bpo-40300: Allow empty logging.Formatter.default_msec_format. (GH-19551)

1 files changed, 13 insertions, 0 deletions

diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index 2ad3c5c208..99e74ebff6 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -3941,6 +3941,19 @@ class FormatterTest(unittest.TestCase):
         f.format(r)
         self.assertEqual(r.asctime, '1993-04-21 08:03:00,123')
 
+    def test_default_msec_format_none(self):
+        class NoMsecFormatter(logging.Formatter):
+            default_msec_format = None
+            default_time_format = '%d/%m/%Y %H:%M:%S'
+
+        r = self.get_record()
+        dt = datetime.datetime(1993, 4, 21, 8, 3, 0, 123, utc)
+        r.created = time.mktime(dt.astimezone(None).timetuple())
+        f = NoMsecFormatter()
+        f.converter = time.gmtime
+        self.assertEqual(f.formatTime(r), '21/04/1993 08:03:00')
+
+
 class TestBufferingFormatter(logging.BufferingFormatter):
     def formatHeader(self, records):
         return '[(%d)' % len(records)