authoring-tests

# Authoring Tests You MUST review @projects/site/src/docs/internal/guidelines/testing.md before making any testing changes. ## When to Use This Skill - Creating new test files for components (`.test.ts`, `.test.axe.ts`, `.test.visual.ts`, `.test.ssr.ts`, `.test.lighthouse.ts`) - Debugging test failures or updating existing tests - Understanding testing utilities from `@internals/testing` - Setting up test configurations or HTML templates - Writing tests that follow project patterns ## Test Type Guidelines Read the specific guideline based on the test type you're working with: - **Unit Tests (`.test.ts`)**: Read [testing-unit.md](/projects/site/src/docs/internal/guidelines/testing-unit.md) - covers `createFixture`, `elementIsStable`, event testing - **Accessibility Tests (`.test.axe.ts`)**: Read [testing-accessibility.md](/projects/site/src/docs/internal/guidelines/testing-accessibility.md) - covers axe-core usage, WCAG compliance - **Visual Tests (`.test.visual.ts`)**: Read [testing-visual.md](/projects/site/src/docs/internal/guidelines/testing-visual.md) - covers Playwright screenshots, theme testing - **SSR Tests (`.test.ssr.ts`)**: Read [testing-ssr.md](/projects/site/src/docs/internal/guidelines/testing-ssr.md) - covers server-side rendering compatibility - **Lighthouse Tests (`.test.lighthouse.ts`)**: Read [testing-lighthouse.md](/projects/site/src/docs/internal/guidelines/testing-lighthouse.md) - covers performance, accessibility scores ## Key Principles 1. **Test Isolation**: Each test should be independent with proper setup/teardown using `createFixture` and `removeFixture` 2. **Wait for Stability**: Always use `elementIsStable()` before making assertions on Lit components 3. **Comprehensive Coverage**: All new components require unit, accessibility, and visual tests at minimum 4. **Real User Events**: Use `emulateClick` and `untilEvent` for realistic event testing 5. **Theme Testing**: Visual tests should cover both light and dark themes ## References - [Testing Overview](/projects/site/src/docs/internal/guidelines/testing.md) - [Unit Testing](/projects/site/src/docs/internal/guidelines/testing-unit.md) - [Accessibility Testing](/projects/site/src/docs/internal/guidelines/testing-accessibility.md) - [Lighthouse Testing](/projects/site/src/docs/internal/guidelines/testing-lighthouse.md) - [SSR Testing](/projects/site/src/docs/internal/guidelines/testing-ssr.md) - [Visual Testing](/projects/site/src/docs/internal/guidelines/testing-visual.md) - [Vite Internals](/projects/internals/vite/README.md)