public async Task It_produces_failed_notifications_for_Back()
{
var sut = new BlindStackNavigator();
// Add 2 items to be able to perform a back operation.
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM()));
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(throwOnDispose: true)));
var events = new List <StackNavigatorEventArgs>();
sut.StateChanged += Sut_StateChanged;
void Sut_StateChanged(object sender, StackNavigatorEventArgs args)
{
events.Add(args);
}
await Assert.ThrowsAsync <InvalidOperationException>(async() => await sut.NavigateBack(CancellationToken.None));
sut.StateChanged -= Sut_StateChanged;
// There must be 2 notifications: 1 Processing when the back starts and 1 FailedToProcess when it ends.
Assert.Equal(2, events.Count);
Assert.Equal(NavigatorRequestState.Processing, events[0].CurrentState.LastRequestState);
Assert.Equal(NavigatorRequestState.FailedToProcess, events[1].CurrentState.LastRequestState);
}
public async Task It_removes_multiple_entries_and_navigate_back_correctly()
{
var sut = new BlindStackNavigator();
// Add 6 items to the stack.
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(0)));
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(1)));
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(2)));
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(3)));
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(4)));
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(5)));
var indexes = Enumerable.Range(2, 3);
// Remove the third, fourth and fifth items
await sut.RemoveEntries(CancellationToken.None, indexes);
// There must be 3 items left
Assert.Equal(3, sut.State.Stack.Count);
// Navigates back
await sut.NavigateBack(CancellationToken.None);
// The viewmodel count should be 2 and the current viewmodel id should be 1
Assert.Equal(2, sut.State.Stack.Count);
Assert.Equal(1, ((TestVM)sut.State.Stack.Last().ViewModel).Id);
}
public async Task It_disposes_VM_when_navigating_back()
{
var sut = new BlindStackNavigator();
// Add 2 items to the stack.
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(0)));
var vm = (TestVM)await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(1)));
// Navigate back to remove the last item.
await sut.NavigateBack(CancellationToken.None);
// The removed entry must be disposed.
Assert.True(vm.IsDisposed);
}
public async Task Interface_contract_changes_can_be_detected()
{
var ct = CancellationToken.None;
IStackNavigator navigator = new BlindStackNavigator();
// If the core contract changes, we get compilation errors here.
INavigableViewModel vmAfterNavigate = await navigator.Navigate(ct, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(), false, false));
INavigableViewModel vmAfterBack = await navigator.NavigateBack(ct);
await navigator.Clear(ct);
// Navigate twice so that RemoveEntries works.
await navigator.Navigate(ct, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(), false, false));
await navigator.Navigate(ct, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(), false, false));
await navigator.RemoveEntries(ct, new int[] { 0 }.AsEnumerable());
}
public async Task It_fails_to_navigate_back_when_there_arent_enough_entries()
{
var sut = new BlindStackNavigator();
// Add 1 item to the stack.
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM()));
var stackBeforeNavigateBack = sut.State.Stack;
// Navigating back must 'fail' if there is only 1 entry.
// There is no exception, but the result vm must be null.
var vm = await sut.NavigateBack(CancellationToken.None);
Assert.Null(vm);
var stackAfterNavigateBack = sut.State.Stack;
// Because the back didn't do anything, the stack must not change.
Assert.Equal(stackAfterNavigateBack, stackBeforeNavigateBack);
}
public async Task It_navigates_back()
{
var sut = new BlindStackNavigator();
// Add 2 items to the stack.
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(0)));
await sut.Navigate(CancellationToken.None, StackNavigatorRequest.GetNavigateRequest(() => new TestVM(1)));
// The last entry must match the last navigation.
Assert.Equal(1, ((TestVM)sut.State.Stack.Last().ViewModel).Id);
var vmFromNavigation = await sut.NavigateBack(CancellationToken.None);
var vmFromStack = (TestVM)sut.State.Stack.Last().ViewModel;
// The ViewModels from the navigation and stack must be the same.
Assert.Equal(vmFromStack, vmFromNavigation);
// The final ViewModel must be the first one we navigated to.
Assert.Equal(0, vmFromStack.Id);
}
