Vitest
Vitest fast unit testing framework powered by Vite with Jest-compatible API.
Install
npx skills add antfu/skills --skill vitest -g -a claude-code -y- Repository
- antfu/skills6k
- Category
- Testing
- Updated
- 5d ago
- License
- MIT
- Context cost
- Lightabout 834 tokens
- Runs scripts
- No, instructions only
What it does
Vitest fast unit testing framework powered by Vite with Jest-compatible API. Use when writing tests, mocking, configuring coverage, or working with test filtering and fixtures.
Vitest is a next-generation testing framework powered by Vite. It provides a Jest-compatible API with native ESM, TypeScript, and JSX support out of the box. Vitest shares the same config, transformers, resolvers, and plugins with your Vite app.
Key Features:
- Vite-native: Uses Vite's transformation pipeline for fast HMR-like test updates
- Jest-compatible: Drop-in replacement for most Jest test suites
- Smart watch mode: Only reruns affected tests based on module graph
- Native ESM, TypeScript, JSX support without configuration
- Multi-threaded workers for parallel test execution
- Built-in coverage via V8 or Istanbul
- Snapshot testing, mocking, and spy utilities
The skill is based on Vitest 5.1.0-beta.1, generated at 2026-10-23.
Core
| Topic | Description | Reference |
|---|---|---|
| Configuration | Vitest and Vite config integration, defineConfig usage | core-config |
| CLI | Command line interface, commands and options | core-cli |
| Test API | test/it function, modifiers like skip, only, concurrent | core-test-api |
| Describe API | describe/suite for grouping tests and nested suites | core-describe |
| Expect API | Assertions with toBe, toEqual, matchers and asymmetric matchers | core-expect |
| Hooks | beforeEach, afterEach, beforeAll, afterAll, aroundEach | core-hooks |
