Vitest Skill

Generates Vitest tests in JavaScript/TypeScript with Vite-native speed. Jest-compatible API with ESM support and HMR. Use when user mentions "Vitest", "vi.mock", "vitest.config". Triggers on: "Vitest", "vi.mock", "vi.fn", "Vite test", "vitest config".

386 stars 76 forksTesting & QAOfficial

Install

skills CLI (Claude Code, Cursor, Codex and more)

npx skills add LambdaTest/agent-skills --skill vitest-skill

Manual install

git clone --depth 1 https://github.com/LambdaTest/agent-skills.git /tmp/agent-skills
mkdir -p ~/.claude/skills
cp -r /tmp/agent-skills/vitest-skill ~/.claude/skills/vitest-skill

Personal skills live in ~/.claude/skills. Use .claude/skills in a project folder to share a skill with your team.

From the SKILL.md

# Vitest Testing Skill

## Core Patterns

### Basic Test

```typescript
import { describe, it, expect, vi, beforeEach } from 'vitest';
import { Calculator } from './calculator';

describe('Calculator', () => {
  let calc: Calculator;
  beforeEach(() => { calc = new Calculator(); });

  it('adds two numbers', () => {
    expect(calc.add(2, 3)).toBe(5);
  });

  it('throws on divide by zero', () => {
    expect(() => calc.divide(10, 0)).toThrow();
  });
});
```

### Mocking (vi instead of jest)

```typescript
import { vi } from 'vitest';

// Mock module
vi.mock('./database', () => ({
  getUser: vi.fn().mockResolvedValue({ name: 'Alice' }),
  saveUser: vi.fn().mockResolvedValue(true),
}));

// Mock function
const mockFn = vi.fn();
mockFn.mockReturnValue(42);
mockFn.mockResolvedValue({ data: 'test' });

// Spy
const spy = vi.spyOn(console, 'log').mockImplementation(() => {});
expect(spy).toHaveBeenCalledWith('message');
spy.mockRestore();

// Timers
vi.useFakeTimers();
vi.advanceTimersByTime(1000);
vi.runAllTimers();
vi.useRealTimers();
```

### In-Source Testing

```typescript
// src/math.ts — tests alongside code!
export function add(a: number, b: number) { return a + b; }
export function multiply(a: number, b: number) { return a * b; }

if (import.meta.vitest) {
  const { it, expect } = import.meta.vitest;
  it('adds', () => { expect(add(2, 3)).toBe(5); });
  it('multiplies', () => { expect(multiply(3, 4)).toBe(12); });
}
```

### Snapshot Testing

Read the full skill on GitHub

Details

Skill name: vitest-skill
Repository: LambdaTest/agent-skills
Path: vitest-skill/SKILL.md
License: MIT
Repo updated: 30 October 2026
Listed in: VoltAgent/awesome-agent-skills

FAQ

What does the Vitest Skill skill do?

How do I install the Vitest Skill skill?

skills CLI (Claude Code, Cursor, Codex and more): npx skills add LambdaTest/agent-skills --skill vitest-skill. Skills go in ~/.claude/skills (personal) or .claude/skills (project), and Claude loads them automatically when a task matches the description.

Is Vitest Skill popular?

It lives in LambdaTest/agent-skills, which has 386 GitHub stars and 76 forks, and is included in 1 curated skill list.

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