AgentSkillsCN

vitest

在编写或修改Vitest测试时使用，遵循测试结构、断言、模拟和覆盖率的最佳实践。

SKILL.md
--- frontmatter
name: vitest
# prettier-ignore
description: Use when writing or modifying Vitest tests to follow best practices for test structure, assertions, mocking, and coverage

Vitest Testing

Quick Start

typescript
import { describe, it, expect, vi, beforeEach } from 'vitest';

describe('MyModule', () => {
  beforeEach(() => {
    vi.clearAllMocks();
  });

  it('should handle basic case', () => {
    expect(myFunction('input')).toBe('expected');
  });

  it('should throw on invalid input', () => {
    expect(() => myFunction(null)).toThrow('Invalid input');
  });
});

Core Patterns

  • •Structure: describe for grouping, it for individual tests
  • •Assertions: expect(value).toBe(), .toEqual(), .toMatchObject(), .toThrow()
  • •Async: async/await or return Promise; use vi.waitFor() for polling
  • •Mocking: vi.fn(), vi.spyOn(), vi.mock('module')
  • •Setup/Teardown: beforeEach, afterEach, beforeAll, afterAll
  • •Snapshots: expect(value).toMatchSnapshot(), update with -u flag

Best Practices

  • •One assertion concept per test (multiple expects OK if testing same behavior)
  • •Use descriptive test names: "should [action] when [condition]"
  • •Avoid test interdependence; each test should be isolated
  • •Mock external dependencies (APIs, file system, time)
  • •Use vi.useFakeTimers() for time-dependent tests

Reference Files