[material_ui] Reduce the material_ui non-wasm web test suite

[elliette]

Work towards flutter/flutter#192308

Introduce new --package-tags flag that can be used to specify which flags to filter a package's tests with. In the case of the web_dart_unit_tests, we specify that material_ui should filter on the new reduced_web_test_set tag.

Pre-Review 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 page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter.
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I linked to at least one issue that this PR fixes in the description above.
• I followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style, or I have commented below to indicate which documented exception this PR falls under¹.
• I updated/added any relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or I have commented below to indicate which test exemption this PR falls under¹.
• All existing and new tests are passing.

changelog exemption: only test/CI changes

If you need help, consider asking for advice on the #hackers-new channel on Discord.

Note: The Flutter team is currently trialing the use of Gemini Code Assist for GitHub. Comments from the gemini-code-assist bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.

Footnotes

1. Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling. ↩ ↩²

[gemini-code-assist]

Code Review

This pull request adds support for a --package-tags option to the dart-test command in the repository tooling, enabling packages to run only tests matching a specified tag. The material_ui package is configured to run a reduced set of web tests using the reduced-web-test-set tag, and CI configurations are updated to utilize this new option. Feedback on the changes suggests handling cases where the package tags YAML file is empty or contains only comments to prevent a misleading error message when loadYaml returns null.

[gemini-code-assist]

If the YAML file is empty or contains only comments, loadYaml will return null. Currently, this will fall through to the else block and throw a ToolExit with a confusing error message ('is not a valid YAML map'). It would be more robust to handle null gracefully by returning an empty map.

    final Object? yaml = loadYaml(file.readAsStringSync());
    if (yaml == null) {
      _packageTags = packageTags;
      return packageTags;
    }
    if (yaml is YamlMap) {
      for (final MapEntry<dynamic, dynamic> entry in yaml.entries) {
        final pkg = entry.key.toString();
        final dynamic val = entry.value;
        if (val != null) {
          packageTags[pkg] = val.toString();
        }
      }
    } else {
      printError('The package tags file "$arg" is not a valid YAML map.');
      throw ToolExit(exitInvalidArguments);
    }

[stuartmorgan-g]

I can do a full review on Tuesday, but as a quick note generally global state initialization goes in an @override Future<void> initializeRun() async, which is called once per run rather than once per package. (Obviously the cost is pretty low here, but there's no need to read and parse a repo-level file N times.)