1 files changed, 58 insertions, 0 deletions
diff --git a/libcxx/test/std/utilities/time/time.hms/time.hms.members/width.pass.cpp b/libcxx/test/std/utilities/time/time.hms/time.hms.members/width.pass.cpp
new file mode 100644
index 00000000000..b18d6465c8c
--- /dev/null
+++ b/libcxx/test/std/utilities/time/time.hms/time.hms.members/width.pass.cpp
@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// 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>
+
+// template <class Duration>
+// class hh_mm_ss
+// {
+// public:
+//     static unsigned constexpr fractional_width = see below;
+//     using precision                            = see below;
+//
+//	fractional_width is the number of fractional decimal digits represented by precision. 
+//  fractional_width has the value of the smallest possible integer in the range [0, 18] 
+//    such that precision will exactly represent all values of Duration. 
+//  If no such value of fractional_width exists, then fractional_width is 6.
+
+   
+#include <chrono>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <typename Duration, unsigned width>
+constexpr bool check_width()
+{
+	using HMS = std::chrono::hh_mm_ss<Duration>;
+	return HMS::fractional_width == width;
+}
+
+int main(int, char**)
+{
+	using microfortnights = std::chrono::duration<int, std::ratio<756, 625>>;
+
+	static_assert( check_width<std::chrono::hours,                               0>(), "");
+	static_assert( check_width<std::chrono::minutes,                             0>(), "");
+	static_assert( check_width<std::chrono::seconds,                             0>(), "");
+	static_assert( check_width<std::chrono::milliseconds,                        3>(), "");
+	static_assert( check_width<std::chrono::microseconds,                        6>(), "");
+	static_assert( check_width<std::chrono::nanoseconds,                         9>(), "");
+	static_assert( check_width<std::chrono::duration<int, std::ratio<  1,   2>>, 1>(), "");
+	static_assert( check_width<std::chrono::duration<int, std::ratio<  1,   3>>, 6>(), "");
+	static_assert( check_width<std::chrono::duration<int, std::ratio<  1,   4>>, 2>(), "");
+	static_assert( check_width<std::chrono::duration<int, std::ratio<  1,   5>>, 1>(), "");
+	static_assert( check_width<std::chrono::duration<int, std::ratio<  1,   6>>, 6>(), "");
+	static_assert( check_width<std::chrono::duration<int, std::ratio<  1,   7>>, 6>(), "");
+	static_assert( check_width<std::chrono::duration<int, std::ratio<  1,   8>>, 3>(), "");
+	static_assert( check_width<std::chrono::duration<int, std::ratio<  1,   9>>, 6>(), "");
+	static_assert( check_width<std::chrono::duration<int, std::ratio<  1,  10>>, 1>(), "");
+	static_assert( check_width<microfortnights,                                  4>(), "");
+
+	return 0;
+}