foo.diff

diff --git a/tests/forms_tests/tests/test_forms.py b/tests/forms_tests/tests/test_forms.py
index 985ff8e..f87b684 100644
--- a/tests/forms_tests/tests/test_forms.py
+++ b/tests/forms_tests/tests/test_forms.py
@@ -740,6 +740,25 @@ class FormsTestCase(TestCase):
         with six.assertRaisesRegex(self, ValueError, "has no field named"):
             f.add_error('missing_field', 'Some error.')
 
+    def test_regression_17(self):
+        class CodeForm(Form):
+            code = CharField(max_length=10)
+
+            def clean(self):
+                try:
+                    raise ValidationError({
+                        'code': [ValidationError('Code error')]
+                    })
+                except ValidationError as e:
+                    for field, error_list in e.update_error_dict({}).items():
+                        self._errors.setdefault(field, self.error_class()).extend(error_list)
+                        del self.cleaned_data[field]
+
+        form = CodeForm({'code': 'hello'})
+        form.is_valid()
+        self.assertEqual(form.cleaned_data, {})
+        self.assertEqual(dict(form.errors), {'code': ['Code error']})
+
     def test_has_error(self):
         class UserRegistration(Form):
             username = CharField(max_length=10)