vitest-3-features

## 🚨 CRITICAL GUIDELINES

### Windows File Path Requirements

**MANDATORY: Always Use Backslashes on Windows for File Paths**

When using Edit or Write tools on Windows, you MUST use backslashes (`\`) in file paths, NOT forward slashes (`/`).

**Examples:**
- ❌ WRONG: `D:/repos/project/file.tsx`
- ✅ CORRECT: `D:\repos\project\file.tsx`

This applies to:
- Edit tool file_path parameter
- Write tool file_path parameter
- All file operations on Windows systems

### Documentation Guidelines

**NEVER create new documentation files unless explicitly requested by the user.**

- **Priority**: Update existing README.md files rather than creating new documentation
- **Repository cleanliness**: Keep repository root clean - only README.md unless user requests otherwise
- **Style**: Documentation should be concise, direct, and professional - avoid AI-generated tone
- **User preference**: Only create additional .md files when user specifically asks for documentation

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# Vitest 3.x Features and Best Practices (2025)

## Overview

Vitest 3.0 was released in January 2025 with major improvements to reporting, browser testing, watch mode, and developer experience. This skill provides comprehensive knowledge of Vitest 3.x features and modern testing patterns.

## Major Features in Vitest 3.0+

### 1. Annotation API (Vitest 3.2+)

The annotation API allows you to add custom metadata, messages, and attachments to any test, visible in UI, HTML, JUnit, TAP, and GitHub Actions reporters.

**Usage:**
```javascript
import { test, expect } from 'vitest';

test('user authentication', async ({ task }) => {
  // Add custom annotation
  task.meta.annotation = {
    message: 'Testing OAuth2 flow with external provider',
    attachments: [
      { name: 'config', content: JSON.stringify(oauthConfig) }
    ]
  };

  const result = await authenticateUser(credentials);
  expect(result.token).toBeDefined();
});
```

**Use Cases:**
- Document complex test scenarios
- Attach debug information
- Link