Playwright Best Practices

This skill provides comprehensive guidance for all aspects of Playwright test development, from writing new tests to debugging and maintaining existing test suites.

Activity-Based Reference Guide

Consult these references based on what you’re doing:

Writing New Tests

When to use: Creating new test files, writing test cases, implementing test scenarios

Mobile & Responsive Testing

When to use: Testing mobile devices, touch interactions, responsive layouts

Real-Time & Browser APIs

When to use: Testing WebSockets, geolocation, permissions, multi-tab flows

Debugging & Troubleshooting

When to use: Test failures, element not found, timeouts, unexpected behavior

Error & Edge Case Testing

When to use: Testing error states, offline mode, network failures, validation

Multi-User & Collaboration Testing

When to use: Testing features involving multiple users, roles, or real-time collaboration

Refactoring & Maintenance

When to use: Improving existing tests, code review, reducing duplication

Infrastructure & Configuration

When to use: Setting up projects, configuring CI/CD, optimizing performance

Advanced Patterns

When to use: Complex scenarios, API mocking, network interception

Quick Decision Tree

What are you doing?
│
├─ Writing a new test?
│  ├─ E2E test → test-organization.md, locators.md, assertions-waiting.md
│  ├─ Component test → component-testing.md
│  ├─ API test → test-organization.md, assertions-waiting.md
│  ├─ Visual/canvas test → canvas-webgl.md, test-organization.md
│  ├─ Accessibility test → accessibility.md
│  ├─ Mobile/responsive test → mobile-testing.md
│  ├─ i18n/locale test → i18n.md
│  ├─ Electron app test → electron.md
│  ├─ Browser extension test → browser-extensions.md
│  └─ Multi-user test → multi-user.md
│
├─ Testing specific features?
│  ├─ File upload/download → file-operations.md
│  ├─ Date/time dependent → clock-mocking.md
│  ├─ WebSocket/real-time → websockets.md
│  ├─ Geolocation/permissions → browser-apis.md
│  ├─ OAuth/SSO mocking → third-party.md, multi-context.md
│  ├─ Payments/email/SMS → third-party.md
│  ├─ iFrames → iframes.md
│  ├─ Canvas/WebGL/charts → canvas-webgl.md
│  ├─ Service workers/PWA → service-workers.md
│  ├─ i18n/localization → i18n.md
│  ├─ Security (XSS, CSRF) → security-testing.md
│  └─ Performance/Web Vitals → performance-testing.md
│
├─ Test is failing/flaky?
│  ├─ Flaky test investigation → flaky-tests.md
│  ├─ Element not found → locators.md, debugging.md
│  ├─ Timeout issues → assertions-waiting.md, debugging.md
│  ├─ Race conditions → flaky-tests.md, debugging.md
│  ├─ Flaky only with multiple workers → flaky-tests.md, performance.md
│  ├─ State leak / isolation → flaky-tests.md, fixtures-hooks.md
│  ├─ Console/JS errors → console-errors.md, debugging.md
│  └─ General debugging → debugging.md
│
├─ Testing error scenarios?
│  ├─ Network failures → error-testing.md, network-advanced.md
│  ├─ Offline (unexpected) → error-testing.md
│  ├─ Offline-first/PWA → service-workers.md
│  ├─ Error boundaries → error-testing.md
│  └─ Form validation → error-testing.md
│
├─ Refactoring existing code?
│  ├─ Implementing POM → page-object-model.md
│  ├─ Improving selectors → locators.md
│  ├─ Extracting fixtures → fixtures-hooks.md
│  └─ Creating data factories → test-data.md
│
├─ Setting up infrastructure?
│  ├─ CI/CD → ci-cd.md
│  ├─ Global setup/teardown → global-setup.md
│  ├─ Project dependencies → projects-dependencies.md
│  ├─ Test performance → performance.md
│  ├─ Test coverage → test-coverage.md
│  └─ Project config → test-organization.md, projects-dependencies.md
│
└─ Organizing tests?
   ├─ Skip/fixme/slow tests → annotations.md
   ├─ Test steps → annotations.md
   └─ Conditional execution → annotations.md

Test Validation Loop

After writing or modifying tests:

1. Run tests: npx playwright test --reporter=list
2. If tests fail:
   • Review error output and trace (npx playwright show-trace)
   • Fix locators, waits, or assertions
   • Re-run tests
3. Only proceed when all tests pass
4. Run multiple times for critical tests: npx playwright test --repeat-each=5