Change integration test parallelization from ClassLevel to MethodLevel#15526
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nohwnd merged 2 commits intomicrosoft:mainfrom Mar 20, 2026
Merged
Change integration test parallelization from ClassLevel to MethodLevel#15526nohwnd merged 2 commits intomicrosoft:mainfrom
nohwnd merged 2 commits intomicrosoft:mainfrom
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Integration tests offload work to child processes (vstest.console, testhost), so there is no shared in-process state between methods. MethodLevel parallelization allows more tests to run concurrently, improving overall test execution time. Fixes microsoft#15488 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
Switches MSTest integration/acceptance test parallelization from class-level to method-level to increase concurrency and reduce overall test runtime, based on the fact that most work is executed in child processes.
Changes:
- Updated MSTest assembly-level
Parallelizescope fromClassLeveltoMethodLevelin two integration test assemblies. - Expanded comments to document why method-level parallelization is considered safe (child-process isolation).
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| test/Microsoft.TestPlatform.Library.IntegrationTests/Properties/AssemblyInfo.cs | Changes MSTest parallelization scope to MethodLevel and documents rationale. |
| test/Microsoft.TestPlatform.Acceptance.IntegrationTests/Properties/AssemblyInfo.cs | Same parallelization scope change for acceptance integration tests. |
Blame tests collect crash/hang dumps from child processes and race when run in parallel at method level, causing dump files to be missed. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
nohwnd
commented
Mar 20, 2026
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| [TestClass] | ||
| [TestCategory("Windows-Review")] | ||
| [DoNotParallelize] // Blame tests collect crash/hang dumps from child processes and race when run in parallel. |
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This was referenced Mar 25, 2026
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Integration tests offload work to child processes (vstest.console, testhost), so there is no shared in-process state between test methods in the same class. ClassLevel parallelization was unnecessarily conservative - switching to MethodLevel allows more tests to run concurrently, improving overall test execution time.
Each test method creates its own TempDirectory and invokes vstest.console independently, so concurrent execution within a class is safe.
Fixes #15488