    def test_list_email_content_error(self, task_history_request):
        """ Test handling of error retrieving email """
        invalid_task = FakeContentTask(0, 0, 0, 'test')
        invalid_task.make_invalid_input()
        task_history_request.return_value = [invalid_task]
        url = reverse('list_email_content', kwargs={'course_id': self.course.id.to_deprecated_string()})
        response = self.client.post(url, {})
        self.assertEqual(response.status_code, 200)

        self.assertTrue(task_history_request.called)
        returned_email_info = json.loads(response.content)['emails']
        self.assertEqual(len(returned_email_info), 1)
        returned_info = returned_email_info[0]
        for info in ['created', 'sent_to', 'email', 'number_sent', 'requester']:
            self.assertEqual(returned_info[info], None)
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.