测试订阅 EventAggregator

Question

感谢这个 SO answer 我已经成功地测试了 PRISM EventAggregator 的发布事件（使用 FakeItEasy 伪造）

[TestCase]
public void test_that_publish_occured()
{
    var fakeEventAg = A.Fake<IEventAggregator>();
    var fakeEvent = A.Fake<MyEvent>();

    A.CallTo(() => fakeEventAg.GetEvent<MyEvent>())
      .Returns(fakeEvent);

    MyViewModel mvm = new MyViewModel(fakeEventAg);

    mvm.ICommandThatCausesPublishToBeCalled.Execute();

    A.CallTo(() => fakeEvent.Publish(A<SomeClass>.Ignored))
      .MustHaveHappened();
}

但是我没有测试订阅这个事件。我尝试了以下方法，但出现异常 "Non virtual methods can not be intercepted".

[TestCase]
public void test_that_event_is_listened()
{
    var fakeEventAg = A.Fake<IEventAggregator>();
    var fakeEvent = A.Fake<MyEvent>();
    A.CallTo(() => fakeEventAg.GetEvent<MyEvent>())
      .Returns(fakeEvent);

    // subscription occurs in the constructor
    MyViewModel2 mvm2 = new MyViewModel2(fakeEventAg);

    A.CallTo(() => fakeEventAg.GetEvent<MyEvent>()
      .Subscribe(A<Action<PayloadClass>>.Ignored))
      .MustHaveHappened();
}

如何测试事件订阅是否已发生？不一定是单元测试，也可以是集成测试。

Answer 1

错误发生是因为 Subscribe 方法不是虚拟的，因此不能被模拟。我看到 EventBase class（MyEvent 基于）有一个 Subscriptions 属性。您应该能够检查该集合以验证您的活动是否已添加。

测试订阅 EventAggregator

Test subscription to EventAggregator

c#

testing

unit-testing

eventaggregator