google Test
+  // testsuite tags.  Returns true if the property is valid.
+  // FIXME: Validate attribute names are legal and human readable.
+  static bool ValidateTestProperty(const std::string& xml_element,
+                                   const TestProperty& test_property);
+
+  // Adds a test part result to the list.
+  void AddTestPartResult(const TestPartResult& test_part_result);
+
+  // Returns the death test count.
+  int death_test_count() const { return death_test_count_; }
+
+  // Increments the death test count, returning the new count.
+  int increment_death_test_count() { return ++death_test_count_; }
+
+  // Clears the test part results.
+  void ClearTestPartResults();
+
+  // Clears the object.
+  void Clear();
+
+  // Protects mutable state of the property vector and of owned
+  // properties, whose values may be updated.
+  internal::Mutex test_properties_mutex_;
+
+  // The vector of TestPartResults
+  std::vector<TestPartResult> test_part_results_;
+  // The vector of TestProperties
+  std::vector<TestProperty> test_properties_;
+  // Running count of death tests.
+  int death_test_count_;
+  // The start time, in milliseconds since UNIX Epoch.
+  TimeInMillis start_timestamp_;
+  // The elapsed time, in milliseconds.
+  TimeInMillis elapsed_time_;
+
+  // We disallow copying TestResult.
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestResult);
+};  // class TestResult
+
+// A TestInfo object stores the following information about a test:
+//
+//   Test suite name
+//   Test name
+//   Whether the test should be run
+//   A function pointer that creates the test object when invoked
+//   Test result
+//
+// The constructor of TestInfo registers itself with the UnitTest
+// singleton such that the RUN_ALL_TESTS() macro knows which tests to
+// run.
+class GTEST_API_ TestInfo {
+ public:
+  // Destructs a TestInfo object.  This function is not virtual, so
+  // don't inherit from TestInfo.
+  ~TestInfo();
+
+  // Returns the test suite name.
+  const char* test_suite_name() const { return test_suite_name_.c_str(); }
+
+// Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  const char* test_case_name() const { return test_suite_name(); }
+#endif  // GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  // Returns the test name.
+  const char* name() const { return name_.c_str(); }
+
+  // Returns the name of the parameter type, or NULL if this is not a typed
+  // or a type-parameterized test.
+  const char* type_param() const {
+    if (type_param_.get() != nullptr) return type_param_->c_str();
+    return nullptr;
+  }
+
+  // Returns the text representation of the value parameter, or NULL if this
+  // is not a value-parameterized test.
+  const char* value_param() const {
+    if (value_param_.get() != nullptr) return value_param_->c_str();
+    return nullptr;
+  }
+
+  // Returns the file name where this test is defined.
+  const char* file() const { return location_.file.c_str(); }
+
+  // Returns the line where this test is defined.
+  int line() const { return location_.line; }
+
+  // Return true if this test should not be run because it's in another shard.
+  bool is_in_another_shard() const { return is_in_another_shard_; }
+
+  // Returns true if this test should run, that is if the test is not
+  // disabled (or it is disabled but the also_run_disabled_tests flag has
+  // been specified) and its full name matches the user-specified filter.
+  //
+  // Google Test allows the user to filter the tests by their full names.
+  // The full name of a test Bar in test suite Foo is defined as
+  // "Foo.Bar".  Only the tests that match the filter will run.
+  //
+  // A filter is a colon-separated list of glob (not regex) patterns,
+  // optionally followed by a '-' and a colon-separated list of
+  // negative patterns (tests to exclude).  A test is run if it
+  // matches one of the positive patterns and does not match any of
+  // the negative patterns.
+  //
+  // For example, *A*:Foo.* is a filter that matches any string that
+  // contains the character 'A' or starts with "Foo.".
+  bool should_run() const { return should_run_; }
+
+  // Returns true if and only if this test will appear in the XML report.
+  bool is_reportable() const {
+    // The XML report includes tests matching the filter, excluding those
+    // run in other shards.
+    return matches_filter_ && !is_in_another_shard_;
+  }
+
+  // Returns the result of the test.
+  const TestResult* result() const { return &result_; }
+
+ private:
+#if GTEST_HAS_DEATH_TEST
+  friend class internal::DefaultDeathTestFactory;
+#endif  // GTEST_HAS_DEATH_TEST
+  friend class Test;
+  friend class TestSuite;
+  friend class internal::UnitTestImpl;
+  friend class internal::StreamingListenerTest;
+  friend TestInfo* internal::MakeAndRegisterTestInfo(
+      const char* test_suite_name, const char* name, const char* type_param,
+      const char* value_param, internal::CodeLocation code_location,
+      internal::TypeId fixture_class_id, internal::SetUpTestSuiteFunc set_up_tc,
+      internal::TearDownTestSuiteFunc tear_down_tc,
+      internal::TestFactoryBase* factory);
+
+  // Constructs a TestInfo object. The newly constructed instance assumes
+  // ownership of the factory object.
+  TestInfo(const std::string& test_suite_name, const std::string& name,
+           const char* a_type_param,   // NULL if not a type-parameterized test
+           const char* a_value_param,  // NULL if not a value-parameterized test
+           internal::CodeLocation a_code_location,
+           internal::TypeId fixture_class_id,
+           internal::TestFactoryBase* factory);
+
+  // Increments the number of death tests encountered in this test so
+  // far.
+  int increment_death_test_count() {
+    return result_.increment_death_test_count();
+  }
+
+  // Creates the test object, runs it, records its result, and then
+  // deletes it.
+  void Run();
+
+  // Skip and records the test result for this object.
+  void Skip();
+
+  static void ClearTestResult(TestInfo* test_info) {
+    test_info->result_.Clear();
+  }
+
+  // These fields are immutable properties of the test.
+  const std::string test_suite_name_;    // test suite name
+  const std::string name_;               // Test name
+  // Name of the parameter type, or NULL if this is not a typed or a
+  // type-parameterized test.
+  const std::unique_ptr<const ::std::string> type_param_;
+  // Text representation of the value parameter, or NULL if this is not a
+  // value-parameterized test.
+  const std::unique_ptr<const ::std::string> value_param_;
+  internal::CodeLocation location_;
+  const internal::TypeId fixture_class_id_;  // ID of the test fixture class
+  bool should_run_;           // True if and only if this test should run
+  bool is_disabled_;          // True if and only if this test is disabled
+  bool matches_filter_;       // True if this test matches the
+                              // user-specified filter.
+  bool is_in_another_shard_;  // Will be run in another shard.
+  internal::TestFactoryBase* const factory_;  // The factory that creates
+                                              // the test object
+
+  // This field is mutable and needs to be reset before running the
+  // test for the second time.
+  TestResult result_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestInfo);
+};
+
+// A test suite, which consists of a vector of TestInfos.
+//
+// TestSuite is not copyable.
+class GTEST_API_ TestSuite {
+ public:
+  // Creates a TestSuite with the given name.
+  //
+  // TestSuite does NOT have a default constructor.  Always use this
+  // constructor to create a TestSuite object.
+  //
+  // Arguments:
+  //
+  //   name:         name of the test suite
+  //   a_type_param: the name of the test's type parameter, or NULL if
+  //                 this is not a type-parameterized test.
+  //   set_up_tc:    pointer to the function that sets up the test suite
+  //   tear_down_tc: pointer to the function that tears down the test suite
+  TestSuite(const char* name, const char* a_type_param,
+            internal::SetUpTestSuiteFunc set_up_tc,
+            internal::TearDownTestSuiteFunc tear_down_tc);
+
+  // Destructor of TestSuite.
+  virtual ~TestSuite();
+
+  // Gets the name of the TestSuite.
+  const char* name() const { return name_.c_str(); }
+
+  // Returns the name of the parameter type, or NULL if this is not a
+  // type-parameterized test suite.
+  const char* type_param() const {
+    if (type_param_.get() != nullptr) return type_param_->c_str();
+    return nullptr;
+  }
+
+  // Returns true if any test in this test suite should run.
+  bool should_run() const { return should_run_; }
+
+  // Gets the number of successful tests in this test suite.
+  int successful_test_count() const;
+
+  // Gets the number of skipped tests in this test suite.
+  int skipped_test_count() const;
+
+  // Gets the number of failed tests in this test suite.
+  int failed_test_count() const;
+
+  // Gets the number of disabled tests that will be reported in the XML report.
+  int reportable_disabled_test_count() const;
+
+  // Gets the number of disabled tests in this test suite.
+  int disabled_test_count() const;
+
+  // Gets the number of tests to be printed in the XML report.
+  int reportable_test_count() const;
+
+  // Get the number of tests in this test suite that should run.
+  int test_to_run_count() const;
+
+  // Gets the number of all tests in this test suite.
+  int total_test_count() const;
+
+  // Returns true if and only if the test suite passed.
+  bool Passed() const { return !Failed(); }
+
+  // Returns true if and only if the test suite failed.
+  bool Failed() const {
+    return failed_test_count() > 0 || ad_hoc_test_result().Failed();
+  }
+
+  // Returns the elapsed time, in milliseconds.
+  TimeInMillis elapsed_time() const { return elapsed_time_; }
+
+  // Gets the time of the test suite start, in ms from the start of the
+  // UNIX epoch.
+  TimeInMillis start_timestamp() const { return start_timestamp_; }
+
+  // Returns the i-th test among all the tests. i can range from 0 to
+  // total_test_count() - 1. If i is not in that range, returns NULL.
+  const TestInfo* GetTestInfo(int i) const;
+
+  // Returns the TestResult that holds test properties recorded during
+  // execution of SetUpTestSuite and TearDownTestSuite.
+  const TestResult& ad_hoc_test_result() const { return ad_hoc_test_result_; }
+
+ private:
+  friend class Test;
+  friend class internal::UnitTestImpl;
+
+  // Gets the (mutable) vector of TestInfos in this TestSuite.
+  std::vector<TestInfo*>& test_info_list() { return test_info_list_; }
+
+  // Gets the (immutable) vector of TestInfos in this TestSuite.
+  const std::vector<TestInfo*>& test_info_list() const {
+    return test_info_list_;
+  }
+
+  // Returns the i-th test among all the tests. i can range from 0 to
+  // total_test_count() - 1. If i is not in that range, returns NULL.
+  TestInfo* GetMutableTestInfo(int i);
+
+  // Sets the should_run member.
+  void set_should_run(bool should) { should_run_ = should; }
+
+  // Adds a TestInfo to this test suite.  Will delete the TestInfo upon
+  // destruction of the TestSuite object.
+  void AddTestInfo(TestInfo * test_info);
+
+  // Clears the results of all tests in this test suite.
+  void ClearResult();
+
+  // Clears the results of all tests in the given test suite.
+  static void ClearTestSuiteResult(TestSuite* test_suite) {
+    test_suite->ClearResult();
+  }
+
+  // Runs every test in this TestSuite.
+  void Run();
+
+  // Skips the execution of tests under this TestSuite
+  void Skip();
+
+  // Runs SetUpTestSuite() for this TestSuite.  This wrapper is needed
+  // for catching exceptions thrown from SetUpTestSuite().
+  void RunSetUpTestSuite() {
+    if (set_up_tc_ != nullptr) {
+      (*set_up_tc_)();
+    }
+  }
+
+  // Runs TearDownTestSuite() for this TestSuite.  This wrapper is
+  // needed for catching exceptions thrown from TearDownTestSuite().
+  void RunTearDownTestSuite() {
+    if (tear_down_tc_ != nullptr) {
+      (*tear_down_tc_)();
+    }
+  }
+
+  // Returns true if and only if test passed.
+  static bool TestPassed(const TestInfo* test_info) {
+    return test_info->should_run() && test_info->result()->Passed();
+  }
+
+  // Returns true if and only if test skipped.
+  static bool TestSkipped(const TestInfo* test_info) {
+    return test_info->should_run() && test_info->result()->Skipped();
+  }
+
+  // Returns true if and only if test failed.
+  static bool TestFailed(const TestInfo* test_info) {
+    return test_info->should_run() && test_info->result()->Failed();
+  }
+
+  // Returns true if and only if the test is disabled and will be reported in
+  // the XML report.
+  static bool TestReportableDisabled(const TestInfo* test_info) {
+    return test_info->is_reportable() && test_info->is_disabled_;
+  }
+
+  // Returns true if and only if test is disabled.
+  static bool TestDisabled(const TestInfo* test_info) {
+    return test_info->is_disabled_;
+  }
+
+  // Returns true if and only if this test will appear in the XML report.
+  static bool TestReportable(const TestInfo* test_info) {
+    return test_info->is_reportable();
+  }
+
+  // Returns true if the given test should run.
+  static bool ShouldRunTest(const TestInfo* test_info) {
+    return test_info->should_run();
+  }
+
+  // Shuffles the tests in this test suite.
+  void ShuffleTests(internal::Random* random);
+
+  // Restores the test order to before the first shuffle.
+  void UnshuffleTests();
+
+  // Name of the test suite.
+  std::string name_;
+  // Name of the parameter type, or NULL if this is not a typed or a
+  // type-parameterized test.
+  const std::unique_ptr<const ::std::string> type_param_;
+  // The vector of TestInfos in their original order.  It owns the
+  // elements in the vector.
+  std::vector<TestInfo*> test_info_list_;
+  // Provides a level of indirection for the test list to allow easy
+  // shuffling and restoring the test order.  The i-th element in this
+  // vector is the index of the i-th test in the shuffled test list.
+  std::vector<int> test_indices_;
+  // Pointer to the function that sets up the test suite.
+  internal::SetUpTestSuiteFunc set_up_tc_;
+  // Pointer to the function that tears down the test suite.
+  internal::TearDownTestSuiteFunc tear_down_tc_;
+  // True if and only if any test in this test suite should run.
+  bool should_run_;
+  // The start time, in milliseconds since UNIX Epoch.
+  TimeInMillis start_timestamp_;
+  // Elapsed time, in milliseconds.
+  TimeInMillis elapsed_time_;
+  // Holds test properties recorded during execution of SetUpTestSuite and
+  // TearDownTestSuite.
+  TestResult ad_hoc_test_result_;
+
+  // We disallow copying TestSuites.
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestSuite);
+};
+
+// An Environment object is capable of setting up and tearing down an
+// environment.  You should subclass this to define your own
+// environment(s).
+//
+// An Environment object does the set-up and tear-down in virtual
+// methods SetUp() and TearDown() instead of the constructor and the
+// destructor, as:
+//
+//   1. You cannot safely throw from a destructor.  This is a problem
+//      as in some cases Google Test is used where exceptions are enabled, and
+//      we may want to implement ASSERT_* using exceptions where they are
+//      available.
+//   2. You cannot use ASSERT_* directly in a constructor or
+//      destructor.
+class Environment {
+ public:
+  // The d'tor is virtual as we need to subclass Environment.
+  virtual ~Environment() {}
+
+  // Override this to define how to set up the environment.
+  virtual void SetUp() {}
+
+  // Override this to define how to tear down the environment.
+  virtual void TearDown() {}
+ private:
+  // If you see an error about overriding the following function or
+  // about it being private, you have mis-spelled SetUp() as Setup().
+  struct Setup_should_be_spelled_SetUp {};
+  virtual Setup_should_be_spelled_SetUp* Setup() { return nullptr; }
+};
+
+#if GTEST_HAS_EXCEPTIONS
+
+// Exception which can be thrown from TestEventListener::OnTestPartResult.
+class GTEST_API_ AssertionException
+    : public internal::GoogleTestFailureException {
+ public:
+  explicit AssertionException(const TestPartResult& result)
+      : GoogleTestFailureException(result) {}
+};
+
+#endif  // GTEST_HAS_EXCEPTIONS
+
+// The interface for tracing execution of tests. The methods are organized in
+// the order the corresponding events are fired.
+class TestEventListener {
+ public:
+  virtual ~TestEventListener() {}
+
+  // Fired before any test activity starts.
+  virtual void OnTestProgramStart(const UnitTest& unit_test) = 0;
+
+  // Fired before each iteration of tests starts.  There may be more than
+  // one iteration if GTEST_FLAG(repeat) is set. iteration is the iteration
+  // index, starting from 0.
+  virtual void OnTestIterationStart(const UnitTest& unit_test,
+                                    int iteration) = 0;
+
+  // Fired before environment set-up for each iteration of tests starts.
+  virtual void OnEnvironmentsSetUpStart(const UnitTest& unit_test) = 0;
+
+  // Fired after environment set-up for each iteration of tests ends.
+  virtual void OnEnvironmentsSetUpEnd(const UnitTest& unit_test) = 0;
+
+  // Fired before the test suite starts.
+  virtual void OnTestSuiteStart(const TestSuite& /*test_suite*/) {}
+
+  //  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  virtual void OnTestCaseStart(const TestCase& /*test_case*/) {}
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  // Fired before the test starts.
+  virtual void OnTestStart(const TestInfo& test_info) = 0;
+
+  // Fired after a failed assertion or a SUCCEED() invocation.
+  // If you want to throw an exception from this function to skip to the next
+  // TEST, it must be AssertionException defined above, or inherited from it.
+  virtual void OnTestPartResult(const TestPartResult& test_part_result) = 0;
+
+  // Fired after the test ends.
+  virtual void OnTestEnd(const TestInfo& test_info) = 0;
+
+  // Fired after the test suite ends.
+  virtual void OnTestSuiteEnd(const TestSuite& /*test_suite*/) {}
+
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  virtual void OnTestCaseEnd(const TestCase& /*test_case*/) {}
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  // Fired before environment tear-down for each iteration of tests starts.
+  virtual void OnEnvironmentsTearDownStart(const UnitTest& unit_test) = 0;
+
+  // Fired after environment tear-down for each iteration of tests ends.
+  virtual void OnEnvironmentsTearDownEnd(const UnitTest& unit_test) = 0;
+
+  // Fired after each iteration of tests finishes.
+  virtual void OnTestIterationEnd(const UnitTest& unit_test,
+                                  int iteration) = 0;
+
+  // Fired after all test activities have ended.
+  virtual void OnTestProgramEnd(const UnitTest& unit_test) = 0;
+};
+
+// The convenience class for users who need to override just one or two
+// methods and are not concerned that a possible change to a signature of
+// the methods they override will not be caught during the build.  For
+// comments about each method please see the definition of TestEventListener
+// above.
+class EmptyTestEventListener : public TestEventListener {
+ public:
+  void OnTestProgramStart(const UnitTest& /*unit_test*/) override {}
+  void OnTestIterationStart(const UnitTest& /*unit_test*/,
+                            int /*iteration*/) override {}
+  void OnEnvironmentsSetUpStart(const UnitTest& /*unit_test*/) override {}
+  void OnEnvironmentsSetUpEnd(const UnitTest& /*unit_test*/) override {}
+  void OnTestSuiteStart(const TestSuite& /*test_suite*/) override {}
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestCaseStart(const TestCase& /*test_case*/) override {}
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  void OnTestStart(const TestInfo& /*test_info*/) override {}
+  void OnTestPartResult(const TestPartResult& /*test_part_result*/) override {}
+  void OnTestEnd(const TestInfo& /*test_info*/) override {}
+  void OnTestSuiteEnd(const TestSuite& /*test_suite*/) override {}
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  void OnTestCaseEnd(const TestCase& /*test_case*/) override {}
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  void OnEnvironmentsTearDownStart(const UnitTest& /*unit_test*/) override {}
+  void OnEnvironmentsTearDownEnd(const UnitTest& /*unit_test*/) override {}
+  void OnTestIterationEnd(const UnitTest& /*unit_test*/,
+                          int /*iteration*/) override {}
+  void OnTestProgramEnd(const UnitTest& /*unit_test*/) override {}
+};
+
+// TestEventListeners lets users add listeners to track events in Google Test.
+class GTEST_API_ TestEventListeners {
+ public:
+  TestEventListeners();
+  ~TestEventListeners();
+
+  // Appends an event listener to the end of the list. Google Test assumes
+  // the ownership of the listener (i.e. it will delete the listener when
+  // the test program finishes).
+  void Append(TestEventListener* listener);
+
+  // Removes the given event listener from the list and returns it.  It then
+  // becomes the caller's responsibility to delete the listener. Returns
+  // NULL if the listener is not found in the list.
+  TestEventListener* Release(TestEventListener* listener);
+
+  // Returns the standard listener responsible for the default console
+  // output.  Can be removed from the listeners list to shut down default
+  // console output.  Note that removing this object from the listener list
+  // with Release transfers its ownership to the caller and makes this
+  // function return NULL the next time.
+  TestEventListener* default_result_printer() const {
+    return default_result_printer_;
+  }
+
+  // Returns the standard listener responsible for the default XML output
+  // controlled by the --gtest_output=xml flag.  Can be removed from the
+  // listeners list by users who want to shut down the default XML output
+  // controlled by this flag and substitute it with custom one.  Note that
+  // removing this object from the listener list with Release transfers its
+  // ownership to the caller and makes this function return NULL the next
+  // time.
+  TestEventListener* default_xml_generator() const {
+    return default_xml_generator_;
+  }
+
+ private:
+  friend class TestSuite;
+  friend class TestInfo;
+  friend class internal::DefaultGlobalTestPartResultReporter;
+  friend class internal::NoExecDeathTest;
+  friend class internal::TestEventListenersAccessor;
+  friend class internal::UnitTestImpl;
+
+  // Returns repeater that broadcasts the TestEventListener events to all
+  // subscribers.
+  TestEventListener* repeater();
+
+  // Sets the default_result_printer attribute to the provided listener.
+  // The listener is also added to the listener list and previous
+  // default_result_printer is removed from it and deleted. The listener can
+  // also be NULL in which case it will not be added to the list. Does
+  // nothing if the previous and the current listener objects are the same.
+  void SetDefaultResultPrinter(TestEventListener* listener);
+
+  // Sets the default_xml_generator attribute to the provided listener.  The
+  // listener is also added to the listener list and previous
+  // default_xml_generator is removed from it and deleted. The listener can
+  // also be NULL in which case it will not be added to the list. Does
+  // nothing if the previous and the current listener objects are the same.
+  void SetDefaultXmlGenerator(TestEventListener* listener);
+
+  // Controls whether events will be forwarded by the repeater to the
+  // listeners in the list.
+  bool EventForwardingEnabled() const;
+  void SuppressEventForwarding();
+
+  // The actual list of listeners.
+  internal::TestEventRepeater* repeater_;
+  // Listener responsible for the standard result output.
+  TestEventListener* default_result_printer_;
+  // Listener responsible for the creation of the XML output file.
+  TestEventListener* default_xml_generator_;
+
+  // We disallow copying TestEventListeners.
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestEventListeners);
+};
+
+// A UnitTest consists of a vector of TestSuites.
+//
+// This is a singleton class.  The only instance of UnitTest is
+// created when UnitTest::GetInstance() is first called.  This
+// instance is never deleted.
+//
+// UnitTest is not copyable.
+//
+// This class is thread-safe as long as the methods are called
+// according to their specification.
+class GTEST_API_ UnitTest {
+ public:
+  // Gets the singleton UnitTest object.  The first time this method
+  // is called, a UnitTest object is constructed and returned.
+  // Consecutive calls will return the same object.
+  static UnitTest* GetInstance();
+
+  // Runs all tests in this UnitTest object and prints the result.
+  // Returns 0 if successful, or 1 otherwise.
+  //
+  // This method can only be called from the main thread.
+  //
+  // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+  int Run() GTEST_MUST_USE_RESULT_;
+
+  // Returns the working directory when the first TEST() or TEST_F()
+  // was executed.  The UnitTest object owns the string.
+  const char* original_working_dir() const;
+
+  // Returns the TestSuite object for the test that's currently running,
+  // or NULL if no test is running.
+  const TestSuite* current_test_suite() const GTEST_LOCK_EXCLUDED_(mutex_);
+
+// Legacy API is still available but deprecated
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  const TestCase* current_test_case() const GTEST_LOCK_EXCLUDED_(mutex_);
+#endif
+
+  // Returns the TestInfo object for the test that's currently running,
+  // or NULL if no test is running.
+  const TestInfo* current_test_info() const
+      GTEST_LOCK_EXCLUDED_(mutex_);
+
+  // Returns the random seed used at the start of the current test run.
+  int random_seed() const;
+
+  // Returns the ParameterizedTestSuiteRegistry object used to keep track of
+  // value-parameterized tests and instantiate and register them.
+  //
+  // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+  internal::ParameterizedTestSuiteRegistry& parameterized_test_registry()
+      GTEST_LOCK_EXCLUDED_(mutex_);
+
+  // Gets the number of successful test suites.
+  int successful_test_suite_count() const;
+
+  // Gets the number of failed test suites.
+  int failed_test_suite_count() const;
+
+  // Gets the number of all test suites.
+  int total_test_suite_count() const;
+
+  // Gets the number of all test suites that contain at least one test
+  // that should run.
+  int test_suite_to_run_count() const;
+
+  //  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  int successful_test_case_count() const;
+  int failed_test_case_count() const;
+  int total_test_case_count() const;
+  int test_case_to_run_count() const;
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  // Gets the number of successful tests.
+  int successful_test_count() const;
+
+  // Gets the number of skipped tests.
+  int skipped_test_count() const;
+
+  // Gets the number of failed tests.
+  int failed_test_count() const;
+
+  // Gets the number of disabled tests that will be reported in the XML report.
+  int reportable_disabled_test_count() const;
+
+  // Gets the number of disabled tests.
+  int disabled_test_count() const;
+
+  // Gets the number of tests to be printed in the XML report.
+  int reportable_test_count() const;
+
+  // Gets the number of all tests.
+  int total_test_count() const;
+
+  // Gets the number of tests that should run.
+  int test_to_run_count() const;
+
+  // Gets the time of the test program start, in ms from the start of the
+  // UNIX epoch.
+  TimeInMillis start_timestamp() const;
+
+  // Gets the elapsed time, in milliseconds.
+  TimeInMillis elapsed_time() const;
+
+  // Returns true if and only if the unit test passed (i.e. all test suites
+  // passed).
+  bool Passed() const;
+
+  // Returns true if and only if the unit test failed (i.e. some test suite
+  // failed or something outside of all tests failed).
+  bool Failed() const;
+
+  // Gets the i-th test suite among all the test suites. i can range from 0 to
+  // total_test_suite_count() - 1. If i is not in that range, returns NULL.
+  const TestSuite* GetTestSuite(int i) const;
+
+//  Legacy API is deprecated but still available
+#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+  const TestCase* GetTestCase(int i) const;
+#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_
+
+  // Returns the TestResult containing information on test failures and
+  // properties logged outside of individual test suites.
+  const TestResult& ad_hoc_test_result() const;
+
+  // Returns the list of event listeners that can be used to track events
+  // inside Google Test.
+  TestEventListeners& listeners();
+
+ private:
+  // Registers and returns a global test environment.  When a test
+  // program is run, all global test environments will be set-up in
+  // the order they were registered.  After all tests in the program
+  // have finished, all global test environments will be torn-down in
+  // the *reverse* order they were registered.
+  //
+  // The UnitTest object takes ownership of the given environment.
+  //
+  // This method can only be called from the main thread.
+  Environment* AddEnvironment(Environment* env);
+
+  // Adds a TestPartResult to the current TestResult object.  All
+  // Google Test assertion macros (e.g. ASSERT_TRUE, EXPECT_EQ, etc)
+  // eventually call this to report their results.  The user code
+  // should use the assertion macros instead of calling this directly.
+  void AddTestPartResult(TestPartResult::Type result_type,
+                         const char* file_name,
+                         int line_number,
+                         const std::string& message,
+                         const std::string& os_stack_trace)
+      GTEST_LOCK_EXCLUDED_(mutex_);
+
+  // Adds a TestProperty to the current TestResult object when invoked from
+  // inside a test, to current TestSuite's ad_hoc_test_result_ when invoked
+  // from SetUpTestSuite or TearDownTestSuite, or to the global property set
+  // when invoked elsewhere.  If the result already contains a property with
+  // the same key, the value will be updated.
+  void RecordProperty(const std::string& key, const std::string& value);
+
+  // Gets the i-th test suite among all the test suites. i can range from 0 to
+  // total_test_suite_count() - 1. If i is not in that range, returns NULL.
+  TestSuite* GetMutableTestSuite(int i);
+
+  // Accessors for the implementation object.
+  internal::UnitTestImpl* impl() { return impl_; }
+  const internal::UnitTestImpl* impl() const { return impl_; }
+
+  // These classes and functions are friends as they need to access private
+  // members of UnitTest.
+  friend class ScopedTrace;
+  friend class Test;
+  friend class internal::AssertHelper;
+  friend class internal::StreamingListenerTest;
+  friend class internal::UnitTestRecordPropertyTestHelper;
+  friend Environment* AddGlobalTestEnvironment(Environment* env);
+  friend std::set<std::string>* internal::GetIgnoredParameterizedTestSuites();
+  friend internal::UnitTestImpl* internal::GetUnitTestImpl();
+  friend void internal::ReportFailureInUnknownLocation(
+      TestPartResult::Type result_type,
+      const std::string& message);
+
+  // Creates an empty UnitTest.
+  UnitTest();
+
+  // D'tor
+  virtual ~UnitTest();
+
+  // Pushes a trace defined by SCOPED_TRACE() on to the per-thread
+  // Google Test trace stack.
+  void PushGTestTrace(const internal::TraceInfo& trace)
+      GTEST_LOCK_EXCLUDED_(mutex_);
+
+  // Pops a trace from the per-thread Google Test trace stack.
+  void PopGTestTrace()
+      GTEST_LOCK_EXCLUDED_(mutex_);
+
+  // Protects mutable state in *impl_.  This is mutable as some const
+  // methods need to lock it too.
+  mutable internal::Mutex mutex_;
+
+  // Opaque implementation object.  This field is never changed once
+  // the object is constructed.  We don't mark it as const here, as
+  // doing so will cause a warning in the constructor of UnitTest.
+  // Mutable state in *impl_ is protected by mutex_.
+  internal::UnitTestImpl* impl_;
+
+  // We disallow copying UnitTest.
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(UnitTest);
+};
+
+// A convenient wrapper for adding an environment for the test
+// program.
+//
+// You should call this before RUN_ALL_TESTS() is called, probably in
+// main().  If you use gtest_main, you need to call this before main()
+// starts for it to take effect.  For example, you can define a global
+// variable like this:
+//
+//   testing::Environment* const foo_env =
+//       testing::AddGlobalTestEnvironment(new FooEnvironment);
+//
+// However, we strongly recommend you to write your own main() and
+// call AddGlobalTestEnvironment() there, as relying on initialization
+// of global variables makes the code harder to read and may cause
+// problems when you register multiple environments from different
+// translation units and the environments have dependencies among them
+// (remember that the compiler doesn't guarantee the order in which
+// global variables from different translation units are initialized).
