Windows: full test suite fails with default 5s timeouts under parallel execution

[HUAN2022A]

Summary

Running pnpm test on Windows (win32 x64, Node.js v22) causes multiple test files to fail with Vitest timeout errors. All of these tests pass individually (npx vitest run <file>), but fail when run as part of the full parallel suite due to the 5-second default testTimeout.

Affected test files

• scripts/oxlint-contract.spec.ts — 7 failures, all timeout-related
• scripts/translation-pairing-merge.spec.ts — 1 failure at 15s timeout
• packages/client/ui-primitives/tests/code-block.client.spec.tsx — 1 failure at 5s timeout
• packages/subagent/subagent-codex/tests/real-product.spec.ts — intermittent failure

Reproduction steps

1. Clone the repository on Windows.
2. Run pnpm install and pnpm run build.
3. Run pnpm test.
4. Observe ~9 timeout-related failures across 4-5 test files.
5. Run any affected file individually (e.g., npx vitest run scripts/oxlint-contract.spec.ts) and confirm it passes.

Expected behavior

The full test suite should pass on Windows, or tests that spawn subprocesses should have a longer or configurable timeout to account for slower I/O and process startup on Windows.

Actual behavior

Tests involving spawnSync, file I/O, or lazy dynamic imports exceed the 5s (or 15s for the translation merge test) timeout when CPU is contended by parallel workers. The same tests pass in isolation.

Environment

• OS: Windows 11 x64
• Node.js: v22.x
• pnpm: v11.7.0
• Vitest: v4.1.8
• Commit: master @ 2026-08-21