diff --git a/tests/test_flask_encoder.py b/tests/test_flask_encoder.py
index e08f31838..ea0553b93 100644
--- a/tests/test_flask_encoder.py
+++ b/tests/test_flask_encoder.py
@@ -63,7 +63,7 @@ def get_value(data, path):
         return data
 
     example = get_value(spec_data, 'paths./datetime.get.{}.example.value'.format(response_path))
-    assert example == '2000-01-23T04:56:07.000008Z'
+    assert example == '2000-01-23T04:56:07.000008+00:00'
     example = get_value(spec_data, 'paths./date.get.{}.example.value'.format(response_path))
     assert example == '2000-01-23'
     example = get_value(spec_data, 'paths./uuid.get.{}.example.value'.format(response_path))