如何等待Silverlight测试中触发事件

Question

我有一个ViewModel，它在构造函数中开始加载模型异步，并在加载模型时触发一个事件。我有一个测试用的Silverlight单元测试框架的工作，像这样：

bool done = false; 

[TestMethod] 
[Asynchronous] 
public void Test_NoCustomerSelected() 
{ 
    ProjectListViewModel viewModel = null; 
    EnqueueCallback(() => viewModel = new ProjectListViewModel()); 
    EnqueueCallback(() => viewModel.ModelLoaded += new EventHandler<EventArgs>(viewModel_ModelLoaded)); 

    EnqueueConditional(() => done); 
    EnqueueCallback(() => Assert.IsNotNull(viewModel.FilteredProjectList)); 
    EnqueueCallback(() => Assert.AreEqual(4, viewModel.FilteredProjectList.Count)); 

    EnqueueTestComplete(); 
} 

void viewModel_ModelLoaded(object sender, EventArgs e) 
{ 
    done = true; 
} 

但我已经开始，其中Rx框架玩，并试图让我的测试工作，但到目前为止，我没有运气。这里有2次尝试：

public void Test_NoCustomerSelected2() 
{ 
    ProjectListViewModel viewModel = null; 
    viewModel = new ProjectListViewModel(eventAggregatorMock.Object, moduleManagerMock.Object); 

    IObservable<IEvent<EventArgs>> eventAsObservable = Observable.FromEvent<EventArgs>(
     ev => viewModel.ModelLoaded += ev, 
     ev => viewModel.ModelLoaded -= ev); 

    eventAsObservable.Subscribe(args => viewModel_ModelLoaded(args.Sender, args.EventArgs)); 
    eventAsObservable.First(); 

    Assert.IsNotNull(viewModel.Model); 
    Assert.AreEqual(4, viewModel.Model.Count); 
} 

[TestMethod] 
public void Test_NoCustomerSelected3() 
{ 
    ProjectListViewModel viewModel = null; 

    var o = Observable.Start(() => viewModel = new ProjectListViewModel(eventAggregatorMock.Object, moduleManagerMock.Object)); 

    IObservable<IEvent<EventArgs>> eventAsObservable = Observable.FromEvent<EventArgs>(
     ev => viewModel.ModelLoaded += ev, 
     ev => viewModel.ModelLoaded -= ev); 

    o.TakeUntil(eventAsObservable) 
      .First(); 

    Assert.IsNotNull(viewModel.Model); 
    Assert.AreEqual(4, viewModel.Model.Count); 
} 

第一次测试中那张永远等待，第二不起作用，因为视图模型为空时，它的FromEvent。

任何人都有一个线索如何正确地做到这一点？

更新：下面是从PL帮助工作的解决方案：

[TestMethod] 
public void Test_NoCustomerSelected4() 
{ 
    var viewModel = new ProjectListViewModel(eventAggregatorMock.Object, moduleManagerMock.Object); 

    Observable 
     .FromEvent<EventArgs>(viewModel, "ModelLoaded")) 
     .Take(1) 
     .Subscribe(e => 
      { 
       Assert.IsNotNull(viewModel.Model); 
       Assert.AreEqual(4, viewModel.Model.Count); 
      }); 
} 

Answer 1

我相信你还是要用排队调用。例如。这样的事情：

var done = false; 
var viewModel = new ProjectListViewModel(eventAggregatorMock.Object, moduleManagerMock.Object); 

Observable 
    .FromEvent<EventArgs>(viewModel, "ModelLoaded")) 
    .Take(1) 
    .Subscribe(viewModel => 
     { 
      Assert.IsNotNull(viewModel.Model); 
      Assert.AreEqual(4, viewModel.Model.Count); 
      done = true; 
     }); 

EnqueueConditional(() => done); 
EnqueueTestComplete();