zebbern Playwright Core Testing
Opinionated, production-tested Playwright guidance — every pattern includes when (and when not) to use it.
46 reference guides covering the full Playwright testing surface: selectors, assertions, fixtures, network mocking, auth, visual regression, accessibility, API testing, debugging, and more — with TypeScript and JavaScript examples throughout.
Golden Rules
getByRole()over CSS/XPath — resilient to markup changes, mirrors how users see the page- Never
page.waitForTimeout()— useexpect(locator).toBeVisible()orpage.waitForURL() - Web-first assertions —
expect(locator)auto-retries;expect(await locator.textContent())does not - Isolate every test — no shared state, no execution-order dependencies
baseURLin config — zero hardcoded URLs in tests- Retries:
2in CI,0locally — surface flakiness where it matters - Traces:
'on-first-retry'— rich debugging artifacts without CI slowdown - Fixtures over globals — share state via
test.extend(), not module-level variables - One behavior per test — multiple related
expect()calls are fine - Mock external services only — never mock your own app; mock third-party APIs, payment gateways, email
Guide Index
Writing Tests
| What you're doing | Guide | Deep dive |
|---|---|---|
| Choosing selectors | locators.md | locator-strategy.md |
| Assertions & waiting | assertions-and-waiting.md | |
| Organizing test suites | test-organization.md | test-architecture.md |
| Playwright config | configuration.md | |
| Fixtures & hooks | fixtures-and-hooks.md | |
| Test data | test-data-management.md | |
| Auth & login | authentication.md | auth-flows.md |
| API testing (REST/GraphQL) | api-testing.md | |
| Visual regression | visual-regression.md | |
| Accessibility | accessibility.md | |
| Mobile & responsive | mobile-and-responsive.md | |
| Component testing | component-testing.md | |
| Network mocking | network-mocking.md | when-to-mock.md |
| Forms & validation | forms-and-validation.md | |
| File uploads/downloads | file-operations.md | file-upload-download.md |
| Error & edge cases | error-and-edge-cases.md | |
| CRUD flows | crud-testing.md | |
| Drag and drop | drag-and-drop.md | |
| Search & filter UI | search-and-filter.md |
Debugging & Fixing
| Problem | Guide |
|---|---|
| General debugging workflow | debugging.md |
| Specific error message | error-index.md |
| Flaky / intermittent tests | flaky-tests.md |
| Common beginner mistakes | common-pitfalls.md |
Framework Recipes
| Framework | Guide |
|---|---|
| Next.js (App Router + Pages Router) | nextjs.md |
| React (CRA, Vite) | react.md |
| Vue 3 / Nuxt | vue.md |
| Angular | angular.md |
Specialized Topics
| Topic | Guide |
|---|---|
| Multi-user & collaboration | multi-user-and-collaboration.md |
| WebSockets & real-time | websockets-and-realtime.md |
| Browser APIs (geo, clipboard, permissions) | browser-apis.md |
| iframes & Shadow DOM | iframes-and-shadow-dom.md |
| Canvas & WebGL | canvas-and-webgl.md |
| Service workers & PWA | service-workers-and-pwa.md |
| Electron apps | electron-testing.md |
| Browser extensions | browser-extensions.md |
| Security testing | security-testing.md |
| Performance & benchmarks | performance-testing.md |
| i18n & localization | i18n-and-localization.md |
| Multi-tab & popups | multi-context-and-popups.md |
| Clock & time mocking | clock-and-time-mocking.md |
| Third-party integrations | third-party-integrations.md |
Architecture Decisions
| Question | Guide |
|---|---|
| Which locator strategy? | locator-strategy.md |
| E2E vs component vs API? | test-architecture.md |
| Mock vs real services? | when-to-mock.md |