'Test whether adding a request to fetch health of a trackerless torrent fails'

@blocking_call_on_reactor_thread
def test_add_gui_request_no_trackers(self):

    test_deferred = Deferred()
    self.torrent_checker._torrent_db.addExternalTorrentNoDef(('a' * 20), 'ubuntu.iso', [['a.test', 1234]], [], 5)
    self.torrent_checker._torrent_db._db.execute_write('DELETE    FROM    TorrentTrackerMapping')
    self.torrent_checker.add_gui_request(('a' * 20)).addErrback((lambda _: test_deferred.callback(None)))
    return test_deferred
