1 files changed, 81 insertions, 0 deletions
diff --git a/dom/quota/test/gtest/TestFlatten.cpp b/dom/quota/test/gtest/TestFlatten.cpp
new file mode 100644
index 0000000000..5ca7675887
--- /dev/null
+++ b/dom/quota/test/gtest/TestFlatten.cpp
@@ -0,0 +1,81 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Flatten.h"
+
+#include "gtest/gtest.h"
+
+#include "mozilla/Unused.h"
+#include "nsTArray.h"
+
+namespace mozilla::dom::quota {
+
+#ifdef __clang__
+#  pragma clang diagnostic push
+#  pragma clang diagnostic ignored "-Wunreachable-code-loop-increment"
+#endif
+TEST(Flatten, FlatEmpty)
+{
+  for (const auto& item : Flatten<int>(nsTArray<int>{})) {
+    Unused << item;
+    FAIL();
+  }
+}
+
+TEST(Flatten, NestedOuterEmpty)
+{
+  for (const auto& item : Flatten<int>(nsTArray<CopyableTArray<int>>{})) {
+    Unused << item;
+    FAIL();
+  }
+}
+
+TEST(Flatten, NestedInnerEmpty)
+{
+  for (const auto& item :
+       Flatten<int>(nsTArray<CopyableTArray<int>>{CopyableTArray<int>{}})) {
+    Unused << item;
+    FAIL();
+  }
+}
+#ifdef __clang__
+#  pragma clang diagnostic pop
+#endif
+
+TEST(Flatten, NestedInnerSingular)
+{
+  nsTArray<int> flattened;
+  for (const auto& item :
+       Flatten<int>(nsTArray<CopyableTArray<int>>{CopyableTArray<int>{1}})) {
+    flattened.AppendElement(item);
+  }
+
+  EXPECT_EQ(nsTArray{1}, flattened);
+}
+
+TEST(Flatten, NestedInnerSingulars)
+{
+  nsTArray<int> flattened;
+  for (const auto& item : Flatten<int>(nsTArray<CopyableTArray<int>>{
+           CopyableTArray<int>{1}, CopyableTArray<int>{2}})) {
+    flattened.AppendElement(item);
+  }
+
+  EXPECT_EQ((nsTArray<int>{{1, 2}}), flattened);
+}
+
+TEST(Flatten, NestedInnerNonSingulars)
+{
+  nsTArray<int> flattened;
+  for (const auto& item : Flatten<int>(nsTArray<CopyableTArray<int>>{
+           CopyableTArray<int>{1, 2}, CopyableTArray<int>{3, 4}})) {
+    flattened.AppendElement(item);
+  }
+
+  EXPECT_EQ((nsTArray<int>{{1, 2, 3, 4}}), flattened);
+}
+
+}  // namespace mozilla::dom::quota