Enable some local_time tests and make them deterministic

Author: vitaut

test/chrono-test.cc

@@ -350,28 +350,17 @@ TEST(chrono_test, system_clock_time_point) {
   }
 }
 
-#if FMT_USE_LOCAL_TIME
-
-template <typename Duration>
-auto strftime_full_local(fmt::local_time<Duration> t) -> std::string {
-  auto sys_time = std::chrono::system_clock::to_time_t(
-      std::chrono::current_zone()->to_sys(t));
-  auto tm = *std::localtime(&sys_time);
-  return system_strftime("%Y-%m-%d %H:%M:%S", &tm);
-}
+TEST(chrono_test, local_time) {
+  using local_time = fmt::local_time<std::chrono::seconds>;
+  auto t = local_time(std::chrono::seconds(290088000));
+  EXPECT_EQ(fmt::format("{:%Y-%m-%d %H:%M:%S}", t), "1979-03-12 12:00:00");
+  EXPECT_EQ(fmt::format("{}", t), "1979-03-12 12:00:00");
+  EXPECT_EQ(fmt::format("{:}", t), "1979-03-12 12:00:00");
 
-TEST(chrono_test, local_system_clock_time_point) {
+#if FMT_USE_LOCAL_TIME
 #  ifdef _WIN32
   return;  // Not supported on Windows.
 #  endif
-  auto t1 = std::chrono::time_point_cast<std::chrono::seconds>(
-      std::chrono::current_zone()->to_local(std::chrono::system_clock::now()));
-  EXPECT_EQ(strftime_full_local(t1), fmt::format("{:%Y-%m-%d %H:%M:%S}", t1));
-  EXPECT_EQ(strftime_full_local(t1), fmt::format("{}", t1));
-  EXPECT_EQ(strftime_full_local(t1), fmt::format("{:}", t1));
-  using time_point = fmt::local_time<std::chrono::seconds>;
-  auto t2 = time_point(std::chrono::seconds(86400 + 42));
-  EXPECT_EQ(strftime_full_local(t2), fmt::format("{:%Y-%m-%d %H:%M:%S}", t2));
 
   std::vector<std::string> spec_list = {
       "%%",  "%n",  "%t",  "%Y",  "%EY", "%y",  "%Oy", "%Ey", "%C",
@@ -418,9 +407,8 @@ TEST(chrono_test, local_system_clock_time_point) {
     EXPECT_EQ(sys_output, fmt::format("{:%Oz}", t1));
     EXPECT_EQ(sys_output, fmt::format("{:%Oz}", tm));
   }
-}
-
 #endif  // FMT_USE_LOCAL_TIME
+}
 
 TEST(chrono_test, daylight_savings_time_end) {
   // 2024-10-27 03:05 as the number of seconds since epoch in Europe/Kyiv time.