public async Task Activate_CallsActivateWithShareOperation_OnViewModel()
        {
            IViewFactory viewFactory = new MockShareTargetViewFactory();
            TestableShareTargetManager shareTargetManager = CreateShareTargetManager(viewFactory: viewFactory);
            shareTargetManager.ShareTargetPageName = "ShareTarget";

            IShareTargetActivatedEventArgs activatedEventArgs = new MockShareTargetActivatedEventArgs();
            await shareTargetManager.Activate(activatedEventArgs);

            MockViewLifetimeContext viewLifetimeContext = shareTargetManager.DisplayedViews.First();
            MockShareTargetPageElement pageViewModel = viewLifetimeContext.ViewModel as MockShareTargetPageElement;
            Assert.IsAssignableFrom(typeof(MockShareOperation), pageViewModel.ActivateEvents[0]);
            Assert.Equal(activatedEventArgs, ((MockShareOperation)pageViewModel.ActivateEvents[0]).ActivatedEventArgs);
        }
        public async Task Activate_CallsActivate_OnViewModel()
        {
            IViewFactory viewFactory = new MockShareTargetViewFactory();
            TestableShareTargetManager shareTargetManager = CreateShareTargetManager(viewFactory: viewFactory);
            shareTargetManager.ShareTargetPageName = "ShareTarget";

            await shareTargetManager.Activate(new MockShareTargetActivatedEventArgs());

            MockViewLifetimeContext viewLifetimeContext = shareTargetManager.DisplayedViews.First();
            MockShareTargetPageElement pageViewModel = viewLifetimeContext.ViewModel as MockShareTargetPageElement;
            Assert.Equal(1, pageViewModel.ActivateEvents.Count);
        }