Fixed #12901. Exclude overridden form fields from model field validation. Thanks, Honza Král.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12496 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/model_forms/tests.py

@@ -0,0 +1,21 @@
+from django.test import TestCase
+from django import forms
+from models import Category
+
+
+class IncompleteCategoryForm(forms.ModelForm):
+    """
+    A form that replaces the model's url field with a custom one. This should
+    prevent the model field's validation from being called.
+    """
+    url = forms.CharField(required=False)
+
+    class Meta:
+        fields = ('name', 'slug')
+        model = Category
+
+class ValidationTest(TestCase):
+    def test_validates_with_replaced_field(self):
+        form = IncompleteCategoryForm(data={'name': 'some name', 'slug': 'some-slug'})
+        assert form.is_valid()
+