Remove list_tile_tester and rendering_tester cross-imports from cupertino tests

[xfce0]

Remove cross-directory test imports of list_tile_tester.dart and rendering_tester.dart from cupertino tests by duplicating the relevant trivial test utilities locally:

• TestListTile (~30 lines) → duplicated into test/cupertino/list_tile_tester.dart, used by cupertino/switch_test.dart
• TestCallbackPainter (~10 lines) → duplicated into test/cupertino/rendering_test_utils.dart, used by cupertino/picker_test.dart and cupertino/tab_scaffold_test.dart

Both utilities are trivial and match the "duplicate the util" criteria from the issue.

Part of #182636.

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the AI contribution guidelines and understand my responsibilities, or I am not using AI tools.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• I followed the breaking change policy and added Data Driven Fixes where supported.
• All existing and new tests are passing.

[gemini-code-assist]

Code Review

This pull request introduces two new testing utility classes, TestListTile and TestCallbackPainter, and updates import paths in existing test files. The review feedback highlights that both new classes lack required documentation for their public members, which is a violation of the project's style guide.

[gemini-code-assist]

According to the Flutter style guide, all public members should have documentation. Please add documentation for the constructor and the public fields of TestListTile.

  /// Creates a [TestListTile].
  const TestListTile({super.key, this.title, this.onTap});

  /// The widget to display in the body of the list tile.
  final Widget? title;

  /// The callback to call when the list tile is tapped.
  final VoidCallback? onTap;

References

1. All public members should have documentation. ^(link)

[gemini-code-assist]

According to the Flutter style guide, all public members should have documentation. Please add documentation for the constructor and the public field of TestCallbackPainter.

Suggested change

	const TestCallbackPainter({required this.onPaint});
	final VoidCallback onPaint;
	/// Creates a [TestCallbackPainter].
	const TestCallbackPainter({required this.onPaint});
	/// The callback to call when the painter paints.
	final VoidCallback onPaint;

References

1. All public members should have documentation. ^(link)

[xfce0]

Note: these two test files also cross-import semantics_tester.dart, which is used across ~40 files (29 material + 11 cupertino) and is ~1300 lines. Given @loic-sharma's concern about keeping duplicated utils in sync (#184519), I left the semantics_tester imports as-is for now. Would it make more sense to move SemanticsTester into flutter_test rather than duplicating it? Happy to help with either approach.

[loic-sharma]

semantics_tester.dart ... is ~1300 lines. Given @loic-sharma's concern about keeping duplicated utils in sync (#184519), I left the semantics_tester imports as-is for now. Would it make more sense to move SemanticsTester into flutter_test rather than duplicating it? Happy to help with either approach.

@chunhtai What are your thoughts here? 1300 lines does indeed seem like too much logic to duplicate across widgets/material/cupertino libraries. It seems preferable to move this logic to flutter_tester - is the API "good enough" to be public though?

[chunhtai]

It seems preferable to move this logic to flutter_tester - is the API "good enough" to be public though?

No, that test is not suitable for public, it is almost the same as semantics scuba diff, but worse. If they really want to assert the entire semantics tree, I would rather use semantics scuba.

We also discourage use of TestSemantics #184367

so in theory no new test should be using it, and that code won't change and should slowly be deprecated, I think it is ok to duplicate the tester util to 3 places.

[victorsanni]

Hi, can you fix the merge conflict in this PR? Thanks

[flutter-dashboard]

This pull request is not mergeable in its current state, likely because of a merge conflict. Pre-submit CI jobs were not triggered. Pushing a new commit to this branch that resolves the issue will result in pre-submit jobs being scheduled.

[xfce0]

Hi! Sorry for the delay — I had to rebase onto the latest master and resolve a merge conflict in tab_scaffold_test.dart. The conflict was caused by upstream changes to imports in that file.

I also added the missing dartdoc to the public members of TestListTile and TestCallbackPainter as requested. All analyzer checks and local tests pass. Please let me know if anything else needs adjustment.

[victorsanni]

Thanks for this PR. Can you grep all instances of TestCallbackPainter in test/cupertino and replace them with the rendering_test_utils.dart import?

[victorsanni]

Shouldn't this class be deleted if we are now importing from rendering_test_utils.dart?

[victorsanni]

Should this public constructor have an API doc comment?

[victorsanni]

Can you fix linux analyze by running dart format packages/flutter/test/cupertino/picker_test.dart?