public static IMainWindowViewModel StubMainWindowViewModel(IObservableSoundService observableSoundService = null, ObservableCollection <ISound> initialSounds = null) { IMainWindowViewModel mainWindowViewModel = MockRepository.GenerateStub <IMainWindowViewModel>(); mainWindowViewModel.Stub(model => model.SoundService) .Return(observableSoundService ?? StubObservableSoundService(initialSounds)); return(mainWindowViewModel); }