+inline Environment* AddGlobalTestEnvironment(Environment* env) {
+  return UnitTest::GetInstance()->AddEnvironment(env);
+}
+
+// Initializes Google Test.  This must be called before calling
+// RUN_ALL_TESTS().  In particular, it parses a command line for the
+// flags that Google Test recognizes.  Whenever a Google Test flag is
+// seen, it is removed from argv, and *argc is decremented.
+//
+// No value is returned.  Instead, the Google Test flag variables are
+// updated.
+//
+// Calling the function for the second time has no user-visible effect.
+GTEST_API_ void InitGoogleTest(int* argc, char** argv);
+
+// This overloaded version can be used in Windows programs compiled in
+// UNICODE mode.
+GTEST_API_ void InitGoogleTest(int* argc, wchar_t** argv);
+
+// This overloaded version can be used on Arduino/embedded platforms where
+// there is no argc/argv.
+GTEST_API_ void InitGoogleTest();
+
+namespace internal {
+
+// Separate the error generating code from the code path to reduce the stack
+// frame size of CmpHelperEQ. This helps reduce the overhead of some sanitizers
+// when calling EXPECT_* in a tight loop.
+template <typename T1, typename T2>
+AssertionResult CmpHelperEQFailure(const char* lhs_expression,
+                                   const char* rhs_expression,
+                                   const T1& lhs, const T2& rhs) {
+  return EqFailure(lhs_expression,
+                   rhs_expression,
+                   FormatForComparisonFailureMessage(lhs, rhs),
+                   FormatForComparisonFailureMessage(rhs, lhs),
+                   false);
+}
+
+// This block of code defines operator==/!=
+// to block lexical scope lookup.
+// It prevents using invalid operator==/!= defined at namespace scope.
+struct faketype {};
+inline bool operator==(faketype, faketype) { return true; }
+inline bool operator!=(faketype, faketype) { return false; }
+
+// The helper function for {ASSERT|EXPECT}_EQ.
+template <typename T1, typename T2>
+AssertionResult CmpHelperEQ(const char* lhs_expression,
+                            const char* rhs_expression,
+                            const T1& lhs,
+                            const T2& rhs) {
+  if (lhs == rhs) {
+    return AssertionSuccess();
+  }
+
+  return CmpHelperEQFailure(lhs_expression, rhs_expression, lhs, rhs);
+}
+
+class EqHelper {
+ public:
+  // This templatized version is for the general case.
+  template <
+      typename T1, typename T2,
+      // Disable this overload for cases where one argument is a pointer
+      // and the other is the null pointer constant.
+      typename std::enable_if<!std::is_integral<T1>::value ||
+                              !std::is_pointer<T2>::value>::type* = nullptr>
+  static AssertionResult Compare(const char* lhs_expression,
+                                 const char* rhs_expression, const T1& lhs,
+                                 const T2& rhs) {
+    return CmpHelperEQ(lhs_expression, rhs_expression, lhs, rhs);
+  }
+
+  // With this overloaded version, we allow anonymous enums to be used
+  // in {ASSERT|EXPECT}_EQ when compiled with gcc 4, as anonymous
+  // enums can be implicitly cast to BiggestInt.
+  //
+  // Even though its body looks the same as the above version, we
+  // cannot merge the two, as it will make anonymous enums unhappy.
+  static AssertionResult Compare(const char* lhs_expression,
+                                 const char* rhs_expression,
+                                 BiggestInt lhs,
+                                 BiggestInt rhs) {
+    return CmpHelperEQ(lhs_expression, rhs_expression, lhs, rhs);
+  }
+
+  template <typename T>
+  static AssertionResult Compare(
+      const char* lhs_expression, const char* rhs_expression,
+      // Handle cases where '0' is used as a null pointer literal.
+      std::nullptr_t /* lhs */, T* rhs) {
+    // We already know that 'lhs' is a null pointer.
+    return CmpHelperEQ(lhs_expression, rhs_expression, static_cast<T*>(nullptr),
+                       rhs);
+  }
+};
+
+// Separate the error generating code from the code path to reduce the stack
+// frame size of CmpHelperOP. This helps reduce the overhead of some sanitizers
+// when calling EXPECT_OP in a tight loop.
+template <typename T1, typename T2>
+AssertionResult CmpHelperOpFailure(const char* expr1, const char* expr2,
+                                   const T1& val1, const T2& val2,
+                                   const char* op) {
+  return AssertionFailure()
+         << "Expected: (" << expr1 << ") " << op << " (" << expr2
+         << "), actual: " << FormatForComparisonFailureMessage(val1, val2)
+         << " vs " << FormatForComparisonFailureMessage(val2, val1);
+}
+
+// A macro for implementing the helper functions needed to implement
+// ASSERT_?? and EXPECT_??.  It is here just to avoid copy-and-paste
+// of similar code.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+
+#define GTEST_IMPL_CMP_HELPER_(op_name, op)\
+template <typename T1, typename T2>\
+AssertionResult CmpHelper##op_name(const char* expr1, const char* expr2, \
+                                   const T1& val1, const T2& val2) {\
+  if (val1 op val2) {\
+    return AssertionSuccess();\
+  } else {\
+    return CmpHelperOpFailure(expr1, expr2, val1, val2, #op);\
+  }\
+}
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+
+// Implements the helper function for {ASSERT|EXPECT}_NE
+GTEST_IMPL_CMP_HELPER_(NE, !=)
+// Implements the helper function for {ASSERT|EXPECT}_LE
+GTEST_IMPL_CMP_HELPER_(LE, <=)
+// Implements the helper function for {ASSERT|EXPECT}_LT
+GTEST_IMPL_CMP_HELPER_(LT, <)
+// Implements the helper function for {ASSERT|EXPECT}_GE
+GTEST_IMPL_CMP_HELPER_(GE, >=)
+// Implements the helper function for {ASSERT|EXPECT}_GT
+GTEST_IMPL_CMP_HELPER_(GT, >)
+
+#undef GTEST_IMPL_CMP_HELPER_
+
+// The helper function for {ASSERT|EXPECT}_STREQ.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+GTEST_API_ AssertionResult CmpHelperSTREQ(const char* s1_expression,
+                                          const char* s2_expression,
+                                          const char* s1,
+                                          const char* s2);
+
+// The helper function for {ASSERT|EXPECT}_STRCASEEQ.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+GTEST_API_ AssertionResult CmpHelperSTRCASEEQ(const char* s1_expression,
+                                              const char* s2_expression,
+                                              const char* s1,
+                                              const char* s2);
+
+// The helper function for {ASSERT|EXPECT}_STRNE.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+GTEST_API_ AssertionResult CmpHelperSTRNE(const char* s1_expression,
+                                          const char* s2_expression,
+                                          const char* s1,
+                                          const char* s2);
+
+// The helper function for {ASSERT|EXPECT}_STRCASENE.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+GTEST_API_ AssertionResult CmpHelperSTRCASENE(const char* s1_expression,
+                                              const char* s2_expression,
+                                              const char* s1,
+                                              const char* s2);
+
+
+// Helper function for *_STREQ on wide strings.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+GTEST_API_ AssertionResult CmpHelperSTREQ(const char* s1_expression,
+                                          const char* s2_expression,
+                                          const wchar_t* s1,
+                                          const wchar_t* s2);
+
+// Helper function for *_STRNE on wide strings.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+GTEST_API_ AssertionResult CmpHelperSTRNE(const char* s1_expression,
+                                          const char* s2_expression,
+                                          const wchar_t* s1,
+                                          const wchar_t* s2);
+
+}  // namespace internal
+
+// IsSubstring() and IsNotSubstring() are intended to be used as the
+// first argument to {EXPECT,ASSERT}_PRED_FORMAT2(), not by
+// themselves.  They check whether needle is a substring of haystack
+// (NULL is considered a substring of itself only), and return an
+// appropriate error message when they fail.
+//
+// The {needle,haystack}_expr arguments are the stringified
+// expressions that generated the two real arguments.
+GTEST_API_ AssertionResult IsSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const char* needle, const char* haystack);
+GTEST_API_ AssertionResult IsSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const wchar_t* needle, const wchar_t* haystack);
+GTEST_API_ AssertionResult IsNotSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const char* needle, const char* haystack);
+GTEST_API_ AssertionResult IsNotSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const wchar_t* needle, const wchar_t* haystack);
+GTEST_API_ AssertionResult IsSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const ::std::string& needle, const ::std::string& haystack);
+GTEST_API_ AssertionResult IsNotSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const ::std::string& needle, const ::std::string& haystack);
+
+#if GTEST_HAS_STD_WSTRING
+GTEST_API_ AssertionResult IsSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const ::std::wstring& needle, const ::std::wstring& haystack);
+GTEST_API_ AssertionResult IsNotSubstring(
+    const char* needle_expr, const char* haystack_expr,
+    const ::std::wstring& needle, const ::std::wstring& haystack);
+#endif  // GTEST_HAS_STD_WSTRING
+
+namespace internal {
+
+// Helper template function for comparing floating-points.
+//
+// Template parameter:
+//
+//   RawType: the raw floating-point type (either float or double)
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+template <typename RawType>
+AssertionResult CmpHelperFloatingPointEQ(const char* lhs_expression,
+                                         const char* rhs_expression,
+                                         RawType lhs_value,
+                                         RawType rhs_value) {
+  const FloatingPoint<RawType> lhs(lhs_value), rhs(rhs_value);
+
+  if (lhs.AlmostEquals(rhs)) {
+    return AssertionSuccess();
+  }
+
+  ::std::stringstream lhs_ss;
+  lhs_ss << std::setprecision(std::numeric_limits<RawType>::digits10 + 2)
+         << lhs_value;
+
+  ::std::stringstream rhs_ss;
+  rhs_ss << std::setprecision(std::numeric_limits<RawType>::digits10 + 2)
+         << rhs_value;
+
+  return EqFailure(lhs_expression,
+                   rhs_expression,
+                   StringStreamToString(&lhs_ss),
+                   StringStreamToString(&rhs_ss),
+                   false);
+}
+
+// Helper function for implementing ASSERT_NEAR.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+GTEST_API_ AssertionResult DoubleNearPredFormat(const char* expr1,
+                                                const char* expr2,
+                                                const char* abs_error_expr,
+                                                double val1,
+                                                double val2,
+                                                double abs_error);
+
+// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
+// A class that enables one to stream messages to assertion macros
+class GTEST_API_ AssertHelper {
+ public:
+  // Constructor.
+  AssertHelper(TestPartResult::Type type,
+               const char* file,
+               int line,
+               const char* message);
+  ~AssertHelper();
+
+  // Message assignment is a semantic trick to enable assertion
+  // streaming; see the GTEST_MESSAGE_ macro below.
+  void operator=(const Message& message) const;
+
+ private:
+  // We put our data in a struct so that the size of the AssertHelper class can
+  // be as small as possible.  This is important because gcc is incapable of
+  // re-using stack space even for temporary variables, so every EXPECT_EQ
+  // reserves stack space for another AssertHelper.
+  struct AssertHelperData {
+    AssertHelperData(TestPartResult::Type t,
+                     const char* srcfile,
+                     int line_num,
+                     const char* msg)
+        : type(t), file(srcfile), line(line_num), message(msg) { }
+
+    TestPartResult::Type const type;
+    const char* const file;
+    int const line;
+    std::string const message;
+
+   private:
+    GTEST_DISALLOW_COPY_AND_ASSIGN_(AssertHelperData);
+  };
+
+  AssertHelperData* const data_;
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(AssertHelper);
+};
+
+}  // namespace internal
+
+// The pure interface class that all value-parameterized tests inherit from.
+// A value-parameterized class must inherit from both ::testing::Test and
+// ::testing::WithParamInterface. In most cases that just means inheriting
+// from ::testing::TestWithParam, but more complicated test hierarchies
+// may need to inherit from Test and WithParamInterface at different levels.
+//
+// This interface has support for accessing the test parameter value via
+// the GetParam() method.
+//
+// Use it with one of the parameter generator defining functions, like Range(),
+// Values(), ValuesIn(), Bool(), and Combine().
+//
+// class FooTest : public ::testing::TestWithParam<int> {
+//  protected:
+//   FooTest() {
+//     // Can use GetParam() here.
+//   }
+//   ~FooTest() override {
+//     // Can use GetParam() here.
+//   }
+//   void SetUp() override {
+//     // Can use GetParam() here.
+//   }
+//   void TearDown override {
+//     // Can use GetParam() here.
+//   }
+// };
+// TEST_P(FooTest, DoesBar) {
+//   // Can use GetParam() method here.
+//   Foo foo;
+//   ASSERT_TRUE(foo.DoesBar(GetParam()));
+// }
+// INSTANTIATE_TEST_SUITE_P(OneToTenRange, FooTest, ::testing::Range(1, 10));
+
+template <typename T>
+class WithParamInterface {
+ public:
+  typedef T ParamType;
+  virtual ~WithParamInterface() {}
+
+  // The current parameter value. Is also available in the test fixture's
+  // constructor.
+  static const ParamType& GetParam() {
+    GTEST_CHECK_(parameter_ != nullptr)
+        << "GetParam() can only be called inside a value-parameterized test "
+        << "-- did you intend to write TEST_P instead of TEST_F?";
+    return *parameter_;
+  }
+
+ private:
+  // Sets parameter value. The caller is responsible for making sure the value
+  // remains alive and unchanged throughout the current test.
+  static void SetParam(const ParamType* parameter) {
+    parameter_ = parameter;
+  }
+
+  // Static value used for accessing parameter during a test lifetime.
+  static const ParamType* parameter_;
+
+  // TestClass must be a subclass of WithParamInterface<T> and Test.
+  template <class TestClass> friend class internal::ParameterizedTestFactory;
+};
+
+template <typename T>
+const T* WithParamInterface<T>::parameter_ = nullptr;
+
+// Most value-parameterized classes can ignore the existence of
+// WithParamInterface, and can just inherit from ::testing::TestWithParam.
+
+template <typename T>
+class TestWithParam : public Test, public WithParamInterface<T> {
+};
+
+// Macros for indicating success/failure in test code.
+
+// Skips test in runtime.
+// Skipping test aborts current function.
+// Skipped tests are neither successful nor failed.
+#define GTEST_SKIP() GTEST_SKIP_("")
+
+// ADD_FAILURE unconditionally adds a failure to the current test.
+// SUCCEED generates a success - it doesn't automatically make the
+// current test successful, as a test is only successful when it has
+// no failure.
+//
+// EXPECT_* verifies that a certain condition is satisfied.  If not,
+// it behaves like ADD_FAILURE.  In particular:
+//
+//   EXPECT_TRUE  verifies that a Boolean condition is true.
+//   EXPECT_FALSE verifies that a Boolean condition is false.
+//
+// FAIL and ASSERT_* are similar to ADD_FAILURE and EXPECT_*, except
+// that they will also abort the current function on failure.  People
+// usually want the fail-fast behavior of FAIL and ASSERT_*, but those
+// writing data-driven tests often find themselves using ADD_FAILURE
+// and EXPECT_* more.
+
+// Generates a nonfatal failure with a generic message.
+#define ADD_FAILURE() GTEST_NONFATAL_FAILURE_("Failed")
+
+// Generates a nonfatal failure at the given source file location with
+// a generic message.
+#define ADD_FAILURE_AT(file, line) \
+  GTEST_MESSAGE_AT_(file, line, "Failed", \
+                    ::testing::TestPartResult::kNonFatalFailure)
+
+// Generates a fatal failure with a generic message.
+#define GTEST_FAIL() GTEST_FATAL_FAILURE_("Failed")
+
+// Like GTEST_FAIL(), but at the given source file location.
+#define GTEST_FAIL_AT(file, line)         \
+  GTEST_MESSAGE_AT_(file, line, "Failed", \
+                    ::testing::TestPartResult::kFatalFailure)
+
+// Define this macro to 1 to omit the definition of FAIL(), which is a
+// generic name and clashes with some other libraries.
+#if !GTEST_DONT_DEFINE_FAIL
+# define FAIL() GTEST_FAIL()
+#endif
+
+// Generates a success with a generic message.
+#define GTEST_SUCCEED() GTEST_SUCCESS_("Succeeded")
+
+// Define this macro to 1 to omit the definition of SUCCEED(), which
+// is a generic name and clashes with some other libraries.
+#if !GTEST_DONT_DEFINE_SUCCEED
+# define SUCCEED() GTEST_SUCCEED()
+#endif
+
+// Macros for testing exceptions.
+//
+//    * {ASSERT|EXPECT}_THROW(statement, expected_exception):
+//         Tests that the statement throws the expected exception.
+//    * {ASSERT|EXPECT}_NO_THROW(statement):
+//         Tests that the statement doesn't throw any exception.
+//    * {ASSERT|EXPECT}_ANY_THROW(statement):
+//         Tests that the statement throws an exception.
+
+#define EXPECT_THROW(statement, expected_exception) \
+  GTEST_TEST_THROW_(statement, expected_exception, GTEST_NONFATAL_FAILURE_)
+#define EXPECT_NO_THROW(statement) \
+  GTEST_TEST_NO_THROW_(statement, GTEST_NONFATAL_FAILURE_)
+#define EXPECT_ANY_THROW(statement) \
+  GTEST_TEST_ANY_THROW_(statement, GTEST_NONFATAL_FAILURE_)
+#define ASSERT_THROW(statement, expected_exception) \
+  GTEST_TEST_THROW_(statement, expected_exception, GTEST_FATAL_FAILURE_)
+#define ASSERT_NO_THROW(statement) \
+  GTEST_TEST_NO_THROW_(statement, GTEST_FATAL_FAILURE_)
+#define ASSERT_ANY_THROW(statement) \
+  GTEST_TEST_ANY_THROW_(statement, GTEST_FATAL_FAILURE_)
+
+// Boolean assertions. Condition can be either a Boolean expression or an
+// AssertionResult. For more information on how to use AssertionResult with
+// these macros see comments on that class.
+#define GTEST_EXPECT_TRUE(condition) \
+  GTEST_TEST_BOOLEAN_(condition, #condition, false, true, \
+                      GTEST_NONFATAL_FAILURE_)
+#define GTEST_EXPECT_FALSE(condition) \
+  GTEST_TEST_BOOLEAN_(!(condition), #condition, true, false, \
+                      GTEST_NONFATAL_FAILURE_)
+#define GTEST_ASSERT_TRUE(condition) \
+  GTEST_TEST_BOOLEAN_(condition, #condition, false, true, \
+                      GTEST_FATAL_FAILURE_)
+#define GTEST_ASSERT_FALSE(condition) \
+  GTEST_TEST_BOOLEAN_(!(condition), #condition, true, false, \
+                      GTEST_FATAL_FAILURE_)
+
+// Define these macros to 1 to omit the definition of the corresponding
+// EXPECT or ASSERT, which clashes with some users' own code.
+
+#if !GTEST_DONT_DEFINE_EXPECT_TRUE
+#define EXPECT_TRUE(condition) GTEST_EXPECT_TRUE(condition)
+#endif
+
+#if !GTEST_DONT_DEFINE_EXPECT_FALSE
+#define EXPECT_FALSE(condition) GTEST_EXPECT_FALSE(condition)
+#endif
+
+#if !GTEST_DONT_DEFINE_ASSERT_TRUE
+#define ASSERT_TRUE(condition) GTEST_ASSERT_TRUE(condition)
+#endif
+
+#if !GTEST_DONT_DEFINE_ASSERT_FALSE
+#define ASSERT_FALSE(condition) GTEST_ASSERT_FALSE(condition)
+#endif
+
+// Macros for testing equalities and inequalities.
+//
+//    * {ASSERT|EXPECT}_EQ(v1, v2): Tests that v1 == v2
+//    * {ASSERT|EXPECT}_NE(v1, v2): Tests that v1 != v2
+//    * {ASSERT|EXPECT}_LT(v1, v2): Tests that v1 < v2
+//    * {ASSERT|EXPECT}_LE(v1, v2): Tests that v1 <= v2
+//    * {ASSERT|EXPECT}_GT(v1, v2): Tests that v1 > v2
+//    * {ASSERT|EXPECT}_GE(v1, v2): Tests that v1 >= v2
+//
+// When they are not, Google Test prints both the tested expressions and
+// their actual values.  The values must be compatible built-in types,
+// or you will get a compiler error.  By "compatible" we mean that the
+// values can be compared by the respective operator.
+//
+// Note:
+//
+//   1. It is possible to make a user-defined type work with
+//   {ASSERT|EXPECT}_??(), but that requires overloading the
+//   comparison operators and is thus discouraged by the Google C++
+//   Usage Guide.  Therefore, you are advised to use the
+//   {ASSERT|EXPECT}_TRUE() macro to assert that two objects are
+//   equal.
+//
+//   2. The {ASSERT|EXPECT}_??() macros do pointer comparisons on
+//   pointers (in particular, C strings).  Therefore, if you use it
+//   with two C strings, you are testing how their locations in memory
+//   are related, not how their content is related.  To compare two C
+//   strings by content, use {ASSERT|EXPECT}_STR*().
+//
+//   3. {ASSERT|EXPECT}_EQ(v1, v2) is preferred to
+//   {ASSERT|EXPECT}_TRUE(v1 == v2), as the former tells you
+//   what the actual value is when it fails, and similarly for the
+//   other comparisons.
+//
+//   4. Do not depend on the order in which {ASSERT|EXPECT}_??()
+//   evaluate their arguments, which is undefined.
+//
+//   5. These macros evaluate their arguments exactly once.
+//
+// Examples:
+//
+//   EXPECT_NE(Foo(), 5);
+//   EXPECT_EQ(a_pointer, NULL);
+//   ASSERT_LT(i, array_size);
+//   ASSERT_GT(records.size(), 0) << "There is no record left.";
+
+#define EXPECT_EQ(val1, val2) \
+  EXPECT_PRED_FORMAT2(::testing::internal::EqHelper::Compare, val1, val2)
+#define EXPECT_NE(val1, val2) \
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperNE, val1, val2)
+#define EXPECT_LE(val1, val2) \
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperLE, val1, val2)
+#define EXPECT_LT(val1, val2) \
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperLT, val1, val2)
+#define EXPECT_GE(val1, val2) \
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperGE, val1, val2)
+#define EXPECT_GT(val1, val2) \
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperGT, val1, val2)
+
+#define GTEST_ASSERT_EQ(val1, val2) \
+  ASSERT_PRED_FORMAT2(::testing::internal::EqHelper::Compare, val1, val2)
+#define GTEST_ASSERT_NE(val1, val2) \
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperNE, val1, val2)
+#define GTEST_ASSERT_LE(val1, val2) \
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperLE, val1, val2)
+#define GTEST_ASSERT_LT(val1, val2) \
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperLT, val1, val2)
+#define GTEST_ASSERT_GE(val1, val2) \
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperGE, val1, val2)
+#define GTEST_ASSERT_GT(val1, val2) \
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperGT, val1, val2)
+
+// Define macro GTEST_DONT_DEFINE_ASSERT_XY to 1 to omit the definition of
+// ASSERT_XY(), which clashes with some users' own code.
+
+#if !GTEST_DONT_DEFINE_ASSERT_EQ
+# define ASSERT_EQ(val1, val2) GTEST_ASSERT_EQ(val1, val2)
+#endif
+
+#if !GTEST_DONT_DEFINE_ASSERT_NE
+# define ASSERT_NE(val1, val2) GTEST_ASSERT_NE(val1, val2)
+#endif
+
+#if !GTEST_DONT_DEFINE_ASSERT_LE
+# define ASSERT_LE(val1, val2) GTEST_ASSERT_LE(val1, val2)
+#endif
+
+#if !GTEST_DONT_DEFINE_ASSERT_LT
+# define ASSERT_LT(val1, val2) GTEST_ASSERT_LT(val1, val2)
+#endif
+
+#if !GTEST_DONT_DEFINE_ASSERT_GE
+# define ASSERT_GE(val1, val2) GTEST_ASSERT_GE(val1, val2)
+#endif
+
+#if !GTEST_DONT_DEFINE_ASSERT_GT
+# define ASSERT_GT(val1, val2) GTEST_ASSERT_GT(val1, val2)
+#endif
+
+// C-string Comparisons.  All tests treat NULL and any non-NULL string
+// as different.  Two NULLs are equal.
+//
+//    * {ASSERT|EXPECT}_STREQ(s1, s2):     Tests that s1 == s2
+//    * {ASSERT|EXPECT}_STRNE(s1, s2):     Tests that s1 != s2
+//    * {ASSERT|EXPECT}_STRCASEEQ(s1, s2): Tests that s1 == s2, ignoring case
+//    * {ASSERT|EXPECT}_STRCASENE(s1, s2): Tests that s1 != s2, ignoring case
+//
+// For wide or narrow string objects, you can use the
+// {ASSERT|EXPECT}_??() macros.
+//
+// Don't depend on the order in which the arguments are evaluated,
+// which is undefined.
+//
+// These macros evaluate their arguments exactly once.
+
+#define EXPECT_STREQ(s1, s2) \
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperSTREQ, s1, s2)
+#define EXPECT_STRNE(s1, s2) \
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperSTRNE, s1, s2)
+#define EXPECT_STRCASEEQ(s1, s2) \
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperSTRCASEEQ, s1, s2)
+#define EXPECT_STRCASENE(s1, s2)\
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperSTRCASENE, s1, s2)
+
+#define ASSERT_STREQ(s1, s2) \
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperSTREQ, s1, s2)
+#define ASSERT_STRNE(s1, s2) \
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperSTRNE, s1, s2)
+#define ASSERT_STRCASEEQ(s1, s2) \
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperSTRCASEEQ, s1, s2)
+#define ASSERT_STRCASENE(s1, s2)\
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperSTRCASENE, s1, s2)
+
+// Macros for comparing floating-point numbers.
+//
+//    * {ASSERT|EXPECT}_FLOAT_EQ(val1, val2):
+//         Tests that two float values are almost equal.
+//    * {ASSERT|EXPECT}_DOUBLE_EQ(val1, val2):
+//         Tests that two double values are almost equal.
+//    * {ASSERT|EXPECT}_NEAR(v1, v2, abs_error):
+//         Tests that v1 and v2 are within the given distance to each other.
+//
+// Google Test uses ULP-based comparison to automatically pick a default
+// error bound that is appropriate for the operands.  See the
+// FloatingPoint template class in gtest-internal.h if you are
+// interested in the implementation details.
+
+#define EXPECT_FLOAT_EQ(val1, val2)\
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperFloatingPointEQ<float>, \
+                      val1, val2)
+
+#define EXPECT_DOUBLE_EQ(val1, val2)\
+  EXPECT_PRED_FORMAT2(::testing::internal::CmpHelperFloatingPointEQ<double>, \
+                      val1, val2)
+
+#define ASSERT_FLOAT_EQ(val1, val2)\
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperFloatingPointEQ<float>, \
+                      val1, val2)
+
+#define ASSERT_DOUBLE_EQ(val1, val2)\
+  ASSERT_PRED_FORMAT2(::testing::internal::CmpHelperFloatingPointEQ<double>, \
+                      val1, val2)
+
+#define EXPECT_NEAR(val1, val2, abs_error)\
+  EXPECT_PRED_FORMAT3(::testing::internal::DoubleNearPredFormat, \
+                      val1, val2, abs_error)
+
+#define ASSERT_NEAR(val1, val2, abs_error)\
+  ASSERT_PRED_FORMAT3(::testing::internal::DoubleNearPredFormat, \
+                      val1, val2, abs_error)
+
+// These predicate format functions work on floating-point values, and
+// can be used in {ASSERT|EXPECT}_PRED_FORMAT2*(), e.g.
+//
+//   EXPECT_PRED_FORMAT2(testing::DoubleLE, Foo(), 5.0);
+
+// Asserts that val1 is less than, or almost equal to, val2.  Fails
+// otherwise.  In particular, it fails if either val1 or val2 is NaN.
+GTEST_API_ AssertionResult FloatLE(const char* expr1, const char* expr2,
+                                   float val1, float val2);
+GTEST_API_ AssertionResult DoubleLE(const char* expr1, const char* expr2,
+                                    double val1, double val2);
+
+
+#if GTEST_OS_WINDOWS
+
+// Macros that test for HRESULT failure and success, these are only useful
+// on Windows, and rely on Windows SDK macros and APIs to compile.
+//
+//    * {ASSERT|EXPECT}_HRESULT_{SUCCEEDED|FAILED}(expr)
+//
+// When expr unexpectedly fails or succeeds, Google Test prints the
+// expected result and the actual result with both a human-readable
+// string representation of the error, if available, as well as the
+// hex result code.
+# define EXPECT_HRESULT_SUCCEEDED(expr) \
+    EXPECT_PRED_FORMAT1(::testing::internal::IsHRESULTSuccess, (expr))
+
+# define ASSERT_HRESULT_SUCCEEDED(expr) \
+    ASSERT_PRED_FORMAT1(::testing::internal::IsHRESULTSuccess, (expr))
+
+# define EXPECT_HRESULT_FAILED(expr) \
+    EXPECT_PRED_FORMAT1(::testing::internal::IsHRESULTFailure, (expr))
+
+# define ASSERT_HRESULT_FAILED(expr) \
+    ASSERT_PRED_FORMAT1(::testing::internal::IsHRESULTFailure, (expr))
+
+#endif  // GTEST_OS_WINDOWS
+
+// Macros that execute statement and check that it doesn't generate new fatal
+// failures in the current thread.
+//
+//   * {ASSERT|EXPECT}_NO_FATAL_FAILURE(statement);
+//
+// Examples:
+//
+//   EXPECT_NO_FATAL_FAILURE(Process());
+//   ASSERT_NO_FATAL_FAILURE(Process()) << "Process() failed";
+//
+#define ASSERT_NO_FATAL_FAILURE(statement) \
+    GTEST_TEST_NO_FATAL_FAILURE_(statement, GTEST_FATAL_FAILURE_)
+#define EXPECT_NO_FATAL_FAILURE(statement) \
+    GTEST_TEST_NO_FATAL_FAILURE_(statement, GTEST_NONFATAL_FAILURE_)
+
+// Causes a trace (including the given source file path and line number,
+// and the given message) to be included in every test failure message generated
+// by code in the scope of the lifetime of an instance of this class. The effect
+// is undone with the destruction of the instance.
+//
+// The message argument can be anything streamable to std::ostream.
+//
+// Example:
+//   testing::ScopedTrace trace("file.cc", 123, "message");
+//
+class GTEST_API_ ScopedTrace {
+ public:
+  // The c'tor pushes the given source file location and message onto
+  // a trace stack maintained by Google Test.
+
+  // Template version. Uses Message() to convert the values into strings.
+  // Slow, but flexible.
+  template <typename T>
+  ScopedTrace(const char* file, int line, const T& message) {
+    PushTrace(file, line, (Message() << message).GetString());
+  }
+
+  // Optimize for some known types.
