Unit Testing

No, this skill is strictly focused on unit testing for isolated logic and utility functions. For testing UI components, database integrations, or full user flows, you should use specialized integration or End-to-End (E2E) skills.

This skill equips Claude with the ability to implement professional Test-Driven Development (TDD) workflows. It automates the setup of Vitest, creates standardized test structures for TypeScript and Next.js, and provides specialized patterns for mocking and Zod validation.

The skill includes patterns for Zod schema validation (using safeParse), async function testing, mocking dependencies with Vitest globals, and structured 'describe' blocks that separate valid inputs from edge cases and error handling.

You should activate this skill whenever you need to add test coverage, set up a new testing environment with Vitest, create utility functions using TDD, or refactor existing code while ensuring logic remains intact through the Red-Green-Refactor cycle.

It eliminates manual boilerplate by automatically generating configuration files (like vitest.config.mts) and scripts. It also enforces a quality assurance checklist that ensures edge cases, error handling, and independent test states are always considered.