def test_timeoutTriggering(self):
        """
        When a non-zero timeout is passed to L{getPage} and that many
        seconds elapse before the server responds to the request. the
        L{Deferred} is errbacked with a L{error.TimeoutError}.
        """
        # This will probably leave some connections around.
        self.cleanupServerConnections = 1
        return self.assertFailure(
            client.getPage(self.getURL("wait"), timeout=0.000001),
            defer.TimeoutError)

        When a non-zero timeout is passed to L{getPage} and that many
        seconds elapse before the server responds to the request. the
        L{Deferred} is errbacked with a L{error.TimeoutError}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_webclient.py