+  ScopedTrace(const char* file, int line, const char* message) {
+    PushTrace(file, line, message ? message : "(null)");
+  }
+
+  ScopedTrace(const char* file, int line, const std::string& message) {
+    PushTrace(file, line, message);
+  }
+
+  // The d'tor pops the info pushed by the c'tor.
+  //
+  // Note that the d'tor is not virtual in order to be efficient.
+  // Don't inherit from ScopedTrace!
+  ~ScopedTrace();
+
+ private:
+  void PushTrace(const char* file, int line, std::string message);
+
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(ScopedTrace);
+} GTEST_ATTRIBUTE_UNUSED_;  // A ScopedTrace object does its job in its
+                            // c'tor and d'tor.  Therefore it doesn't
+                            // need to be used otherwise.
+
+// Causes a trace (including the source file path, the current line
+// number, and the given message) to be included in every test failure
+// message generated by code in the current scope.  The effect is
+// undone when the control leaves the current scope.
+//
+// The message argument can be anything streamable to std::ostream.
+//
+// In the implementation, we include the current line number as part
+// of the dummy variable name, thus allowing multiple SCOPED_TRACE()s
+// to appear in the same block - as long as they are on different
+// lines.
+//
+// Assuming that each thread maintains its own stack of traces.
+// Therefore, a SCOPED_TRACE() would (correctly) only affect the
+// assertions in its own thread.
+#define SCOPED_TRACE(message) \
+  ::testing::ScopedTrace GTEST_CONCAT_TOKEN_(gtest_trace_, __LINE__)(\
+    __FILE__, __LINE__, (message))
+
+// Compile-time assertion for type equality.
+// StaticAssertTypeEq<type1, type2>() compiles if and only if type1 and type2
+// are the same type.  The value it returns is not interesting.
+//
+// Instead of making StaticAssertTypeEq a class template, we make it a
+// function template that invokes a helper class template.  This
+// prevents a user from misusing StaticAssertTypeEq<T1, T2> by
+// defining objects of that type.
+//
+// CAVEAT:
+//
+// When used inside a method of a class template,
+// StaticAssertTypeEq<T1, T2>() is effective ONLY IF the method is
+// instantiated.  For example, given:
+//
+//   template <typename T> class Foo {
+//    public:
+//     void Bar() { testing::StaticAssertTypeEq<int, T>(); }
+//   };
+//
+// the code:
+//
+//   void Test1() { Foo<bool> foo; }
+//
+// will NOT generate a compiler error, as Foo<bool>::Bar() is never
+// actually instantiated.  Instead, you need:
+//
+//   void Test2() { Foo<bool> foo; foo.Bar(); }
+//
+// to cause a compiler error.
+template <typename T1, typename T2>
+constexpr bool StaticAssertTypeEq() noexcept {
+  static_assert(std::is_same<T1, T2>::value, "T1 and T2 are not the same type");
+  return true;
+}
+
+// Defines a test.
+//
+// The first parameter is the name of the test suite, and the second
+// parameter is the name of the test within the test suite.
+//
+// The convention is to end the test suite name with "Test".  For
+// example, a test suite for the Foo class can be named FooTest.
+//
+// Test code should appear between braces after an invocation of
+// this macro.  Example:
+//
+//   TEST(FooTest, InitializesCorrectly) {
+//     Foo foo;
+//     EXPECT_TRUE(foo.StatusIsOK());
+//   }
+
+// Note that we call GetTestTypeId() instead of GetTypeId<
+// ::testing::Test>() here to get the type ID of testing::Test.  This
+// is to work around a suspected linker bug when using Google Test as
+// a framework on Mac OS X.  The bug causes GetTypeId<
+// ::testing::Test>() to return different values depending on whether
+// the call is from the Google Test framework itself or from user test
+// code.  GetTestTypeId() is guaranteed to always return the same
+// value, as it always calls GetTypeId<>() from the Google Test
+// framework.
+#define GTEST_TEST(test_suite_name, test_name)             \
+  GTEST_TEST_(test_suite_name, test_name, ::testing::Test, \
+              ::testing::internal::GetTestTypeId())
+
+// Define this macro to 1 to omit the definition of TEST(), which
+// is a generic name and clashes with some other libraries.
+#if !GTEST_DONT_DEFINE_TEST
+#define TEST(test_suite_name, test_name) GTEST_TEST(test_suite_name, test_name)
+#endif
+
+// Defines a test that uses a test fixture.
+//
+// The first parameter is the name of the test fixture class, which
+// also doubles as the test suite name.  The second parameter is the
+// name of the test within the test suite.
+//
+// A test fixture class must be declared earlier.  The user should put
+// the test code between braces after using this macro.  Example:
+//
+//   class FooTest : public testing::Test {
+//    protected:
+//     void SetUp() override { b_.AddElement(3); }
+//
+//     Foo a_;
+//     Foo b_;
+//   };
+//
+//   TEST_F(FooTest, InitializesCorrectly) {
+//     EXPECT_TRUE(a_.StatusIsOK());
+//   }
+//
+//   TEST_F(FooTest, ReturnsElementCountCorrectly) {
+//     EXPECT_EQ(a_.size(), 0);
+//     EXPECT_EQ(b_.size(), 1);
+//   }
+//
+// GOOGLETEST_CM0011 DO NOT DELETE
+#if !GTEST_DONT_DEFINE_TEST
+#define TEST_F(test_fixture, test_name)\
+  GTEST_TEST_(test_fixture, test_name, test_fixture, \
+              ::testing::internal::GetTypeId<test_fixture>())
+#endif  // !GTEST_DONT_DEFINE_TEST
+
+// Returns a path to temporary directory.
+// Tries to determine an appropriate directory for the platform.
+GTEST_API_ std::string TempDir();
+
+#ifdef _MSC_VER
+#  pragma warning(pop)
+#endif
+
+// Dynamically registers a test with the framework.
+//
+// This is an advanced API only to be used when the `TEST` macros are
+// insufficient. The macros should be preferred when possible, as they avoid
+// most of the complexity of calling this function.
+//
+// The `factory` argument is a factory callable (move-constructible) object or
+// function pointer that creates a new instance of the Test object. It
+// handles ownership to the caller. The signature of the callable is
+// `Fixture*()`, where `Fixture` is the test fixture class for the test. All
+// tests registered with the same `test_suite_name` must return the same
+// fixture type. This is checked at runtime.
+//
+// The framework will infer the fixture class from the factory and will call
+// the `SetUpTestSuite` and `TearDownTestSuite` for it.
+//
+// Must be called before `RUN_ALL_TESTS()` is invoked, otherwise behavior is
+// undefined.
+//
+// Use case example:
+//
+// class MyFixture : public ::testing::Test {
+//  public:
+//   // All of these optional, just like in regular macro usage.
+//   static void SetUpTestSuite() { ... }
+//   static void TearDownTestSuite() { ... }
+//   void SetUp() override { ... }
+//   void TearDown() override { ... }
+// };
+//
+// class MyTest : public MyFixture {
+//  public:
+//   explicit MyTest(int data) : data_(data) {}
+//   void TestBody() override { ... }
+//
+//  private:
+//   int data_;
+// };
+//
+// void RegisterMyTests(const std::vector<int>& values) {
+//   for (int v : values) {
+//     ::testing::RegisterTest(
+//         "MyFixture", ("Test" + std::to_string(v)).c_str(), nullptr,
+//         std::to_string(v).c_str(),
+//         __FILE__, __LINE__,
+//         // Important to use the fixture type as the return type here.
+//         [=]() -> MyFixture* { return new MyTest(v); });
+//   }
+// }
+// ...
+// int main(int argc, char** argv) {
+//   std::vector<int> values_to_test = LoadValuesFromConfig();
+//   RegisterMyTests(values_to_test);
+//   ...
+//   return RUN_ALL_TESTS();
+// }
+//
+template <int&... ExplicitParameterBarrier, typename Factory>
+TestInfo* RegisterTest(const char* test_suite_name, const char* test_name,
+                       const char* type_param, const char* value_param,
+                       const char* file, int line, Factory factory) {
+  using TestT = typename std::remove_pointer<decltype(factory())>::type;
+
+  class FactoryImpl : public internal::TestFactoryBase {
+   public:
+    explicit FactoryImpl(Factory f) : factory_(std::move(f)) {}
+    Test* CreateTest() override { return factory_(); }
+
+   private:
+    Factory factory_;
+  };
+
+  return internal::MakeAndRegisterTestInfo(
+      test_suite_name, test_name, type_param, value_param,
+      internal::CodeLocation(file, line), internal::GetTypeId<TestT>(),
+      internal::SuiteApiResolver<TestT>::GetSetUpCaseOrSuite(file, line),
+      internal::SuiteApiResolver<TestT>::GetTearDownCaseOrSuite(file, line),
+      new FactoryImpl{std::move(factory)});
+}
+
+}  // namespace testing
+
+// Use this function in main() to run all tests.  It returns 0 if all
+// tests are successful, or 1 otherwise.
+//
+// RUN_ALL_TESTS() should be invoked after the command line has been
+// parsed by InitGoogleTest().
+//
+// This function was formerly a macro; thus, it is in the global
+// namespace and has an all-caps name.
+int RUN_ALL_TESTS() GTEST_MUST_USE_RESULT_;
+
+inline int RUN_ALL_TESTS() {
+  return ::testing::UnitTest::GetInstance()->Run();
+}
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251
+
+#endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_H_
diff --git a/src/fmt/test/header-only-test.cc b/src/fmt/test/header-only-test.cc
new file mode 100644
index 000000000..570f09a56
--- /dev/null
+++ b/src/fmt/test/header-only-test.cc
@@ -0,0 +1,11 @@
+// Header-only configuration test
+
+#include "fmt/core.h"
+#include "fmt/ostream.h"
+#include "gtest/gtest.h"
+
+#ifndef FMT_HEADER_ONLY
+#  error "Not in the header-only mode."
+#endif
+
+TEST(header_only_test, format) { EXPECT_EQ(fmt::format("foo"), "foo"); }
diff --git a/src/fmt/test/mock-allocator.h b/src/fmt/test/mock-allocator.h
new file mode 100644
index 000000000..6a67e08f4
--- /dev/null
+++ b/src/fmt/test/mock-allocator.h
@@ -0,0 +1,64 @@
+// Formatting library for C++ - mock allocator
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_MOCK_ALLOCATOR_H_
+#define FMT_MOCK_ALLOCATOR_H_
+
+#include <assert.h>  // assert
+#include <stddef.h>  // size_t
+
+#include <memory>  // std::allocator_traits
+
+#include "gmock/gmock.h"
+
+template <typename T> class mock_allocator {
+ public:
+  mock_allocator() {}
+  mock_allocator(const mock_allocator&) {}
+  using value_type = T;
+  MOCK_METHOD1_T(allocate, T*(size_t n));
+  MOCK_METHOD2_T(deallocate, void(T* p, size_t n));
+};
+
+template <typename Allocator> class allocator_ref {
+ private:
+  Allocator* alloc_;
+
+  void move(allocator_ref& other) {
+    alloc_ = other.alloc_;
+    other.alloc_ = nullptr;
+  }
+
+ public:
+  using value_type = typename Allocator::value_type;
+
+  explicit allocator_ref(Allocator* alloc = nullptr) : alloc_(alloc) {}
+
+  allocator_ref(const allocator_ref& other) : alloc_(other.alloc_) {}
+  allocator_ref(allocator_ref&& other) { move(other); }
+
+  allocator_ref& operator=(allocator_ref&& other) {
+    assert(this != &other);
+    move(other);
+    return *this;
+  }
+
+  allocator_ref& operator=(const allocator_ref& other) {
+    alloc_ = other.alloc_;
+    return *this;
+  }
+
+ public:
+  Allocator* get() const { return alloc_; }
+
+  value_type* allocate(size_t n) {
+    return std::allocator_traits<Allocator>::allocate(*alloc_, n);
+  }
+  void deallocate(value_type* p, size_t n) { alloc_->deallocate(p, n); }
+};
+
+#endif  // FMT_MOCK_ALLOCATOR_H_
diff --git a/src/fmt/test/module-test.cc b/src/fmt/test/module-test.cc
new file mode 100644
index 000000000..62e5fe8ba
--- /dev/null
+++ b/src/fmt/test/module-test.cc
@@ -0,0 +1,572 @@
+// Formatting library for C++ - module tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+//
+// Copyright (c) 2021 - present, Daniela Engert
+// All Rights Reserved
+// {fmt} module.
+
+#ifdef _MSC_FULL_VER
+// hide some implementation bugs in msvc
+// that are not essential to users of the module.
+#  define FMT_HIDE_MODULE_BUGS
+#endif
+
+#define FMT_MODULE_TEST
+
+#include <bit>
+#include <chrono>
+#include <exception>
+#include <iterator>
+#include <locale>
+#include <memory>
+#include <ostream>
+#include <string>
+#include <string_view>
+#include <system_error>
+
+#if (__has_include(<fcntl.h>) || defined(__APPLE__) || \
+     defined(__linux__)) &&                              \
+    (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
+#  include <fcntl.h>
+#  define FMT_USE_FCNTL 1
+#else
+#  define FMT_USE_FCNTL 0
+#endif
+#if defined(_WIN32) && !defined(__MINGW32__)
+#  define FMT_POSIX(call) _##call
+#else
+#  define FMT_POSIX(call) call
+#endif
+#define FMT_OS_H_  // don't pull in os.h directly or indirectly
+
+import fmt;
+
+// check for macros leaking from BMI
+static bool macro_leaked =
+#if defined(FMT_CORE_H_) || defined(FMT_FORMAT_H_)
+    true;
+#else
+    false;
+#endif
+
+// Include sources to pick up functions and classes from the module rather than
+// from the non-modular library which is baked into the 'test-main' library.
+// This averts linker problems:
+// - strong ownership model: missing linker symbols
+// - weak ownership model: duplicate linker symbols
+#include "gtest-extra.cc"
+#include "util.cc"
+
+// an implicitly exported namespace must be visible [module.interface]/2.2
+TEST(module_test, namespace) {
+  using namespace fmt;
+  using namespace fmt::literals;
+  ASSERT_TRUE(true);
+}
+
+namespace detail {
+bool oops_detail_namespace_is_visible;
+}
+
+namespace fmt {
+bool namespace_detail_invisible() {
+#if defined(FMT_HIDE_MODULE_BUGS) && defined(_MSC_FULL_VER) && \
+    ((_MSC_VER == 1929 && _MSC_FULL_VER <= 192930136) ||       \
+     (_MSC_VER == 1930 && _MSC_FULL_VER <= 193030704))
+  // bug in msvc up to 16.11.5 / 17.0-pre5:
+
+  // the namespace is visible even when it is neither
+  // implicitly nor explicitly exported
+  return true;
+#else
+  using namespace detail;
+  // this fails to compile if fmt::detail is visible
+  return !oops_detail_namespace_is_visible;
+#endif
+}
+}  // namespace fmt
+
+// the non-exported namespace 'detail' must be invisible [module.interface]/2
+TEST(module_test, detail_namespace) {
+  EXPECT_TRUE(fmt::namespace_detail_invisible());
+}
+
+// macros must not be imported from a *named* module  [cpp.import]/5.1
+TEST(module_test, macros) {
+#if defined(FMT_HIDE_MODULE_BUGS) && defined(_MSC_FULL_VER) && \
+    _MSC_FULL_VER <= 192930130
+  // bug in msvc up to 16.11-pre2:
+  // include-guard macros leak from BMI
+  // and even worse: they cannot be #undef-ined
+  macro_leaked = false;
+#endif
+  EXPECT_FALSE(macro_leaked);
+}
+
+// The following is less about functional testing (that's done elsewhere)
+// but rather visibility of all client-facing overloads, reachability of
+// non-exported entities, name lookup and overload resolution within
+// template instantitions.
+// Excercise all exported entities of the API at least once.
+// Instantiate as many code paths as possible.
+
+TEST(module_test, to_string) {
+  EXPECT_EQ("42", fmt::to_string(42));
+  EXPECT_EQ("42", fmt::to_string(42.0));
+
+  EXPECT_EQ(L"42", fmt::to_wstring(42));
+  EXPECT_EQ(L"42", fmt::to_wstring(42.0));
+}
+
+TEST(module_test, format) {
+  EXPECT_EQ("42", fmt::format("{:}", 42));
+  EXPECT_EQ("-42", fmt::format("{0}", -42.0));
+
+  EXPECT_EQ(L"42", fmt::format(L"{:}", 42));
+  EXPECT_EQ(L"-42", fmt::format(L"{0}", -42.0));
+}
+
+TEST(module_test, format_to) {
+  std::string s;
+  fmt::format_to(std::back_inserter(s), "{}", 42);
+  EXPECT_EQ("42", s);
+
+  char buffer[4] = {0};
+  fmt::format_to(buffer, "{}", 42);
+  EXPECT_EQ("42", std::string_view(buffer));
+
+  fmt::memory_buffer mb;
+  fmt::format_to(mb, "{}", 42);
+  EXPECT_EQ("42", std::string_view(buffer));
+
+  std::wstring w;
+  fmt::format_to(std::back_inserter(w), L"{}", 42);
+  EXPECT_EQ(L"42", w);
+
+  wchar_t wbuffer[4] = {0};
+  fmt::format_to(wbuffer, L"{}", 42);
+  EXPECT_EQ(L"42", std::wstring_view(wbuffer));
+
+  fmt::wmemory_buffer wb;
+  fmt::format_to(wb, L"{}", 42);
+  EXPECT_EQ(L"42", std::wstring_view(wbuffer));
+}
+
+TEST(module_test, formatted_size) {
+  EXPECT_EQ(2u, fmt::formatted_size("{}", 42));
+  EXPECT_EQ(2u, fmt::formatted_size(L"{}", 42));
+}
+
+TEST(module_test, format_to_n) {
+  std::string s;
+  auto result = fmt::format_to_n(std::back_inserter(s), 1, "{}", 42);
+  EXPECT_EQ(2u, result.size);
+  char buffer[4] = {0};
+  fmt::format_to_n(buffer, 3, "{}", 12345);
+
+  std::wstring w;
+  auto wresult = fmt::format_to_n(std::back_inserter(w), 1, L"{}", 42);
+  EXPECT_EQ(2u, wresult.size);
+  wchar_t wbuffer[4] = {0};
+  fmt::format_to_n(wbuffer, 3, L"{}", 12345);
+}
+
+TEST(module_test, format_args) {
+  auto no_args = fmt::format_args();
+  EXPECT_FALSE(no_args.get(1));
+
+  fmt::basic_format_args args = fmt::make_format_args(42);
+  EXPECT_TRUE(args.max_size() > 0);
+  auto arg0 = args.get(0);
+  EXPECT_TRUE(arg0);
+  decltype(arg0) arg_none;
+  EXPECT_FALSE(arg_none);
+  EXPECT_TRUE(arg0.type() != arg_none.type());
+}
+
+TEST(module_test, wformat_args) {
+  auto no_args = fmt::wformat_args();
+  EXPECT_FALSE(no_args.get(1));
+  fmt::basic_format_args args = fmt::make_wformat_args(42);
+  EXPECT_TRUE(args.get(0));
+}
+
+TEST(module_test, dynamic_format_args) {
+  fmt::dynamic_format_arg_store<fmt::format_context> dyn_store;
+  dyn_store.push_back(fmt::arg("a42", 42));
+  fmt::basic_format_args args = dyn_store;
+  EXPECT_FALSE(args.get(3));
+  EXPECT_TRUE(args.get(fmt::string_view("a42")));
+
+  fmt::dynamic_format_arg_store<fmt::wformat_context> wdyn_store;
+  wdyn_store.push_back(fmt::arg(L"a42", 42));
+  fmt::basic_format_args wargs = wdyn_store;
+  EXPECT_FALSE(wargs.get(3));
+  EXPECT_TRUE(wargs.get(fmt::wstring_view(L"a42")));
+}
+
+TEST(module_test, vformat) {
+  EXPECT_EQ("42", fmt::vformat("{}", fmt::make_format_args(42)));
+  EXPECT_EQ(L"42", fmt::vformat(fmt::to_string_view(L"{}"),
+                                fmt::make_wformat_args(42)));
+}
+
+TEST(module_test, vformat_to) {
+  auto store = fmt::make_format_args(42);
+  std::string s;
+  fmt::vformat_to(std::back_inserter(s), "{}", store);
+  EXPECT_EQ("42", s);
+
+  char buffer[4] = {0};
+  fmt::vformat_to(buffer, "{:}", store);
+  EXPECT_EQ("42", std::string_view(buffer));
+
+  auto wstore = fmt::make_wformat_args(42);
+  std::wstring w;
+  fmt::vformat_to(std::back_inserter(w), L"{}", wstore);
+  EXPECT_EQ(L"42", w);
+
+  wchar_t wbuffer[4] = {0};
+  fmt::vformat_to(wbuffer, L"{:}", wstore);
+  EXPECT_EQ(L"42", std::wstring_view(wbuffer));
+}
+
+TEST(module_test, vformat_to_n) {
+  auto store = fmt::make_format_args(12345);
+  std::string s;
+  auto result = fmt::vformat_to_n(std::back_inserter(s), 1, "{}", store);
+  char buffer[4] = {0};
+  fmt::vformat_to_n(buffer, 3, "{:}", store);
+
+  auto wstore = fmt::make_wformat_args(12345);
+  std::wstring w;
+  auto wresult = fmt::vformat_to_n(std::back_inserter(w), 1,
+                                   fmt::to_string_view(L"{}"), wstore);
+  wchar_t wbuffer[4] = {0};
+  fmt::vformat_to_n(wbuffer, 3, fmt::to_string_view(L"{:}"), wstore);
+}
+
+std::string as_string(std::wstring_view text) {
+  return {reinterpret_cast<const char*>(text.data()),
+          text.size() * sizeof(text[0])};
+}
+
+TEST(module_test, print) {
+  EXPECT_WRITE(stdout, fmt::print("{}µ", 42), "42µ");
+  EXPECT_WRITE(stderr, fmt::print(stderr, "{}µ", 4.2), "4.2µ");
+  if (false) {
+    EXPECT_WRITE(stdout, fmt::print(L"{}µ", 42), as_string(L"42µ"));
+    EXPECT_WRITE(stderr, fmt::print(stderr, L"{}µ", 4.2), as_string(L"4.2µ"));
+  }
+}
+
+TEST(module_test, vprint) {
+  EXPECT_WRITE(stdout, fmt::vprint("{:}µ", fmt::make_format_args(42)), "42µ");
+  EXPECT_WRITE(stderr, fmt::vprint(stderr, "{}", fmt::make_format_args(4.2)),
+               "4.2");
+  if (false) {
+    EXPECT_WRITE(stdout, fmt::vprint(L"{:}µ", fmt::make_wformat_args(42)),
+                 as_string(L"42µ"));
+    EXPECT_WRITE(stderr, fmt::vprint(stderr, L"{}", fmt::make_wformat_args(42)),
+                 as_string(L"42"));
+  }
+}
+
+TEST(module_test, named_args) {
+  EXPECT_EQ("42", fmt::format("{answer}", fmt::arg("answer", 42)));
+  EXPECT_EQ(L"42", fmt::format(L"{answer}", fmt::arg(L"answer", 42)));
+}
+
+TEST(module_test, literals) {
+  using namespace fmt::literals;
+  EXPECT_EQ("42", fmt::format("{answer}", "answer"_a = 42));
+  EXPECT_EQ("42", "{}"_format(42));
+  EXPECT_EQ(L"42", fmt::format(L"{answer}", L"answer"_a = 42));
+  EXPECT_EQ(L"42", L"{}"_format(42));
+}
+
+TEST(module_test, locale) {
+  auto store = fmt::make_format_args(4.2);
+  const auto classic = std::locale::classic();
+  EXPECT_EQ("4.2", fmt::format(classic, "{:L}", 4.2));
+  EXPECT_EQ("4.2", fmt::vformat(classic, "{:L}", store));
+  std::string s;
+  fmt::vformat_to(std::back_inserter(s), classic, "{:L}", store);
+  EXPECT_EQ("4.2", s);
+  EXPECT_EQ("4.2", fmt::format("{:L}", 4.2));
+
+  auto wstore = fmt::make_wformat_args(4.2);
+  EXPECT_EQ(L"4.2", fmt::format(classic, L"{:L}", 4.2));
+  EXPECT_EQ(L"4.2", fmt::vformat(classic, L"{:L}", wstore));
+  std::wstring w;
+  fmt::vformat_to(std::back_inserter(w), classic, L"{:L}", wstore);
+  EXPECT_EQ(L"4.2", w);
+  EXPECT_EQ(L"4.2", fmt::format(L"{:L}", 4.2));
+}
+
+TEST(module_test, string_view) {
+  fmt::string_view nsv("fmt");
+  EXPECT_EQ("fmt", nsv);
+  EXPECT_TRUE(fmt::string_view("fmt") == nsv);
+
+  fmt::wstring_view wsv(L"fmt");
+  EXPECT_EQ(L"fmt", wsv);
+  EXPECT_TRUE(fmt::wstring_view(L"fmt") == wsv);
+}
+
+TEST(module_test, memory_buffer) {
+  fmt::basic_memory_buffer<char, fmt::inline_buffer_size> buffer;
+  fmt::format_to(buffer, "{}", "42");
+  EXPECT_EQ("42", to_string(buffer));
+  fmt::memory_buffer nbuffer(std::move(buffer));
+  EXPECT_EQ("42", to_string(nbuffer));
+  buffer = std::move(nbuffer);
+  EXPECT_EQ("42", to_string(buffer));
+  nbuffer.clear();
+  EXPECT_EQ(0u, to_string(nbuffer).size());
+
+  fmt::wmemory_buffer wbuffer;
+  EXPECT_EQ(0u, to_string(wbuffer).size());
+}
+
+TEST(module_test, is_char) {
+  EXPECT_TRUE(fmt::is_char<char>());
+  EXPECT_TRUE(fmt::is_char<wchar_t>());
+  EXPECT_TRUE(fmt::is_char<char8_t>());
+  EXPECT_TRUE(fmt::is_char<char16_t>());
+  EXPECT_TRUE(fmt::is_char<char32_t>());
+  EXPECT_FALSE(fmt::is_char<signed char>());
+}
+
+TEST(module_test, ptr) {
+  uintptr_t answer = 42;
+  auto p = std::bit_cast<int*>(answer);
+  EXPECT_EQ("0x2a", fmt::to_string(fmt::ptr(p)));
+  std::unique_ptr<int> up(p);
+  EXPECT_EQ("0x2a", fmt::to_string(fmt::ptr(up)));
+  up.release();
+  auto sp = std::make_shared<int>(0);
+  p = sp.get();
+  EXPECT_EQ(fmt::to_string(fmt::ptr(p)), fmt::to_string(fmt::ptr(sp)));
+}
+
+TEST(module_test, errors) {
+  auto store = fmt::make_format_args(42);
+  EXPECT_THROW(throw fmt::format_error("oops"), std::exception);
+  EXPECT_THROW(throw fmt::vsystem_error(0, "{}", store), std::system_error);
+  EXPECT_THROW(throw fmt::system_error(0, "{}", 42), std::system_error);
+
+  fmt::memory_buffer buffer;
+  fmt::format_system_error(buffer, 0, "oops");
+  auto oops = to_string(buffer);
+  EXPECT_TRUE(oops.size() > 0);
+  EXPECT_WRITE(stderr, fmt::report_system_error(0, "oops"), oops + '\n');
+
+#ifdef _WIN32
+  EXPECT_THROW(throw fmt::vwindows_error(0, "{}", store), std::system_error);
+  EXPECT_THROW(throw fmt::windows_error(0, "{}", 42), std::system_error);
+  output_redirect redirect(stderr);
+  fmt::report_windows_error(0, "oops");
+  EXPECT_TRUE(redirect.restore_and_read().size() > 0);
+#endif
+}
+
+TEST(module_test, error_code) {
+  EXPECT_EQ("generic:42",
+            fmt::format("{0}", std::error_code(42, std::generic_category())));
+  EXPECT_EQ("system:42",
+            fmt::format("{0}", std::error_code(42, fmt::system_category())));
+  EXPECT_EQ(L"generic:42",
+            fmt::format(L"{0}", std::error_code(42, std::generic_category())));
+}
+
+TEST(module_test, format_int) {
