C# 单元测试完成peek时使用的异步回调方法

我希望对一个回调方法进行单元测试，该方法在完成对messagequeue的查看时调用，但不知道如何执行

我的抽象类

public abstract class QueueHandler : WindowsServiceBase
{
    private readonly IMessageQueueWrapper _listeningQueue;
    private PeekCompletedEventHandler _peekHandler;

    protected QueueHandler(IMessageQueueWrapper listeningQueue) 
        : base()
    {
        _listeningQueue = listeningQueue;
    }

    protected override void ExecuteInternal()
    {
        _listeningQueue.BeginPeek();
    }

    protected override void ConfigureInternal()
    {
        if (_peekHandler != null) return;

        _peekHandler = OnPeekCompleted;
        _listeningQueue.PeekCompleted += OnPeekCompleted;
    }

    protected void OnPeekCompleted(object sender, PeekCompletedEventArgs e)
    {
        try
        {
            var msg = _listeningQueue.EndPeek(e.AsyncResult);

            ...
        }
        catch (Exception ex)
        {
            ...
        }
    }
}

我的混凝土类用于单元测试

internal class QueueuHandlerImplementation : QueueHandler
{
    public QueueuHandlerImplementation(IMessageQueueWrapper listeningQueue)
        : base(listeningQueue)
    {
    }
}

我的单元测试

public void OnPeekCompletedWhenBeginPeekShouldCallOnPeekCompleted()
{
        QueueuHandlerImplementation queueHandler = new QueueuHandlerImplementation(_listeningQueueMock.Object);

    //Arrange
    queueHandler.Configure();
    _listeningQueueMock.Setup(m => m.BeginPeek()).Raises(
                    m => m.PeekCompleted += null, new PeekCompletedEventArgs() { AsyncResult = new Mock<IAsyncResult>().Object});

    //Act
    _queueHandler.Execute();

    //Assert
    Assert.AreEqual(true, _queueHandler.IsConfigured);
}

---

这看起来不错，但在调用execute时，我收到一个错误，即类型为“System.EventArgs”的对象无法转换为类型为“System.Messaging.PeekCompletedEventArgs”。。。如果我能做到这一点，我没有任何异步结果需要考虑。

您可以使用内部构造函数创建一个实例：

MessageQueue sender = null;
IAsyncResult result = null;
var e = Activator.CreateInstance(typeof(System.Messaging.PeekCompletedEventArgs),
                                 BindingFlags.NonPublic | BindingFlags.Instance,
                                 null, new object[]{sender, result}, null);

注意：

sender

为

null

这一事实将导致在访问

消息

属性时出现NullReferenceException

MessageQueue sender = null;
IAsyncResult result = null;
var e = Activator.CreateInstance(typeof(System.Messaging.PeekCompletedEventArgs),
                                 BindingFlags.NonPublic | BindingFlags.Instance,
                                 null, new object[]{sender, result}, null);