1 files changed, 52 insertions, 0 deletions
diff --git a/src/boost/libs/hana/test/concept/integral_constant.cpp b/src/boost/libs/hana/test/concept/integral_constant.cpp
new file mode 100644
index 000000000..ad69759fc
--- /dev/null
+++ b/src/boost/libs/hana/test/concept/integral_constant.cpp
@@ -0,0 +1,52 @@
+// Copyright Louis Dionne 2013-2017
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#include <boost/hana/concept/constant.hpp>
+#include <boost/hana/concept/integral_constant.hpp>
+#include <boost/hana/core/when.hpp>
+#include <boost/hana/fwd/core/to.hpp>
+#include <boost/hana/value.hpp>
+namespace hana = boost::hana;
+
+
+// Define a simple model of IntegralConstant
+struct constant_tag { using value_type = int; };
+template <int i>
+struct constant {
+    static constexpr int value = i;
+    using hana_tag = constant_tag;
+};
+
+namespace boost { namespace hana {
+    template <>
+    struct IntegralConstant<constant_tag> {
+        static constexpr bool value = true;
+    };
+
+    template <typename From>
+    struct to_impl<constant_tag, From, when<IntegralConstant<From>::value>> {
+        template <typename N>
+        static constexpr auto apply(N const&)
+        { return constant<N::value>{}; }
+    };
+}}
+
+// Make sure we really satisfy IntegralConstant<>.
+static_assert(hana::IntegralConstant<constant<0>>::value, "");
+static_assert(hana::IntegralConstant<constant<1>>::value, "");
+static_assert(hana::IntegralConstant<constant<2>>::value, "");
+
+// Make sure we're also a model of Constant automatically.
+static_assert(hana::Constant<constant<0>>::value, "");
+static_assert(hana::Constant<constant<1>>::value, "");
+static_assert(hana::Constant<constant<2>>::value, "");
+
+// Make sure we have the hana::value<> function defined automatically.
+static_assert(hana::value<constant<0>>() == 0, "");
+static_assert(hana::value<constant<1>>() == 1, "");
+static_assert(hana::value<constant<2>>() == 2, "");
+static_assert(hana::value<constant<3>>() == 3, "");
+
+
+int main() { }