159 // Test the utctime decoration

   160 TEST(LogDecorations, iso8601_utctime) {

   161   LogDecorators decorator_selection;

   162   ASSERT_TRUE(decorator_selection.parse("utctime"));

   163   LogDecorations decorations(LogLevel::Info, tagset, decorator_selection);

   164 

   165   const char *timestr = decorations.decoration(LogDecorators::utctime_decorator);

   166   time_t expected_ts = time(NULL);

   167 

   168   // Verify format

   169   char trailing_character;

   170   int y, M, d, h, m, offset;

   171   double s;

   172   int read = sscanf(timestr, "%d-%d-%dT%d:%d:%lf%c%d", &y, &M, &d, &h, &m, &s, &trailing_character, &offset);

   173   ASSERT_GT(read, 7) << "Invalid format: " << timestr;

   174 

   175   // Ensure time is UTC (no offset)

   176   if (trailing_character == '+') {

   177     ASSERT_EQ(0, offset) << "Invalid offset: " << timestr;

   178   } else {

   179     ASSERT_EQ('Z', trailing_character) << "Invalid offset: " << timestr;

   180   }

   181 

   182   struct tm reported_time = {0};

   183   reported_time.tm_year = y - 1900;

   184   reported_time.tm_mon = M - 1;

   185   reported_time.tm_mday = d;

   186   reported_time.tm_hour = h;

   187   reported_time.tm_min = m;

   188   reported_time.tm_sec = s;

   189   reported_time.tm_isdst = 0; // No DST for UTC timestamps

   190   time_t reported_ts = mktime(&reported_time);

   191   expected_ts = mktime(gmtime(&expected_ts));

   192   time_t diff = reported_ts - expected_ts;

   193   if (diff < 0) {

   194     diff = -diff;

   195   }

   196   // Allow up to 10 seconds in difference

   197   ASSERT_LE(diff, 10) << "Reported time: " << reported_ts << " (" << timestr << ")"

   198       << ", expected time: " << expected_ts;

   199 }

   200