public void ToggleWindow_WhenViewIsActive_ShouldHideIt() { //---------------Set up test pack------------------- var viewModel = new AboutViewModel(); var sut = Create(); sut.ShowWindow(viewModel); //---------------Assert Precondition---------------- var window = viewModel.GetView() as Window; Assert.IsTrue(window.IsVisible); //---------------Execute Test ---------------------- sut.ToggleWindow(viewModel); //---------------Test Result ----------------------- Assert.IsFalse(window.IsVisible); }