Support test filters across xUnit runners

[max-charlamb]

Summary

• Preserve the existing eng/build.ps1 -methodfilter and -classfilter interface.
• Pass neutral filter properties into the test traversal.
• Translate filters to -method/-class for the legacy xUnit runner and --filter-method/--filter-class for xUnit v3 using Microsoft Testing Platform.

This allows legacy SOS.UnitTests and the new SOS.Tests project to run in the same test invocation while using their respective command-line syntax.

Testing

• Ran a filtered legacy SOS.UnitTests method through eng/build.ps1.
• Ran one filtered xUnit v3 method through eng/build.ps1.
• Ran four filtered xUnit v3 class tests through eng/build.ps1.

Note

This pull request description was generated with GitHub Copilot.

[Copilot]

🟡 Changes recommended

The new MSBuild condition relies on UseMicrosoftTestingPlatformRunner, which is not set anywhere in-repo and could cause xUnit v3 filtering to silently fall back to legacy arguments depending on external target behavior.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR extends the existing eng/build.ps1 -methodfilter / -classfilter interface so it can filter tests correctly across both the legacy xUnit console runner and the newer xUnit v3 runner (Microsoft Testing Platform) during a single traversal-based test invocation.

Changes:

• Replaces direct TestRunnerAdditionalArguments injection from eng/build.ps1 with neutral MSBuild properties (DiagnosticsTestMethodFilter / DiagnosticsTestClassFilter).
• Translates those neutral properties into runner-specific CLI arguments in src/tests/Directory.Build.targets (-method/-class vs --filter-method/--filter-class).

File summaries

File	Description
src/tests/Directory.Build.targets	Adds translation from neutral filter properties into runner-specific arguments for legacy xUnit vs xUnit v3 (MTP).
eng/build.ps1	Preserves the existing script interface but now passes neutral filter properties into MSBuild instead of runner-specific args.

Review details

Suppressed comments (1)

src/tests/Directory.Build.targets:12

• Same as the method-filter block: UseMicrosoftTestingPlatformRunner is not set anywhere in-repo, so this condition may silently choose the legacy -class syntax for XUnitV3 if the external targets don’t define that property. Prefer conditioning solely on TestRunnerName == XUnitV3 (or define a default when using the XUnitV3 runner).

  <PropertyGroup Condition="'$(DiagnosticsTestClassFilter)' != ''">
    <TestRunnerAdditionalArguments Condition="'$(TestRunnerName)' == 'XUnitV3' and '$(UseMicrosoftTestingPlatformRunner)' == 'true'">$(TestRunnerAdditionalArguments) --filter-class $(DiagnosticsTestClassFilter)</TestRunnerAdditionalArguments>
    <TestRunnerAdditionalArguments Condition="'$(TestRunnerName)' != 'XUnitV3' or '$(UseMicrosoftTestingPlatformRunner)' != 'true'">$(TestRunnerAdditionalArguments) -class $(DiagnosticsTestClassFilter)</TestRunnerAdditionalArguments>

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Lite

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