RequestNavigate() private method

private RequestNavigate ( Uri target, Action navigationCallback ) : void
target System.Uri
navigationCallback Action
return void
        public void WhenNavigating_ViewIsActivated()
        {
            // Prepare
            object view = new object();
            Uri viewUri = new Uri(view.GetType().Name, UriKind.Relative);

            IRegion region = new Region();
            region.Add(view);

            string regionName = "RegionName";
            RegionManager regionManager = new RegionManager();
            regionManager.Regions.Add(regionName, region);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());

            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new RegionNavigationContentLoader(serviceLocator);
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            // Act
            bool isNavigationSuccessful = false;
            target.RequestNavigate(viewUri, nr => isNavigationSuccessful = nr.Result == true);

            // Verify
            Assert.IsTrue(isNavigationSuccessful);
            bool isViewActive = region.ActiveViews.Contains(view);
            Assert.IsTrue(isViewActive);
        }
        public void WhenNavigatingWithNullCallback_ThenThrows()
        {
            var region = new Region();

            var navigationUri = new Uri("/", UriKind.Relative);
            IServiceLocator serviceLocator = new Mock<IServiceLocator>().Object;
            RegionNavigationContentLoader contentLoader = new Mock<RegionNavigationContentLoader>(serviceLocator).Object;
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            ExceptionAssert.Throws<ArgumentNullException>(
                () =>
                {
                    target.RequestNavigate(navigationUri, null);
                });
        }
        public void WhenNavigatingFromActiveViewWithNavigatinAwareDataConext_NotifiesContextOfNavigatingFrom()
        {
            // Arrange
            var region = new Region();

            var mockDataContext = new Mock<INavigationAware>();

            var view1Mock = new Mock<FrameworkElement>();
            var view1 = view1Mock.Object;
            view1.DataContext = mockDataContext.Object;

            region.Add(view1);

            var view2 = new object();
            region.Add(view2);

            region.Activate(view1);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());

            var navigationUri = new Uri(view2.GetType().Name, UriKind.Relative);
            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new Mock<RegionNavigationContentLoader>(serviceLocator).Object;
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            // Act
            target.RequestNavigate(navigationUri, nr => { });

            // Verify
            mockDataContext.Verify(v => v.OnNavigatedFrom(It.Is<NavigationContext>(ctx => ctx.Uri == navigationUri && ctx.Parameters.Count() == 0)));
        }
        public void WhenNavigationFromViewThatIsNavigationAware_OnlyNotifiesOnNavigateFromForActiveViews()
        {
            // Arrange

            bool navigationFromInvoked = false;

            var region = new Region();

            var viewMock = new Mock<INavigationAware>();
            viewMock
                .Setup(x => x.OnNavigatedFrom(It.IsAny<NavigationContext>())).Callback(() => navigationFromInvoked = true);
            var view = viewMock.Object;
            region.Add(view);

            var targetViewMock = new Mock<INavigationAware>();
            region.Add(targetViewMock.Object);

            var activeViewMock = new Mock<INavigationAware>();
            region.Add(activeViewMock.Object);

            region.Activate(activeViewMock.Object);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());

            var navigationUri = new Uri(targetViewMock.Object.GetType().Name, UriKind.Relative);
            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new Mock<RegionNavigationContentLoader>(serviceLocator).Object;
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            // Act
            target.RequestNavigate(navigationUri, nr => { });

            // Verify
            Assert.IsFalse(navigationFromInvoked);
        }
        public void WhenTargetViewCreationThrowsWithAsyncConfirmation_ThenExceptionIsProvidedToNavigationCallback()
        {
            var serviceLocatorMock = new Mock<IServiceLocator>();

            var targetException = new Exception();
            var targetHandlerMock = new Mock<IRegionNavigationContentLoader>();
            targetHandlerMock
                .Setup(th => th.LoadContent(It.IsAny<IRegion>(), It.IsAny<NavigationContext>()))
                .Throws(targetException);

            var journalMock = new Mock<IRegionNavigationJournal>();

