1 files changed, 45 insertions, 0 deletions
diff --git a/libcxx/test/std/utilities/time/time.hms/time.12/make24.pass.cpp b/libcxx/test/std/utilities/time/time.hms/time.12/make24.pass.cpp
new file mode 100644
index 00000000000..46a5419076f
--- /dev/null
+++ b/libcxx/test/std/utilities/time/time.hms/time.12/make24.pass.cpp
@@ -0,0 +1,45 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+// <chrono>
+
+// constexpr hours make24(const hours& h, bool is_pm) noexcept;
+//   Returns: If is_pm is false, returns the 24-hour equivalent of h in the range [0h, 11h], 
+//       assuming h represents an ante meridiem hour. 
+//     Else returns the 24-hour equivalent of h in the range [12h, 23h], 
+//       assuming h represents a post meridiem hour. 
+//     If h is not in the range [1h, 12h], the value returned is unspecified.
+
+#include <chrono>
+#include <cassert>
+
+#include "test_macros.h"
+
+int main(int, char**)
+{
+    using hours = std::chrono::hours;
+    ASSERT_SAME_TYPE(hours, decltype(std::chrono::make24(std::declval<hours>(), false)));
+    ASSERT_NOEXCEPT(                 std::chrono::make24(std::declval<hours>(), false));
+
+    static_assert( std::chrono::make24(hours( 1), false) == hours( 1), "");
+    static_assert( std::chrono::make24(hours(11), false) == hours(11), "");
+    static_assert( std::chrono::make24(hours(12), false) == hours( 0), "");
+    static_assert( std::chrono::make24(hours( 1), true)  == hours(13), "");
+    static_assert( std::chrono::make24(hours(11), true)  == hours(23), "");
+    static_assert( std::chrono::make24(hours(12), true)  == hours(12), "");
+    
+    for (int i = 1; i < 11; ++i)
+    {
+        assert((std::chrono::make24(hours(i), false)) == hours(i));
+        assert((std::chrono::make24(hours(i), true))  == hours(12+i));
+    }
+    assert((std::chrono::make24(hours(12), false)) == hours( 0));
+    assert((std::chrono::make24(hours(12), true))  == hours(12));
+
+    return 0;
+}