Test for TimeField not handling empty values

Author: areski

tests/test_fields.py

@@ -1031,6 +1031,7 @@ class TestTimeField(FieldValues):
     }
     outputs = {
         datetime.time(13, 00): '13:00:00',
+        '00:00:00': '00:00:00',
         None: None,
         '': None,
     }