[1.1.X] Fixed #12285. ModelForm raises a more informative error if it doesn't have a model class defined. Backport of [12526] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@12530 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/model_forms_regress/tests.py

@@ -100,4 +100,10 @@ class CustomFieldSaveTests(TestCase):
         # It's enough that the form saves without error -- the custom save routine will
         # generate an AssertionError if it is called more than once during save.
         form = CFFForm(data = {'f': None})
-        form.save()
+        form.save()
+
+class ModelClassTests(TestCase):
+    def test_no_model_class(self):
+        class NoModelModelForm(forms.ModelForm):
+            pass
+        self.assertRaises(ValueError, NoModelModelForm)