+  fmt::format_int sanswer(42);
+  EXPECT_EQ("42", fmt::string_view(sanswer.data(), sanswer.size()));
+  fmt::format_int uanswer(42u);
+  EXPECT_EQ("42", fmt::string_view(uanswer.data(), uanswer.size()));
+}
+
+struct test_formatter : fmt::formatter<char> {
+  bool check() { return true; }
+};
+
+struct test_dynamic_formatter : fmt::dynamic_formatter<> {
+  bool check() { return true; }
+};
+
+TEST(module_test, formatter) {
+  EXPECT_TRUE(test_formatter{}.check());
+  EXPECT_TRUE(test_dynamic_formatter{}.check());
+}
+
+TEST(module_test, join) {
+  int arr[3] = {1, 2, 3};
+  std::vector<double> vec{1.0, 2.0, 3.0};
+  std::initializer_list<int> il{1, 2, 3};
+  auto sep = fmt::to_string_view(", ");
+  EXPECT_EQ("1, 2, 3", to_string(fmt::join(arr + 0, arr + 3, sep)));
+  EXPECT_EQ("1, 2, 3", to_string(fmt::join(arr, sep)));
+  EXPECT_EQ("1, 2, 3", to_string(fmt::join(vec.begin(), vec.end(), sep)));
+  EXPECT_EQ("1, 2, 3", to_string(fmt::join(vec, sep)));
+  EXPECT_EQ("1, 2, 3", to_string(fmt::join(il, sep)));
+
+  auto wsep = fmt::to_string_view(L", ");
+  EXPECT_EQ(L"1, 2, 3", fmt::format(L"{}", fmt::join(arr + 0, arr + 3, wsep)));
+  EXPECT_EQ(L"1, 2, 3", fmt::format(L"{}", fmt::join(arr, wsep)));
+  EXPECT_EQ(L"1, 2, 3", fmt::format(L"{}", fmt::join(il, wsep)));
+}
+
+TEST(module_test, time) {
+  auto time_now = std::time(nullptr);
+  EXPECT_TRUE(fmt::localtime(time_now).tm_year > 120);
+  EXPECT_TRUE(fmt::gmtime(time_now).tm_year > 120);
+  auto chrono_now = std::chrono::system_clock::now();
+  EXPECT_TRUE(fmt::localtime(chrono_now).tm_year > 120);
+  EXPECT_TRUE(fmt::gmtime(chrono_now).tm_year > 120);
+}
+
+TEST(module_test, time_point) {
+  auto now = std::chrono::system_clock::now();
+  std::string_view past("2021-05-20 10:30:15");
+  EXPECT_TRUE(past < fmt::format("{:%Y-%m-%d %H:%M:%S}", now));
+  std::wstring_view wpast(L"2021-05-20 10:30:15");
+  EXPECT_TRUE(wpast < fmt::format(L"{:%Y-%m-%d %H:%M:%S}", now));
+}
+
+TEST(module_test, time_duration) {
+  using us = std::chrono::duration<double, std::micro>;
+  EXPECT_EQ("42s", fmt::format("{}", std::chrono::seconds{42}));
+  EXPECT_EQ("4.2µs", fmt::format("{:3.1}", us{4.234}));
+  EXPECT_EQ("4.2µs", fmt::format(std::locale::classic(), "{:L}", us{4.2}));
+
+  EXPECT_EQ(L"42s", fmt::format(L"{}", std::chrono::seconds{42}));
+  EXPECT_EQ(L"4.2µs", fmt::format(L"{:3.1}", us{4.234}));
+  EXPECT_EQ(L"4.2µs", fmt::format(std::locale::classic(), L"{:L}", us{4.2}));
+}
+
+TEST(module_test, weekday) {
+  EXPECT_EQ("Mon", fmt::format(std::locale::classic(), "{}", fmt::weekday(1)));
+}
+
+TEST(module_test, to_string_view) {
+  using fmt::to_string_view;
+  fmt::string_view nsv{to_string_view("42")};
+  EXPECT_EQ("42", nsv);
+  fmt::wstring_view wsv{to_string_view(L"42")};
+  EXPECT_EQ(L"42", wsv);
+}
+
+TEST(module_test, printf) {
+  EXPECT_WRITE(stdout, fmt::printf("%f", 42.123456), "42.123456");
+  EXPECT_WRITE(stdout, fmt::printf("%d", 42), "42");
+  if (false) {
+    EXPECT_WRITE(stdout, fmt::printf(L"%f", 42.123456),
+                 as_string(L"42.123456"));
+    EXPECT_WRITE(stdout, fmt::printf(L"%d", 42), as_string(L"42"));
+  }
+}
+
+TEST(module_test, fprintf) {
+  EXPECT_WRITE(stderr, fmt::fprintf(stderr, "%d", 42), "42");
+  std::ostringstream os;
+  fmt::fprintf(os, "%s", "bla");
+  EXPECT_EQ("bla", os.str());
+
+  EXPECT_WRITE(stderr, fmt::fprintf(stderr, L"%d", 42), as_string(L"42"));
+  std::wostringstream ws;
+  fmt::fprintf(ws, L"%s", L"bla");
+  EXPECT_EQ(L"bla", ws.str());
+}
+
+TEST(module_test, sprintf) {
+  EXPECT_EQ("42", fmt::sprintf("%d", 42));
+  EXPECT_EQ(L"42", fmt::sprintf(L"%d", 42));
+}
+
+TEST(module_test, vprintf) {
+  EXPECT_WRITE(stdout, fmt::vprintf("%d", fmt::make_printf_args(42)), "42");
+  if (false) {
+    EXPECT_WRITE(stdout, fmt::vprintf(L"%d", fmt::make_wprintf_args(42)),
+                 as_string(L"42"));
+  }
+}
+
+TEST(module_test, vfprintf) {
+  auto args = fmt::make_printf_args(42);
+  EXPECT_WRITE(stderr, fmt::vfprintf(stderr, "%d", args), "42");
+  std::ostringstream os;
+  fmt::vfprintf(os, "%d", args);
+  EXPECT_EQ("42", os.str());
+  auto wargs = fmt::make_wprintf_args(42);
+  if (false) {
+    EXPECT_WRITE(stderr, fmt::vfprintf(stderr, L"%d", wargs), as_string(L"42"));
+  }
+  std::wostringstream ws;
+  fmt::vfprintf(ws, L"%d", wargs);
+  EXPECT_EQ(L"42", ws.str());
+}
+
+TEST(module_test, vsprintf) {
+  EXPECT_EQ("42", fmt::vsprintf("%d", fmt::make_printf_args(42)));
+  EXPECT_EQ(L"42", fmt::vsprintf(L"%d", fmt::make_wprintf_args(42)));
+}
+
+TEST(module_test, color) {
+  auto fg_check = fg(fmt::rgb(255, 200, 30));
+  auto bg_check = bg(fmt::color::dark_slate_gray) | fmt::emphasis::italic;
+  auto emphasis_check = fmt::emphasis::underline | fmt::emphasis::bold;
+  EXPECT_EQ("\x1B[30m42\x1B[0m",
+            fmt::format(fg(fmt::terminal_color::black), "{}", 42));
+  EXPECT_EQ(L"\x1B[30m42\x1B[0m",
+            fmt::format(fg(fmt::terminal_color::black), L"{}", 42));
+}
+
+TEST(module_test, cstring_view) {
+  auto s = "fmt";
+  EXPECT_EQ(s, fmt::cstring_view(s).c_str());
+  auto w = L"fmt";
+  EXPECT_EQ(w, fmt::wcstring_view(w).c_str());
+}
+
+TEST(module_test, buffered_file) {
+  EXPECT_TRUE(fmt::buffered_file{}.get() == nullptr);
+}
+
+TEST(module_test, output_file) {
+  fmt::ostream out = fmt::output_file("module-test", fmt::buffer_size = 1);
+  out.close();
+}
+
+struct custom_context {
+  using char_type = char;
+  using parse_context_type = fmt::format_parse_context;
+};
+
+TEST(module_test, custom_context) {
+  fmt::basic_format_arg<custom_context> custom_arg;
+  EXPECT_TRUE(!custom_arg);
+}
+
+struct disabled_formatter {};
+
+TEST(module_test, has_formatter) {
+  EXPECT_FALSE(
+      (fmt::has_formatter<disabled_formatter, fmt::format_context>::value));
+}
+
+TEST(module_test, is_formattable) {
+  EXPECT_FALSE(fmt::is_formattable<disabled_formatter>::value);
+}
+
+TEST(module_test, compile_format_string) {
+  using namespace fmt::literals;
+  EXPECT_EQ("42", fmt::format("{0:x}"_cf, 0x42));
+  EXPECT_EQ(L"42", fmt::format(L"{:}"_cf, 42));
+  EXPECT_EQ("4.2", fmt::format("{arg:3.1f}"_cf, "arg"_a = 4.2));
+  EXPECT_EQ(L" 42", fmt::format(L"{arg:>3}"_cf, L"arg"_a = L"42"));
+}
diff --git a/src/fmt/test/noexception-test.cc b/src/fmt/test/noexception-test.cc
new file mode 100644
index 000000000..bf3472fd1
--- /dev/null
+++ b/src/fmt/test/noexception-test.cc
@@ -0,0 +1,18 @@
+// Formatting library for C++ - Noexception tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/args.h"
+#include "fmt/chrono.h"
+#include "fmt/color.h"
+#include "fmt/compile.h"
+#include "fmt/core.h"
+#include "fmt/format.h"
+#include "fmt/os.h"
+#include "fmt/ostream.h"
+#include "fmt/printf.h"
+#include "fmt/ranges.h"
+#include "fmt/xchar.h"
diff --git a/src/fmt/test/os-test.cc b/src/fmt/test/os-test.cc
new file mode 100644
index 000000000..a1745c8c8
--- /dev/null
+++ b/src/fmt/test/os-test.cc
@@ -0,0 +1,547 @@
+// Formatting library for C++ - tests of the OS-specific functionality
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/os.h"
+
+#include <cstdlib>  // std::exit
+#include <cstring>
+#include <memory>
+
+#include "gtest-extra.h"
+#include "util.h"
+
+using fmt::buffered_file;
+using testing::HasSubstr;
+using wstring_view = fmt::basic_string_view<wchar_t>;
+
+#ifdef _WIN32
+
+#  include <windows.h>
+
+TEST(util_test, utf16_to_utf8) {
+  auto s = std::string("ёжик");
+  fmt::detail::utf16_to_utf8 u(L"\x0451\x0436\x0438\x043A");
+  EXPECT_EQ(s, u.str());
+  EXPECT_EQ(s.size(), u.size());
+}
+
+TEST(util_test, utf16_to_utf8_empty_string) {
+  std::string s = "";
+  fmt::detail::utf16_to_utf8 u(L"");
+  EXPECT_EQ(s, u.str());
+  EXPECT_EQ(s.size(), u.size());
+}
+
+template <typename Converter, typename Char>
+void check_utf_conversion_error(const char* message,
+                                fmt::basic_string_view<Char> str =
+                                    fmt::basic_string_view<Char>(nullptr, 1)) {
+  fmt::memory_buffer out;
+  fmt::detail::format_windows_error(out, ERROR_INVALID_PARAMETER, message);
+  auto error = std::system_error(std::error_code());
+  try {
+    (Converter)(str);
+  } catch (const std::system_error& e) {
+    error = e;
+  }
+  EXPECT_EQ(ERROR_INVALID_PARAMETER, error.code().value());
+  EXPECT_THAT(error.what(), HasSubstr(fmt::to_string(out)));
+}
+
+TEST(util_test, utf16_to_utf8_error) {
+  check_utf_conversion_error<fmt::detail::utf16_to_utf8, wchar_t>(
+      "cannot convert string from UTF-16 to UTF-8");
+}
+
+TEST(util_test, utf16_to_utf8_convert) {
+  fmt::detail::utf16_to_utf8 u;
+  EXPECT_EQ(ERROR_INVALID_PARAMETER, u.convert(wstring_view(nullptr, 1)));
+  EXPECT_EQ(ERROR_INVALID_PARAMETER,
+            u.convert(wstring_view(L"foo", INT_MAX + 1u)));
+}
+
+TEST(os_test, format_std_error_code) {
+  EXPECT_EQ("generic:42",
+            fmt::format(FMT_STRING("{0}"),
+                        std::error_code(42, std::generic_category())));
+  EXPECT_EQ("system:42",
+            fmt::format(FMT_STRING("{0}"),
+                        std::error_code(42, fmt::system_category())));
+  EXPECT_EQ("system:-42",
+            fmt::format(FMT_STRING("{0}"),
+                        std::error_code(-42, fmt::system_category())));
+}
+
+TEST(os_test, format_windows_error) {
+  LPWSTR message = nullptr;
+  auto result = FormatMessageW(
+      FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+          FORMAT_MESSAGE_IGNORE_INSERTS,
+      nullptr, ERROR_FILE_EXISTS, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+      reinterpret_cast<LPWSTR>(&message), 0, nullptr);
+  fmt::detail::utf16_to_utf8 utf8_message(wstring_view(message, result - 2));
+  LocalFree(message);
+  fmt::memory_buffer actual_message;
+  fmt::detail::format_windows_error(actual_message, ERROR_FILE_EXISTS, "test");
+  EXPECT_EQ(fmt::format("test: {}", utf8_message.str()),
+            fmt::to_string(actual_message));
+  actual_message.resize(0);
+}
+
+TEST(os_test, format_long_windows_error) {
+  LPWSTR message = nullptr;
+  // this error code is not available on all Windows platforms and
+  // Windows SDKs, so do not fail the test if the error string cannot
+  // be retrieved.
+  int provisioning_not_allowed = 0x80284013L;  // TBS_E_PROVISIONING_NOT_ALLOWED
+  auto result = FormatMessageW(
+      FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+          FORMAT_MESSAGE_IGNORE_INSERTS,
+      nullptr, static_cast<DWORD>(provisioning_not_allowed),
+      MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+      reinterpret_cast<LPWSTR>(&message), 0, nullptr);
+  if (result == 0) {
+    LocalFree(message);
+    return;
+  }
+  fmt::detail::utf16_to_utf8 utf8_message(wstring_view(message, result - 2));
+  LocalFree(message);
+  fmt::memory_buffer actual_message;
+  fmt::detail::format_windows_error(actual_message, provisioning_not_allowed,
+                                    "test");
+  EXPECT_EQ(fmt::format("test: {}", utf8_message.str()),
+            fmt::to_string(actual_message));
+}
+
+TEST(os_test, windows_error) {
+  auto error = std::system_error(std::error_code());
+  try {
+    throw fmt::windows_error(ERROR_FILE_EXISTS, "test {}", "error");
+  } catch (const std::system_error& e) {
+    error = e;
+  }
+  fmt::memory_buffer message;
+  fmt::detail::format_windows_error(message, ERROR_FILE_EXISTS, "test error");
+  EXPECT_THAT(error.what(), HasSubstr(to_string(message)));
+  EXPECT_EQ(ERROR_FILE_EXISTS, error.code().value());
+}
+
+TEST(os_test, report_windows_error) {
+  fmt::memory_buffer out;
+  fmt::detail::format_windows_error(out, ERROR_FILE_EXISTS, "test error");
+  out.push_back('\n');
+  EXPECT_WRITE(stderr,
+               fmt::report_windows_error(ERROR_FILE_EXISTS, "test error"),
+               fmt::to_string(out));
+}
+
+#endif  // _WIN32
+
+#if FMT_USE_FCNTL
+
+using fmt::file;
+
+bool isclosed(int fd) {
+  char buffer;
+  auto result = std::streamsize();
+  SUPPRESS_ASSERT(result = FMT_POSIX(read(fd, &buffer, 1)));
+  return result == -1 && errno == EBADF;
+}
+
+// Opens a file for reading.
+file open_file() {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  write_end.write(file_content, std::strlen(file_content));
+  write_end.close();
+  return read_end;
+}
+
+// Attempts to write a string to a file.
+void write(file& f, fmt::string_view s) {
+  size_t num_chars_left = s.size();
+  const char* ptr = s.data();
+  do {
+    size_t count = f.write(ptr, num_chars_left);
+    ptr += count;
+    // We can't write more than size_t bytes since num_chars_left
+    // has type size_t.
+    num_chars_left -= count;
+  } while (num_chars_left != 0);
+}
+
+TEST(buffered_file_test, default_ctor) {
+  auto f = buffered_file();
+  EXPECT_TRUE(f.get() == nullptr);
+}
+
+TEST(buffered_file_test, move_ctor) {
+  buffered_file bf = open_buffered_file();
+  FILE* fp = bf.get();
+  EXPECT_TRUE(fp != nullptr);
+  buffered_file bf2(std::move(bf));
+  EXPECT_EQ(fp, bf2.get());
+  EXPECT_TRUE(bf.get() == nullptr);
+}
+
+TEST(buffered_file_test, move_assignment) {
+  buffered_file bf = open_buffered_file();
+  FILE* fp = bf.get();
+  EXPECT_TRUE(fp != nullptr);
+  buffered_file bf2;
+  bf2 = std::move(bf);
+  EXPECT_EQ(fp, bf2.get());
+  EXPECT_TRUE(bf.get() == nullptr);
+}
+
+TEST(buffered_file_test, move_assignment_closes_file) {
+  buffered_file bf = open_buffered_file();
+  buffered_file bf2 = open_buffered_file();
+  int old_fd = bf2.descriptor();
+  bf2 = std::move(bf);
+  EXPECT_TRUE(isclosed(old_fd));
+}
+
+TEST(buffered_file_test, move_from_temporary_in_ctor) {
+  FILE* fp = nullptr;
+  buffered_file f = open_buffered_file(&fp);
+  EXPECT_EQ(fp, f.get());
+}
+
+TEST(buffered_file_test, move_from_temporary_in_assignment) {
+  FILE* fp = nullptr;
+  auto f = buffered_file();
+  f = open_buffered_file(&fp);
+  EXPECT_EQ(fp, f.get());
+}
+
+TEST(buffered_file_test, move_from_temporary_in_assignment_closes_file) {
+  buffered_file f = open_buffered_file();
+  int old_fd = f.descriptor();
+  f = open_buffered_file();
+  EXPECT_TRUE(isclosed(old_fd));
+}
+
+TEST(buffered_file_test, close_file_in_dtor) {
+  int fd = 0;
+  {
+    buffered_file f = open_buffered_file();
+    fd = f.descriptor();
+  }
+  EXPECT_TRUE(isclosed(fd));
+}
+
+TEST(buffered_file_test, close_error_in_dtor) {
+  auto f =
+      std::unique_ptr<buffered_file>(new buffered_file(open_buffered_file()));
+  EXPECT_WRITE(
+      stderr,
+      {
+        // The close function must be called inside EXPECT_WRITE,
+        // otherwise the system may recycle closed file descriptor when
+        // redirecting the output in EXPECT_STDERR and the second close
+        // will break output redirection.
+        FMT_POSIX(close(f->descriptor()));
+        SUPPRESS_ASSERT(f.reset(nullptr));
+      },
+      system_error_message(EBADF, "cannot close file") + "\n");
+}
+
+TEST(buffered_file_test, close) {
+  buffered_file f = open_buffered_file();
+  int fd = f.descriptor();
+  f.close();
+  EXPECT_TRUE(f.get() == nullptr);
+  EXPECT_TRUE(isclosed(fd));
+}
+
+TEST(buffered_file_test, close_error) {
+  buffered_file f = open_buffered_file();
+  FMT_POSIX(close(f.descriptor()));
+  EXPECT_SYSTEM_ERROR_NOASSERT(f.close(), EBADF, "cannot close file");
+  EXPECT_TRUE(f.get() == nullptr);
+}
+
+TEST(buffered_file_test, descriptor) {
+  auto f = open_buffered_file();
+  EXPECT_TRUE(f.descriptor() != -1);
+  file copy = file::dup(f.descriptor());
+  EXPECT_READ(copy, file_content);
+}
+
+TEST(ostream_test, move) {
+  fmt::ostream out = fmt::output_file("test-file");
+  fmt::ostream moved(std::move(out));
+  moved.print("hello");
+}
+
+TEST(ostream_test, move_while_holding_data) {
+  {
+    fmt::ostream out = fmt::output_file("test-file");
+    out.print("Hello, ");
+    fmt::ostream moved(std::move(out));
+    moved.print("world!\n");
+  }
+  {
+    file in("test-file", file::RDONLY);
+    EXPECT_READ(in, "Hello, world!\n");
+  }
+}
+
+TEST(ostream_test, print) {
+  fmt::ostream out = fmt::output_file("test-file");
+  out.print("The answer is {}.\n",
+            fmt::join(std::initializer_list<int>{42}, ", "));
+  out.close();
+  file in("test-file", file::RDONLY);
+  EXPECT_READ(in, "The answer is 42.\n");
+}
+
+TEST(ostream_test, buffer_boundary) {
+  auto str = std::string(4096, 'x');
+  fmt::ostream out = fmt::output_file("test-file");
+  out.print("{}", str);
+  out.print("{}", str);
+  out.close();
+  file in("test-file", file::RDONLY);
+  EXPECT_READ(in, str + str);
+}
+
+TEST(ostream_test, buffer_size) {
+  fmt::ostream out = fmt::output_file("test-file", fmt::buffer_size = 1);
+  out.print("{}", "foo");
+  out.close();
+  file in("test-file", file::RDONLY);
+  EXPECT_READ(in, "foo");
+}
+
+TEST(ostream_test, truncate) {
+  {
+    fmt::ostream out = fmt::output_file("test-file");
+    out.print("0123456789");
+  }
+  {
+    fmt::ostream out = fmt::output_file("test-file");
+    out.print("foo");
+  }
+  file in("test-file", file::RDONLY);
+  EXPECT_EQ("foo", read(in, 4));
+}
+
+TEST(ostream_test, flush) {
+  auto out = fmt::output_file("test-file");
+  out.print("x");
+  out.flush();
+  auto in = fmt::file("test-file", file::RDONLY);
+  EXPECT_READ(in, "x");
+}
+
+TEST(file_test, default_ctor) {
+  file f;
+  EXPECT_EQ(-1, f.descriptor());
+}
+
+TEST(file_test, open_buffered_file_in_ctor) {
+  FILE* fp = safe_fopen("test-file", "w");
+  std::fputs(file_content, fp);
+  std::fclose(fp);
+  file f("test-file", file::RDONLY);
+  // Check if the file is open by reading one character from it.
+  char buffer;
+  bool isopen = FMT_POSIX(read(f.descriptor(), &buffer, 1)) == 1;
+  ASSERT_TRUE(isopen);
+}
+
+TEST(file_test, open_buffered_file_error) {
+  EXPECT_SYSTEM_ERROR(file("nonexistent", file::RDONLY), ENOENT,
+                      "cannot open file nonexistent");
+}
+
+TEST(file_test, move_ctor) {
+  file f = open_file();
+  int fd = f.descriptor();
+  EXPECT_NE(-1, fd);
+  file f2(std::move(f));
+  EXPECT_EQ(fd, f2.descriptor());
+  EXPECT_EQ(-1, f.descriptor());
+}
+
+TEST(file_test, move_assignment) {
+  file f = open_file();
+  int fd = f.descriptor();
+  EXPECT_NE(-1, fd);
+  file f2;
+  f2 = std::move(f);
+  EXPECT_EQ(fd, f2.descriptor());
+  EXPECT_EQ(-1, f.descriptor());
+}
+
+TEST(file_test, move_assignment_closes_file) {
+  file f = open_file();
+  file f2 = open_file();
+  int old_fd = f2.descriptor();
+  f2 = std::move(f);
+  EXPECT_TRUE(isclosed(old_fd));
+}
+
+file open_buffered_file(int& fd) {
+  file f = open_file();
+  fd = f.descriptor();
+  return f;
+}
+
+TEST(file_test, move_from_temporary_in_ctor) {
+  int fd = 0xdead;
+  file f(open_buffered_file(fd));
+  EXPECT_EQ(fd, f.descriptor());
+}
+
+TEST(file_test, move_from_temporary_in_assignment) {
+  int fd = 0xdead;
+  file f;
+  f = open_buffered_file(fd);
+  EXPECT_EQ(fd, f.descriptor());
+}
+
+TEST(file_test, move_from_temporary_in_assignment_closes_file) {
+  int fd = 0xdead;
+  file f = open_file();
+  int old_fd = f.descriptor();
+  f = open_buffered_file(fd);
+  EXPECT_TRUE(isclosed(old_fd));
+}
+
+TEST(file_test, close_file_in_dtor) {
+  int fd = 0;
+  {
+    file f = open_file();
+    fd = f.descriptor();
+  }
+  EXPECT_TRUE(isclosed(fd));
+}
+
+TEST(file_test, close_error_in_dtor) {
+  std::unique_ptr<file> f(new file(open_file()));
+  EXPECT_WRITE(
+      stderr,
+      {
+        // The close function must be called inside EXPECT_WRITE,
+        // otherwise the system may recycle closed file descriptor when
+        // redirecting the output in EXPECT_STDERR and the second close
+        // will break output redirection.
+        FMT_POSIX(close(f->descriptor()));
+        SUPPRESS_ASSERT(f.reset(nullptr));
+      },
+      system_error_message(EBADF, "cannot close file") + "\n");
+}
+
+TEST(file_test, close) {
+  file f = open_file();
+  int fd = f.descriptor();
+  f.close();
+  EXPECT_EQ(-1, f.descriptor());
+  EXPECT_TRUE(isclosed(fd));
+}
+
+TEST(file_test, close_error) {
+  file f = open_file();
+  FMT_POSIX(close(f.descriptor()));
+  EXPECT_SYSTEM_ERROR_NOASSERT(f.close(), EBADF, "cannot close file");
+  EXPECT_EQ(-1, f.descriptor());
+}
+
+TEST(file_test, read) {
+  file f = open_file();
+  EXPECT_READ(f, file_content);
+}
+
+TEST(file_test, read_error) {
+  file f("test-file", file::WRONLY);
+  char buf;
+  // We intentionally read from a file opened in the write-only mode to
+  // cause error.
+  EXPECT_SYSTEM_ERROR(f.read(&buf, 1), EBADF, "cannot read from file");
+}
+
+TEST(file_test, write) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  write(write_end, "test");
+  write_end.close();
+  EXPECT_READ(read_end, "test");
+}
+
+TEST(file_test, write_error) {
+  file f("test-file", file::RDONLY);
+  // We intentionally write to a file opened in the read-only mode to
+  // cause error.
+  EXPECT_SYSTEM_ERROR(f.write(" ", 1), EBADF, "cannot write to file");
+}
+
+TEST(file_test, dup) {
+  file f = open_file();
+  file copy = file::dup(f.descriptor());
+  EXPECT_NE(f.descriptor(), copy.descriptor());
+  EXPECT_EQ(file_content, read(copy, std::strlen(file_content)));
+}
+
+#  ifndef __COVERITY__
+TEST(file_test, dup_error) {
+  int value = -1;
+  EXPECT_SYSTEM_ERROR_NOASSERT(file::dup(value), EBADF,
+                               "cannot duplicate file descriptor -1");
+}
+#  endif
+
+TEST(file_test, dup2) {
+  file f = open_file();
+  file copy = open_file();
+  f.dup2(copy.descriptor());
+  EXPECT_NE(f.descriptor(), copy.descriptor());
+  EXPECT_READ(copy, file_content);
+}
+
+TEST(file_test, dup2_error) {
+  file f = open_file();
+  EXPECT_SYSTEM_ERROR_NOASSERT(
+      f.dup2(-1), EBADF,
+      fmt::format("cannot duplicate file descriptor {} to -1", f.descriptor()));
+}
+
+TEST(file_test, dup2_noexcept) {
+  file f = open_file();
+  file copy = open_file();
+  std::error_code ec;
+  f.dup2(copy.descriptor(), ec);
+  EXPECT_EQ(ec.value(), 0);
+  EXPECT_NE(f.descriptor(), copy.descriptor());
+  EXPECT_READ(copy, file_content);
+}
+
+TEST(file_test, dup2_noexcept_error) {
+  file f = open_file();
+  std::error_code ec;
+  SUPPRESS_ASSERT(f.dup2(-1, ec));
+  EXPECT_EQ(EBADF, ec.value());
+}
+
+TEST(file_test, pipe) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  EXPECT_NE(-1, read_end.descriptor());
+  EXPECT_NE(-1, write_end.descriptor());
+  write(write_end, "test");
+  EXPECT_READ(read_end, "test");
+}
+
+TEST(file_test, fdopen) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  int read_fd = read_end.descriptor();
+  EXPECT_EQ(read_fd, FMT_POSIX(fileno(read_end.fdopen("r").get())));
+}
+#endif  // FMT_USE_FCNTL
diff --git a/src/fmt/test/ostream-test.cc b/src/fmt/test/ostream-test.cc
new file mode 100644
index 000000000..a3a51d532
--- /dev/null
+++ b/src/fmt/test/ostream-test.cc
@@ -0,0 +1,322 @@
+// Formatting library for C++ - std::ostream support tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <fstream>
+
+#include "fmt/format.h"
+
+using fmt::runtime;
+
+struct test {};
+
+// Test that there is no issues with specializations when fmt/ostream.h is
+// included after fmt/format.h.
+namespace fmt {
+template <> struct formatter<test> : formatter<int> {
+  auto format(const test&, format_context& ctx) -> decltype(ctx.out()) {
+    return formatter<int>::format(42, ctx);
+  }
+};
+}  // namespace fmt
+
+#include <sstream>
+
+#include "fmt/compile.h"
+#include "fmt/ostream.h"
+#include "fmt/ranges.h"
+#include "gmock/gmock.h"
+#include "gtest-extra.h"
+#include "util.h"
+
+auto operator<<(std::ostream& os, const date& d) -> std::ostream& {
+  os << d.year() << '-' << d.month() << '-' << d.day();
+  return os;
+}
+
+auto operator<<(std::wostream& os, const date& d) -> std::wostream& {
+  os << d.year() << L'-' << d.month() << L'-' << d.day();
+  return os;
+}
+
+// Make sure that overloaded comma operators do no harm to is_streamable.
