name: testing description: Comprehensive testing skill for validating code changes. Covers unit testing (Vitest, Jest), integration testing, E2E testing (Playwright, Cypress), component testing, mocking (MSW, vi.mock), async/hook testing, CI/CD integration, and code coverage. Use after code changes or code-executor to ensure quality. license: MIT version: 1.0.0

Testing Skill

Validate code changes with 2025-2026 testing best practices.

When to Use

• After code changes or code-executor completes
• Before committing or pushing code
• When adding new features or fixing bugs
• During code review validation

Quick Decision Matrix

Testing Pyramid

Core Principles

1. Test behavior, not implementation
2. Arrange-Act-Assert (AAA) pattern
3. Fast, isolated, repeatable tests
4. Mock external dependencies
5. CI/CD integration mandatory

Reference Files

Quick Validation Checklist

[ ] Run unit tests: npm test
[ ] Run integration tests: npm run test:integration
[ ] Check coverage: npm run test:coverage
[ ] Run E2E (critical paths): npm run test:e2e
[ ] Verify CI pipeline passes

Quick Start

import { describe, it, expect, vi } from 'vitest';

describe('MyFunction', () => {
  it('returns expected result', () => {
    // Arrange
    const input = 'test';
    // Act
    const result = myFunction(input);
    // Assert
    expect(result).toBe('expected');
  });
});

Resources

• Vitest: https://vitest.dev/
• Testing Library: https://testing-library.com/
• Playwright: https://playwright.dev/
• MSW: https://mswjs.io/