Testing Patterns & Strategies

Comprehensive guide to testing JavaScript/TypeScript applications. Complements the tdd skill (which focuses on workflow) by providing concrete patterns, strategies, and anti-patterns.

When to Use This Skill

Activate when the user:

• Wants to write tests for existing or new code
• Needs to establish a testing strategy for a project
• Wants to improve test coverage or reliability
• Has flaky or brittle tests
• Asks about mocking, stubbing, or test doubles
• Needs guidance on unit vs integration vs E2E tests

Testing Pyramid