Playwright Testing Best Practices

Description

This skill teaches WHAT makes good tests and WHY certain patterns prevent failures. Provides the decision-making framework behind test structure, locator selection, assertion strategies, and debugging approaches. Works in conjunction with playwright-cli skill (which teaches HOW to execute commands). Apply when planning test strategy, choosing between ARIA snapshots vs individual locators, structuring assertions, debugging test failures, reviewing test code, or advising on test architecture. Emphasizes ARIA snapshot testing for structural validation, user-visible behavior testing, locator resilience hierarchy, web-first assertion patterns, test isolation principles, and production-proven debugging strategies.

Core Testing Philosophy

Test User-Visible Behavior

Principle: Tests should verify what end users experience, not implementation details.

Rules:

• Focus on rendered output that users can see and interact with
• Avoid testing internal function names, data structures, or CSS class names
• Test the same interface that users experience
• Don't assert on implementation details that could change without affecting user experience