您可以通过不实际创建直接依赖项来对其进行单元测试System.Threading.Timer
。相反,创建一个ITimer
接口和包装器System.Threading.Timer
实现它。
首先,您需要将回调转换为事件,以便它可以成为接口的一部分:
public delegate void TimerEventHandler(object sender, TimerEventArgs e);
public class TimerEventArgs : EventArgs
{
public TimerEventArgs(object state)
{
this.State = state;
}
public object State { get; private set; }
}
然后创建一个接口:
public interface ITimer
{
void Change(TimeSpan dueTime, TimeSpan period);
event TimerEventHandler Tick;
}
还有一个包装纸:
public class ThreadingTimer : ITimer, IDisposable
{
private Timer timer;
public ThreadingTimer(object state, TimeSpan dueTime, TimeSpan period)
{
timer = new Timer(TimerCallback, state, dueTime, period);
}
public void Change(TimeSpan dueTime, TimeSpan period)
{
timer.Change(dueTime, period);
}
public void Dispose()
{
timer.Dispose();
}
private void TimerCallback(object state)
{
EventHandler tick = Tick;
if (tick != null)
tick(this, new TimerEventArgs(state));
}
public event TimerEventHandler Tick;
}
显然你会添加构造函数和/或的任何重载Change
您需要使用的方法Threading.Timer
。现在您可以对任何内容进行单元测试ITimer
使用假定时器:
public class FakeTimer : ITimer
{
private object state;
public FakeTimer(object state)
{
this.state = state;
}
public void Change(TimeSpan dueTime, TimeSpan period)
{
// Do nothing
}
public void RaiseTickEvent()
{
EventHandler tick = Tick;
if (tick != null)
tick(this, new TimerEventArgs(state));
}
public event TimerEventHandler Tick;
}
每当你想模拟蜱虫时,只需调用RaiseTickEvent
就假的。
[TestMethod]
public void Component_should_respond_to_tick
{
ITimer timer = new FakeTimer(someState);
MyClass c = new MyClass(timer);
timer.RaiseTickEvent();
Assert.AreEqual(true, c.TickOccurred);
}