plugin-test-coverage

name	plugin-test-coverage
description	Guides agents through expanding Vitest and Playwright e2e coverage for a monorepo plugin. Use when adding or improving plugin tests, wiring e2e-studio, or following the internationalized-array / document-internationalization coverage playbook.

Plugin Test Coverage

Use this skill when expanding Vitest and/or Playwright e2e coverage for a plugin under plugins/.

Reference implementations:

• @sanity/document-internationalization — Vitest + e2e under e2e/tests/document-internationalization/
• sanity-plugin-internationalized-array — Vitest + e2e under e2e/tests/internationalized-array/

Also read e2e/README.md before writing Playwright specs.

When to use

• Filling unit/integration gaps for a published plugin
• Wiring a plugin into dev/e2e-studio and adding Playwright specs
• Porting the doc-i18n / internationalized-array coverage process to another plugin

Workflow

1. Inventory use cases from README + source (authoring loops, config knobs, integrations).
2. Map each use case to Vitest (pure logic, components with mocks) vs Playwright (studio UX that needs a real form).
3. Fill Vitest gaps co-located under plugins/<pkg>/src/ — plugin assembly, context/providers, utils, components.
4. Wire e2e-studio — definePlugin example file, register in both chromium/firefox workspaces.
5. Add helpers + specs — e2e/helpers/<plugin>/, e2e/tests/<plugin>/.
6. Changesets — separate patch changeset per published package that gained data-testids or runtime changes. Private e2e/studio files need none.
7. Verify — pnpm format && pnpm lint && pnpm knip && pnpm build && pnpm test (and targeted e2e when secrets allow).
8. PR — draft, 🤖 bot label, inventory + e2e test table in the description.

Skip one-off tooling (migrations, banners) unless they are part of the main authoring loop.

Vitest patterns

• Co-locate *.test.ts(x) next to source; use jsdom via the package vitest.config.ts.
• Shared mocks/fixtures in src/test/helpers.ts and src/test/component-helpers.tsx (ThemeWrapper for @sanity/ui).
• Plugin assembly tests: call the plugin factory, assert schema type names, document layout, form input wrappers, nested plugins.
• Context/provider tests: mock useClient / useWorkspace / pane hooks; use Suspense + act for async React.use language resolution; call any module-level clear() between tests.
• Timeouts: test('name', {timeout: 30_000}, async () => { … }) — options object as second arg.
• Keep the package-exports snapshot test; update with pnpm test -u only when exports intentionally change.
• React Compiler is on — do not add unnecessary useMemo / useCallback.

Run a single package:

pnpm --filter <package-name> test run

E2e structure

e2e/
├── tests/
│   ├── smoke.spec.ts                 # studio-wide only
│   └── <plugin-name>/
│       └── <plugin-name>.spec.ts
└── helpers/
    └── <plugin-name>/
        └── <helpers>.ts

Do not dump plugin specs at the top level of tests/.

E2e-studio wiring

1. Add dev/e2e-studio/src/<example>.ts with definePlugin that registers schema + the plugin under test.
2. Import and add it to both workspaces in dev/e2e-studio/sanity.config.ts.
3. Ensure the workspace package.json already depends on the plugin (workspace:*).
4. Update the “Currently wired” list in e2e/README.md.

Hard-won Playwright lessons

• Project baseURL must end with a trailing slash (…/chromium/, …/firefox/).
• Navigate with relative intents: intent/edit/id=…;type=…. Never host-absolute /intent/… (drops workspace basePath → “Workspace not found”).
• Auth: Playwright storageState seeds __studio_auth_token_<projectId>; preflight /users/me. Never use SANITY_DEPLOY_TOKEN for e2e session auth.
• Local pitfall: stale server on :3333 + reuseExistingServer → signed-out studio. Kill and restart.
• Prefer accessible role/name locators; add data-testid + a patch changeset only when selectors are flaky or ambiguous (e.g. duplicate add-button grids).
• Seed documents via the Content Lake API; always try/finally cleanup.
• Video: SANITY_E2E_VIDEO=on when debugging.
• Document existence matters: some plugins only auto-seed after _rev exists — seed empty persisted docs, don’t rely on brand-new unsaved drafts.

PR checklist

• Separate changeset per published package touched
• Draft PR with 🤖 bot label
• Use-case inventory + e2e test table in the description
• pnpm format / lint / knip / build / test green
• CI e2e (chromium + firefox) green when studio wiring changed

Pointers

• e2e/README.md
• AGENTS.md — CI commands, changesets, Node version notes
• Doc-i18n + internationalized-array as living examples