'Tests discussion topic does not exist for the given topic id.'

def test_discussion_topic_404(self):

    topic_id = u'courseware-topic-id'
    self.make_discussion_xblock(topic_id, u'test_category', u'test_target')
    url = u'{}?topic_id=invalid_topic_id'.format(self.url)
    response = self.client.get(url)
    self.assert_response_correct(response, 404, {u'developer_message': u"Discussion    not    found    for    'invalid_topic_id'."})
