Using a Delayed Future in Widget test stops the test from completing

[maks]

@felangel thanks for this fantastic package, you've saved mocking for us in the NS age!

I've have run into an issue though and I'm not sure if this is a case of my not doing something correctly but I've found that trying to use Future.delayed() in a mocked method in a widgetTest causes the test to hang and never complete.

My code is:

testWidgets('home page shows progress indicator when loading',
      (tester) async {
    final api = MockApiService();
    final lvm = LoginViewModel(api);

    when(api).calls(#requestLoginCode).thenAnswer((_) async {
      await Future<void>.delayed(Duration(seconds: 1));
      return APIResult.Error;
    });

    final w = ProviderScope(
      overrides: [loginProvider.overrideWithProvider(Provider((ref) => lvm))],
      child: HomePage(),
    );

    await tester.pumpWidget(wrapForTest(w));

    await lvm.requestCode('12345');

    await tester.pump();

    await tester.pump(Duration(seconds: 2));

    final hasSpinner = tester.any(find.byType(CircularProgressIndicator));
  
    expect(hasSpinner, true);
  });

where requestCode() calls the ApiService objects requestLoginCode() method which returns a Future that completes once its network API call (in the real, nnon mocked ApiService class) completes.

If I remove the Future.delayed() everything works as expected, BUT I want the delay in there because I'm trying to test that a CircularProgressIndicator is displayed during the period before the Future returned by requestLoginCode completes.

I've included the Riverpod setup code, but I don't think its relevant here.

My suspicion is this is maybe due to widgetTests running inside a FakeAsync zone though according to this SO question this approach should work (or at least used to work with mockito).

[felangel]

Hi @maks 👋
Thanks for opening an issue!

Are you still able to reproduce this in the latest release (v0.0.2-dev.5)? Thanks! 🙏

[felangel]

@maks any updates or can this be closed?

[maks]

@felangel sorry for the slow reply, its been a long weekend holiday here.
I've upgraded to 0.0.2-dev.5 and changed my test to now use new type-safe syntax:

    when(() => authRepo.requestOtp('12345')).thenAnswer((_) async {
      await Future<void>.delayed(Duration(seconds: 1));
      return AuthResult.error(400, 'test error');
    });

But unfortunately still seeing the test hang.

[felangel]

@maks no worries thanks for getting back to me!

Just to clarify, you said this was not a problem using mockito?

I think this is expected because in a widget test you will need to use tester.runAsync(() {...}) in this situation.

[maks]

@felangel actually I realised when I looked again at my test that I was making it more complicated than it needed to be as I could just override my providers state and not even need to worry about the async behaviour.

I still think there maybe an issue with async handling as I would have expected that FakeAsync to work with the Future I was declaring inside the FaskAsync Zone, but I'll close this for now until I get a chance to see if I can write a simple standalone test to reproduce the issue. Thanks again for looking at it!