playwright-core

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

1. getByRole() over CSS/XPath — resilient to markup changes, mirrors how users see the page
2. Never page.waitForTimeout() — use expect(locator).toBeVisible() or page.waitForURL()
3. Web-first assertions — expect(locator) auto-retries; expect(await locator.textContent()) does not
4. Isolate every test — no shared state, no execution-order dependencies
5. baseURL in config — zero hardcoded URLs in tests
6. Retries: 2 in CI, 0 locally — surface flakiness where it matters
7. Traces: 'on-first-retry' — rich debugging artifacts without CI slowdown
8. Fixtures over globals — share state via test.extend(), not module-level variables
9. One behavior per test — multiple related expect() calls are fine
10. 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](locators.md) | [locator-strategy.md](locator-strategy.md) |

| Assertions & waiting | [assertions-and-waiting.md](assertions-and-waiting.md) | |

| Organizing test suites | [test-organization.md](test-organization.md) | [test-architecture.md](test-architecture.md) |

| Playwright config | [configuration.md](configuration.md) | |

| Fixtures & hooks | [fixtures-and-hooks.md](fixtures-and-hooks.md) | |

| Test data | [test-data-management.md](test-data-management.md) | |

| Auth & login | [authentication.md](authentication.md) | [auth-flows.md](auth-flows.md) |

| API testing (REST/GraphQL) | [api-testing.md](api-testing.md) | |

| Visual regression | [visual-regression.md](visual-regression.md) | |

| Accessibility | [accessibility.md](accessibility.md) | |

| Mobile & responsive | [mobile-and-responsive.md](mobile-and-responsive.md) | |

| Component testing | [component-testing.md](component-testing.md) | |

| Network mocking | [network-mocking.md](network-mocking.md) | [when-to-mock.md](when-to-mock.md) |

| Forms & validation | [forms-and-validation.md](forms-and-validation.md) | |

| File uploads/downloads | [file-operations.md](file-operations.md) | [file-upload-download.md](file-upload-download.md) |

| Error & edge cases | [error-and-edge-cases.md](error-and-edge-cases.md) | |

| CRUD flows | [crud-testing.md](crud-testing.md) | |

| Drag and drop | [drag-and-drop.md](drag-and-drop.md) | |

| Search & filter UI | [search-and-filter.md](search-and-filter.md) | |

Debugging & Fixing

| Problem | Guide |

| -------------------------- | ---------------------------------------- |

| General debugging workflow | [debugging.md](debugging.md) |

| Specific error message | [error-index.md](error-index.md) |

| Flaky / intermittent tests | [flaky-tests.md](flaky-tests.md) |

| Common beginner mistakes | [common-pitfalls.md](common-pitfalls.md) |

Framework Recipes

| Framework | Guide |

| ----------------------------------- | ------------------------ |

| Next.js (App Router + Pages Router) | [nextjs.md](nextjs.md) |

| React (CRA, Vite) | [react.md](react.md) |

| Vue 3 / Nuxt | [vue.md](vue.md) |

| Angular | [angular.md](angular.md) |

Specialized Topics

| Topic | Guide |

| ------------------------------------------ | ------------------------------------------------------------------ |

| Multi-user & collaboration | [multi-user-and-collaboration.md](multi-user-and-collaboration.md) |

| WebSockets & real-time | [websockets-and-realtime.md](websockets-and-realtime.md) |

| Browser APIs (geo, clipboard, permissions) | [browser-apis.md](browser-apis.md) |

| iframes & Shadow DOM | [iframes-and-shadow-dom.md](iframes-and-shadow-dom.md) |

| Canvas & WebGL | [canvas-and-webgl.md](canvas-and-webgl.md) |

| Service workers & PWA | [service-workers-and-pwa.md](service-workers-and-pwa.md) |

| Electron apps | [electron-testing.md](electron-testing.md) |

| Browser extensions | [browser-extensions.md](browser-extensions.md) |

| Security testing | [security-testing.md](security-testing.md) |

| Performance & benchmarks | [performance-testing.md](performance-testing.md) |

| i18n & localization | [i18n-and-localization.md](i18n-and-localization.md) |

| Multi-tab & popups | [multi-context-and-popups.md](multi-context-and-popups.md) |

| Clock & time mocking | [clock-and-time-mocking.md](clock-and-time-mocking.md) |

| Third-party integrations | [third-party-integrations.md](third-party-integrations.md) |

Architecture Decisions

| Question | Guide |

| ------------------------ | -------------------------------------------- |

| Which locator strategy? | [locator-strategy.md](locator-strategy.md) |

| E2E vs component vs API? | [test-architecture.md](test-architecture.md) |

| Mock vs real services? | [when-to-mock.md](when-to-mock.md) |