def METHOD_NAME(self):
    test_page = buyersguide_factories.BuyersGuidePageFactory()
    form = self.form_class(
        data=(
            {
                "title": "Test CTA",
                "link_target_url": "http://test.com",
                "link_target_page": test_page,
            }
        )
    )
    self.assertFalse(form.is_valid())
    self.assertEqual(1, len(form.errors))
    self.assertIn("link_label", form.errors)