def test_processTransportInterface(self):
        """
        L{IReactorProcess.spawnProcess} connects the protocol passed to it
        to a transport which provides L{IProcessTransport}.
        """
        ended = Deferred()
        protocol = _ShutdownCallbackProcessProtocol(ended)

        reactor = self.buildReactor()
        transport = reactor.spawnProcess(
            protocol, pyExe, [pyExe, b"-c", b""],
            usePTY=self.usePTY)

        # The transport is available synchronously, so we can check it right
        # away (unlike many transport-based tests).  This is convenient even
        # though it's probably not how the spawnProcess interface should really
        # work.
        # We're not using verifyObject here because part of
        # IProcessTransport is a lie - there are no getHost or getPeer
        # methods.  See #1124.
        self.assertTrue(IProcessTransport.providedBy(transport))

        # Let the process run and exit so we don't leave a zombie around.
        ended.addCallback(lambda ignored: reactor.stop())
        self.runReactor(reactor)

        L{IReactorProcess.spawnProcess} connects the protocol passed to it
        to a transport which provides L{IProcessTransport}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_process.py