Add test for custom time zone support

test/tz_test/OffsetZone.pass.cpp

@@ -0,0 +1,81 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2017 Howard Hinnant
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+// Test custom time zone support
+
+#include "tz.h"
+
+class OffsetZone
+{
+    std::chrono::minutes offset_;
+
+public:
+    explicit OffsetZone(std::chrono::minutes offset)
+        : offset_{offset}
+        {}
+
+    template <class Duration>
+        auto
+        to_local(date::sys_time<Duration> tp) const
+        {
+            using namespace date;
+            using namespace std::chrono;
+            using LT = local_time<std::common_type_t<Duration, minutes>>;
+            return LT{(tp + offset_).time_since_epoch()};
+        }
+
+    template <class Duration>
+        auto
+        to_sys(date::local_time<Duration> tp) const
+        {
+            using namespace date;
+            using namespace std::chrono;
+            using ST = sys_time<std::common_type_t<Duration, minutes>>;
+            return ST{(tp - offset_).time_since_epoch()};
+        }
+
+    template <class Duration>
+        date::sys_info
+        get_info(date::sys_time<Duration> st) const
+        {
+            using namespace date;
+            using namespace std::chrono;
+            return {sys_seconds::min(), sys_seconds::max(), offset_,
+                    minutes{0}, offset_ >= minutes{0} ? "+" + date::format("%H%M", offset_)
+                                          : "-" + date::format("%H%M", -offset_)};
+        }
+
+    const OffsetZone* operator->() const {return this;}
+};
+
+#include <cassert>
+
+int
+main()
+{
+    using namespace date;
+    using namespace std::chrono;
+    auto now = system_clock::now();
+    auto offset = hours{-4};
+    zoned_time<system_clock::duration, OffsetZone> zt{OffsetZone{offset}, now};
+    assert(zt.get_local_time().time_since_epoch() == now.time_since_epoch() + offset);
+}