public void StopMachineTest()
        {
            Task startTask = Task.Run(() => StartMachineTset());
            Task stopTask  = Task.Run(() =>
            {
                while (true)
                {
                    System.Threading.Thread.Sleep(5000);
                    if (machine != null)
                    {
                        machine.Stop();
                        break;
                    }
                }
            }
                                      );

            Task.WaitAll(startTask, stopTask);

            Assert.IsTrue(true);
        }