+struct type_with_comma_op {};
+template <typename T> void operator,(type_with_comma_op, const T&);
+template <typename T> type_with_comma_op operator<<(T&, const date&);
+
+enum streamable_enum {};
+
+auto operator<<(std::ostream& os, streamable_enum) -> std::ostream& {
+  return os << "streamable_enum";
+}
+
+enum unstreamable_enum {};
+auto format_as(unstreamable_enum e) -> int { return e; }
+
+struct empty_test {};
+auto operator<<(std::ostream& os, empty_test) -> std::ostream& {
+  return os << "";
+}
+
+namespace fmt {
+template <> struct formatter<test_string> : ostream_formatter {};
+template <> struct formatter<date> : ostream_formatter {};
+template <> struct formatter<streamable_enum> : ostream_formatter {};
+template <> struct formatter<empty_test> : ostream_formatter {};
+}  // namespace fmt
+
+TEST(ostream_test, enum) {
+  EXPECT_EQ("streamable_enum", fmt::format("{}", streamable_enum()));
+  EXPECT_EQ("0", fmt::format("{}", unstreamable_enum()));
+}
+
+TEST(ostream_test, format) {
+  EXPECT_EQ("a string", fmt::format("{0}", test_string("a string")));
+  EXPECT_EQ("The date is 2012-12-9",
+            fmt::format("The date is {0}", date(2012, 12, 9)));
+}
+
+TEST(ostream_test, format_specs) {
+  using fmt::format_error;
+  EXPECT_EQ("def  ", fmt::format("{0:<5}", test_string("def")));
+  EXPECT_EQ("  def", fmt::format("{0:>5}", test_string("def")));
+  EXPECT_EQ(" def ", fmt::format("{0:^5}", test_string("def")));
+  EXPECT_EQ("def**", fmt::format("{0:*<5}", test_string("def")));
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:+}"), test_string()),
+                   format_error, "format specifier requires numeric argument");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:-}"), test_string()),
+                   format_error, "format specifier requires numeric argument");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0: }"), test_string()),
+                   format_error, "format specifier requires numeric argument");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:#}"), test_string()),
+                   format_error, "format specifier requires numeric argument");
+  EXPECT_THROW_MSG((void)fmt::format(runtime("{0:05}"), test_string()),
+                   format_error, "format specifier requires numeric argument");
+  EXPECT_EQ("test         ", fmt::format("{0:13}", test_string("test")));
+  EXPECT_EQ("test         ", fmt::format("{0:{1}}", test_string("test"), 13));
+  EXPECT_EQ("te", fmt::format("{0:.2}", test_string("test")));
+  EXPECT_EQ("te", fmt::format("{0:.{1}}", test_string("test"), 2));
+}
+
+TEST(ostream_test, empty_custom_output) {
+  EXPECT_EQ("", fmt::format("{}", empty_test()));
+}
+
+TEST(ostream_test, print) {
+  std::ostringstream os;
+  fmt::print(os, "Don't {}!", "panic");
+  EXPECT_EQ("Don't panic!", os.str());
+}
+
+TEST(ostream_test, write_to_ostream) {
+  std::ostringstream os;
+  fmt::memory_buffer buffer;
+  const char* foo = "foo";
+  buffer.append(foo, foo + std::strlen(foo));
+  fmt::detail::write_buffer(os, buffer);
+  EXPECT_EQ("foo", os.str());
+}
+
+TEST(ostream_test, write_to_ostream_max_size) {
+  auto max_size = fmt::detail::max_value<size_t>();
+  auto max_streamsize = fmt::detail::max_value<std::streamsize>();
+  if (max_size <= fmt::detail::to_unsigned(max_streamsize)) return;
+
+  struct test_buffer final : fmt::detail::buffer<char> {
+    explicit test_buffer(size_t size)
+        : fmt::detail::buffer<char>(nullptr, size, size) {}
+    void grow(size_t) override {}
+  } buffer(max_size);
+
+  struct mock_streambuf : std::streambuf {
+    MOCK_METHOD2(xsputn, std::streamsize(const void* s, std::streamsize n));
+    auto xsputn(const char* s, std::streamsize n) -> std::streamsize override {
+      const void* v = s;
+      return xsputn(v, n);
+    }
+  } streambuf;
+
+  struct test_ostream : std::ostream {
+    explicit test_ostream(mock_streambuf& output_buffer)
+        : std::ostream(&output_buffer) {}
+  } os(streambuf);
+
+  testing::InSequence sequence;
+  const char* data = nullptr;
+  using ustreamsize = std::make_unsigned<std::streamsize>::type;
+  ustreamsize size = max_size;
+  do {
+    auto n = std::min(size, fmt::detail::to_unsigned(max_streamsize));
+    EXPECT_CALL(streambuf, xsputn(data, static_cast<std::streamsize>(n)))
+        .WillOnce(testing::Return(max_streamsize));
+    data += n;
+    size -= n;
+  } while (size != 0);
+  fmt::detail::write_buffer(os, buffer);
+}
+
+TEST(ostream_test, join) {
+  int v[3] = {1, 2, 3};
+  EXPECT_EQ("1, 2, 3", fmt::format("{}", fmt::join(v, v + 3, ", ")));
+}
+
+TEST(ostream_test, join_fallback_formatter) {
+  auto strs = std::vector<test_string>{test_string("foo"), test_string("bar")};
+  EXPECT_EQ("foo, bar", fmt::format("{}", fmt::join(strs, ", ")));
+}
+
+#if FMT_USE_CONSTEXPR
+TEST(ostream_test, constexpr_string) {
+  EXPECT_EQ("42", fmt::format(FMT_STRING("{}"), std::string("42")));
+  EXPECT_EQ("a string",
+            fmt::format(FMT_STRING("{0}"), test_string("a string")));
+}
+#endif
+
+namespace fmt_test {
+struct abc {};
+
+template <typename Output> auto operator<<(Output& out, abc) -> Output& {
+  return out << "abc";
+}
+}  // namespace fmt_test
+
+template <typename T> struct test_template {};
+
+template <typename T>
+auto operator<<(std::ostream& os, test_template<T>) -> std::ostream& {
+  return os << 1;
+}
+
+namespace fmt {
+template <typename T> struct formatter<test_template<T>> : formatter<int> {
+  auto format(test_template<T>, format_context& ctx) -> decltype(ctx.out()) {
+    return formatter<int>::format(2, ctx);
+  }
+};
+
+template <> struct formatter<fmt_test::abc> : ostream_formatter {};
+}  // namespace fmt
+
+TEST(ostream_test, template) {
+  EXPECT_EQ("2", fmt::format("{}", test_template<int>()));
+}
+
+TEST(ostream_test, format_to_n) {
+  char buffer[4];
+  buffer[3] = 'x';
+  auto result = fmt::format_to_n(buffer, 3, "{}", fmt_test::abc());
+  EXPECT_EQ(3u, result.size);
+  EXPECT_EQ(buffer + 3, result.out);
+  EXPECT_EQ("abcx", fmt::string_view(buffer, 4));
+  result = fmt::format_to_n(buffer, 3, "x{}y", fmt_test::abc());
+  EXPECT_EQ(5u, result.size);
+  EXPECT_EQ(buffer + 3, result.out);
+  EXPECT_EQ("xabx", fmt::string_view(buffer, 4));
+}
+
+template <typename T> struct convertible {
+  T value;
+  explicit convertible(const T& val) : value(val) {}
+  operator T() const { return value; }
+};
+
+TEST(ostream_test, disable_builtin_ostream_operators) {
+  EXPECT_EQ("42", fmt::format("{:d}", convertible<unsigned short>(42)));
+  EXPECT_EQ("foo", fmt::format("{}", convertible<const char*>("foo")));
+}
+
+struct streamable_and_convertible_to_bool {
+  operator bool() const { return true; }
+};
+
+std::ostream& operator<<(std::ostream& os, streamable_and_convertible_to_bool) {
+  return os << "foo";
+}
+
+TEST(ostream_test, format_convertible_to_bool) {
+  // operator<< is intentionally not used because of potential ODR violations.
+  EXPECT_EQ(fmt::format("{}", streamable_and_convertible_to_bool()), "true");
+}
+
+struct streamable_and_convertible_to_string_view {
+  operator fmt::string_view() const { return "foo"; }
+};
+
+std::ostream& operator<<(std::ostream& os,
+                         streamable_and_convertible_to_string_view) {
+  return os << "bar";
+}
+
+TEST(ostream_test, format_convertible_to_string_vew) {
+  // operator<< is intentionally not used because of potential ODR violations.
+  EXPECT_EQ(fmt::format("{}", streamable_and_convertible_to_string_view()),
+            "foo");
+}
+
+struct copyfmt_test {};
+
+std::ostream& operator<<(std::ostream& os, copyfmt_test) {
+  std::ios ios(nullptr);
+  ios.copyfmt(os);
+  return os << "foo";
+}
+
+namespace fmt {
+template <> struct formatter<copyfmt_test> : ostream_formatter {};
+}  // namespace fmt
+
+TEST(ostream_test, copyfmt) {
+  EXPECT_EQ("foo", fmt::format("{}", copyfmt_test()));
+}
+
+TEST(ostream_test, to_string) {
+  EXPECT_EQ("abc", fmt::to_string(fmt_test::abc()));
+}
+
+TEST(ostream_test, range) {
+  auto strs = std::vector<test_string>{test_string("foo"), test_string("bar")};
+  EXPECT_EQ("[foo, bar]", fmt::format("{}", strs));
+}
+
+struct abstract {
+  virtual ~abstract() = default;
+  virtual void f() = 0;
+  friend auto operator<<(std::ostream& os, const abstract&) -> std::ostream& {
+    return os;
+  }
+};
+
+namespace fmt {
+template <> struct formatter<abstract> : ostream_formatter {};
+}  // namespace fmt
+
+void format_abstract_compiles(const abstract& a) {
+  fmt::format(FMT_COMPILE("{}"), a);
+}
+
+TEST(ostream_test, is_formattable) {
+  EXPECT_TRUE(fmt::is_formattable<std::string>());
+  EXPECT_TRUE(fmt::is_formattable<fmt::detail::std_string_view<char>>());
+}
+
+struct streamable_and_unformattable {};
+
+auto operator<<(std::ostream& os, streamable_and_unformattable)
+    -> std::ostream& {
+  return os << "foo";
+}
+
+TEST(ostream_test, streamed) {
+  EXPECT_FALSE(fmt::is_formattable<streamable_and_unformattable>());
+  EXPECT_EQ(fmt::format("{}", fmt::streamed(streamable_and_unformattable())),
+            "foo");
+}
+
+TEST(ostream_test, closed_ofstream) {
+  std::ofstream ofs;
+  fmt::print(ofs, "discard");
+}
diff --git a/src/fmt/test/posix-mock-test.cc b/src/fmt/test/posix-mock-test.cc
new file mode 100644
index 000000000..819a94dfb
--- /dev/null
+++ b/src/fmt/test/posix-mock-test.cc
@@ -0,0 +1,459 @@
+// Tests of the C++ interface to POSIX functions that require mocks
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+// Disable bogus MSVC warnings.
+#if !defined(_CRT_SECURE_NO_WARNINGS) && defined(_MSC_VER)
+#  define _CRT_SECURE_NO_WARNINGS
+#endif
+
+#include "posix-mock.h"
+
+#include <errno.h>
+#include <fcntl.h>
+
+#include <climits>
+#include <memory>
+
+#include "../src/os.cc"
+
+#ifdef _WIN32
+#  include <io.h>
+#  undef max
+#endif
+
+#include "gmock/gmock.h"
+#include "gtest-extra.h"
+#include "util.h"
+
+using fmt::buffered_file;
+
+using testing::_;
+using testing::Return;
+using testing::StrEq;
+
+template <typename Mock> struct scoped_mock : testing::StrictMock<Mock> {
+  scoped_mock() { Mock::instance = this; }
+  ~scoped_mock() { Mock::instance = nullptr; }
+};
+
+namespace {
+int open_count;
+int close_count;
+int dup_count;
+int dup2_count;
+int fdopen_count;
+int read_count;
+int write_count;
+int pipe_count;
+int fopen_count;
+int fclose_count;
+int fileno_count;
+size_t read_nbyte;
+size_t write_nbyte;
+bool sysconf_error;
+
+enum { none, max_size, error } fstat_sim;
+}  // namespace
+
+#define EMULATE_EINTR(func, error_result) \
+  if (func##_count != 0) {                \
+    if (func##_count++ != 3) {            \
+      errno = EINTR;                      \
+      return error_result;                \
+    }                                     \
+  }
+
+#ifndef _MSC_VER
+int test::open(const char* path, int oflag, int mode) {
+  EMULATE_EINTR(open, -1);
+  return ::open(path, oflag, mode);
+}
+#else
+errno_t test::sopen_s(int* pfh, const char* filename, int oflag, int shflag,
+                      int pmode) {
+  EMULATE_EINTR(open, EINTR);
+  return _sopen_s(pfh, filename, oflag, shflag, pmode);
+}
+#endif
+
+#ifndef _WIN32
+
+long test::sysconf(int name) {
+  long result = ::sysconf(name);
+  if (!sysconf_error) return result;
+  // Simulate an error.
+  errno = EINVAL;
+  return -1;
+}
+
+static off_t max_file_size() { return std::numeric_limits<off_t>::max(); }
+
+int test::fstat(int fd, struct stat* buf) {
+  int result = ::fstat(fd, buf);
+  if (fstat_sim == max_size) buf->st_size = max_file_size();
+  return result;
+}
+
+#else
+
+static LONGLONG max_file_size() { return std::numeric_limits<LONGLONG>::max(); }
+
+DWORD test::GetFileSize(HANDLE hFile, LPDWORD lpFileSizeHigh) {
+  if (fstat_sim == error) {
+    SetLastError(ERROR_ACCESS_DENIED);
+    return INVALID_FILE_SIZE;
+  }
+  if (fstat_sim == max_size) {
+    DWORD max = std::numeric_limits<DWORD>::max();
+    *lpFileSizeHigh = max >> 1;
+    return max;
+  }
+  return ::GetFileSize(hFile, lpFileSizeHigh);
+}
+
+#endif
+
+int test::close(int fildes) {
+  // Close the file first because close shouldn't be retried.
+  int result = ::FMT_POSIX(close(fildes));
+  EMULATE_EINTR(close, -1);
+  return result;
+}
+
+int test::dup(int fildes) {
+  EMULATE_EINTR(dup, -1);
+  return ::FMT_POSIX(dup(fildes));
+}
+
+int test::dup2(int fildes, int fildes2) {
+  EMULATE_EINTR(dup2, -1);
+  return ::FMT_POSIX(dup2(fildes, fildes2));
+}
+
+FILE* test::fdopen(int fildes, const char* mode) {
+  EMULATE_EINTR(fdopen, nullptr);
+  return ::FMT_POSIX(fdopen(fildes, mode));
+}
+
+test::ssize_t test::read(int fildes, void* buf, test::size_t nbyte) {
+  read_nbyte = nbyte;
+  EMULATE_EINTR(read, -1);
+  return ::FMT_POSIX(read(fildes, buf, nbyte));
+}
+
+test::ssize_t test::write(int fildes, const void* buf, test::size_t nbyte) {
+  write_nbyte = nbyte;
+  EMULATE_EINTR(write, -1);
+  return ::FMT_POSIX(write(fildes, buf, nbyte));
+}
+
+#ifndef _WIN32
+int test::pipe(int fildes[2]) {
+  EMULATE_EINTR(pipe, -1);
+  return ::pipe(fildes);
+}
+#else
+int test::pipe(int* pfds, unsigned psize, int textmode) {
+  EMULATE_EINTR(pipe, -1);
+  return _pipe(pfds, psize, textmode);
+}
+#endif
+
+FILE* test::fopen(const char* filename, const char* mode) {
+  EMULATE_EINTR(fopen, nullptr);
+  return ::fopen(filename, mode);
+}
+
+int test::fclose(FILE* stream) {
+  EMULATE_EINTR(fclose, EOF);
+  return ::fclose(stream);
+}
+
+int(test::fileno)(FILE* stream) {
+  EMULATE_EINTR(fileno, -1);
+#ifdef fileno
+  return FMT_POSIX(fileno(stream));
+#else
+  return ::FMT_POSIX(fileno(stream));
+#endif
+}
+
+#ifndef _WIN32
+#  define EXPECT_RETRY(statement, func, message) \
+    func##_count = 1;                            \
+    statement;                                   \
+    EXPECT_EQ(4, func##_count);                  \
+    func##_count = 0;
+#  define EXPECT_EQ_POSIX(expected, actual) EXPECT_EQ(expected, actual)
+#else
+#  define EXPECT_RETRY(statement, func, message)    \
+    func##_count = 1;                               \
+    EXPECT_SYSTEM_ERROR(statement, EINTR, message); \
+    func##_count = 0;
+#  define EXPECT_EQ_POSIX(expected, actual)
+#endif
+
+#if FMT_USE_FCNTL
+void write_file(fmt::cstring_view filename, fmt::string_view content) {
+  fmt::buffered_file f(filename, "w");
+  f.print("{}", content);
+}
+
+using fmt::file;
+
+TEST(os_test, getpagesize) {
+#  ifdef _WIN32
+  SYSTEM_INFO si = {};
+  GetSystemInfo(&si);
+  EXPECT_EQ(si.dwPageSize, fmt::getpagesize());
+#  else
+  EXPECT_EQ(sysconf(_SC_PAGESIZE), fmt::getpagesize());
+  sysconf_error = true;
+  EXPECT_SYSTEM_ERROR(fmt::getpagesize(), EINVAL,
+                      "cannot get memory page size");
+  sysconf_error = false;
+#  endif
+}
+
+TEST(file_test, open_retry) {
+  write_file("temp", "there must be something here");
+  std::unique_ptr<file> f{nullptr};
+  EXPECT_RETRY(f.reset(new file("temp", file::RDONLY)), open,
+               "cannot open file temp");
+#  ifndef _WIN32
+  char c = 0;
+  f->read(&c, 1);
+#  endif
+}
+
+TEST(file_test, close_no_retry_in_dtor) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  std::unique_ptr<file> f(new file(std::move(read_end)));
+  int saved_close_count = 0;
+  EXPECT_WRITE(
+      stderr,
+      {
+        close_count = 1;
+        f.reset(nullptr);
+        saved_close_count = close_count;
+        close_count = 0;
+      },
+      system_error_message(EINTR, "cannot close file") + "\n");
+  EXPECT_EQ(2, saved_close_count);
+}
+
+TEST(file_test, close_no_retry) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  close_count = 1;
+  EXPECT_SYSTEM_ERROR(read_end.close(), EINTR, "cannot close file");
+  EXPECT_EQ(2, close_count);
+  close_count = 0;
+}
+
+TEST(file_test, size) {
+  std::string content = "top secret, destroy before reading";
+  write_file("temp", content);
+  file f("temp", file::RDONLY);
+  EXPECT_GE(f.size(), 0);
+  EXPECT_EQ(content.size(), static_cast<unsigned long long>(f.size()));
+#  ifdef _WIN32
+  auto error_code = std::error_code();
+  fstat_sim = error;
+  try {
+    f.size();
+  } catch (const std::system_error& e) {
+    error_code = e.code();
+  }
+  fstat_sim = none;
+  EXPECT_EQ(error_code,
+            std::error_code(ERROR_ACCESS_DENIED, fmt::system_category()));
+#  else
+  f.close();
+  EXPECT_SYSTEM_ERROR(f.size(), EBADF, "cannot get file attributes");
+#  endif
+}
+
+TEST(file_test, max_size) {
+  write_file("temp", "");
+  file f("temp", file::RDONLY);
+  fstat_sim = max_size;
+  EXPECT_GE(f.size(), 0);
+  EXPECT_EQ(max_file_size(), f.size());
+  fstat_sim = none;
+}
+
+TEST(file_test, read_retry) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  enum { SIZE = 4 };
+  write_end.write("test", SIZE);
+  write_end.close();
+  char buffer[SIZE];
+  size_t count = 0;
+  EXPECT_RETRY(count = read_end.read(buffer, SIZE), read,
+               "cannot read from file");
+  EXPECT_EQ_POSIX(static_cast<std::streamsize>(SIZE), count);
+}
+
+TEST(file_test, write_retry) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  enum { SIZE = 4 };
+  size_t count = 0;
+  EXPECT_RETRY(count = write_end.write("test", SIZE), write,
+               "cannot write to file");
+  write_end.close();
+#  ifndef _WIN32
+  EXPECT_EQ(static_cast<std::streamsize>(SIZE), count);
+  char buffer[SIZE + 1];
+  read_end.read(buffer, SIZE);
+  buffer[SIZE] = '\0';
+  EXPECT_STREQ("test", buffer);
+#  endif
+}
+
+#  ifdef _WIN32
+TEST(file_test, convert_read_count) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  char c;
+  size_t size = UINT_MAX;
+  if (sizeof(unsigned) != sizeof(size_t)) ++size;
+  read_count = 1;
+  read_nbyte = 0;
+  EXPECT_THROW(read_end.read(&c, size), std::system_error);
+  read_count = 0;
+  EXPECT_EQ(UINT_MAX, read_nbyte);
+}
+
+TEST(file_test, convert_write_count) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  char c;
+  size_t size = UINT_MAX;
+  if (sizeof(unsigned) != sizeof(size_t)) ++size;
+  write_count = 1;
+  write_nbyte = 0;
+  EXPECT_THROW(write_end.write(&c, size), std::system_error);
+  write_count = 0;
+  EXPECT_EQ(UINT_MAX, write_nbyte);
+}
+#  endif
+
+TEST(file_test, dup_no_retry) {
+  int stdout_fd = FMT_POSIX(fileno(stdout));
+  dup_count = 1;
+  EXPECT_SYSTEM_ERROR(
+      file::dup(stdout_fd), EINTR,
+      fmt::format("cannot duplicate file descriptor {}", stdout_fd));
+  dup_count = 0;
+}
+
+TEST(file_test, dup2_retry) {
+  int stdout_fd = FMT_POSIX(fileno(stdout));
+  file f1 = file::dup(stdout_fd), f2 = file::dup(stdout_fd);
+  EXPECT_RETRY(f1.dup2(f2.descriptor()), dup2,
+               fmt::format("cannot duplicate file descriptor {} to {}",
+                           f1.descriptor(), f2.descriptor()));
+}
+
+TEST(file_test, dup2_no_except_retry) {
+  int stdout_fd = FMT_POSIX(fileno(stdout));
+  file f1 = file::dup(stdout_fd), f2 = file::dup(stdout_fd);
+  std::error_code ec;
+  dup2_count = 1;
+  f1.dup2(f2.descriptor(), ec);
+#  ifndef _WIN32
+  EXPECT_EQ(4, dup2_count);
+#  else
+  EXPECT_EQ(EINTR, ec.value());
+#  endif
+  dup2_count = 0;
+}
+
+TEST(file_test, pipe_no_retry) {
+  file read_end, write_end;
+  pipe_count = 1;
+  EXPECT_SYSTEM_ERROR(file::pipe(read_end, write_end), EINTR,
+                      "cannot create pipe");
+  pipe_count = 0;
+}
+
+TEST(file_test, fdopen_no_retry) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  fdopen_count = 1;
+  EXPECT_SYSTEM_ERROR(read_end.fdopen("r"), EINTR,
+                      "cannot associate stream with file descriptor");
+  fdopen_count = 0;
+}
+
+TEST(buffered_file_test, open_retry) {
+  write_file("temp", "there must be something here");
+  std::unique_ptr<buffered_file> f{nullptr};
+  EXPECT_RETRY(f.reset(new buffered_file("temp", "r")), fopen,
+               "cannot open file temp");
+#  ifndef _WIN32
+  char c = 0;
+  if (fread(&c, 1, 1, f->get()) < 1)
+    throw fmt::system_error(errno, "fread failed");
+#  endif
+}
+
+TEST(buffered_file_test, close_no_retry_in_dtor) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  std::unique_ptr<buffered_file> f(new buffered_file(read_end.fdopen("r")));
+  int saved_fclose_count = 0;
+  EXPECT_WRITE(
+      stderr,
+      {
+        fclose_count = 1;
+        f.reset(nullptr);
+        saved_fclose_count = fclose_count;
+        fclose_count = 0;
+      },
+      system_error_message(EINTR, "cannot close file") + "\n");
+  EXPECT_EQ(2, saved_fclose_count);
+}
+
+TEST(buffered_file_test, close_no_retry) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  buffered_file f = read_end.fdopen("r");
+  fclose_count = 1;
+  EXPECT_SYSTEM_ERROR(f.close(), EINTR, "cannot close file");
+  EXPECT_EQ(2, fclose_count);
+  fclose_count = 0;
+}
+
+TEST(buffered_file_test, fileno_no_retry) {
+  file read_end, write_end;
+  file::pipe(read_end, write_end);
+  buffered_file f = read_end.fdopen("r");
+  fileno_count = 1;
+  EXPECT_SYSTEM_ERROR((f.descriptor)(), EINTR, "cannot get file descriptor");
+  EXPECT_EQ(2, fileno_count);
+  fileno_count = 0;
+}
+#endif  // FMT_USE_FCNTL
+
+struct test_mock {
+  static test_mock* instance;
+} * test_mock::instance;
+
+TEST(scoped_mock, scope) {
+  {
+    scoped_mock<test_mock> mock;
+    EXPECT_EQ(&mock, test_mock::instance);
+    test_mock& copy = mock;
+    static_cast<void>(copy);
+  }
+  EXPECT_EQ(nullptr, test_mock::instance);
+}
diff --git a/src/fmt/test/posix-mock.h b/src/fmt/test/posix-mock.h
new file mode 100644
index 000000000..e76af7002
--- /dev/null
+++ b/src/fmt/test/posix-mock.h
@@ -0,0 +1,77 @@
+// Formatting library for C++ - mocks of POSIX functions
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_POSIX_TEST_H
+#define FMT_POSIX_TEST_H
+
+#include <errno.h>
+#include <locale.h>
+#include <stdio.h>
+#ifdef __APPLE__
+#  include <xlocale.h>
+#endif
+
+#ifdef _WIN32
+#  include <windows.h>
+#else
+#  include <sys/param.h>  // for FreeBSD version
+#  include <sys/types.h>  // for ssize_t
+#endif
+
+#ifndef _MSC_VER
+struct stat;
+#endif
+
+namespace test {
+
+#ifndef _MSC_VER
+// Size type for read and write.
+typedef size_t size_t;
+typedef ssize_t ssize_t;
+int open(const char* path, int oflag, int mode);
+int fstat(int fd, struct stat* buf);
+#else
+typedef unsigned size_t;
+typedef int ssize_t;
+errno_t sopen_s(int* pfh, const char* filename, int oflag, int shflag,
+                int pmode);
+#endif
+
+#ifndef _WIN32
+long sysconf(int name);
+#else
+DWORD GetFileSize(HANDLE hFile, LPDWORD lpFileSizeHigh);
+#endif
+
+int close(int fildes);
+
+int dup(int fildes);
+int dup2(int fildes, int fildes2);
+
+FILE* fdopen(int fildes, const char* mode);
+
+ssize_t read(int fildes, void* buf, size_t nbyte);
+ssize_t write(int fildes, const void* buf, size_t nbyte);
+
+#ifndef _WIN32
+int pipe(int fildes[2]);
+#else
+int pipe(int* pfds, unsigned psize, int textmode);
+#endif
+
+FILE* fopen(const char* filename, const char* mode);
+int fclose(FILE* stream);
+int(fileno)(FILE* stream);
+
+#if defined(FMT_LOCALE) && !defined(_WIN32)
+locale_t newlocale(int category_mask, const char* locale, locale_t base);
+#endif
+}  // namespace test
+
+#define FMT_SYSTEM(call) test::call
+
+#endif  // FMT_POSIX_TEST_H
diff --git a/src/fmt/test/printf-test.cc b/src/fmt/test/printf-test.cc
new file mode 100644
index 000000000..383ffb83b
--- /dev/null
+++ b/src/fmt/test/printf-test.cc
@@ -0,0 +1,584 @@
+// Formatting library for C++ - printf tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/printf.h"
+
+#include <cctype>
+#include <climits>
+#include <cstring>
+
+#include "fmt/xchar.h"
+#include "gtest-extra.h"
+#include "util.h"
+
+using fmt::format;
+using fmt::format_error;
+using fmt::detail::max_value;
+
+const unsigned big_num = INT_MAX + 1u;
+
+// Makes format string argument positional.
+static std::string make_positional(fmt::string_view format) {
+  std::string s(format.data(), format.size());
+  s.replace(s.find('%'), 1, "%1$");
+  return s;
+}
+
+static std::wstring make_positional(fmt::basic_string_view<wchar_t> format) {
+  std::wstring s(format.data(), format.size());
+  s.replace(s.find(L'%'), 1, L"%1$");
+  return s;
+}
+
+// A wrapper around fmt::sprintf to workaround bogus warnings about invalid
+// format strings in MSVC.
+template <typename... Args>
+std::string test_sprintf(fmt::string_view format, const Args&... args) {
+  return fmt::sprintf(format, args...);
+}
+template <typename... Args>
+std::wstring test_sprintf(fmt::basic_string_view<wchar_t> format,
+                          const Args&... args) {
+  return fmt::sprintf(format, args...);
+}
+
+#define EXPECT_PRINTF(expected_output, format, arg)     \
+  EXPECT_EQ(expected_output, test_sprintf(format, arg)) \
+      << "format: " << format;                          \
+  EXPECT_EQ(expected_output, fmt::sprintf(make_positional(format), arg))
+
+TEST(printf_test, no_args) {
+  EXPECT_EQ("test", test_sprintf("test"));
+  EXPECT_EQ(L"test", fmt::sprintf(L"test"));
+}
+
+TEST(printf_test, escape) {
+  EXPECT_EQ("%", test_sprintf("%%"));
+  EXPECT_EQ("before %", test_sprintf("before %%"));
+  EXPECT_EQ("% after", test_sprintf("%% after"));
+  EXPECT_EQ("before % after", test_sprintf("before %% after"));
+  EXPECT_EQ("%s", test_sprintf("%%s"));
+  EXPECT_EQ(L"%", fmt::sprintf(L"%%"));
+  EXPECT_EQ(L"before %", fmt::sprintf(L"before %%"));
+  EXPECT_EQ(L"% after", fmt::sprintf(L"%% after"));
+  EXPECT_EQ(L"before % after", fmt::sprintf(L"before %% after"));
+  EXPECT_EQ(L"%s", fmt::sprintf(L"%%s"));
+}
+
+TEST(printf_test, positional_args) {
+  EXPECT_EQ("42", test_sprintf("%1$d", 42));
+  EXPECT_EQ("before 42", test_sprintf("before %1$d", 42));
+  EXPECT_EQ("42 after", test_sprintf("%1$d after", 42));
+  EXPECT_EQ("before 42 after", test_sprintf("before %1$d after", 42));
+  EXPECT_EQ("answer = 42", test_sprintf("%1$s = %2$d", "answer", 42));
+  EXPECT_EQ("42 is the answer", test_sprintf("%2$d is the %1$s", "answer", 42));
+  EXPECT_EQ("abracadabra", test_sprintf("%1$s%2$s%1$s", "abra", "cad"));
+}
+
+TEST(printf_test, automatic_arg_indexing) {
+  EXPECT_EQ("abc", test_sprintf("%c%c%c", 'a', 'b', 'c'));
+}
+
+TEST(printf_test, number_is_too_big_in_arg_index) {
+  EXPECT_THROW_MSG(test_sprintf(format("%{}$", big_num)), format_error,
+                   "argument not found");
+  EXPECT_THROW_MSG(test_sprintf(format("%{}$d", big_num)), format_error,
+                   "argument not found");
+}
+
+TEST(printf_test, switch_arg_indexing) {
+  EXPECT_THROW_MSG(test_sprintf("%1$d%", 1, 2), format_error,
+                   "cannot switch from manual to automatic argument indexing");
+  EXPECT_THROW_MSG(test_sprintf(format("%1$d%{}d", big_num), 1, 2),
+                   format_error, "number is too big");
+  EXPECT_THROW_MSG(test_sprintf("%1$d%d", 1, 2), format_error,
+                   "cannot switch from manual to automatic argument indexing");
+
+  EXPECT_THROW_MSG(test_sprintf("%d%1$", 1, 2), format_error,
+                   "cannot switch from automatic to manual argument indexing");
+  EXPECT_THROW_MSG(test_sprintf(format("%d%{}$d", big_num), 1, 2), format_error,
+                   "cannot switch from automatic to manual argument indexing");
+  EXPECT_THROW_MSG(test_sprintf("%d%1$d", 1, 2), format_error,
+                   "cannot switch from automatic to manual argument indexing");
+
+  // Indexing errors override width errors.
+  EXPECT_THROW_MSG(test_sprintf(format("%d%1${}d", big_num), 1, 2),
+                   format_error, "number is too big");
+  EXPECT_THROW_MSG(test_sprintf(format("%1$d%{}d", big_num), 1, 2),
+                   format_error, "number is too big");
+}
+
+TEST(printf_test, invalid_arg_index) {
+  EXPECT_THROW_MSG(test_sprintf("%0$d", 42), format_error,
+                   "argument not found");
+  EXPECT_THROW_MSG(test_sprintf("%2$d", 42), format_error,
+                   "argument not found");
+  EXPECT_THROW_MSG(test_sprintf(format("%{}$d", INT_MAX), 42), format_error,
+                   "argument not found");
+
+  EXPECT_THROW_MSG(test_sprintf("%2$", 42), format_error, "argument not found");
+  EXPECT_THROW_MSG(test_sprintf(format("%{}$d", big_num), 42), format_error,
+                   "argument not found");
+}
+
+TEST(printf_test, default_align_right) {
+  EXPECT_PRINTF("   42", "%5d", 42);
+  EXPECT_PRINTF("  abc", "%5s", "abc");
+}
+
+TEST(printf_test, zero_flag) {
+  EXPECT_PRINTF("00042", "%05d", 42);
+  EXPECT_PRINTF("-0042", "%05d", -42);
+
+  EXPECT_PRINTF("00042", "%05d", 42);
+  EXPECT_PRINTF("-0042", "%05d", -42);
+  EXPECT_PRINTF("-004.2", "%06g", -4.2);
+
+  EXPECT_PRINTF("+00042", "%00+6d", 42);
+
+  EXPECT_PRINTF("   42", "%05.d", 42);
+  EXPECT_PRINTF(" 0042", "%05.4d", 42);
+
+  // '0' flag is ignored for non-numeric types.
