如何为触发的事件编写单元测试？ [英] How Do I Write A Unit Test For An Event Being Triggered?

问题描述

我有一个类，当它的内部状态发生变化时会引发一个偶数（大致类似于INotifyPropertyChange但略有不同）。



我应该如何编写单元测试验证此事件确实已经提出？

（事件中ExpectedException与模型相同？）

I have a class that raises an even when its internal state changes (broadly similar to INotifyPropertyChange but slightly different).

How should I write a unit test that verifies that this event is indeed raised?
(There's nothing in the same model as "ExpectedException" for events?)

推荐答案

你好，



您可以在单元测试中使用代表来完成。



例如：

Hello,

You could do it using delegates in your unit tests.

for example:

[TestMethod]
public void EventShouldBeRaised()
{
    ClassToTest classToTest = new ClassToTest();
    bool eventRaised = false;

    classToTest.EventRaised += delegate(object sender, ClassToTestEventArgs e)
    {
        eventRaised = true;
    };

    classToTest.Property1 = "somthing";
    // this property raises an event, test if the boolean is set to true in the delegate call.
    Assert.AreEqual(eventRaised, true);
}

[TestMethod]
public void EventShouldNotBeRaised()
{
    ClassToTest classToTest = new ClassToTest();
    bool eventRaised = false;

    classToTest.EventRaised += delegate(object sender, ClassToTestEventArgs e)
    {
        eventRaised = true;
    };

    classToTest.AnotherProperty = "somthing";
    // This property does not raise the event, so we test that the eventRaised boolean is false.
    Assert.AreEqual(eventRaised, false);
}

Valery。

Valery.

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