def test_resetDelayedCall(self):
        """
        If a delayed call is reset, the timeout passed to C{doIteration} is
        based on the interval between the time when reset is called and the
        new delay of the call.
        """
        reactor = TimeoutReportReactor()
        call = reactor.callLater(50, lambda: None)
        reactor.now += 25
        call.reset(15)
        timeout = self._checkIterationTimeout(reactor)
        self.assertEqual(timeout, 15)

        If a delayed call is reset, the timeout passed to C{doIteration} is
        based on the interval between the time when reset is called and the
        new delay of the call.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_posixbase.py