+  EXPECT_PRINTF("    x", "%05c", 'x');
+}
+
+TEST(printf_test, plus_flag) {
+  EXPECT_PRINTF("+42", "%+d", 42);
+  EXPECT_PRINTF("-42", "%+d", -42);
+  EXPECT_PRINTF("+0042", "%+05d", 42);
+  EXPECT_PRINTF("+0042", "%0++5d", 42);
+
+  // '+' flag is ignored for non-numeric types.
+  EXPECT_PRINTF("x", "%+c", 'x');
+
+  // '+' flag wins over space flag
+  EXPECT_PRINTF("+42", "%+ d", 42);
+  EXPECT_PRINTF("-42", "%+ d", -42);
+  EXPECT_PRINTF("+42", "% +d", 42);
+  EXPECT_PRINTF("-42", "% +d", -42);
+  EXPECT_PRINTF("+0042", "% +05d", 42);
+  EXPECT_PRINTF("+0042", "%0+ 5d", 42);
+
+  // '+' flag and space flag are both ignored for non-numeric types.
+  EXPECT_PRINTF("x", "%+ c", 'x');
+  EXPECT_PRINTF("x", "% +c", 'x');
+}
+
+TEST(printf_test, minus_flag) {
+  EXPECT_PRINTF("abc  ", "%-5s", "abc");
+  EXPECT_PRINTF("abc  ", "%0--5s", "abc");
+
+  EXPECT_PRINTF("7    ", "%-5d", 7);
+  EXPECT_PRINTF("97   ", "%-5hhi", 'a');
+  EXPECT_PRINTF("a    ", "%-5c", 'a');
+
+  // '0' flag is ignored if '-' flag is given
+  EXPECT_PRINTF("7    ", "%-05d", 7);
+  EXPECT_PRINTF("7    ", "%0-5d", 7);
+  EXPECT_PRINTF("a    ", "%-05c", 'a');
+  EXPECT_PRINTF("a    ", "%0-5c", 'a');
+  EXPECT_PRINTF("97   ", "%-05hhi", 'a');
+  EXPECT_PRINTF("97   ", "%0-5hhi", 'a');
+
+  // '-' and space flag don't interfere
+  EXPECT_PRINTF(" 42", "%- d", 42);
+}
+
+TEST(printf_test, space_flag) {
+  EXPECT_PRINTF(" 42", "% d", 42);
+  EXPECT_PRINTF("-42", "% d", -42);
+  EXPECT_PRINTF(" 0042", "% 05d", 42);
+  EXPECT_PRINTF(" 0042", "%0  5d", 42);
+
+  // ' ' flag is ignored for non-numeric types.
+  EXPECT_PRINTF("x", "% c", 'x');
+}
+
+TEST(printf_test, hash_flag) {
+  EXPECT_PRINTF("042", "%#o", 042);
+  EXPECT_PRINTF(fmt::format("0{:o}", static_cast<unsigned>(-042)), "%#o", -042);
+  EXPECT_PRINTF("0", "%#o", 0);
+
+  EXPECT_PRINTF("0x42", "%#x", 0x42);
+  EXPECT_PRINTF("0X42", "%#X", 0x42);
+  EXPECT_PRINTF(fmt::format("0x{:x}", static_cast<unsigned>(-0x42)), "%#x",
+                -0x42);
+  EXPECT_PRINTF("0", "%#x", 0);
+
+  EXPECT_PRINTF("0x0042", "%#06x", 0x42);
+  EXPECT_PRINTF("0x0042", "%0##6x", 0x42);
+
+  EXPECT_PRINTF("-42.000000", "%#f", -42.0);
+  EXPECT_PRINTF("-42.000000", "%#F", -42.0);
+
+  char buffer[256];
+  safe_sprintf(buffer, "%#e", -42.0);
+  EXPECT_PRINTF(buffer, "%#e", -42.0);
+  safe_sprintf(buffer, "%#E", -42.0);
+  EXPECT_PRINTF(buffer, "%#E", -42.0);
+
+  EXPECT_PRINTF("-42.0000", "%#g", -42.0);
+  EXPECT_PRINTF("-42.0000", "%#G", -42.0);
+
+  safe_sprintf(buffer, "%#a", 16.0);
+  EXPECT_PRINTF(buffer, "%#a", 16.0);
+  safe_sprintf(buffer, "%#A", 16.0);
+  EXPECT_PRINTF(buffer, "%#A", 16.0);
+
+  // '#' flag is ignored for non-numeric types.
+  EXPECT_PRINTF("x", "%#c", 'x');
+}
+
+TEST(printf_test, width) {
+  EXPECT_PRINTF("  abc", "%5s", "abc");
+
+  // Width cannot be specified twice.
+  EXPECT_THROW_MSG(test_sprintf("%5-5d", 42), format_error,
+                   "invalid type specifier");
+
+  EXPECT_THROW_MSG(test_sprintf(format("%{}d", big_num), 42), format_error,
+                   "number is too big");
+  EXPECT_THROW_MSG(test_sprintf(format("%1${}d", big_num), 42), format_error,
+                   "number is too big");
+}
+
+TEST(printf_test, dynamic_width) {
+  EXPECT_EQ("   42", test_sprintf("%*d", 5, 42));
+  EXPECT_EQ("42   ", test_sprintf("%*d", -5, 42));
+  EXPECT_THROW_MSG(test_sprintf("%*d", 5.0, 42), format_error,
+                   "width is not integer");
+  EXPECT_THROW_MSG(test_sprintf("%*d"), format_error, "argument not found");
+  EXPECT_THROW_MSG(test_sprintf("%*d", big_num, 42), format_error,
+                   "number is too big");
+}
+
+TEST(printf_test, int_precision) {
+  EXPECT_PRINTF("00042", "%.5d", 42);
+  EXPECT_PRINTF("-00042", "%.5d", -42);
+  EXPECT_PRINTF("00042", "%.5x", 0x42);
+  EXPECT_PRINTF("0x00042", "%#.5x", 0x42);
+  EXPECT_PRINTF("00042", "%.5o", 042);
+  EXPECT_PRINTF("00042", "%#.5o", 042);
+
+  EXPECT_PRINTF("  00042", "%7.5d", 42);
+  EXPECT_PRINTF("  00042", "%7.5x", 0x42);
+  EXPECT_PRINTF("   0x00042", "%#10.5x", 0x42);
+  EXPECT_PRINTF("  00042", "%7.5o", 042);
+  EXPECT_PRINTF("     00042", "%#10.5o", 042);
+
+  EXPECT_PRINTF("00042  ", "%-7.5d", 42);
+  EXPECT_PRINTF("00042  ", "%-7.5x", 0x42);
+  EXPECT_PRINTF("0x00042   ", "%-#10.5x", 0x42);
+  EXPECT_PRINTF("00042  ", "%-7.5o", 042);
+  EXPECT_PRINTF("00042     ", "%-#10.5o", 042);
+}
+
+TEST(printf_test, float_precision) {
+  char buffer[256];
+  safe_sprintf(buffer, "%.3e", 1234.5678);
+  EXPECT_PRINTF(buffer, "%.3e", 1234.5678);
+  EXPECT_PRINTF("1234.568", "%.3f", 1234.5678);
+  EXPECT_PRINTF("1.23e+03", "%.3g", 1234.5678);
+  safe_sprintf(buffer, "%.3a", 1234.5678);
+  EXPECT_PRINTF(buffer, "%.3a", 1234.5678);
+}
+
+TEST(printf_test, string_precision) {
+  char test[] = {'H', 'e', 'l', 'l', 'o'};
+  EXPECT_EQ(fmt::sprintf("%.4s", test), "Hell");
+}
+
+TEST(printf_test, ignore_precision_for_non_numeric_arg) {
+  EXPECT_PRINTF("abc", "%.5s", "abc");
+}
+
+TEST(printf_test, dynamic_precision) {
+  EXPECT_EQ("00042", test_sprintf("%.*d", 5, 42));
+  EXPECT_EQ("42", test_sprintf("%.*d", -5, 42));
+  EXPECT_THROW_MSG(test_sprintf("%.*d", 5.0, 42), format_error,
+                   "precision is not integer");
+  EXPECT_THROW_MSG(test_sprintf("%.*d"), format_error, "argument not found");
+  EXPECT_THROW_MSG(test_sprintf("%.*d", big_num, 42), format_error,
+                   "number is too big");
+  if (sizeof(long long) != sizeof(int)) {
+    long long prec = static_cast<long long>(INT_MIN) - 1;
+    EXPECT_THROW_MSG(test_sprintf("%.*d", prec, 42), format_error,
+                     "number is too big");
+  }
+}
+
+template <typename T> struct make_signed { typedef T type; };
+
+#define SPECIALIZE_MAKE_SIGNED(T, S) \
+  template <> struct make_signed<T> { typedef S type; }
+
+SPECIALIZE_MAKE_SIGNED(char, signed char);
+SPECIALIZE_MAKE_SIGNED(unsigned char, signed char);
+SPECIALIZE_MAKE_SIGNED(unsigned short, short);
+SPECIALIZE_MAKE_SIGNED(unsigned, int);
+SPECIALIZE_MAKE_SIGNED(unsigned long, long);
+SPECIALIZE_MAKE_SIGNED(unsigned long long, long long);
+
+// Test length format specifier ``length_spec``.
+template <typename T, typename U>
+void test_length(const char* length_spec, U value) {
+  long long signed_value = 0;
+  unsigned long long unsigned_value = 0;
+  // Apply integer promotion to the argument.
+  unsigned long long max = max_value<U>();
+  using fmt::detail::const_check;
+  if (const_check(max <= static_cast<unsigned>(max_value<int>()))) {
+    signed_value = static_cast<int>(value);
+    unsigned_value = static_cast<unsigned long long>(value);
+  } else if (const_check(max <= max_value<unsigned>())) {
+    signed_value = static_cast<unsigned>(value);
+    unsigned_value = static_cast<unsigned long long>(value);
+  }
+  if (sizeof(U) <= sizeof(int) && sizeof(int) < sizeof(T)) {
+    signed_value = static_cast<long long>(value);
+    unsigned_value = static_cast<unsigned long long>(
+        static_cast<typename std::make_unsigned<unsigned>::type>(value));
+  } else {
+    signed_value = static_cast<typename make_signed<T>::type>(value);
+    unsigned_value = static_cast<typename std::make_unsigned<T>::type>(value);
+  }
+  std::ostringstream os;
+  os << signed_value;
+  EXPECT_PRINTF(os.str(), fmt::format("%{}d", length_spec), value);
+  EXPECT_PRINTF(os.str(), fmt::format("%{}i", length_spec), value);
+  os.str("");
+  os << unsigned_value;
+  EXPECT_PRINTF(os.str(), fmt::format("%{}u", length_spec), value);
+  os.str("");
+  os << std::oct << unsigned_value;
+  EXPECT_PRINTF(os.str(), fmt::format("%{}o", length_spec), value);
+  os.str("");
+  os << std::hex << unsigned_value;
+  EXPECT_PRINTF(os.str(), fmt::format("%{}x", length_spec), value);
+  os.str("");
+  os << std::hex << std::uppercase << unsigned_value;
+  EXPECT_PRINTF(os.str(), fmt::format("%{}X", length_spec), value);
+}
+
+template <typename T> void test_length(const char* length_spec) {
+  T min = std::numeric_limits<T>::min(), max = max_value<T>();
+  test_length<T>(length_spec, 42);
+  test_length<T>(length_spec, -42);
+  test_length<T>(length_spec, min);
+  test_length<T>(length_spec, max);
+  long long long_long_min = std::numeric_limits<long long>::min();
+  if (static_cast<long long>(min) > long_long_min)
+    test_length<T>(length_spec, static_cast<long long>(min) - 1);
+  unsigned long long long_long_max = max_value<long long>();
+  if (static_cast<unsigned long long>(max) < long_long_max)
+    test_length<T>(length_spec, static_cast<long long>(max) + 1);
+  test_length<T>(length_spec, std::numeric_limits<short>::min());
+  test_length<T>(length_spec, max_value<unsigned short>());
+  test_length<T>(length_spec, std::numeric_limits<int>::min());
+  test_length<T>(length_spec, max_value<int>());
+  test_length<T>(length_spec, std::numeric_limits<unsigned>::min());
+  test_length<T>(length_spec, max_value<unsigned>());
+  test_length<T>(length_spec, std::numeric_limits<long long>::min());
+  test_length<T>(length_spec, max_value<long long>());
+  test_length<T>(length_spec, std::numeric_limits<unsigned long long>::min());
+  test_length<T>(length_spec, max_value<unsigned long long>());
+}
+
+TEST(printf_test, length) {
+  test_length<char>("hh");
+  test_length<signed char>("hh");
+  test_length<unsigned char>("hh");
+  test_length<short>("h");
+  test_length<unsigned short>("h");
+  test_length<long>("l");
+  test_length<unsigned long>("l");
+  test_length<long long>("ll");
+  test_length<unsigned long long>("ll");
+  test_length<intmax_t>("j");
+  test_length<size_t>("z");
+  test_length<std::ptrdiff_t>("t");
+  long double max = max_value<long double>();
+  EXPECT_PRINTF(fmt::format("{:.6}", max), "%g", max);
+  EXPECT_PRINTF(fmt::format("{:.6}", max), "%Lg", max);
+}
+
+TEST(printf_test, bool) {
+  EXPECT_PRINTF("1", "%d", true);
+  EXPECT_PRINTF("true", "%s", true);
+}
+
+TEST(printf_test, int) {
+  EXPECT_PRINTF("-42", "%d", -42);
+  EXPECT_PRINTF("-42", "%i", -42);
+  unsigned u = 0 - 42u;
+  EXPECT_PRINTF(fmt::format("{}", u), "%u", -42);
+  EXPECT_PRINTF(fmt::format("{:o}", u), "%o", -42);
+  EXPECT_PRINTF(fmt::format("{:x}", u), "%x", -42);
+  EXPECT_PRINTF(fmt::format("{:X}", u), "%X", -42);
+}
+
+TEST(printf_test, long_long) {
+  // fmt::printf allows passing long long arguments to %d without length
+  // specifiers.
+  long long max = max_value<long long>();
+  EXPECT_PRINTF(fmt::format("{}", max), "%d", max);
+}
+
+TEST(printf_test, float) {
+  EXPECT_PRINTF("392.650000", "%f", 392.65);
+  EXPECT_PRINTF("392.65", "%.2f", 392.65);
+  EXPECT_PRINTF("392.6", "%.1f", 392.65);
+  EXPECT_PRINTF("393", "%.f", 392.65);
+  EXPECT_PRINTF("392.650000", "%F", 392.65);
+  char buffer[256];
+  safe_sprintf(buffer, "%e", 392.65);
+  EXPECT_PRINTF(buffer, "%e", 392.65);
+  safe_sprintf(buffer, "%E", 392.65);
+  EXPECT_PRINTF(buffer, "%E", 392.65);
+  EXPECT_PRINTF("392.65", "%g", 392.65);
+  EXPECT_PRINTF("392.65", "%G", 392.65);
+  EXPECT_PRINTF("392", "%g", 392.0);
+  EXPECT_PRINTF("392", "%G", 392.0);
+  EXPECT_PRINTF("4.56e-07", "%g", 0.000000456);
+  safe_sprintf(buffer, "%a", -392.65);
+  EXPECT_EQ(buffer, format("{:a}", -392.65));
+  safe_sprintf(buffer, "%A", -392.65);
+  EXPECT_EQ(buffer, format("{:A}", -392.65));
+}
+
+TEST(printf_test, inf) {
+  double inf = std::numeric_limits<double>::infinity();
+  for (const char* type = "fega"; *type; ++type) {
+    EXPECT_PRINTF("inf", fmt::format("%{}", *type), inf);
+    char upper = static_cast<char>(std::toupper(*type));
+    EXPECT_PRINTF("INF", fmt::format("%{}", upper), inf);
+  }
+}
+
+TEST(printf_test, char) {
+  EXPECT_PRINTF("x", "%c", 'x');
+  int max = max_value<int>();
+  EXPECT_PRINTF(fmt::format("{}", static_cast<char>(max)), "%c", max);
+  // EXPECT_PRINTF("x", "%lc", L'x');
+  EXPECT_PRINTF(L"x", L"%c", L'x');
+  EXPECT_PRINTF(fmt::format(L"{}", static_cast<wchar_t>(max)), L"%c", max);
+}
+
+TEST(printf_test, string) {
+  EXPECT_PRINTF("abc", "%s", "abc");
+  const char* null_str = nullptr;
+  EXPECT_PRINTF("(null)", "%s", null_str);
+  EXPECT_PRINTF("    (null)", "%10s", null_str);
+  EXPECT_PRINTF(L"abc", L"%s", L"abc");
+  const wchar_t* null_wstr = nullptr;
+  EXPECT_PRINTF(L"(null)", L"%s", null_wstr);
+  EXPECT_PRINTF(L"    (null)", L"%10s", null_wstr);
+}
+
+TEST(printf_test, pointer) {
+  int n;
+  void* p = &n;
+  EXPECT_PRINTF(fmt::format("{}", p), "%p", p);
+  p = nullptr;
+  EXPECT_PRINTF("(nil)", "%p", p);
+  EXPECT_PRINTF("     (nil)", "%10p", p);
+  const char* s = "test";
+  EXPECT_PRINTF(fmt::format("{:p}", s), "%p", s);
+  const char* null_str = nullptr;
+  EXPECT_PRINTF("(nil)", "%p", null_str);
+
+  p = &n;
+  EXPECT_PRINTF(fmt::format(L"{}", p), L"%p", p);
+  p = nullptr;
+  EXPECT_PRINTF(L"(nil)", L"%p", p);
+  EXPECT_PRINTF(L"     (nil)", L"%10p", p);
+  const wchar_t* w = L"test";
+  EXPECT_PRINTF(fmt::format(L"{:p}", w), L"%p", w);
+  const wchar_t* null_wstr = nullptr;
+  EXPECT_PRINTF(L"(nil)", L"%p", null_wstr);
+}
+
+enum test_enum { answer = 42 };
+auto format_as(test_enum e) -> int { return e; }
+
+TEST(printf_test, enum) {
+  EXPECT_PRINTF("42", "%d", answer);
+  volatile test_enum volatile_enum = answer;
+  EXPECT_PRINTF("42", "%d", volatile_enum);
+}
+
+#if FMT_USE_FCNTL
+TEST(printf_test, examples) {
+  const char* weekday = "Thursday";
+  const char* month = "August";
+  int day = 21;
+  EXPECT_WRITE(stdout, fmt::printf("%1$s, %3$d %2$s", weekday, month, day),
+               "Thursday, 21 August");
+}
+
+TEST(printf_test, printf_error) {
+  fmt::file read_end, write_end;
+  fmt::file::pipe(read_end, write_end);
+  int result = fmt::fprintf(read_end.fdopen("r").get(), "test");
+  EXPECT_LT(result, 0);
+}
+#endif
+
+TEST(printf_test, wide_string) {
+  EXPECT_EQ(L"abc", fmt::sprintf(L"%s", L"abc"));
+}
+
+TEST(printf_test, vprintf) {
+  fmt::format_arg_store<fmt::printf_context, int> as{42};
+  fmt::basic_format_args<fmt::printf_context> args(as);
+  EXPECT_EQ(fmt::vsprintf("%d", args), "42");
+  EXPECT_WRITE(stdout, fmt::vprintf("%d", args), "42");
+  EXPECT_WRITE(stdout, fmt::vfprintf(stdout, "%d", args), "42");
+}
+
+template <typename... Args>
+void check_format_string_regression(fmt::string_view s, const Args&... args) {
+  fmt::sprintf(s, args...);
+}
+
+TEST(printf_test, check_format_string_regression) {
+  check_format_string_regression("%c%s", 'x', "");
+}
+
+TEST(printf_test, fixed_large_exponent) {
+  EXPECT_EQ("1000000000000000000000", fmt::sprintf("%.*f", -13, 1e21));
+}
+
+TEST(printf_test, vsprintf_make_args_example) {
+  fmt::format_arg_store<fmt::printf_context, int, const char*> as{42,
+                                                                  "something"};
+  fmt::basic_format_args<fmt::printf_context> args(as);
+  EXPECT_EQ("[42] something happened", fmt::vsprintf("[%d] %s happened", args));
+  auto as2 = fmt::make_printf_args(42, "something");
+  fmt::basic_format_args<fmt::printf_context> args2(as2);
+  EXPECT_EQ("[42] something happened",
+            fmt::vsprintf("[%d] %s happened", args2));
+  EXPECT_EQ("[42] something happened",
+            fmt::vsprintf("[%d] %s happened",
+                          {fmt::make_printf_args(42, "something")}));
+}
+
+TEST(printf_test, vsprintf_make_wargs_example) {
+  fmt::format_arg_store<fmt::wprintf_context, int, const wchar_t*> as{
+      42, L"something"};
+  fmt::basic_format_args<fmt::wprintf_context> args(as);
+  EXPECT_EQ(L"[42] something happened",
+            fmt::vsprintf(L"[%d] %s happened", args));
+  auto as2 = fmt::make_wprintf_args(42, L"something");
+  fmt::basic_format_args<fmt::wprintf_context> args2(as2);
+  EXPECT_EQ(L"[42] something happened",
+            fmt::vsprintf(L"[%d] %s happened", args2));
+  EXPECT_EQ(L"[42] something happened",
+            fmt::vsprintf(L"[%d] %s happened",
+                          {fmt::make_wprintf_args(42, L"something")}));
+}
diff --git a/src/fmt/test/ranges-odr-test.cc b/src/fmt/test/ranges-odr-test.cc
new file mode 100644
index 000000000..031354d3c
--- /dev/null
+++ b/src/fmt/test/ranges-odr-test.cc
@@ -0,0 +1,17 @@
+// Formatting library for C++ - the core API
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <vector>
+
+#include "fmt/ranges.h"
+#include "gtest/gtest.h"
+
+// call fmt::format from another translation unit to test ODR
+TEST(ranges_odr_test, format_vector) {
+  auto v = std::vector<int>{1, 2, 3, 5, 7, 11};
+  EXPECT_EQ(fmt::format("{}", v), "[1, 2, 3, 5, 7, 11]");
+}
diff --git a/src/fmt/test/ranges-test.cc b/src/fmt/test/ranges-test.cc
new file mode 100644
index 000000000..3221e2ed0
--- /dev/null
+++ b/src/fmt/test/ranges-test.cc
@@ -0,0 +1,424 @@
+// Formatting library for C++ - the core API
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+//
+// Copyright (c) 2018 - present, Remotion (Igor Schulz)
+// All Rights Reserved
+// {fmt} support for ranges, containers and types tuple interface.
+
+#include "fmt/ranges.h"
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+
+#if !FMT_GCC_VERSION || FMT_GCC_VERSION >= 601
+#  define FMT_RANGES_TEST_ENABLE_C_STYLE_ARRAY
+#endif
+
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION > 1910
+#  define FMT_RANGES_TEST_ENABLE_JOIN
+#  define FMT_RANGES_TEST_ENABLE_FORMAT_STRUCT
+#endif
+
+#ifdef FMT_RANGES_TEST_ENABLE_C_STYLE_ARRAY
+TEST(ranges_test, format_array) {
+  int arr[] = {1, 2, 3, 5, 7, 11};
+  EXPECT_EQ(fmt::format("{}", arr), "[1, 2, 3, 5, 7, 11]");
+}
+
+TEST(ranges_test, format_2d_array) {
+  int arr[][2] = {{1, 2}, {3, 5}, {7, 11}};
+  EXPECT_EQ(fmt::format("{}", arr), "[[1, 2], [3, 5], [7, 11]]");
+}
+
+TEST(ranges_test, format_array_of_literals) {
+  const char* arr[] = {"1234", "abcd"};
+  EXPECT_EQ(fmt::format("{}", arr), "[\"1234\", \"abcd\"]");
+  EXPECT_EQ(fmt::format("{:n}", arr), "\"1234\", \"abcd\"");
+  EXPECT_EQ(fmt::format("{:n:}", arr), "1234, abcd");
+}
+#endif  // FMT_RANGES_TEST_ENABLE_C_STYLE_ARRAY
+
+TEST(ranges_test, format_vector) {
+  auto v = std::vector<int>{1, 2, 3, 5, 7, 11};
+  EXPECT_EQ(fmt::format("{}", v), "[1, 2, 3, 5, 7, 11]");
+  EXPECT_EQ(fmt::format("{::#x}", v), "[0x1, 0x2, 0x3, 0x5, 0x7, 0xb]");
+  EXPECT_EQ(fmt::format("{:n:#x}", v), "0x1, 0x2, 0x3, 0x5, 0x7, 0xb");
+}
+
+TEST(ranges_test, format_vector2) {
+  auto v = std::vector<std::vector<int>>{{1, 2}, {3, 5}, {7, 11}};
+  EXPECT_EQ(fmt::format("{}", v), "[[1, 2], [3, 5], [7, 11]]");
+  EXPECT_EQ(fmt::format("{:::#x}", v), "[[0x1, 0x2], [0x3, 0x5], [0x7, 0xb]]");
+  EXPECT_EQ(fmt::format("{:n:n:#x}", v), "0x1, 0x2, 0x3, 0x5, 0x7, 0xb");
+}
+
+TEST(ranges_test, format_map) {
+  auto m = std::map<std::string, int>{{"one", 1}, {"two", 2}};
+  EXPECT_EQ(fmt::format("{}", m), "{\"one\": 1, \"two\": 2}");
+  EXPECT_EQ(fmt::format("{:n}", m), "\"one\": 1, \"two\": 2");
+}
+
+TEST(ranges_test, format_set) {
+  EXPECT_EQ(fmt::format("{}", std::set<std::string>{"one", "two"}),
+            "{\"one\", \"two\"}");
+}
+
+namespace adl {
+struct box {
+  int value;
+};
+
+auto begin(const box& b) -> const int* { return &b.value; }
+
+auto end(const box& b) -> const int* { return &b.value + 1; }
+}  // namespace adl
+
+TEST(ranges_test, format_adl_begin_end) {
+  auto b = adl::box{42};
+  EXPECT_EQ(fmt::format("{}", b), "[42]");
+}
+
+TEST(ranges_test, format_pair) {
+  auto p = std::pair<int, float>(42, 1.5f);
+  EXPECT_EQ(fmt::format("{}", p), "(42, 1.5)");
+}
+
+struct unformattable {};
+
+TEST(ranges_test, format_tuple) {
+  auto t =
+      std::tuple<int, float, std::string, char>(42, 1.5f, "this is tuple", 'i');
+  EXPECT_EQ(fmt::format("{}", t), "(42, 1.5, \"this is tuple\", 'i')");
+  EXPECT_EQ(fmt::format("{}", std::tuple<>()), "()");
+
+  EXPECT_TRUE((fmt::is_formattable<std::tuple<>>::value));
+  EXPECT_FALSE((fmt::is_formattable<unformattable>::value));
+  EXPECT_FALSE((fmt::is_formattable<std::tuple<unformattable>>::value));
+  EXPECT_FALSE((fmt::is_formattable<std::tuple<unformattable, int>>::value));
+  EXPECT_FALSE((fmt::is_formattable<std::tuple<int, unformattable>>::value));
+  EXPECT_FALSE(
+      (fmt::is_formattable<std::tuple<unformattable, unformattable>>::value));
+  EXPECT_TRUE((fmt::is_formattable<std::tuple<int, float>>::value));
+}
+
+#ifdef FMT_RANGES_TEST_ENABLE_FORMAT_STRUCT
+struct tuple_like {
+  int i;
+  std::string str;
+
+  template <size_t N> fmt::enable_if_t<N == 0, int> get() const noexcept {
+    return i;
+  }
+  template <size_t N>
+  fmt::enable_if_t<N == 1, fmt::string_view> get() const noexcept {
+    return str;
+  }
+};
+
+template <size_t N>
+auto get(const tuple_like& t) noexcept -> decltype(t.get<N>()) {
+  return t.get<N>();
+}
+
+namespace std {
+template <>
+struct tuple_size<tuple_like> : std::integral_constant<size_t, 2> {};
+
+template <size_t N> struct tuple_element<N, tuple_like> {
+  using type = decltype(std::declval<tuple_like>().get<N>());
+};
+}  // namespace std
+
+TEST(ranges_test, format_struct) {
+  auto t = tuple_like{42, "foo"};
+  EXPECT_EQ(fmt::format("{}", t), "(42, \"foo\")");
+}
+#endif  // FMT_RANGES_TEST_ENABLE_FORMAT_STRUCT
+
+TEST(ranges_test, format_to) {
+  char buf[10];
+  auto end = fmt::format_to(buf, "{}", std::vector<int>{1, 2, 3});
+  *end = '\0';
+  EXPECT_STREQ(buf, "[1, 2, 3]");
+}
+
+struct path_like {
+  const path_like* begin() const;
+  const path_like* end() const;
+
+  operator std::string() const;
+};
+
+TEST(ranges_test, path_like) {
+  EXPECT_FALSE((fmt::is_range<path_like, char>::value));
+}
+
+#ifdef FMT_USE_STRING_VIEW
+struct string_like {
+  const char* begin();
+  const char* end();
+  operator fmt::string_view() const { return "foo"; }
+  operator std::string_view() const { return "foo"; }
+};
+
+TEST(ranges_test, format_string_like) {
+  EXPECT_EQ(fmt::format("{}", string_like()), "foo");
+}
+#endif  // FMT_USE_STRING_VIEW
+
+// A range that provides non-const only begin()/end() to test fmt::join handles
+// that.
+//
+// Some ranges (e.g. those produced by range-v3's views::filter()) can cache
+// information during iteration so they only provide non-const begin()/end().
