testing_skill

Overview

This skill helps you write and manage tests using TDD with Pest (PHP), Vitest (React), pytest (Python), and Playwright (E2E). It focuses on feature tests, unit tests, component tests, visual regression, and improving test coverage. Use this skill when you want disciplined test-driven workflows and reliable test suites.

How this skill works

I guide you through a TDD feedback loop: write a failing test, implement the minimal change to pass, then refactor while keeping tests green. I provide concrete test patterns for Pest, Vitest, and pytest, and orchestrate visual testing with Playwright screenshots plus Vision AI analysis. After changes I always recommend running the validation commands to confirm suite status and coverage.

When to use it

• When adding new features and you want tests-first development
• When increasing or validating test coverage for critical modules
• When writing unit, integration, or component tests for backend or frontend
• When setting up visual regression tests for UI changes using Playwright
• When debugging or fixing flaky or failing tests

Best practices

• Follow the TDD loop: Red → Green → Refactor for every behavior
• Keep tests small and focused: one assertion per behavior where practical
• Use factories/fixtures and dependency injection to minimize brittle tests
• Record baseline screenshots for UI tests and compare after changes
• Run the full validation commands after changes (composer test, npm run test, pytest)

Example use cases

• Write feature tests for a Laravel PostController with Pest and database assertions
• Add unit tests for a Python service using pytest and parametrized edge cases
• Implement component tests for a React form using Vitest and user-event to simulate interactions
• Create Playwright visual regression: capture baseline, change UI, capture new screenshot, analyze differences with Vision AI
• Fix a failing test by reproducing failure, applying minimal fix, then running full test/coverage commands