vitest

name	vitest
description	Vitest configuration, mocking, coverage, snapshot testing, and performance.
allowed-tools	Read, Write, Edit, Bash, Glob, Grep
graph	{"domains":["domain:web-development"],"specializations":["specialization:web-development"],"skillAreas":["skill-area:react-testing","skill-area:unit-testing"],"roles":["role:frontend-engineer","role:qa-engineer"],"topics":["topic:test-driven-development"]}

Vitest Skill

Expert assistance for unit and integration testing with Vitest.

Capabilities

• Configure Vitest for projects
• Write unit and integration tests
• Implement mocking strategies
• Configure coverage reporting
• Optimize test performance

Test Patterns

import { describe, it, expect, vi, beforeEach } from 'vitest';
import { render, screen } from '@testing-library/react';
import { UserService } from './user.service';

describe('UserService', () => {
  const mockDb = { user: { findMany: vi.fn() } };

  beforeEach(() => {
    vi.clearAllMocks();
  });

  it('should fetch users', async () => {
    mockDb.user.findMany.mockResolvedValue([{ id: '1', name: 'John' }]);

    const service = new UserService(mockDb);
    const users = await service.findAll();

    expect(users).toHaveLength(1);
    expect(mockDb.user.findMany).toHaveBeenCalledOnce();
  });
});

Configuration

// vitest.config.ts
export default defineConfig({
  test: {
    globals: true,
    environment: 'jsdom',
    coverage: {
      provider: 'v8',
      reporter: ['text', 'html'],
    },
  },
});

Target Processes

• unit-testing
• react-testing
• tdd-development