使用 Rhino 模拟和数据绑定的 InvalidOperationException

Question

我正在为一个类（例如称为ClassUnderTest）编写一些单元测试，该类具有与其模型中的属性绑定的属性。由于模型是使用接口 (IModel) 定义的，因此模型由 Rhino Mocks 模拟来模拟。

示例代码：

模型接口：

public interface IModel : INotifyPropertyChanged
{
   event PropertyChangedEventHandler PropertyChanged;
   int SourceValue { get; set; }
}

要测试的类：

public class ClassUnderTest : DependencyObject
{
   private IModel model;

   public int TargetValue
   {
      get { return (int)GetValue(TargetValueProperty); }
      set { SetValue(TargetValueProperty, value); }
   }

   public static readonly DependencyProperty TargetValueProperty = DependencyProperty.Register("TargetValue", typeof(int), typeof(ClassUnderTest), new PropertyMetadata(0));

   public ClassUnderTest(IModel model)
   {
      this.model = model;
      var b = new Binding("SourceValue") { Source = this.model, Mode = BindingMode.OneWay };
      BindingOperations.SetBinding(this, TargetValueProperty, b);
   }
}

单元测试方法：

[TestMethod]
public void TestMethod()
{
   var repo = new MockRepository();
   var modelMock = repo.StrictMock<IModel>();
   const int expectedValue = 4;
   IEventRaiser propertyChanged;

   using (repo.Record())
   {
      propertyChanged = Expect.Call(delegate { modelMock.PropertyChanged += null; }).IgnoreArguments().GetEventRaiser();
      Expect.Call(() => modelMock.PropertyChanged -= null).Constraints(Is.NotNull()).Repeat.Any();
      Expect.Call(modelMock.SourceValue).Return(expectedValue).Repeat.Any();             
   }

   using (repo.Playback())
   {
      var cuT = new ClassUnderTest(modelMock);
      propertyChanged.Raise(modelMock, new PropertyChangedEventArgs("SourceValue"));
      Assert.AreEqual(expectedValue, cuT.TargetValue);
   }
}

运行测试方法，一切正常。在模型模拟上引发属性更改事件也会引发 ClassUnderTest 类的更改。

我现在遇到的问题只能在调试模式下观察到。在测试结束时，我得到一个 无效操作异常：

This action is invalid when the mock object is in verified state.:
at Rhino.Mocks.Impl.VerifiedMockState.MethodCall(IInvocation invocation, MethodInfo method, Object[] args)
at Rhino.Mocks.MockRepository.MethodCall(IInvocation invocation, Object proxy, MethodInfo method, Object[] args)
at Rhino.Mocks.Impl.RhinoInterceptor.Intercept(IInvocation invocation)
at Castle.DynamicProxy.AbstractInvocation.Proceed()
at IModelProxy2856c01157e54c29a4a7328a5a7ef52a.remove_PropertyChanged(PropertyChangedEventHandler value)
at System.ComponentModel.PropertyChangedEventManager.StopListening(Object source)
at System.ComponentModel.PropertyChangedEventManager.Purge(Object source, Object data, Boolean purgeAll)
at MS.Internal.WeakEventTable.Purge(Boolean purgeAll)
at MS.Internal.WeakEventTable.WeakEventTableShutDownListener.OnShutDown(Object target, Object sender, EventArgs e)
at MS.Internal.ShutDownListener.HandleShutDown(Object sender, EventArgs e)

据我了解，这是因为绑定通过在测试结束时处理所有对象来引发取消订阅，但模拟已经处于验证状态并且不再允许任何交互。

所以我的问题是：有没有办法避免这种异常或取消订阅。还是我使用 Rhino Mocks 的方式不正确？

感谢您的帮助

Answer 1

你试过了吗：

using (repo.Playback())
{
    using (var cuT = new ClassUnderTest(modelMock))
    {
        propertyChanged.Raise(modelMock, new PropertyChangedEventArgs("SourceValue"));
        Assert.AreEqual(expectedValue, cuT.TargetValue);
    }
}