Can't found widget key flutter test

Question

So, i'm trying to test my flutter app. Here is what i do

class MockSplashScreenBloc extends MockBloc<SplashScreenState>
    implements SplashScreenBloc {}

void main() {
  MockSplashScreenBloc splashScreenBloc;

  Widget MyWidget() {
    return MaterialApp(
      home: BlocProvider(
        create: (context) {
          return SplashScreenBloc(url: "google.com");
        },
        child: SplashScreen(),
      ),
    );
  }

  group('Splash Screen Widget Test', () {
    setUp(() {
      splashScreenBloc = MockSplashScreenBloc();
    });
    tearDown(() {
      splashScreenBloc?.close();
    });

    testWidgets('should render Container when state is Default State',
        (WidgetTester tester) async {
      when(splashScreenBloc.state).thenAnswer((_) => Default());
      await tester.pumpWidget(MyWidget());
      expect(find.byKey(ValueKey("container_empty")), findsOneWidget);
    });

    testWidgets('should render LoadingIndicator when state is Loading State',
        (WidgetTester tester) async {
      when(splashScreenBloc.state).thenReturn(LoadingState());

      await tester.pumpWidget(MyWidget());

      expect(find.byKey(ValueKey("splash_loading_bar")), findsOneWidget);
    });
  });

}

Here is my SplashScreen

class SplashScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: BlocBuilder<SplashScreenBloc, SplashScreenState>(
          builder: (context, state) {
            if (state is LoadingState) {
              return CircularProgressIndicator(
                key: Key("splash_loading_bar"),
              );
            } else if (state is NotConnected) {
              return Text("Could not connect to server",
                  key: ValueKey("splash_screen_not_connected"));
            } else if (state is Connected) {
              return Text(
                "Connected",
                key: Key("splash_screen_connected"),
              );
            } else {
              return Container(key: Key("container_empty"));
            }
          },
        ),
      ),
    );
  }
}

i can't pass this test should render LoadingIndicator when state is Loading State , i alrady try to use expect(find.byType(CircularProgressIndicator), findsOneWidget); but it is still not working, here is the error

══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════ The following TestFailure object was thrown running a test: Expected: exactly one matching node in the widget tree Actual: _KeyFinder:<zero widgets with key [<'splash_loading_bar'>] (ignoring offstage widgets)>
Which: means none were found but one was expected

how can i fix it ?

Answer 1

Did you try await tester.pumpAndSettle()?

tester.pump()
Triggers a rebuild of the widget after a given duration.

tester.pumpAndSettle()
Repeatedly calls pump with the given duration until there are no longer any frames scheduled. This essentially waits for all animations to complete.

Please try the following code :

   testWidgets('should render LoadingIndicator when state is Loading State',
        (WidgetTester tester) async {
      when(splashScreenBloc.state).thenReturn(LoadingState());

      await tester.pumpWidget(MyWidget());

      await tester.pumpAndSettle();

      expect(find.byKey(ValueKey("splash_loading_bar")), findsOneWidget);
    });