Unit testing with Vitest

This skill provides patterns and conventions for writing comprehensive unit tests in TypeScript projects using Vitest.

When to use this skill

• Writing unit tests for TypeScript utilities, services, or API clients
• Testing stores (Pinia, Zustand, etc.)
• Testing API transforms and services
• Adding test coverage to existing code
• Debugging failing tests

Test file structure

Location and naming

• Place tests in __tests__/ directory next to the file being tested
• Name test files with .test.ts suffix matching the source file name
• Example: config.ts → __tests__/config.test.ts