'Test with an invalid action parameter.'

def test_modify_access_bad_action(self):

    url = reverse('modify_access', kwargs={'course_id': self.course.id.to_deprecated_string()})
    response = self.client.post(url, {'unique_student_identifier': self.other_staff.email, 'rolename': 'staff', 'action': 'robot-not-an-action'})
    self.assertEqual(response.status_code, 400)