+template <typename T> class non_const_only_range {
+ private:
+  std::vector<T> vec;
+
+ public:
+  using const_iterator = typename ::std::vector<T>::const_iterator;
+
+  template <typename... Args>
+  explicit non_const_only_range(Args&&... args)
+      : vec(std::forward<Args>(args)...) {}
+
+  const_iterator begin() { return vec.begin(); }
+  const_iterator end() { return vec.end(); }
+};
+
+template <typename T> class noncopyable_range {
+ private:
+  std::vector<T> vec;
+
+ public:
+  using const_iterator = typename ::std::vector<T>::const_iterator;
+
+  template <typename... Args>
+  explicit noncopyable_range(Args&&... args)
+      : vec(std::forward<Args>(args)...) {}
+
+  noncopyable_range(noncopyable_range const&) = delete;
+  noncopyable_range(noncopyable_range&) = delete;
+
+  const_iterator begin() const { return vec.begin(); }
+  const_iterator end() const { return vec.end(); }
+};
+
+TEST(ranges_test, range) {
+  noncopyable_range<int> w(3u, 0);
+  EXPECT_EQ(fmt::format("{}", w), "[0, 0, 0]");
+  EXPECT_EQ(fmt::format("{}", noncopyable_range<int>(3u, 0)), "[0, 0, 0]");
+
+  non_const_only_range<int> x(3u, 0);
+  EXPECT_EQ(fmt::format("{}", x), "[0, 0, 0]");
+  EXPECT_EQ(fmt::format("{}", non_const_only_range<int>(3u, 0)), "[0, 0, 0]");
+
+  auto y = std::vector<int>(3u, 0);
+  EXPECT_EQ(fmt::format("{}", y), "[0, 0, 0]");
+  EXPECT_EQ(fmt::format("{}", std::vector<int>(3u, 0)), "[0, 0, 0]");
+
+  const auto z = std::vector<int>(3u, 0);
+  EXPECT_EQ(fmt::format("{}", z), "[0, 0, 0]");
+}
+
+enum test_enum { foo };
+auto format_as(test_enum e) -> int { return e; }
+
+TEST(ranges_test, enum_range) {
+  auto v = std::vector<test_enum>{test_enum::foo};
+  EXPECT_EQ(fmt::format("{}", v), "[0]");
+}
+
+#if !FMT_MSC_VERSION
+
+TEST(ranges_test, unformattable_range) {
+  EXPECT_FALSE((fmt::has_formatter<std::vector<unformattable>,
+                                   fmt::format_context>::value));
+}
+#endif
+
+#ifdef FMT_RANGES_TEST_ENABLE_JOIN
+TEST(ranges_test, join_tuple) {
+  // Value tuple args.
+  auto t1 = std::tuple<char, int, float>('a', 1, 2.0f);
+  EXPECT_EQ(fmt::format("({})", fmt::join(t1, ", ")), "(a, 1, 2)");
+
+  // Testing lvalue tuple args.
+  int x = 4;
+  auto t2 = std::tuple<char, int&>('b', x);
+  EXPECT_EQ(fmt::format("{}", fmt::join(t2, " + ")), "b + 4");
+
+  // Empty tuple.
+  auto t3 = std::tuple<>();
+  EXPECT_EQ(fmt::format("{}", fmt::join(t3, "|")), "");
+
+  // Single element tuple.
+  auto t4 = std::tuple<float>(4.0f);
+  EXPECT_EQ(fmt::format("{}", fmt::join(t4, "/")), "4");
+
+#  if FMT_TUPLE_JOIN_SPECIFIERS
+  // Specs applied to each element.
+  auto t5 = std::tuple<int, int, long>(-3, 100, 1);
+  EXPECT_EQ(fmt::format("{:+03}", fmt::join(t5, ", ")), "-03, +100, +01");
+
+  auto t6 = std::tuple<float, double, long double>(3, 3.14, 3.1415);
+  EXPECT_EQ(fmt::format("{:5.5f}", fmt::join(t6, ", ")),
+            "3.00000, 3.14000, 3.14150");
+
+  // Testing lvalue tuple args.
+  int y = -1;
+  auto t7 = std::tuple<int, int&, const int&>(3, y, y);
+  EXPECT_EQ(fmt::format("{:03}", fmt::join(t7, ", ")), "003, -01, -01");
+#  endif
+}
+
+TEST(ranges_test, join_initializer_list) {
+  EXPECT_EQ(fmt::format("{}", fmt::join({1, 2, 3}, ", ")), "1, 2, 3");
+  EXPECT_EQ(fmt::format("{}", fmt::join({"fmt", "rocks", "!"}, " ")),
+            "fmt rocks !");
+}
+
+struct zstring_sentinel {};
+
+bool operator==(const char* p, zstring_sentinel) { return *p == '\0'; }
+bool operator!=(const char* p, zstring_sentinel) { return *p != '\0'; }
+
+struct zstring {
+  const char* p;
+  const char* begin() const { return p; }
+  zstring_sentinel end() const { return {}; }
+};
+
+#  ifdef __cpp_lib_ranges
+struct cpp20_only_range {
+  struct iterator {
+    int val = 0;
+
+    using value_type = int;
+    using difference_type = std::ptrdiff_t;
+    using iterator_concept = std::input_iterator_tag;
+
+    iterator() = default;
+    iterator(int i) : val(i) {}
+    int operator*() const { return val; }
+    iterator& operator++() {
+      ++val;
+      return *this;
+    }
+    void operator++(int) { ++*this; }
+    bool operator==(const iterator& rhs) const { return val == rhs.val; }
+  };
+
+  int lo;
+  int hi;
+
+  iterator begin() const { return iterator(lo); }
+  iterator end() const { return iterator(hi); }
+};
+
+static_assert(std::input_iterator<cpp20_only_range::iterator>);
+#  endif
+
+TEST(ranges_test, join_sentinel) {
+  auto hello = zstring{"hello"};
+  EXPECT_EQ(fmt::format("{}", hello), "['h', 'e', 'l', 'l', 'o']");
+  EXPECT_EQ(fmt::format("{::}", hello), "[h, e, l, l, o]");
+  EXPECT_EQ(fmt::format("{}", fmt::join(hello, "_")), "h_e_l_l_o");
+}
+
+TEST(ranges_test, join_range) {
+  noncopyable_range<int> w(3u, 0);
+  EXPECT_EQ(fmt::format("{}", fmt::join(w, ",")), "0,0,0");
+  EXPECT_EQ(fmt::format("{}", fmt::join(noncopyable_range<int>(3u, 0), ",")),
+            "0,0,0");
+
+  non_const_only_range<int> x(3u, 0);
+  EXPECT_EQ(fmt::format("{}", fmt::join(x, ",")), "0,0,0");
+  EXPECT_EQ(fmt::format("{}", fmt::join(non_const_only_range<int>(3u, 0), ",")),
+            "0,0,0");
+
+  auto y = std::vector<int>(3u, 0);
+  EXPECT_EQ(fmt::format("{}", fmt::join(y, ",")), "0,0,0");
+  EXPECT_EQ(fmt::format("{}", fmt::join(std::vector<int>(3u, 0), ",")),
+            "0,0,0");
+
+  const auto z = std::vector<int>(3u, 0);
+  EXPECT_EQ(fmt::format("{}", fmt::join(z, ",")), "0,0,0");
+
+#  ifdef __cpp_lib_ranges
+  EXPECT_EQ(fmt::format("{}", cpp20_only_range{.lo = 0, .hi = 5}),
+            "[0, 1, 2, 3, 4]");
+  EXPECT_EQ(
+      fmt::format("{}", fmt::join(cpp20_only_range{.lo = 0, .hi = 5}, ",")),
+      "0,1,2,3,4");
+#  endif
+}
+#endif  // FMT_RANGES_TEST_ENABLE_JOIN
+
+TEST(ranges_test, is_printable) {
+  using fmt::detail::is_printable;
+  EXPECT_TRUE(is_printable(0x0323));
+  EXPECT_FALSE(is_printable(0x0378));
+  EXPECT_FALSE(is_printable(0x110000));
+}
+
+TEST(ranges_test, escape_string) {
+  using vec = std::vector<std::string>;
+  EXPECT_EQ(fmt::format("{}", vec{"\n\r\t\"\\"}), "[\"\\n\\r\\t\\\"\\\\\"]");
+  EXPECT_EQ(fmt::format("{}", vec{"\x07"}), "[\"\\x07\"]");
+  EXPECT_EQ(fmt::format("{}", vec{"\x7f"}), "[\"\\x7f\"]");
+  EXPECT_EQ(fmt::format("{}", vec{"n\xcc\x83"}), "[\"n\xcc\x83\"]");
+
+  if (fmt::detail::is_utf8()) {
+    EXPECT_EQ(fmt::format("{}", vec{"\xcd\xb8"}), "[\"\\u0378\"]");
+    // Unassigned Unicode code points.
+    EXPECT_EQ(fmt::format("{}", vec{"\xf0\xaa\x9b\x9e"}), "[\"\\U0002a6de\"]");
+    // Broken utf-8.
+    EXPECT_EQ(fmt::format("{}", vec{"\xf4\x8f\xbf\xc0"}),
+              "[\"\\xf4\\x8f\\xbf\\xc0\"]");
+    EXPECT_EQ(fmt::format("{}", vec{"\xf0\x28"}), "[\"\\xf0(\"]");
+    EXPECT_EQ(fmt::format("{}", vec{"\xe1\x28"}), "[\"\\xe1(\"]");
+    EXPECT_EQ(fmt::format("{}", vec{std::string("\xf0\x28\0\0anything", 12)}),
+              "[\"\\xf0(\\x00\\x00anything\"]");
+
+    // Correct utf-8.
+    EXPECT_EQ(fmt::format("{}", vec{"понедельник"}), "[\"понедельник\"]");
+  }
+}
+
+#ifdef FMT_USE_STRING_VIEW
+struct convertible_to_string_view {
+  operator std::string_view() const { return "foo"; }
+};
+
+TEST(ranges_test, escape_convertible_to_string_view) {
+  EXPECT_EQ(fmt::format("{}", std::vector<convertible_to_string_view>(1)),
+            "[\"foo\"]");
+}
+#endif  // FMT_USE_STRING_VIEW
+
+template <typename R> struct fmt_ref_view {
+  R* r;
+
+  auto begin() const -> decltype(r->begin()) { return r->begin(); }
+  auto end() const -> decltype(r->end()) { return r->end(); }
+};
+
+TEST(ranges_test, range_of_range_of_mixed_const) {
+  std::vector<std::vector<int>> v = {{1, 2, 3}, {4, 5}};
+  EXPECT_EQ(fmt::format("{}", v), "[[1, 2, 3], [4, 5]]");
+
+  fmt_ref_view<decltype(v)> r{&v};
+  EXPECT_EQ(fmt::format("{}", r), "[[1, 2, 3], [4, 5]]");
+}
+
+TEST(ranges_test, vector_char) {
+  EXPECT_EQ(fmt::format("{}", std::vector<char>{'a', 'b'}), "['a', 'b']");
+}
diff --git a/src/fmt/test/scan-test.cc b/src/fmt/test/scan-test.cc
new file mode 100644
index 000000000..7e327ea3f
--- /dev/null
+++ b/src/fmt/test/scan-test.cc
@@ -0,0 +1,116 @@
+// Formatting library for C++ - scanning API test
+//
+// Copyright (c) 2019 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "scan.h"
+
+#include <time.h>
+
+#include <climits>
+
+#include "gmock/gmock.h"
+#include "gtest-extra.h"
+
+TEST(scan_test, read_text) {
+  auto s = fmt::string_view("foo");
+  auto end = fmt::scan(s, "foo");
+  EXPECT_EQ(end, s.end());
+  EXPECT_THROW_MSG(fmt::scan("fob", "foo"), fmt::format_error, "invalid input");
+}
+
+TEST(scan_test, read_int) {
+  auto n = int();
+  fmt::scan("42", "{}", n);
+  EXPECT_EQ(n, 42);
+  fmt::scan("-42", "{}", n);
+  EXPECT_EQ(n, -42);
+}
+
+TEST(scan_test, read_longlong) {
+  long long n = 0;
+  fmt::scan("42", "{}", n);
+  EXPECT_EQ(n, 42);
+  fmt::scan("-42", "{}", n);
+  EXPECT_EQ(n, -42);
+}
+
+TEST(scan_test, read_uint) {
+  auto n = unsigned();
+  fmt::scan("42", "{}", n);
+  EXPECT_EQ(n, 42);
+  EXPECT_THROW_MSG(fmt::scan("-42", "{}", n), fmt::format_error,
+                   "invalid input");
+}
+
+TEST(scan_test, read_ulonglong) {
+  unsigned long long n = 0;
+  fmt::scan("42", "{}", n);
+  EXPECT_EQ(n, 42);
+  EXPECT_THROW_MSG(fmt::scan("-42", "{}", n), fmt::format_error,
+                   "invalid input");
+}
+
+TEST(scan_test, read_string) {
+  auto s = std::string();
+  fmt::scan("foo", "{}", s);
+  EXPECT_EQ(s, "foo");
+}
+
+TEST(scan_test, read_string_view) {
+  auto s = fmt::string_view();
+  fmt::scan("foo", "{}", s);
+  EXPECT_EQ(s, "foo");
+}
+
+#ifndef _WIN32
+namespace fmt {
+template <> struct scanner<tm> {
+  std::string format;
+
+  scan_parse_context::iterator parse(scan_parse_context& ctx) {
+    auto it = ctx.begin();
+    if (it != ctx.end() && *it == ':') ++it;
+    auto end = it;
+    while (end != ctx.end() && *end != '}') ++end;
+    format.reserve(detail::to_unsigned(end - it + 1));
+    format.append(it, end);
+    format.push_back('\0');
+    return end;
+  }
+
+  template <class ScanContext>
+  typename ScanContext::iterator scan(tm& t, ScanContext& ctx) {
+    auto result = strptime(ctx.begin(), format.c_str(), &t);
+    if (!result) throw format_error("failed to parse time");
+    return result;
+  }
+};
+}  // namespace fmt
+
+TEST(scan_test, read_custom) {
+  auto input = "Date: 1985-10-25";
+  auto t = tm();
+  fmt::scan(input, "Date: {0:%Y-%m-%d}", t);
+  EXPECT_EQ(t.tm_year, 85);
+  EXPECT_EQ(t.tm_mon, 9);
+  EXPECT_EQ(t.tm_mday, 25);
+}
+#endif
+
+TEST(scan_test, invalid_format) {
+  EXPECT_THROW_MSG(fmt::scan("", "{}"), fmt::format_error,
+                   "argument index out of range");
+  EXPECT_THROW_MSG(fmt::scan("", "{"), fmt::format_error,
+                   "invalid format string");
+}
+
+TEST(scan_test, example) {
+  auto key = std::string();
+  auto value = int();
+  fmt::scan("answer = 42", "{} = {}", key, value);
+  EXPECT_EQ(key, "answer");
+  EXPECT_EQ(value, 42);
+}
diff --git a/src/fmt/test/scan.h b/src/fmt/test/scan.h
new file mode 100644
index 000000000..41748ae89
--- /dev/null
+++ b/src/fmt/test/scan.h
@@ -0,0 +1,241 @@
+// Formatting library for C++ - scanning API proof of concept
+//
+// Copyright (c) 2019 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <array>
+#include <cassert>
+#include <climits>
+
+#include "fmt/format.h"
+
+FMT_BEGIN_NAMESPACE
+template <typename T, typename Char = char> struct scanner {
+  // A deleted default constructor indicates a disabled scanner.
+  scanner() = delete;
+};
+
+class scan_parse_context {
+ private:
+  string_view format_;
+
+ public:
+  using iterator = string_view::iterator;
+
+  explicit FMT_CONSTEXPR scan_parse_context(string_view format)
+      : format_(format) {}
+
+  FMT_CONSTEXPR iterator begin() const { return format_.begin(); }
+  FMT_CONSTEXPR iterator end() const { return format_.end(); }
+
+  void advance_to(iterator it) {
+    format_.remove_prefix(detail::to_unsigned(it - begin()));
+  }
+};
+
+struct scan_context {
+ private:
+  string_view input_;
+
+ public:
+  using iterator = const char*;
+
+  explicit scan_context(string_view input) : input_(input) {}
+
+  iterator begin() const { return input_.data(); }
+  iterator end() const { return begin() + input_.size(); }
+
+  void advance_to(iterator it) {
+    input_.remove_prefix(detail::to_unsigned(it - begin()));
+  }
+};
+
+namespace detail {
+enum class scan_type {
+  none_type,
+  int_type,
+  uint_type,
+  long_long_type,
+  ulong_long_type,
+  string_type,
+  string_view_type,
+  custom_type
+};
+
+struct custom_scan_arg {
+  void* value;
+  void (*scan)(void* arg, scan_parse_context& parse_ctx, scan_context& ctx);
+};
+
+class scan_arg {
+ public:
+  scan_type type;
+  union {
+    int* int_value;
+    unsigned* uint_value;
+    long long* long_long_value;
+    unsigned long long* ulong_long_value;
+    std::string* string;
+    fmt::string_view* string_view;
+    custom_scan_arg custom;
+    // TODO: more types
+  };
+
+  scan_arg() : type(scan_type::none_type) {}
+  scan_arg(int& value) : type(scan_type::int_type), int_value(&value) {}
+  scan_arg(unsigned& value) : type(scan_type::uint_type), uint_value(&value) {}
+  scan_arg(long long& value)
+      : type(scan_type::long_long_type), long_long_value(&value) {}
+  scan_arg(unsigned long long& value)
+      : type(scan_type::ulong_long_type), ulong_long_value(&value) {}
+  scan_arg(std::string& value) : type(scan_type::string_type), string(&value) {}
+  scan_arg(fmt::string_view& value)
+      : type(scan_type::string_view_type), string_view(&value) {}
+  template <typename T> scan_arg(T& value) : type(scan_type::custom_type) {
+    custom.value = &value;
+    custom.scan = scan_custom_arg<T>;
+  }
+
+ private:
+  template <typename T>
+  static void scan_custom_arg(void* arg, scan_parse_context& parse_ctx,
+                              scan_context& ctx) {
+    scanner<T> s;
+    parse_ctx.advance_to(s.parse(parse_ctx));
+    ctx.advance_to(s.scan(*static_cast<T*>(arg), ctx));
+  }
+};
+}  // namespace detail
+
+struct scan_args {
+  int size;
+  const detail::scan_arg* data;
+
+  template <size_t N>
+  scan_args(const std::array<detail::scan_arg, N>& store)
+      : size(N), data(store.data()) {
+    static_assert(N < INT_MAX, "too many arguments");
+  }
+};
+
+namespace detail {
+
+struct scan_handler : error_handler {
+ private:
+  scan_parse_context parse_ctx_;
+  scan_context scan_ctx_;
+  scan_args args_;
+  int next_arg_id_;
+  scan_arg arg_;
+
+  template <typename T = unsigned> T read_uint() {
+    T value = 0;
+    auto it = scan_ctx_.begin(), end = scan_ctx_.end();
+    while (it != end) {
+      char c = *it++;
+      if (c < '0' || c > '9') on_error("invalid input");
+      // TODO: check overflow
+      value = value * 10 + static_cast<unsigned>(c - '0');
+    }
+    scan_ctx_.advance_to(it);
+    return value;
+  }
+
+  template <typename T = int> T read_int() {
+    auto it = scan_ctx_.begin(), end = scan_ctx_.end();
+    bool negative = it != end && *it == '-';
+    if (negative) ++it;
+    scan_ctx_.advance_to(it);
+    const auto value = read_uint<typename std::make_unsigned<T>::type>();
+    if (negative) return -static_cast<T>(value);
+    return static_cast<T>(value);
+  }
+
+ public:
+  scan_handler(string_view format, string_view input, scan_args args)
+      : parse_ctx_(format), scan_ctx_(input), args_(args), next_arg_id_(0) {}
+
+  const char* pos() const { return scan_ctx_.begin(); }
+
+  void on_text(const char* begin, const char* end) {
+    auto size = to_unsigned(end - begin);
+    auto it = scan_ctx_.begin();
+    if (it + size > scan_ctx_.end() ||
+        !std::equal(begin, end, make_checked(it, size))) {
+      on_error("invalid input");
+    }
+    scan_ctx_.advance_to(it + size);
+  }
+
+  FMT_CONSTEXPR int on_arg_id() { return on_arg_id(next_arg_id_++); }
+  FMT_CONSTEXPR int on_arg_id(int id) {
+    if (id >= args_.size) on_error("argument index out of range");
+    arg_ = args_.data[id];
+    return id;
+  }
+  FMT_CONSTEXPR int on_arg_id(string_view id) {
+    if (id.data()) on_error("invalid format");
+    return 0;
+  }
+
+  void on_replacement_field(int, const char*) {
+    auto it = scan_ctx_.begin(), end = scan_ctx_.end();
+    switch (arg_.type) {
+    case scan_type::int_type:
+      *arg_.int_value = read_int();
+      break;
+    case scan_type::uint_type:
+      *arg_.uint_value = read_uint();
+      break;
+    case scan_type::long_long_type:
+      *arg_.long_long_value = read_int<long long>();
+      break;
+    case scan_type::ulong_long_type:
+      *arg_.ulong_long_value = read_uint<unsigned long long>();
+      break;
+    case scan_type::string_type:
+      while (it != end && *it != ' ') arg_.string->push_back(*it++);
+      scan_ctx_.advance_to(it);
+      break;
+    case scan_type::string_view_type: {
+      auto s = it;
+      while (it != end && *it != ' ') ++it;
+      *arg_.string_view = fmt::string_view(s, to_unsigned(it - s));
+      scan_ctx_.advance_to(it);
+      break;
+    }
+    case scan_type::none_type:
+    case scan_type::custom_type:
+      assert(false);
+    }
+  }
+
+  const char* on_format_specs(int, const char* begin, const char*) {
+    if (arg_.type != scan_type::custom_type) return begin;
+    parse_ctx_.advance_to(begin);
+    arg_.custom.scan(arg_.custom.value, parse_ctx_, scan_ctx_);
+    return parse_ctx_.begin();
+  }
+};
+}  // namespace detail
+
+template <typename... Args>
+std::array<detail::scan_arg, sizeof...(Args)> make_scan_args(Args&... args) {
+  return {{args...}};
+}
+
+string_view::iterator vscan(string_view input, string_view format_str,
+                            scan_args args) {
+  detail::scan_handler h(format_str, input, args);
+  detail::parse_format_string<false>(format_str, h);
+  return input.begin() + (h.pos() - &*input.begin());
+}
+
+template <typename... Args>
+string_view::iterator scan(string_view input, string_view format_str,
+                           Args&... args) {
+  return vscan(input, format_str, make_scan_args(args...));
+}
+FMT_END_NAMESPACE
diff --git a/src/fmt/test/static-export-test/CMakeLists.txt b/src/fmt/test/static-export-test/CMakeLists.txt
new file mode 100644
index 000000000..7690d7b5a
--- /dev/null
+++ b/src/fmt/test/static-export-test/CMakeLists.txt
@@ -0,0 +1,30 @@
+cmake_minimum_required(VERSION 3.1...3.18)
+
+project(fmt-link CXX)
+
+set(BUILD_SHARED_LIBS OFF)
+set(CMAKE_VISIBILITY_INLINES_HIDDEN TRUE)
+set(CMAKE_CXX_VISIBILITY_PRESET "hidden")
+
+# Broken LTO on GCC 4
+if (CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5)
+  set(BROKEN_LTO ON)
+endif ()
+
+if (NOT BROKEN_LTO AND CMAKE_VERSION VERSION_GREATER "3.8")
+  # CMake 3.9+
+  include(CheckIPOSupported)
+  check_ipo_supported(RESULT HAVE_IPO)
+  if (HAVE_IPO)
+    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
+  endif ()
+endif ()
+
+add_subdirectory(../.. fmt)
+set_property(TARGET fmt PROPERTY POSITION_INDEPENDENT_CODE ON)
+
+add_library(library-test SHARED library.cc)
+target_link_libraries(library-test PRIVATE fmt::fmt)
+
+add_executable(exe-test main.cc)
+target_link_libraries(exe-test PRIVATE library-test)
diff --git a/src/fmt/test/static-export-test/library.cc b/src/fmt/test/static-export-test/library.cc
new file mode 100644
index 000000000..fe4801ba5
--- /dev/null
+++ b/src/fmt/test/static-export-test/library.cc
@@ -0,0 +1,5 @@
+#include <fmt/compile.h>
+
+__attribute__((visibility("default"))) std::string foo() {
+  return fmt::format(FMT_COMPILE("foo bar {}"), 4242);
+}
diff --git a/src/fmt/test/static-export-test/main.cc b/src/fmt/test/static-export-test/main.cc
new file mode 100644
index 000000000..38f7999ed
--- /dev/null
+++ b/src/fmt/test/static-export-test/main.cc
@@ -0,0 +1,6 @@
+#include <iostream>
+#include <string>
+
+extern std::string foo();
+
+int main() { std::cout << foo() << std::endl; }
diff --git a/src/fmt/test/std-test.cc b/src/fmt/test/std-test.cc
new file mode 100644
index 000000000..c22b3e38f
--- /dev/null
+++ b/src/fmt/test/std-test.cc
@@ -0,0 +1,79 @@
+// Formatting library for C++ - tests of formatters for standard library types
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/std.h"
+#include "fmt/ranges.h"
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+
+TEST(std_test, path) {
+#ifdef __cpp_lib_filesystem
+  EXPECT_EQ(fmt::format("{:8}", std::filesystem::path("foo")), "\"foo\"   ");
+  EXPECT_EQ(fmt::format("{}", std::filesystem::path("foo\"bar.txt")),
+            "\"foo\\\"bar.txt\"");
+
+#  ifdef _WIN32
+  // File.txt in Russian.
+  const wchar_t unicode_path[] = {0x424, 0x430, 0x439, 0x43b, 0x2e,
+                                  0x74,  0x78,  0x74,  0};
+  const char unicode_u8path[] = {'"',        char(0xd0), char(0xa4), char(0xd0),
+                                 char(0xb0), char(0xd0), char(0xb9), char(0xd0),
+                                 char(0xbb), '.',        't',        'x',
+                                 't',        '"',        '\0'};
+  EXPECT_EQ(fmt::format("{}", std::filesystem::path(unicode_path)),
+            unicode_u8path);
+#  endif
+#endif
+}
+
+TEST(ranges_std_test, format_vector_path) {
+// Test ambiguity problem described in #2954.
+#ifdef __cpp_lib_filesystem
+  auto p = std::filesystem::path("foo/bar.txt");
+  auto c = std::vector<std::string>{"abc", "def"};
+  EXPECT_EQ(fmt::format("path={}, range={}", p, c),
+            "path=\"foo/bar.txt\", range=[\"abc\", \"def\"]");
+#endif
+}
+
+TEST(std_test, thread_id) {
+  EXPECT_FALSE(fmt::format("{}", std::this_thread::get_id()).empty());
+}
+
+TEST(std_test, variant) {
+#ifdef __cpp_lib_variant
+  EXPECT_EQ(fmt::format("{}", std::monostate{}), "monostate");
+  using V0 = std::variant<int, float, std::string, char>;
+  V0 v0(42);
+  V0 v1(1.5f);
+  V0 v2("hello");
+  V0 v3('i');
+  EXPECT_EQ(fmt::format("{}", v0), "variant(42)");
+  EXPECT_EQ(fmt::format("{}", v1), "variant(1.5)");
+  EXPECT_EQ(fmt::format("{}", v2), "variant(\"hello\")");
+  EXPECT_EQ(fmt::format("{}", v3), "variant('i')");
+
+  struct unformattable {};
+  EXPECT_FALSE((fmt::is_formattable<unformattable>::value));
+  EXPECT_FALSE((fmt::is_formattable<std::variant<unformattable>>::value));
+  EXPECT_FALSE((fmt::is_formattable<std::variant<unformattable, int>>::value));
+  EXPECT_FALSE((fmt::is_formattable<std::variant<int, unformattable>>::value));
+  EXPECT_FALSE(
+      (fmt::is_formattable<std::variant<unformattable, unformattable>>::value));
+  EXPECT_TRUE((fmt::is_formattable<std::variant<int, float>>::value));
+
+  using V1 = std::variant<std::monostate, std::string, std::string>;
+  V1 v4{};
+  V1 v5{std::in_place_index<1>, "yes, this is variant"};
+
+  EXPECT_EQ(fmt::format("{}", v4), "variant(monostate)");
+  EXPECT_EQ(fmt::format("{}", v5), "variant(\"yes, this is variant\")");
+#endif
+}
diff --git a/src/fmt/test/test-assert.h b/src/fmt/test/test-assert.h
new file mode 100644
index 000000000..ab7b2bf73
--- /dev/null
+++ b/src/fmt/test/test-assert.h
@@ -0,0 +1,39 @@
+// Formatting library for C++ - test version of FMT_ASSERT
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_TEST_ASSERT_H_
+#define FMT_TEST_ASSERT_H_
+
+#include <stdexcept>
+
+void throw_assertion_failure(const char* message);
+#define FMT_ASSERT(condition, message) \
+  if (!(condition)) throw_assertion_failure(message);
+
+#include "gtest/gtest.h"
+
+class assertion_failure : public std::logic_error {
+ public:
+  explicit assertion_failure(const char* message) : std::logic_error(message) {}
+
+ private:
+  virtual void avoid_weak_vtable();
+};
+
+void assertion_failure::avoid_weak_vtable() {}
+
+// We use a separate function (rather than throw directly from FMT_ASSERT) to
+// avoid GCC's -Wterminate warning when FMT_ASSERT is used in a destructor.
+inline void throw_assertion_failure(const char* message) {
+  throw assertion_failure(message);
+}
+
+// Expects an assertion failure.
+#define EXPECT_ASSERT(stmt, message) \
+  FMT_TEST_THROW_(stmt, assertion_failure, message, GTEST_NONFATAL_FAILURE_)
+
+#endif  // FMT_TEST_ASSERT_H_
diff --git a/src/fmt/test/test-main.cc b/src/fmt/test/test-main.cc
new file mode 100644
index 000000000..39d2789d3
--- /dev/null
+++ b/src/fmt/test/test-main.cc
@@ -0,0 +1,43 @@
+// Formatting library for C++ - test main function.
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <cstdlib>
+
+#include "gtest/gtest.h"
+
+#ifdef _WIN32
+#  include <windows.h>
+#endif
+
+#ifdef _MSC_VER
+#  include <crtdbg.h>
+#endif
+
+int main(int argc, char** argv) {
+#ifdef _WIN32
+  // Don't display any error dialogs. This also suppresses message boxes
+  // on assertion failures in MinGW where _set_error_mode/CrtSetReportMode
+  // doesn't help.
+  SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX |
+               SEM_NOOPENFILEERRORBOX);
+#endif
+#ifdef _MSC_VER
+  // Disable message boxes on assertion failures.