            Action<bool> navigationCallback = null;
            var viewMock = new Mock<IConfirmNavigationRequest>();
            viewMock
                .Setup(v => v.ConfirmNavigationRequest(It.IsAny<NavigationContext>(), It.IsAny<Action<bool>>()))
                .Callback<NavigationContext, Action<bool>>((nc, c) => { navigationCallback = c; });

            var region = new Region();
            region.Add(viewMock.Object);
            region.Activate(viewMock.Object);

            var target = new RegionNavigationService(serviceLocatorMock.Object, targetHandlerMock.Object, journalMock.Object);
            target.Region = region;

            NavigationResult result = null;
            target.RequestNavigate(new Uri("", UriKind.Relative), nr => result = nr);
            navigationCallback(true);

            Assert.IsNotNull(result);
            Assert.AreSame(targetException, result.Error);
        }
        public void BeforeNavigating_NavigatingEventIsRaised()
        {
            // Prepare
            object view = new object();
            Uri viewUri = new Uri(view.GetType().Name, UriKind.Relative);

            IRegion region = new Region();
            region.Add(view);

            string regionName = "RegionName";
            RegionManager regionManager = new RegionManager();
            regionManager.Regions.Add(regionName, region);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());

            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new RegionNavigationContentLoader(serviceLocator);
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            bool isNavigatingRaised = false;
            target.Navigating += delegate(object sender, RegionNavigationEventArgs e)
            {
                if (sender == target)
                {
                    isNavigatingRaised = true;
                }
            };


            // Act
            bool isNavigationSuccessful = false;
            target.RequestNavigate(viewUri, nr => isNavigationSuccessful = nr.Result == true);

            // Verify
            Assert.IsTrue(isNavigationSuccessful);
            Assert.IsTrue(isNavigatingRaised);

        }
        public void WhenViewModelAcceptsNavigationOutAfterNewIncomingRequestIsReceived_ThenOriginalRequestIsIgnored()
        {
            var region = new Region();

            var viewModelMock = new Mock<IConfirmNavigationRequest>();

            var viewMock = new Mock<FrameworkElement>();
            var view = viewMock.Object;
            view.DataContext = viewModelMock.Object;

            var confirmationRequests = new List<Action<bool>>();

            viewModelMock
                .Setup(icnr => icnr.ConfirmNavigationRequest(It.IsAny<NavigationContext>(), It.IsAny<Action<bool>>()))
                .Callback<NavigationContext, Action<bool>>((nc, c) => { confirmationRequests.Add(c); });

            region.Add(view);
            region.Activate(view);

            var navigationUri = new Uri("", UriKind.Relative);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock
                .Setup(x => x.GetInstance<IRegionNavigationJournalEntry>())
                .Returns(new RegionNavigationJournalEntry());

            var contentLoaderMock = new Mock<IRegionNavigationContentLoader>();
            contentLoaderMock
                .Setup(cl => cl.LoadContent(region, It.IsAny<NavigationContext>()))
                .Returns(view);

            var serviceLocator = serviceLocatorMock.Object;
            var contentLoader = contentLoaderMock.Object;
            var journal = new Mock<IRegionNavigationJournal>().Object;

            var target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            bool firstNavigation = false;
            bool secondNavigation = false;
            target.RequestNavigate(navigationUri, nr => firstNavigation = nr.Result.Value);
            target.RequestNavigate(navigationUri, nr => secondNavigation = nr.Result.Value);

            Assert.AreEqual(2, confirmationRequests.Count);

            confirmationRequests[0](true);
            confirmationRequests[1](true);

            Assert.IsFalse(firstNavigation);
            Assert.IsTrue(secondNavigation);
        }
        public void WhenNavigationFailsBecauseTheContentViewCannotBeRetrieved_ThenNavigationFailedIsRaised()
        {
            // Prepare
            var region = new Region { Name = "RegionName" };

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock
                .Setup(x => x.GetInstance<IRegionNavigationJournalEntry>())
                .Returns(new RegionNavigationJournalEntry());

            var contentLoaderMock = new Mock<IRegionNavigationContentLoader>();
            contentLoaderMock
                .Setup(cl => cl.LoadContent(region, It.IsAny<NavigationContext>()))
                .Throws<InvalidOperationException>();

            var serviceLocator = serviceLocatorMock.Object;
            var contentLoader = contentLoaderMock.Object;
            var journal = new Mock<IRegionNavigationJournal>().Object;

            var target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            RegionNavigationFailedEventArgs eventArgs = null;
            target.NavigationFailed += delegate(object sender, RegionNavigationFailedEventArgs e)
            {
                if (sender == target)
                {
                    eventArgs = e;
                }
            };

