'Assert that the given `response` contains correct failure data.
It should have a 400 status code, and its content should be a JSON
object containing the specified `field` and an `error`.'

def _assert_bad_request(self, response, field, zendesk_mock_class, datadog_mock):

    self.assertEqual(response.status_code, 400)
    resp_json = json.loads(response.content)
    self.assertIn('field', resp_json)
    self.assertEqual(resp_json['field'], field)
    self.assertIn('error', resp_json)
    self.assertFalse(zendesk_mock_class.return_value.mock_calls)
    self.assertFalse(datadog_mock.mock_calls)
