diff --git a/tests/test_fields.py b/tests/test_fields.py
index 8b449887..f58afb7a 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -1,5 +1,5 @@
 from collections import OrderedDict
-from datetime import date, datetime
+from datetime import date, datetime, timedelta, timezone
 from decimal import Decimal
 from functools import partial
 
@@ -10,6 +10,9 @@
 from flask_restx import fields, Api
 
 
+_CET_TIMEZONE = timezone(timedelta(hours=1), "CET")
+
+
 class FieldTestCase(object):
     field_class = None
 
@@ -542,7 +545,7 @@ def test_max_exclusive(self):
                 "Sat, 01 Jan 2011 23:59:59 -0000",
             ),
             (
-                datetime(2011, 1, 1, 23, 59, 59, tzinfo=pytz.timezone("CET")),
+                datetime(2011, 1, 1, 23, 59, 59, tzinfo=_CET_TIMEZONE),
                 "Sat, 01 Jan 2011 22:59:59 -0000",
             ),
         ],
@@ -566,7 +569,7 @@ def test_rfc822_value(self, value, expected):
                 "2011-01-01T23:59:59.001000+00:00",
             ),
             (
-                datetime(2011, 1, 1, 23, 59, 59, tzinfo=pytz.timezone("CET")),
+                datetime(2011, 1, 1, 23, 59, 59, tzinfo=_CET_TIMEZONE),
                 "2011-01-01T23:59:59+01:00",
             ),
         ],
@@ -676,7 +679,7 @@ def test_max_exclusive(self):
             (datetime(2011, 1, 1, 23, 59, 59, tzinfo=pytz.utc), "2011-01-01"),
             (datetime(2011, 1, 1, 23, 59, 59, 1000, tzinfo=pytz.utc), "2011-01-01"),
             (
-                datetime(2011, 1, 1, 23, 59, 59, tzinfo=pytz.timezone("CET")),
+                datetime(2011, 1, 1, 23, 59, 59, tzinfo=_CET_TIMEZONE),
                 "2011-01-01",
             ),
         ],