Finder fails on on visible widget

[FritzMatthaeus]

I cannot find out, why my widgets are not found:

I run Patrol Tests (Patrol 3.13.1) and i frequently run into the problem, that
await $(Key('myWidgetKey')).waitUntilVisible() and also expect($(Key('myWidgetKey')).visible, equals(true))) fail though i can see MyWidget on the screen. The finder seems to find one as expect($(Key('myWidgetKey')).exists, equals(true))) is successful. This is the error i get when calling waitUntilVisible():

The following WaitUntilVisibleTimeoutException was thrown running a test:
        TimeoutException after 0:00:10.000000: Finder "Found 1 widget with key [<'successResultKey'>]: [
          Success-[<'successResultKey'>],
        ]" did not find any visible (i.e. hit-testable) widgets

assume i have this widget:

class ElementA extends StatelessWidget {
  const ElementA() : super(key: Keys.elementA);

  @override
  Widget build(BuildContext context) {
    return const Text(
      'Element A',
    );
  }
}

The test fails when searching by Key: await $(Keys.elementA).waitUntilVisible();.
It will also fail if i search by Class: await $(MyApp).$(ElementA).waitUntilVisible();.
But it succeeds if i search by the Text: await $(MyApp).$('Element A').waitUntilVisible();.

Usually i have an interaction before checking the visibility like await $(Key('myButton')).tap();

I would really appreciate any help as the only option i see right now is only using the find by text method in all tests, which is not a nice solution.

This might be related to #2404

[FritzMatthaeus]

Maybe i should mention that i use MobX as State Management. So the UI update is done via reactive progamming depending on Mobx Observables. I have created a test project to find out if the Patrol tests where incompatible with Mobx, but that was not the case.

[FritzMatthaeus]

I have found an answer on why the waitUntilVisible() test fails when using a Key or searching by Class. It has to do with the Widget containing a Column with a SizedBox.

this will be found when calling $(Keys.elementA).waitUnitilVisible() :

class ElementA extends StatelessWidget {
  ElementA() : super(key: Keys.elementA);

  @override
  Widget build(BuildContext context) {
    return const Column(
      children: [
        Text(
          'Element A',
        ),
      ],
    );
  }
}

this will NOT be found when calling $(Keys.elementB).waitUnitilVisible() or $(ElementB).waitUntilVisible():

class ElementB extends StatelessWidget {
  ElementB() : super(key: Keys.elementB);

  @override
  Widget build(BuildContext context) {
    return const Column(
      children: [
        Text(
          'Element B',
        ),
        SizedBox(height: 48)
      ],
    );
  }
}

I have created a reproducable example: Patrol Bug Finder Example

[FritzMatthaeus]

I have created an issue #2463 and a Pull Request to address the issue: #2464

[FritzMatthaeus]

The issue cannot be finally solved. While the PR fixes some problems, the visibilty issues will persist. So updating the Docs will probably be the best way for "Newbies" like me. I have made the suggestions here: #2463

[FritzMatthaeus]

After a lot of learnings i have found out: Do not test "visibility" on Columns, Rows or Widgets with Columns or Rows. Take a nested Widget to test "visibility". Thanks to the LeanCode Team for this great package!