Fixed #12590. Changed an expression in the validators tests to work correctly with python 2.4. Thanks, ramiro.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12270 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/validators/tests.py

@@ -119,7 +119,7 @@ TEST_DATA = (
 )
 
 def create_simple_test_method(validator, expected, value, num):
-    if isinstance(expected, type) and issubclass(expected, Exception):
+    if expected is not None and issubclass(expected, Exception):
         test_mask = 'test_%s_raises_error_%d'
         def test_func(self):
             self.assertRaises(expected, validator, value)