Review Vitest

Review Vitest

Review the Vitest setup for alignment with current official Vitest and Cloudflare Workers testing best practices - shared config correctness, pool selection, agent-friendly output, and the repo's unit/integration testing split. Your reply must be a plan of suggested changes: concise, actionable, structured - not only prose.

Invocation

Text after the slash command is additional scope/focus (e.g. "workers pool only", "reporters") - narrow the review accordingly.

Ground truth (mandatory)

Your pre-trained knowledge of Vitest may be outdated. Do not draft suggestions from memory alone.

1. Resolve "Vitest" via the Context7 MCP (resolve-library-id → query-docs) at v4: config API (mergeConfig/defineConfig), pool options (threads/forks/vmThreads), reporter list (including agent-aware auto-detection), project/workspace patterns, experimental flags validity.
2. Also resolve "@cloudflare/vitest-plugin" (or "Cloudflare Workers" docs) for current Workers-pool guidance; prefer the cloudflare-docs MCP for Workers testing questions.
3. For anything Context7 lacks, use Firecrawl search/scrape restricted to official domains (vitest.dev, developers.cloudflare.com/workers/testing/) - vitest config reference, Workers testing guide, createTestHarness() reference.
4. Version currency: catalog vitest, @cloudflare/vitest-plugin in pnpm-workspace.yaml vs latest stable; flag deprecated config keys still present in presets or per-app configs.
5. Cite the retrieved source next to every finding; label anything unverifiable as Unverified.

Scope artifacts

• packages/vitest-config/src/index.ts (defineNodeConfig) and src/workers.ts (defineWorkersConfig)
• Per-app configs: apps/front-app/vitest.config.ts, apps/worker-api/vitest.config.mts
• Suites under apps/*/tests/; repo testing-split policy (root + packages/vitest-config/AGENTS.md)
• Root scripts test / test:watch turbo wiring

Analysis axes

• Shared defaults: mock lifecycle (restoreMocks/clearMocks/unstub) coherent; passWithNoTests acceptable only as starter scaffolding - flag if permanent; include globs match reality.
• Pool selection: Node suites on threads + isolate: false justified by cleanup discipline (verify tests actually clean up); Workers suites never isolate:false/custom env; no cross-contamination between entries (Node apps must not resolve the Cloudflare pool package).
• Workers testing split: single-Worker route tests inside workerd via the Vitest pool; multi-Worker integration reserved for Wrangler createTestHarness() from a Node suite - confirm no drift.
• Reporter & CI behavior: agent-aware reporter detection preserved (no custom reporters defeating it); GitHub job summaries intact; watch vs run mode wiring correct.
• Version currency: experimental flags (fsModuleCache) still valid at installed version; new stable options worth adopting.

DX & AI-agentic workflow

Verify agent-friendliness: test runs fast enough for iterative agents (per-app filter documented); failure output parseable; DOM/RTL depth delegated to the front-vitest skill rather than duplicated.

Steps

1. Collect ground truth before reading config.
2. Read both preset entries and every per-app config; sample one Node and one Workers suite.
3. Walk each analysis axis; note findings or explicit one-line "no issues".
4. Compose the plan grouped Critical / Improvements / Optional with what, where, why, and source citations.

Output format

1. Critical - broken isolation, pool misuse, deprecated-and-failing config.
2. Improvements - speed and split-policy alignment with current guidance.
3. Optional - nice-to-haves; prefix pure polish with Nit:.

Read-only review: produce the plan only; implement nothing unless explicitly asked afterwards.