            // Act
            bool? isNavigationSuccessful = null;
            target.RequestNavigate(new Uri("invalid", UriKind.Relative), nr => isNavigationSuccessful = nr.Result);

            // Verify
            Assert.IsFalse(isNavigationSuccessful.Value);
            Assert.IsNotNull(eventArgs);
            Assert.IsNotNull(eventArgs.Error);
        }
        public void WhenNavigatingAndDataContextOnCurrentlyActiveViewImplementsINavigateWithVeto_ThenNavigationRequestQueriesForVeto()
        {
            // Prepare
            var region = new Region();

            var viewModelMock = new Mock<IConfirmNavigationRequest>();
            viewModelMock
                .Setup(ina => ina.ConfirmNavigationRequest(It.IsAny<NavigationContext>(), It.IsAny<Action<bool>>()))
                .Verifiable();

            var viewMock = new Mock<FrameworkElement>();

            var view = viewMock.Object;
            view.DataContext = viewModelMock.Object;

            region.Add(view);
            region.Activate(view);

            var navigationUri = new Uri(view.GetType().Name, UriKind.Relative);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());

            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new Mock<RegionNavigationContentLoader>(serviceLocator).Object;
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            // Act
            target.RequestNavigate(navigationUri, nr => { });

            // Verify
            viewModelMock.VerifyAll();
        }
        public void WhenNavigating_ThenNavigationRequestQueriesForVetoOnAllActiveViewsIfAllSucceed()
        {
            // Prepare
            var region = new Region();

            var view1Mock = new Mock<IConfirmNavigationRequest>();
            view1Mock
                .Setup(ina => ina.ConfirmNavigationRequest(It.IsAny<NavigationContext>(), It.IsAny<Action<bool>>()))
                .Callback<NavigationContext, Action<bool>>((nc, c) => c(true))
                .Verifiable();

            var view1 = view1Mock.Object;
            region.Add(view1);
            region.Activate(view1);

            var view2Mock = new Mock<IConfirmNavigationRequest>();

            var view2 = view2Mock.Object;
            region.Add(view2);

            var view3Mock = new Mock<INavigationAware>();

            var view3 = view3Mock.Object;
            region.Add(view3);
            region.Activate(view3);

            var view4Mock = new Mock<IConfirmNavigationRequest>();
            view4Mock
                .Setup(ina => ina.ConfirmNavigationRequest(It.IsAny<NavigationContext>(), It.IsAny<Action<bool>>()))
                .Callback<NavigationContext, Action<bool>>((nc, c) => c(true))
                .Verifiable();

            var view4 = view4Mock.Object;
            region.Add(view4);
            region.Activate(view4);

            var navigationUri = new Uri(view1.GetType().Name, UriKind.Relative);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());

            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new Mock<RegionNavigationContentLoader>(serviceLocator).Object;
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            // Act
            target.RequestNavigate(navigationUri, nr => { });

            // Verify
            view1Mock.VerifyAll();
            view2Mock.Verify(ina => ina.ConfirmNavigationRequest(It.IsAny<NavigationContext>(), It.IsAny<Action<bool>>()), Times.Never());
            view3Mock.VerifyAll();
            view4Mock.VerifyAll();
        }
        public void WhenNavigating_NavigationIsRecordedInJournal()
        {
            // Prepare
            object view = new object();
            Uri viewUri = new Uri(view.GetType().Name, UriKind.Relative);

            IRegion region = new Region();
            region.Add(view);

            string regionName = "RegionName";
            RegionManager regionManager = new RegionManager();
            regionManager.Regions.Add(regionName, region);

            IRegionNavigationJournalEntry journalEntry = new RegionNavigationJournalEntry();

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>())
                .Returns(journalEntry);

            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new RegionNavigationContentLoader(serviceLocator);

            var journalMock = new Mock<IRegionNavigationJournal>();
            journalMock.Setup(x => x.RecordNavigation(journalEntry)).Verifiable();

            IRegionNavigationJournal journal = journalMock.Object;


