'Test whether we do nothing when tracker URL is invalid'

@blocking_call_on_reactor_thread
def test_tracker_test_invalid_tracker(self):

    tracker_url = u'udp://non123exiszzting456tracker89fle.abc:80'
    bad_tracker_url = u'xyz://non123exiszzting456tracker89fle.abc:80'
    self.torrent_checker._torrent_db.addExternalTorrentNoDef(('a' * 20), 'ubuntu.iso', [['a.test', 1234]], [tracker_url], 5)
    self.session.lm.tracker_manager._tracker_dict[bad_tracker_url] = self.session.lm.tracker_manager._tracker_dict[tracker_url]
    del self.session.lm.tracker_manager._tracker_dict[tracker_url]
    tracker_id = self.session.lm.tracker_manager._tracker_dict[bad_tracker_url][u'id']
    sql_stmt = u'UPDATE    TrackerInfo    SET    tracker    =    ?    WHERE    tracker_id    =    ?'
    value_tuple = (bad_tracker_url, tracker_id)
    self.session.sqlite_db.execute(sql_stmt, value_tuple)
    self.torrent_checker._task_select_tracker()
