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);
        }