why can't the widget finder in my integration test find a widget after my test successfully signs into my flutter app?

I am trying to write some integration tests that start off with a login attempt then proceeds to navigate the app a bit to a certain page. The attempt to sign in actually succeeds but after that my attempts to find any widgets fails so I cannot navigate further.

After the sign-in the page the app automatically navigates away to the next page in the app correctly but then my test script cannot find any widgets on that page even though I can see them in the android emulator onscreen.

My app_test.dat file looks like this:

 
import ...

void main() {
  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
  
  group('sign in : ', () {
    testWidgets('try to SIGN IN and  open the menu ',
        (WidgetTester tester) async {
      app.main();
      await tester.pumpAndSettle(const Duration(milliseconds: 5000));
      await tester.pumpAndSettle();

      expect(find.text('SIGN IN', skipOffstage: false), findsWidgets);

      expect(find.byKey(Key('loginPagePasswordField')), findsOneWidget);
      expect(find.byKey(Key('loginPageEmailField')), findsOneWidget);
      print('found fields');
      await tester.enterText(
          find.byKey(Key('loginPageEmailField')), 'myname@here.com');
      await tester.enterText(
          find.byKey(Key('loginPagePasswordField')), 'myname123zxc');
      print('entered text');
      await tester.testTextInput.receiveAction(TextInputAction.done);
      await tester.pump();
      print('entered DONE');
 
      await tester.pumpAndSettle(const Duration(milliseconds: 5000));
      await tester.pumpAndSettle();


      // Now try to find the menu icon button
      var x = find.byTooltip('Open navigation menu'); 
      expect(x, findsOneWidget);  // this fails but is needed to navigate the app
      print('find tab1 ');
      // Now try to find the 'ASD' Tab 
      final tabFinder = find.text('ASD', skipOffstage: false);
      expect(tabFinder, findsWidgets); // this also fails
  
    });
 
  });
}

and my f doctor (I use fvm):

[✓] Flutter (Channel stable, 2.8.0, on macOS 12.1 21C52 darwin-arm, locale en-CA)
[✓] Android toolchain - develop for Android devices (Android SDK version 32.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 13.2)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2020.3)
[✓] VS Code (version 1.63.0)
[✓] Connected device (2 available)

• No issues found!

It seems that the trick is that the AppBar's default "leading" widget or the default leading widget's default tooltip is not present when the integration test is run. When the app is run in debug-mode in the emulator it is there - it can be found with a debug-watch on MaterialLocalizations.of(context).openAppDrawerTooltip. That watch does not find the tooltip when I run debug on the test file - then again no watches seem to work in that case.

The fix is to manually add the "leading" widget into the AppBar like so:

appBar: AppBar(
              title: "my title",
              leading: Builder(
                builder: (BuildContext context) {
                  return IconButton(
                    icon: Icon(Icons.menu),
                    onPressed: () {
                      Scaffold.of(context).openDrawer();
                    },
                    tooltip: 'Open navigation menu',
                  );
                },
              ),
...

Now, on to the next problem - why does the next test in the group fail to find any widgets?