如何测试已以AssertWasCalled（AAA）方式注册的事件？

Question

我有一个服务类和一个动作类，并且动作在事件触发时发生。 因此在服务类中测试注册事件是很重要的。

我尝试使用Rhino Mock测试RegisterEvent函数，但是我无法通过测试，AssertWasCalled总是失败。

如果有人可以给我一些指导或文章链接，我将不胜感激。

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

您的问题出在其他地方-在RegisterEvent您将创建ActionClass新实例，该实例将覆盖测试中的模拟一组。 要通过测试，您只需要从RegisterEvent删除该实例化行：

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

Answer 3

感谢@jimmy_keen发现了我的错误，现在有两个有效的断言。

这是一个可行的解决方案...

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.
}