def test_non_owner_edit(self):
        """Check that users cannot edit each other's submissions."""
        self.client.login(username='bob', password='bob')
        data = self._edit_data()
        data.update(BLANK_EXTERNALS)
        response = self.client.post(self.edit_path, data)
        assert_equal(response.status_code, 403)
        assert 'seriously' not in Submission.objects.get().description