+  _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
+  _CrtSetReportFile(_CRT_ERROR, _CRTDBG_FILE_STDERR);
+  _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
+  _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR);
+#endif
+  try {
+    testing::InitGoogleTest(&argc, argv);
+    testing::FLAGS_gtest_death_test_style = "threadsafe";
+    return RUN_ALL_TESTS();
+  } catch (...) {
+    // Catch all exceptions to make Coverity happy.
+  }
+  return EXIT_FAILURE;
+}
diff --git a/src/fmt/test/unicode-test.cc b/src/fmt/test/unicode-test.cc
new file mode 100644
index 000000000..e9ea5e5e0
--- /dev/null
+++ b/src/fmt/test/unicode-test.cc
@@ -0,0 +1,48 @@
+// Formatting library for C++ - Unicode tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <iomanip>
+#include <locale>
+#include <vector>
+
+#include "fmt/chrono.h"
+#include "gmock/gmock.h"
+#include "util.h"  // get_locale
+
+using testing::Contains;
+
+TEST(unicode_test, is_utf8) { EXPECT_TRUE(fmt::detail::is_utf8()); }
+
+TEST(unicode_test, legacy_locale) {
+  auto loc = get_locale("be_BY.CP1251", "Belarusian_Belarus.1251");
+  if (loc == std::locale::classic()) return;
+
+  auto s = std::string();
+  try {
+    s = fmt::format(loc, "Дзень тыдня: {:L}", fmt::weekday(1));
+  } catch (const fmt::format_error& e) {
+    // Formatting can fail due to an unsupported encoding.
+    fmt::print("Format error: {}\n", e.what());
+    return;
+  }
+
+#if !FMT_GCC_VERSION || FMT_GCC_VERSION >= 500
+  auto&& os = std::ostringstream();
+  os.imbue(loc);
+  auto tm = std::tm();
+  tm.tm_wday = 1;
+  os << std::put_time(&tm, "%a");
+  auto wd = os.str();
+  if (wd == "??") {
+    EXPECT_EQ(s, "Дзень тыдня: ??");
+    fmt::print("std::locale gives ?? as a weekday.\n");
+    return;
+  }
+#endif
+  EXPECT_THAT((std::vector<std::string>{"Дзень тыдня: пн", "Дзень тыдня: Пан"}),
+              Contains(s));
+}
diff --git a/src/fmt/test/util.cc b/src/fmt/test/util.cc
new file mode 100644
index 000000000..f4cb74ca0
--- /dev/null
+++ b/src/fmt/test/util.cc
@@ -0,0 +1,46 @@
+// Formatting library for C++ - test utilities
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "util.h"
+
+#include <cstring>
+
+const char* const file_content = "Don't panic!";
+
+fmt::buffered_file open_buffered_file(FILE** fp) {
+#if FMT_USE_FCNTL
+  fmt::file read_end, write_end;
+  fmt::file::pipe(read_end, write_end);
+  write_end.write(file_content, std::strlen(file_content));
+  write_end.close();
+  fmt::buffered_file f = read_end.fdopen("r");
+  if (fp) *fp = f.get();
+#else
+  fmt::buffered_file f("test-file", "w");
+  fputs(file_content, f.get());
+  if (fp) *fp = f.get();
+#endif
+  return f;
+}
+
+std::locale do_get_locale(const char* name) {
+  try {
+    return std::locale(name);
+  } catch (const std::runtime_error&) {
+  }
+  return std::locale::classic();
+}
+
+std::locale get_locale(const char* name, const char* alt_name) {
+  auto loc = do_get_locale(name);
+  if (loc == std::locale::classic() && alt_name) {
+    loc = do_get_locale(alt_name);
+  }
+  if (loc == std::locale::classic())
+    fmt::print(stderr, "{} locale is missing.\n", name);
+  return loc;
+}
diff --git a/src/fmt/test/util.h b/src/fmt/test/util.h
new file mode 100644
index 000000000..2e58ad950
--- /dev/null
+++ b/src/fmt/test/util.h
@@ -0,0 +1,85 @@
+// Formatting library for C++ - test utilities
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <cstdarg>
+#include <cstdio>
+#include <locale>
+#include <string>
+
+#ifdef FMT_MODULE_TEST
+import fmt;
+#else
+#  include "fmt/os.h"
+#endif  // FMT_MODULE_TEST
+
+#ifdef _MSC_VER
+#  define FMT_VSNPRINTF vsprintf_s
+#else
+#  define FMT_VSNPRINTF vsnprintf
+#endif
+
+template <size_t SIZE>
+void safe_sprintf(char (&buffer)[SIZE], const char* format, ...) {
+  std::va_list args;
+  va_start(args, format);
+  FMT_VSNPRINTF(buffer, SIZE, format, args);
+  va_end(args);
+}
+
+extern const char* const file_content;
+
+// Opens a buffered file for reading.
+fmt::buffered_file open_buffered_file(FILE** fp = nullptr);
+
+inline FILE* safe_fopen(const char* filename, const char* mode) {
+#if defined(_WIN32) && !defined(__MINGW32__)
+  // Fix MSVC warning about "unsafe" fopen.
+  FILE* f = nullptr;
+  errno = fopen_s(&f, filename, mode);
+  return f;
+#else
+  return std::fopen(filename, mode);
+#endif
+}
+
+template <typename Char> class basic_test_string {
+ private:
+  std::basic_string<Char> value_;
+
+  static const Char empty[];
+
+ public:
+  explicit basic_test_string(const Char* value = empty) : value_(value) {}
+
+  const std::basic_string<Char>& value() const { return value_; }
+};
+
+template <typename Char> const Char basic_test_string<Char>::empty[] = {0};
+
+typedef basic_test_string<char> test_string;
+typedef basic_test_string<wchar_t> test_wstring;
+
+template <typename Char>
+std::basic_ostream<Char>& operator<<(std::basic_ostream<Char>& os,
+                                     const basic_test_string<Char>& s) {
+  os << s.value();
+  return os;
+}
+
+class date {
+  int year_, month_, day_;
+
+ public:
+  date(int year, int month, int day) : year_(year), month_(month), day_(day) {}
+
+  int year() const { return year_; }
+  int month() const { return month_; }
+  int day() const { return day_; }
+};
+
+// Returns a locale with the given name if available or classic locale othewise.
+std::locale get_locale(const char* name, const char* alt_name = nullptr);
diff --git a/src/fmt/test/xchar-test.cc b/src/fmt/test/xchar-test.cc
new file mode 100644
index 000000000..290042a63
--- /dev/null
+++ b/src/fmt/test/xchar-test.cc
@@ -0,0 +1,521 @@
+// Formatting library for C++ - formatting library tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/xchar.h"
+
+#include <complex>
+#include <cwchar>
+#include <vector>
+
+#include "fmt/chrono.h"
+#include "fmt/color.h"
+#include "fmt/ostream.h"
+#include "fmt/ranges.h"
+#include "gtest-extra.h"  // Contains
+#include "util.h"         // get_locale
+
+using fmt::detail::max_value;
+using testing::Contains;
+
+namespace test_ns {
+template <typename Char> class test_string {
+ private:
+  std::basic_string<Char> s_;
+
+ public:
+  test_string(const Char* s) : s_(s) {}
+  const Char* data() const { return s_.data(); }
+  size_t length() const { return s_.size(); }
+  operator const Char*() const { return s_.c_str(); }
+};
+
+template <typename Char>
+fmt::basic_string_view<Char> to_string_view(const test_string<Char>& s) {
+  return {s.data(), s.length()};
+}
+
+struct non_string {};
+}  // namespace test_ns
+
+template <typename T> class is_string_test : public testing::Test {};
+
+using string_char_types = testing::Types<char, wchar_t, char16_t, char32_t>;
+TYPED_TEST_SUITE(is_string_test, string_char_types);
+
+template <typename Char>
+struct derived_from_string_view : fmt::basic_string_view<Char> {};
+
+TYPED_TEST(is_string_test, is_string) {
+  EXPECT_TRUE(fmt::detail::is_string<TypeParam*>::value);
+  EXPECT_TRUE(fmt::detail::is_string<const TypeParam*>::value);
+  EXPECT_TRUE(fmt::detail::is_string<TypeParam[2]>::value);
+  EXPECT_TRUE(fmt::detail::is_string<const TypeParam[2]>::value);
+  EXPECT_TRUE(fmt::detail::is_string<std::basic_string<TypeParam>>::value);
+  EXPECT_TRUE(fmt::detail::is_string<fmt::basic_string_view<TypeParam>>::value);
+  EXPECT_TRUE(
+      fmt::detail::is_string<derived_from_string_view<TypeParam>>::value);
+  using fmt_string_view = fmt::detail::std_string_view<TypeParam>;
+  EXPECT_TRUE(std::is_empty<fmt_string_view>::value !=
+              fmt::detail::is_string<fmt_string_view>::value);
+  EXPECT_TRUE(fmt::detail::is_string<test_ns::test_string<TypeParam>>::value);
+  EXPECT_FALSE(fmt::detail::is_string<test_ns::non_string>::value);
+}
+
+// std::is_constructible is broken in MSVC until version 2015.
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1900
+struct explicitly_convertible_to_wstring_view {
+  explicit operator fmt::wstring_view() const { return L"foo"; }
+};
+
+TEST(xchar_test, format_explicitly_convertible_to_wstring_view) {
+  // Types explicitly convertible to wstring_view are not formattable by
+  // default because it may introduce ODR violations.
+  static_assert(
+      !fmt::is_formattable<explicitly_convertible_to_wstring_view>::value, "");
+}
+#endif
+
+TEST(xchar_test, format) {
+  EXPECT_EQ(L"42", fmt::format(L"{}", 42));
+  EXPECT_EQ(L"4.2", fmt::format(L"{}", 4.2));
+  EXPECT_EQ(L"abc", fmt::format(L"{}", L"abc"));
+  EXPECT_EQ(L"z", fmt::format(L"{}", L'z'));
+  EXPECT_THROW(fmt::format(fmt::runtime(L"{:*\x343E}"), 42), fmt::format_error);
+  EXPECT_EQ(L"true", fmt::format(L"{}", true));
+  EXPECT_EQ(L"a", fmt::format(L"{0}", 'a'));
+  EXPECT_EQ(L"a", fmt::format(L"{0}", L'a'));
+  EXPECT_EQ(L"Cyrillic letter \x42e",
+            fmt::format(L"Cyrillic letter {}", L'\x42e'));
+  EXPECT_EQ(L"abc1", fmt::format(L"{}c{}", L"ab", 1));
+}
+
+TEST(xchar_test, is_formattable) {
+  static_assert(!fmt::is_formattable<const wchar_t*>::value, "");
+}
+
+TEST(xchar_test, compile_time_string) {
+  EXPECT_EQ(fmt::format(fmt::wformat_string<int>(L"{}"), 42), L"42");
+#if defined(FMT_USE_STRING_VIEW) && FMT_CPLUSPLUS >= 201703L
+  EXPECT_EQ(fmt::format(FMT_STRING(std::wstring_view(L"{}")), 42), L"42");
+#endif
+}
+
+#if FMT_CPLUSPLUS > 201103L
+struct custom_char {
+  int value;
+  custom_char() = default;
+
+  template <typename T>
+  constexpr custom_char(T val) : value(static_cast<int>(val)) {}
+
+  operator int() const { return value; }
+};
+
+int to_ascii(custom_char c) { return c; }
+
+FMT_BEGIN_NAMESPACE
+template <> struct is_char<custom_char> : std::true_type {};
+FMT_END_NAMESPACE
+
+TEST(xchar_test, format_custom_char) {
+  const custom_char format[] = {'{', '}', 0};
+  auto result = fmt::format(format, custom_char('x'));
+  EXPECT_EQ(result.size(), 1);
+  EXPECT_EQ(result[0], custom_char('x'));
+}
+#endif
+
+// Convert a char8_t string to std::string. Otherwise GTest will insist on
+// inserting `char8_t` NTBS into a `char` stream which is disabled by P1423.
+template <typename S> std::string from_u8str(const S& str) {
+  return std::string(str.begin(), str.end());
+}
+
+TEST(xchar_test, format_utf8_precision) {
+  using str_type = std::basic_string<fmt::detail::char8_type>;
+  auto format =
+      str_type(reinterpret_cast<const fmt::detail::char8_type*>(u8"{:.4}"));
+  auto str = str_type(reinterpret_cast<const fmt::detail::char8_type*>(
+      u8"caf\u00e9s"));  // cafés
+  auto result = fmt::format(format, str);
+  EXPECT_EQ(fmt::detail::compute_width(result), 4);
+  EXPECT_EQ(result.size(), 5);
+  EXPECT_EQ(from_u8str(result), from_u8str(str.substr(0, 5)));
+}
+
+TEST(xchar_test, format_to) {
+  auto buf = std::vector<wchar_t>();
+  fmt::format_to(std::back_inserter(buf), L"{}{}", 42, L'\0');
+  EXPECT_STREQ(buf.data(), L"42");
+}
+
+TEST(xchar_test, vformat_to) {
+  using wcontext = fmt::wformat_context;
+  fmt::basic_format_arg<wcontext> warg = fmt::detail::make_arg<wcontext>(42);
+  auto wargs = fmt::basic_format_args<wcontext>(&warg, 1);
+  auto w = std::wstring();
+  fmt::vformat_to(std::back_inserter(w), L"{}", wargs);
+  EXPECT_EQ(L"42", w);
+  w.clear();
+  fmt::vformat_to(std::back_inserter(w), FMT_STRING(L"{}"), wargs);
+  EXPECT_EQ(L"42", w);
+}
+
+TEST(format_test, wide_format_to_n) {
+  wchar_t buffer[4];
+  buffer[3] = L'x';
+  auto result = fmt::format_to_n(buffer, 3, L"{}", 12345);
+  EXPECT_EQ(5u, result.size);
+  EXPECT_EQ(buffer + 3, result.out);
+  EXPECT_EQ(L"123x", fmt::wstring_view(buffer, 4));
+  buffer[0] = L'x';
+  buffer[1] = L'x';
+  buffer[2] = L'x';
+  result = fmt::format_to_n(buffer, 3, L"{}", L'A');
+  EXPECT_EQ(1u, result.size);
+  EXPECT_EQ(buffer + 1, result.out);
+  EXPECT_EQ(L"Axxx", fmt::wstring_view(buffer, 4));
+  result = fmt::format_to_n(buffer, 3, L"{}{} ", L'B', L'C');
+  EXPECT_EQ(3u, result.size);
+  EXPECT_EQ(buffer + 3, result.out);
+  EXPECT_EQ(L"BC x", fmt::wstring_view(buffer, 4));
+}
+
+#if FMT_USE_USER_DEFINED_LITERALS
+TEST(xchar_test, named_arg_udl) {
+  using namespace fmt::literals;
+  auto udl_a =
+      fmt::format(L"{first}{second}{first}{third}", L"first"_a = L"abra",
+                  L"second"_a = L"cad", L"third"_a = 99);
+  EXPECT_EQ(
+      fmt::format(L"{first}{second}{first}{third}", fmt::arg(L"first", L"abra"),
+                  fmt::arg(L"second", L"cad"), fmt::arg(L"third", 99)),
+      udl_a);
+}
+#endif  // FMT_USE_USER_DEFINED_LITERALS
+
+TEST(xchar_test, print) {
+  // Check that the wide print overload compiles.
+  if (fmt::detail::const_check(false)) fmt::print(L"test");
+}
+
+TEST(xchar_test, join) {
+  int v[3] = {1, 2, 3};
+  EXPECT_EQ(fmt::format(L"({})", fmt::join(v, v + 3, L", ")), L"(1, 2, 3)");
+  auto t = std::tuple<wchar_t, int, float>('a', 1, 2.0f);
+  EXPECT_EQ(fmt::format(L"({})", fmt::join(t, L", ")), L"(a, 1, 2)");
+}
+
+enum streamable_enum {};
+
+std::wostream& operator<<(std::wostream& os, streamable_enum) {
+  return os << L"streamable_enum";
+}
+
+namespace fmt {
+template <>
+struct formatter<streamable_enum, wchar_t> : basic_ostream_formatter<wchar_t> {
+};
+}  // namespace fmt
+
+enum unstreamable_enum {};
+auto format_as(unstreamable_enum e) -> int { return e; }
+
+TEST(xchar_test, enum) {
+  EXPECT_EQ(L"streamable_enum", fmt::format(L"{}", streamable_enum()));
+  EXPECT_EQ(L"0", fmt::format(L"{}", unstreamable_enum()));
+}
+
+struct streamable_and_unformattable {};
+
+auto operator<<(std::wostream& os, streamable_and_unformattable)
+    -> std::wostream& {
+  return os << L"foo";
+}
+
+TEST(xchar_test, streamed) {
+  EXPECT_FALSE(fmt::is_formattable<streamable_and_unformattable>());
+  EXPECT_EQ(fmt::format(L"{}", fmt::streamed(streamable_and_unformattable())),
+            L"foo");
+}
+
+TEST(xchar_test, sign_not_truncated) {
+  wchar_t format_str[] = {
+      L'{', L':',
+      '+' | static_cast<wchar_t>(1 << fmt::detail::num_bits<char>()), L'}', 0};
+  EXPECT_THROW(fmt::format(fmt::runtime(format_str), 42), fmt::format_error);
+}
+
+TEST(xchar_test, chrono) {
+  auto tm = std::tm();
+  tm.tm_year = 116;
+  tm.tm_mon = 3;
+  tm.tm_mday = 25;
+  tm.tm_hour = 11;
+  tm.tm_min = 22;
+  tm.tm_sec = 33;
+  EXPECT_EQ(fmt::format("The date is {:%Y-%m-%d %H:%M:%S}.", tm),
+            "The date is 2016-04-25 11:22:33.");
+  EXPECT_EQ(L"42s", fmt::format(L"{}", std::chrono::seconds(42)));
+  EXPECT_EQ(fmt::format(L"{:%F}", tm), L"2016-04-25");
+  EXPECT_EQ(fmt::format(L"{:%T}", tm), L"11:22:33");
+}
+
+std::wstring system_wcsftime(const std::wstring& format, const std::tm* timeptr,
+                             std::locale* locptr = nullptr) {
+  auto loc = locptr ? *locptr : std::locale::classic();
+  auto& facet = std::use_facet<std::time_put<wchar_t>>(loc);
+  std::wostringstream os;
+  os.imbue(loc);
+  facet.put(os, os, L' ', timeptr, format.c_str(),
+            format.c_str() + format.size());
+#ifdef _WIN32
+  // Workaround a bug in older versions of Universal CRT.
+  auto str = os.str();
+  if (str == L"-0000") str = L"+0000";
+  return str;
+#else
+  return os.str();
+#endif
+}
+
+TEST(chrono_test_wchar, time_point) {
+  auto t1 = std::chrono::system_clock::now();
+
+  std::vector<std::wstring> spec_list = {
+      L"%%",  L"%n",  L"%t",  L"%Y",  L"%EY", L"%y",  L"%Oy", L"%Ey", L"%C",
+      L"%EC", L"%G",  L"%g",  L"%b",  L"%h",  L"%B",  L"%m",  L"%Om", L"%U",
+      L"%OU", L"%W",  L"%OW", L"%V",  L"%OV", L"%j",  L"%d",  L"%Od", L"%e",
+      L"%Oe", L"%a",  L"%A",  L"%w",  L"%Ow", L"%u",  L"%Ou", L"%H",  L"%OH",
+      L"%I",  L"%OI", L"%M",  L"%OM", L"%S",  L"%OS", L"%x",  L"%Ex", L"%X",
+      L"%EX", L"%D",  L"%F",  L"%R",  L"%T",  L"%p",  L"%z",  L"%Z"};
+#ifndef _WIN32
+  // Disabled on Windows, because these formats is not consistent among
+  // platforms.
+  spec_list.insert(spec_list.end(), {L"%c", L"%Ec", L"%r"});
+#elif defined(__MINGW32__) && !defined(_UCRT)
+  // Only C89 conversion specifiers when using MSVCRT instead of UCRT
+  spec_list = {L"%%", L"%Y", L"%y", L"%b", L"%B", L"%m", L"%U",
+               L"%W", L"%j", L"%d", L"%a", L"%A", L"%w", L"%H",
+               L"%I", L"%M", L"%S", L"%x", L"%X", L"%p", L"%Z"};
+#endif
+  spec_list.push_back(L"%Y-%m-%d %H:%M:%S");
+
+  for (const auto& spec : spec_list) {
+    auto t = std::chrono::system_clock::to_time_t(t1);
+    auto tm = *std::localtime(&t);
+
+    auto sys_output = system_wcsftime(spec, &tm);
+
+    auto fmt_spec = fmt::format(L"{{:{}}}", spec);
+    EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), t1));
+    EXPECT_EQ(sys_output, fmt::format(fmt::runtime(fmt_spec), tm));
+  }
+}
+
+TEST(xchar_test, color) {
+  EXPECT_EQ(fmt::format(fg(fmt::rgb(255, 20, 30)), L"rgb(255,20,30) wide"),
+            L"\x1b[38;2;255;020;030mrgb(255,20,30) wide\x1b[0m");
+}
+
+TEST(xchar_test, ostream) {
+#if !FMT_GCC_VERSION || FMT_GCC_VERSION >= 409
+  std::wostringstream wos;
+  fmt::print(wos, L"Don't {}!", L"panic");
+  EXPECT_EQ(wos.str(), L"Don't panic!");
+#endif
+}
+
+TEST(xchar_test, format_map) {
+  auto m = std::map<std::wstring, int>{{L"one", 1}, {L"t\"wo", 2}};
+  EXPECT_EQ(fmt::format(L"{}", m), L"{\"one\": 1, \"t\\\"wo\": 2}");
+}
+
+TEST(xchar_test, escape_string) {
+  using vec = std::vector<std::wstring>;
+  EXPECT_EQ(fmt::format(L"{}", vec{L"\n\r\t\"\\"}), L"[\"\\n\\r\\t\\\"\\\\\"]");
+  EXPECT_EQ(fmt::format(L"{}", vec{L"понедельник"}), L"[\"понедельник\"]");
+}
+
+TEST(xchar_test, to_wstring) { EXPECT_EQ(L"42", fmt::to_wstring(42)); }
+
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+template <typename Char> struct numpunct : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const override { return '?'; }
+  std::string do_grouping() const override { return "\03"; }
+  Char do_thousands_sep() const override { return '~'; }
+};
+
+template <typename Char> struct no_grouping : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const override { return '.'; }
+  std::string do_grouping() const override { return ""; }
+  Char do_thousands_sep() const override { return ','; }
+};
+
+template <typename Char> struct special_grouping : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const override { return '.'; }
+  std::string do_grouping() const override { return "\03\02"; }
+  Char do_thousands_sep() const override { return ','; }
+};
+
+template <typename Char> struct small_grouping : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const override { return '.'; }
+  std::string do_grouping() const override { return "\01"; }
+  Char do_thousands_sep() const override { return ','; }
+};
+
+TEST(locale_test, localized_double) {
+  auto loc = std::locale(std::locale(), new numpunct<char>());
+  EXPECT_EQ(fmt::format(loc, "{:L}", 1.23), "1?23");
+  EXPECT_EQ(fmt::format(loc, "{:Lf}", 1.23), "1?230000");
+  EXPECT_EQ(fmt::format(loc, "{:L}", 1234.5), "1~234?5");
+  EXPECT_EQ(fmt::format(loc, "{:L}", 12000.0), "12~000");
+  EXPECT_EQ(fmt::format(loc, "{:8L}", 1230.0), "   1~230");
+}
+
+TEST(locale_test, format) {
+  auto loc = std::locale(std::locale(), new numpunct<char>());
+  EXPECT_EQ("1234567", fmt::format(std::locale(), "{:L}", 1234567));
+  EXPECT_EQ("1~234~567", fmt::format(loc, "{:L}", 1234567));
+  EXPECT_EQ("-1~234~567", fmt::format(loc, "{:L}", -1234567));
+  EXPECT_EQ("-256", fmt::format(loc, "{:L}", -256));
+  fmt::format_arg_store<fmt::format_context, int> as{1234567};
+  EXPECT_EQ("1~234~567", fmt::vformat(loc, "{:L}", fmt::format_args(as)));
+  auto s = std::string();
+  fmt::format_to(std::back_inserter(s), loc, "{:L}", 1234567);
+  EXPECT_EQ("1~234~567", s);
+
+  auto no_grouping_loc = std::locale(std::locale(), new no_grouping<char>());
+  EXPECT_EQ("1234567", fmt::format(no_grouping_loc, "{:L}", 1234567));
+
+  auto special_grouping_loc =
+      std::locale(std::locale(), new special_grouping<char>());
+  EXPECT_EQ("1,23,45,678", fmt::format(special_grouping_loc, "{:L}", 12345678));
+  EXPECT_EQ("12,345", fmt::format(special_grouping_loc, "{:L}", 12345));
+
+  auto small_grouping_loc =
+      std::locale(std::locale(), new small_grouping<char>());
+  EXPECT_EQ("4,2,9,4,9,6,7,2,9,5",
+            fmt::format(small_grouping_loc, "{:L}", max_value<uint32_t>()));
+}
+
+TEST(locale_test, format_detault_align) {
+  auto loc = std::locale({}, new special_grouping<char>());
+  EXPECT_EQ("  12,345", fmt::format(loc, "{:8L}", 12345));
+}
+
+TEST(locale_test, format_plus) {
+  auto loc = std::locale({}, new special_grouping<char>());
+  EXPECT_EQ("+100", fmt::format(loc, "{:+L}", 100));
+}
+
+TEST(locale_test, wformat) {
+  auto loc = std::locale(std::locale(), new numpunct<wchar_t>());
+  EXPECT_EQ(L"1234567", fmt::format(std::locale(), L"{:L}", 1234567));
+  EXPECT_EQ(L"1~234~567", fmt::format(loc, L"{:L}", 1234567));
+  using wcontext = fmt::buffer_context<wchar_t>;
+  fmt::format_arg_store<wcontext, int> as{1234567};
+  EXPECT_EQ(L"1~234~567",
+            fmt::vformat(loc, L"{:L}", fmt::basic_format_args<wcontext>(as)));
+  EXPECT_EQ(L"1234567", fmt::format(std::locale("C"), L"{:L}", 1234567));
+
+  auto no_grouping_loc = std::locale(std::locale(), new no_grouping<wchar_t>());
+  EXPECT_EQ(L"1234567", fmt::format(no_grouping_loc, L"{:L}", 1234567));
+
+  auto special_grouping_loc =
+      std::locale(std::locale(), new special_grouping<wchar_t>());
+  EXPECT_EQ(L"1,23,45,678",
+            fmt::format(special_grouping_loc, L"{:L}", 12345678));
+
+  auto small_grouping_loc =
+      std::locale(std::locale(), new small_grouping<wchar_t>());
+  EXPECT_EQ(L"4,2,9,4,9,6,7,2,9,5",
+            fmt::format(small_grouping_loc, L"{:L}", max_value<uint32_t>()));
+}
+
+TEST(locale_test, double_formatter) {
+  auto loc = std::locale(std::locale(), new special_grouping<char>());
+  auto f = fmt::formatter<int>();
+  auto parse_ctx = fmt::format_parse_context("L");
+  f.parse(parse_ctx);
+  char buf[10] = {};
+  fmt::basic_format_context<char*, char> format_ctx(
+      buf, {}, fmt::detail::locale_ref(loc));
+  *f.format(12345, format_ctx) = 0;
+  EXPECT_STREQ("12,345", buf);
+}
+
+FMT_BEGIN_NAMESPACE
+template <class charT> struct formatter<std::complex<double>, charT> {
+ private:
+  detail::dynamic_format_specs<char> specs_;
+
+ public:
+  FMT_CONSTEXPR typename basic_format_parse_context<charT>::iterator parse(
+      basic_format_parse_context<charT>& ctx) {
+    using handler_type =
+        detail::dynamic_specs_handler<basic_format_parse_context<charT>>;
+    detail::specs_checker<handler_type> handler(handler_type(specs_, ctx),
+                                                detail::type::string_type);
+    auto it = parse_format_specs(ctx.begin(), ctx.end(), handler);
+    detail::parse_float_type_spec(specs_, ctx.error_handler());
+    return it;
+  }
+
+  template <class FormatContext>
+  typename FormatContext::iterator format(const std::complex<double>& c,
+                                          FormatContext& ctx) {
+    detail::handle_dynamic_spec<detail::precision_checker>(
+        specs_.precision, specs_.precision_ref, ctx);
+    auto specs = std::string();
+    if (specs_.precision > 0) specs = fmt::format(".{}", specs_.precision);
+    if (specs_.type == presentation_type::fixed_lower) specs += 'f';
+    auto real = fmt::format(ctx.locale().template get<std::locale>(),
+                            fmt::runtime("{:" + specs + "}"), c.real());
+    auto imag = fmt::format(ctx.locale().template get<std::locale>(),
+                            fmt::runtime("{:" + specs + "}"), c.imag());
+    auto fill_align_width = std::string();
+    if (specs_.width > 0) fill_align_width = fmt::format(">{}", specs_.width);
+    return format_to(ctx.out(), runtime("{:" + fill_align_width + "}"),
+                     c.real() != 0 ? fmt::format("({}+{}i)", real, imag)
+                                   : fmt::format("{}i", imag));
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(locale_test, complex) {
+  std::string s = fmt::format("{}", std::complex<double>(1, 2));
+  EXPECT_EQ(s, "(1+2i)");
+  EXPECT_EQ(fmt::format("{:.2f}", std::complex<double>(1, 2)), "(1.00+2.00i)");
+  EXPECT_EQ(fmt::format("{:8}", std::complex<double>(1, 2)), "  (1+2i)");
+}
+
+TEST(locale_test, chrono_weekday) {
+  auto loc = get_locale("ru_RU.UTF-8", "Russian_Russia.1251");
+  auto loc_old = std::locale::global(loc);
+  auto mon = fmt::weekday(1);
+  EXPECT_EQ(fmt::format(L"{}", mon), L"Mon");
+  if (loc != std::locale::classic()) {
+    // {L"\x43F\x43D", L"\x41F\x43D", L"\x43F\x43D\x434", L"\x41F\x43D\x434"}
+    // {L"пн", L"Пн", L"пнд", L"Пнд"}
+    EXPECT_THAT(
+        (std::vector<std::wstring>{L"\x43F\x43D", L"\x41F\x43D",
+                                   L"\x43F\x43D\x434", L"\x41F\x43D\x434"}),
+        Contains(fmt::format(loc, L"{:L}", mon)));
+  }
+  std::locale::global(loc_old);
+}
+
+TEST(locale_test, sign) {
+  EXPECT_EQ(fmt::format(std::locale(), L"{:L}", -50), L"-50");
+}
+
+#endif  // FMT_STATIC_THOUSANDS_SEPARATOR