def METHOD_NAME(self):
    self.assertEqual(
        self.client.post(url_for('register'), json={
            'op_url': 'not_valid_url',
            'redirect_uris': ['https://clienttoberegistered.com/oidc_callback']
        }).status_code,
        400,
        'not returning status 400 if values are not valid urls'
    )