1 files changed, 106 insertions, 0 deletions
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
new file mode 100644
index 00000000000..acf93ef1883
--- /dev/null
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
@@ -0,0 +1,106 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <chrono>
+// class year_month;
+
+// constexpr year_month operator+(const year_month& ym, const years& dy) noexcept;
+// Returns: (ym.year() + dy) / ym.month().
+// 
+// constexpr year_month operator+(const years& dy, const year_month& ym) noexcept;
+// Returns: ym + dy.
+//
+// constexpr year_month operator+(const year_month& ym, const months& dm) noexcept;
+// Returns: A year_month value z such that z - ym == dm. 
+// Complexity: O(1) with respect to the value of dm.
+// 
+// constexpr year_month operator+(const months& dm, const year_month& ym) noexcept;
+// Returns: ym + dm.
+
+
+
+#include <chrono>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+constexpr bool testConstexprYears(std::chrono::year_month ym)
+{
+    std::chrono::years offset{23};
+    if (static_cast<int>((ym         ).year()) !=  1) return false;
+    if (static_cast<int>((ym + offset).year()) != 24) return false;
+    if (static_cast<int>((offset + ym).year()) != 24) return false;
+    return true;
+}
+
+
+constexpr bool testConstexprMonths(std::chrono::year_month ym)
+{
+    std::chrono::months offset{6};
+    if (static_cast<unsigned>((ym         ).month()) !=  1) return false;
+    if (static_cast<unsigned>((ym + offset).month()) !=  7) return false;
+    if (static_cast<unsigned>((offset + ym).month()) !=  7) return false;
+    return true;
+}
+
+
+int main()
+{
+    using year       = std::chrono::year;
+    using years      = std::chrono::years;
+    using month      = std::chrono::month;
+    using months     = std::chrono::months;
+    using year_month = std::chrono::year_month;
+
+    {   // year_month + years
+    ASSERT_NOEXCEPT(std::declval<year_month>() + std::declval<years>());
+    ASSERT_NOEXCEPT(std::declval<years>() + std::declval<year_month>());
+
+    ASSERT_SAME_TYPE(year_month, decltype(std::declval<year_month>() + std::declval<years>()));
+    ASSERT_SAME_TYPE(year_month, decltype(std::declval<years>() + std::declval<year_month>()));
+    
+    static_assert(testConstexprYears (year_month{year{1}, month{1}}), "");
+
+    year_month ym{year{1234}, std::chrono::January};
+    for (int i = 0; i <= 10; ++i)
+    {
+        year_month ym1 = ym + years{i};
+        year_month ym2 = years{i} + ym;
+        assert(static_cast<int>(ym1.year()) == i + 1234);
+        assert(static_cast<int>(ym2.year()) == i + 1234);
+        assert(ym1.month() == std::chrono::January);
+        assert(ym2.month() == std::chrono::January);
+        assert(ym1 == ym2);
+    }
+    }
+
+    {   // year_month + months
+    ASSERT_NOEXCEPT(std::declval<year_month>() + std::declval<months>());
+    ASSERT_NOEXCEPT(std::declval<months>() + std::declval<year_month>());
+
+    ASSERT_SAME_TYPE(year_month, decltype(std::declval<year_month>() + std::declval<months>()));
+    ASSERT_SAME_TYPE(year_month, decltype(std::declval<months>() + std::declval<year_month>()));
+
+    static_assert(testConstexprMonths(year_month{year{1}, month{1}}), "");
+
+    year_month ym{year{1234}, std::chrono::January};
+    for (int i = 0; i <= 10; ++i)  // TODO test wrap-around
+    {
+        year_month ym1 = ym + months{i};
+        year_month ym2 = months{i} + ym;
+        assert(static_cast<int>(ym1.year()) == 1234);
+        assert(static_cast<int>(ym2.year()) == 1234);
+        assert(ym1.month() == month(1 + i));
+        assert(ym2.month() == month(1 + i));
+        assert(ym1 == ym2);
+    }
+    }
+}