            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            // Act
            target.RequestNavigate(viewUri, nr => { });

            // Verify
            Assert.IsNotNull(journalEntry);
            Assert.AreEqual(viewUri, journalEntry.Uri);
            journalMock.VerifyAll();
        }
        public void WhenNavigatingAndBothViewAndDataContextImplementINavigationAware_ThenNavigatedIsInvokesOnNavigation()
        {
            // Prepare
            var region = new Region();

            Mock<FrameworkElement> mockFrameworkElement = new Mock<FrameworkElement>();
            Mock<INavigationAware> mockINavigationAwareView = mockFrameworkElement.As<INavigationAware>();
            mockINavigationAwareView.Setup(ina => ina.IsNavigationTarget(It.IsAny<NavigationContext>())).Returns(true);

            Mock<INavigationAware> mockINavigationAwareDataContext = new Mock<INavigationAware>();
            mockINavigationAwareDataContext.Setup(ina => ina.IsNavigationTarget(It.IsAny<NavigationContext>())).Returns(true);
            mockFrameworkElement.Object.DataContext = mockINavigationAwareDataContext.Object;

            var view = mockFrameworkElement.Object;
            region.Add(view);

            var navigationUri = new Uri(view.GetType().Name, UriKind.Relative);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());

            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new RegionNavigationContentLoader(serviceLocator);
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            // Act
            target.RequestNavigate(navigationUri, nr => { });

            // Verify
            mockINavigationAwareView.Verify(v => v.OnNavigatedTo(It.Is<NavigationContext>(nc => nc.Uri == navigationUri)));
            mockINavigationAwareDataContext.Verify(v => v.OnNavigatedTo(It.Is<NavigationContext>(nc => nc.Uri == navigationUri)));
        }
        public void WhenNavigatingWithNullUri_Throws()
        {
            // Prepare
            IRegion region = new Region();

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());

            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new Mock<RegionNavigationContentLoader>(serviceLocator).Object;
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            // Act
            NavigationResult navigationResult = null;
            target.RequestNavigate((Uri)null, nr => navigationResult = nr);

            // Verify
            Assert.IsFalse(navigationResult.Result.Value);
            Assert.IsNotNull(navigationResult.Error);
            Assert.IsInstanceOfType(navigationResult.Error, typeof(ArgumentNullException));
        }
        public void WhenNavigationFailsBecauseDataContextForActiveViewRejectsIt_ThenNavigationFailedIsRaised()
        {
            // Prepare
            var region = new Region { Name = "RegionName" };

            var viewModel1Mock = new Mock<IConfirmNavigationRequest>();
            viewModel1Mock
                .Setup(ina => ina.ConfirmNavigationRequest(It.IsAny<NavigationContext>(), It.IsAny<Action<bool>>()))
                .Callback<NavigationContext, Action<bool>>((nc, c) => c(false))
                .Verifiable();


            var view1Mock = new Mock<FrameworkElement>();
            var view1 = view1Mock.Object;
            view1.DataContext = viewModel1Mock.Object;

            var view2 = new object();

            region.Add(view1);
            region.Add(view2);

            region.Activate(view1);

            var navigationUri = new Uri(view2.GetType().Name, UriKind.Relative);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock
                .Setup(x => x.GetInstance<IRegionNavigationJournalEntry>())
                .Returns(new RegionNavigationJournalEntry());

            var contentLoaderMock = new Mock<IRegionNavigationContentLoader>();
            contentLoaderMock
                .Setup(cl => cl.LoadContent(region, It.IsAny<NavigationContext>()))
                .Returns(view2);

            var serviceLocator = serviceLocatorMock.Object;
            var contentLoader = contentLoaderMock.Object;
            var journal = new Mock<IRegionNavigationJournal>().Object;

            var target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            RegionNavigationFailedEventArgs eventArgs = null;
            target.NavigationFailed += delegate(object sender, RegionNavigationFailedEventArgs e)
            {
                if (sender == target)
                {
                    eventArgs = e;
                }
            };

            // Act
            bool? isNavigationSuccessful = null;
            target.RequestNavigate(navigationUri, nr => isNavigationSuccessful = nr.Result);

