anchor.diff:            ],
           );
           await completer.future;
  -        verifyNever(portForwarder.forward(devicePort));
  +        expect(portForwarder.devicePort, null);
  +        expect(portForwarder.hostPort, 42);
   
           await expectLoggerInterruptEndsTask(task, logger);
           await loggerSubscription.cancel();
  
positive.code:         });
          final Future<void> task = createTestCommandRunner(AttachCommand()).run(<String>['attach']);
          await completer.future;
          verify(
            portForwarder.forward(devicePort, hostPort: anyNamed('hostPort')),
          ).called(1);
          await fakeLogReader.dispose();
          await expectLoggerInterruptEndsTask(task, logger);
          await loggerSubscription.cancel();
  
negative.code:       });
  
        testUsingContext('exits when ipv6 is specified and debug-port is not', () async {
          testDeviceManager.addDevice(device);
  
          final AttachCommand command = AttachCommand();
  