from zerver.lib.test_classes import ZulipTestCase class LegacySubjectTest(ZulipTestCase): def test_legacy_subject(self) -> None: self.login('hamlet') payload = dict( type='stream', to='Verona', client='test suite', content='Test message', ) payload['subject'] = 'whatever' result = self.client_post("/json/messages", payload) self.assert_json_success(result) # You can't use both subject and topic. payload['topic'] = 'whatever' result = self.client_post("/json/messages", payload) self.assert_json_error(result, "Can't decide between 'topic' and 'subject' arguments")