'Confirms that large messages, none of which fit in a cookie, are stored
in the SessionBackend (and nothing is stored in the CookieBackend).'

def test_session_fallback_only(self):

    storage = self.get_storage()
    response = self.get_response()
    storage.add(constants.INFO, ('x' * 5000))
    storage.update(response)
    cookie_storing = self.stored_cookie_messages_count(storage, response)
    self.assertEqual(cookie_storing, 0)
    session_storing = self.stored_session_messages_count(storage, response)
    self.assertEqual(session_storing, 1)
