如何測試已以AssertWasCalled（AAA）方式注冊的事件？

Question

我有一個服務類和一個動作類，並且動作在事件觸發時發生。 因此在服務類中測試注冊事件是很重要的。

我嘗試使用Rhino Mock測試RegisterEvent函數，但是我無法通過測試，AssertWasCalled總是失敗。

如果有人可以給我一些指導或文章鏈接，我將不勝感激。

public class ServiceClass
{
    public ActionClass Printer {set; get;}
    public void RegisterEvent()
    {
        Printer = new ActionClass ();
        Printer.PrintPage += Printer.ActionClass_PrintPage;
    }
}
public class ActionClass
{
    event PrintPageEventHandler PrintPage;
    public void ActionClass_OnAction( object sender, PrintPageEventArgs e )
    {
        // Action here.
    }
}
[Test]
public void RegisterEvent_Test()
{
    var service = new ServiceClass();

    var mockActionClass = MockRepository.GenerateMock<IActionClass>();

    service.Printer = mockActionClass;
    service.RegisterEvent();
    mockActionClass.AssertWasCalled( x => x.PrintPage += Arg<PrintPageEventHandler>.Is.Anything );
}

Answer 1

更改

Arg<EventHandler>.Is.Anything 

至

Arg<EventHandler<YourEventArgTypeName>>.Is.Anything

Answer 2

您的問題出在其他地方-在RegisterEvent您將創建ActionClass新實例，該實例將覆蓋測試中的模擬一組。 要通過測試，您只需要從RegisterEvent刪除該實例化行：

public void RegisterEvent()
{
    // This overrides mock you set in test
    // Printer = new ActionClass ();
    Printer.PrintPage += Printer.ActionClass_PrintPage;
}

Answer 3

感謝@jimmy_keen發現了我的錯誤，現在有兩個有效的斷言。

這是一個可行的解決方案...

public class ServiceClass
{
    public IActionClass Printer {set; get;}
    public void RegisterEvent()
    {
        Printer.PrintPage += ActionClass_PrintPage;
    }
}
public class ActionClass : IActionClass 
{
    event PrintPageEventHandler PrintPage;
    public void ActionClass_PrintPage( object sender, PrintPageEventArgs e )
    {
        // Action here.
    }
}
[Test]
public void RegisterEvent_Test()
{
    var service = new ServiceClass();

    var mockActionClass = MockRepository.GenerateMock<IActionClass>();

    service.Printer = mockActionClass;
    service.RegisterEvent();
    mockActionClass.AssertWasCalled(x => x.PrintPage += Arg<PrintPageEventHandler>.Is.Anything); // This does work. Credit to @jimmy_keen
    //mockActionClass.AssertWasCalled(x => x.PrintPage += Arg<EventHandler<PrintPageEventArgs>>.Is.Anything); // Can not compile.
    mockActionClass.AssertWasCalled(x => x.PrintPage += x.ActionClass_PrintPage); // This works.
}