Fix: LazyRfc3339UtcTime return correct utc time

2 files changed, 32 insertions, 3 deletions

diff --git a/cherrypy/_cplogging.py b/cherrypy/_cplogging.py
index 151d3b40..0e57c6ac 100644
--- a/cherrypy/_cplogging.py
+++ b/cherrypy/_cplogging.py
@@ -452,6 +452,5 @@ class WSGIErrorHandler(logging.Handler):
 
 class LazyRfc3339UtcTime(object):
     def __str__(self):
-        """Return now() in RFC3339 UTC Format."""
-        now = datetime.datetime.now()
-        return now.isoformat('T') + 'Z'
+        """Return utcnow() in RFC3339 UTC Format."""
+        return f"{datetime.datetime.utcnow().isoformat('T')}Z"
diff --git a/cherrypy/test/test_logging.py b/cherrypy/test/test_logging.py
index 2d4aa56f..7968220f 100644
--- a/cherrypy/test/test_logging.py
+++ b/cherrypy/test/test_logging.py
@@ -197,6 +197,36 @@ def test_custom_log_format(log_tracker, monkeypatch, server):
     )
 
 
+def test_utc_in_timez(monkeypatch):
+    """Test utc timestamp is used in 
+    cherrypy._cplogging.LazyRfc3339UtcTime"""
+    import datetime
+
+    utcoffset8_local_time_in_naive_utc = (
+        datetime.datetime(
+            year=2020,
+            month=1,
+            day=1,
+            hour=1,
+            minute=23,
+            second=45,
+            tzinfo=datetime.timezone(datetime.timedelta(hours=8)),
+        )
+        .astimezone(datetime.timezone.utc)
+        .replace(tzinfo=None)
+    )
+
+    class mock_datetime:
+        @classmethod
+        def utcnow(cls):
+            return utcoffset8_local_time_in_naive_utc
+
+    monkeypatch.setattr('datetime.datetime', mock_datetime)
+    rfc3339_utc_time = str(cherrypy._cplogging.LazyRfc3339UtcTime())
+    expected_time = '2019-12-31T17:23:45Z'
+    assert rfc3339_utc_time == expected_time
+
+
 def test_timez_log_format(log_tracker, monkeypatch, server):
     """Test a customized access_log_format string, which is a
     feature of _cplogging.LogManager.access()."""