            // Verify
            viewModel1Mock.VerifyAll();
            Assert.IsFalse(isNavigationSuccessful.Value);
            Assert.IsNotNull(eventArgs);
            Assert.IsNull(eventArgs.Error);
        }
        public void WhenNavigatingWithNoRegionSet_ThenMarshallExceptionToCallback()
        {
            var navigationUri = new Uri("/", UriKind.Relative);
            IServiceLocator serviceLocator = new Mock<IServiceLocator>().Object;
            RegionNavigationContentLoader contentLoader = new Mock<RegionNavigationContentLoader>(serviceLocator).Object;
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);

            Exception error = null;
            target.RequestNavigate(navigationUri, nr => error = nr.Error);

            Assert.IsNotNull(error);
            Assert.IsInstanceOfType(error, typeof(InvalidOperationException));
        }
        public void WhenRequestNavigateAwayOnDataContextRejectsThroughCallback_ThenNavigationDoesNotProceed()
        {
            // Prepare
            var region = new Region();

            var view1DataContextMock = new Mock<IConfirmNavigationRequest>();
            view1DataContextMock
                .Setup(ina => ina.ConfirmNavigationRequest(It.IsAny<NavigationContext>(), It.IsAny<Action<bool>>()))
                .Callback<NavigationContext, Action<bool>>((nc, c) => c(false))
                .Verifiable();

            var view1Mock = new Mock<FrameworkElement>();
            var view1 = view1Mock.Object;
            view1.DataContext = view1DataContextMock.Object;

            var view2 = new object();

            region.Add(view1);
            region.Add(view2);

            region.Activate(view1);

            var navigationUri = new Uri(view2.GetType().Name, UriKind.Relative);

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());

            IServiceLocator serviceLocator = serviceLocatorMock.Object;
            RegionNavigationContentLoader contentLoader = new Mock<RegionNavigationContentLoader>(serviceLocator).Object;
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = region;

            // Act
            var navigationFailed = false;
            target.RequestNavigate(navigationUri, nr => { navigationFailed = nr.Result == false; });

            // Verify
            view1DataContextMock.VerifyAll();
            Assert.IsTrue(navigationFailed);
            CollectionAssert.AreEqual(new object[] { view1 }, region.ActiveViews.ToArray());
        }
        public void WhenNavigatingWithNullUri_ThenMarshallExceptionToCallback()
        {
            IServiceLocator serviceLocator = new Mock<IServiceLocator>().Object;
            RegionNavigationContentLoader contentLoader = new Mock<RegionNavigationContentLoader>(serviceLocator).Object;
            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, contentLoader, journal);
            target.Region = new Region();

            Exception error = null;
            target.RequestNavigate(null, nr => error = nr.Error);

            Assert.IsNotNull(error);
            Assert.IsInstanceOfType(error, typeof(ArgumentNullException));
        }
        public void WhenNavigatingAndViewCannotBeAcquired_ThenNavigationResultHasError()
        {
            // Prepare             
            object view = new object();
            Uri viewUri = new Uri(view.GetType().Name, UriKind.Relative);

            IRegion region = new Region();
            region.Add(view);

            string otherType = "OtherType";

            var serviceLocatorMock = new Mock<IServiceLocator>();
            serviceLocatorMock.Setup(x => x.GetInstance<IRegionNavigationJournalEntry>()).Returns(new RegionNavigationJournalEntry());
            IServiceLocator serviceLocator = serviceLocatorMock.Object;

            Mock<IRegionNavigationContentLoader> targetHandlerMock = new Mock<IRegionNavigationContentLoader>();
            targetHandlerMock.Setup(th => th.LoadContent(It.IsAny<IRegion>(), It.IsAny<NavigationContext>())).Throws<ArgumentException>();

            IRegionNavigationJournal journal = new Mock<IRegionNavigationJournal>().Object;

            RegionNavigationService target = new RegionNavigationService(serviceLocator, targetHandlerMock.Object, journal);
            target.Region = region;

            // Act
            Exception error = null;
            target.RequestNavigate(
                new Uri(otherType.GetType().Name, UriKind.Relative),
                nr =>
                {
                    error = nr.Error;
                });

            // Verify
            bool isViewActive = region.ActiveViews.Contains(view);
            Assert.IsFalse(isViewActive);
            Assert.IsInstanceOfType(error, typeof(ArgumentException));
        }