Auto-Tests Backend

A Node.js + Express + TypeScript backend that generates unit tests for code using OpenAI's GPT-4o API.

Features

• 🧪 Generate unit tests for any programming language/framework
• 🤖 Powered by OpenAI GPT-4o for intelligent test generation
• 🚀 Fast and lightweight Express server
• 📝 Comprehensive error handling
• 🔒 Environment variable configuration
• 🌐 CORS enabled for frontend integration

Quick Start

1. Install Dependencies

npm install

2. Environment Setup

Copy the environment example file and add your OpenAI API key:

cp env.example .env

Edit .env and add your OpenAI API key:

OPENAI_API_KEY=your_actual_api_key_here

3. Development

# Start development server with hot reload
npm run dev

# Or build and run production
npm run build
npm start

The server will start on port 3000 (or the port specified in your .env file).

API Endpoints

POST /api/generate-tests

Generates unit tests for the provided code using the specified testing framework.

Request Body:

{
  "code": "function add(a, b) { return a + b; }",
  "framework": "jest"
}

Response:

{
  "tests": "describe('add function', () => {\n  test('should add two positive numbers', () => {\n    expect(add(2, 3)).toBe(5);\n  });\n});"
}

Error Responses:

• 400 - Missing or invalid parameters
• 401 - Invalid OpenAI API key
• 429 - Rate limit exceeded
• 500 - Server error or OpenAI API failure

GET /health

Health check endpoint to verify the server is running.

Supported Testing Frameworks

The backend can generate tests for any framework you specify. Common examples:

• Jest (JavaScript/TypeScript)
• Mocha (JavaScript)
• PyTest (Python)
• JUnit (Java)
• NUnit (.NET)

Project Structure

src/
├── index.ts          # Main server file
├── routes/
│   └── generateTests.ts  # Test generation endpoint
├── package.json      # Dependencies and scripts
├── tsconfig.json     # TypeScript configuration
└── env.example       # Environment variables template

Development

• TypeScript: Full type safety with strict mode enabled
• Hot Reload: Development server automatically restarts on file changes
• Error Handling: Comprehensive error handling for API failures and validation
• CORS: Enabled for frontend integration

Next Steps

1. Set up your OpenAI API key in the .env file
2. Start the development server with npm run dev
3. Test the endpoint with a tool like Postman or curl
4. Integrate with your frontend/extension

Example Usage

curl -X POST http://localhost:3000/api/generate-tests \
  -H "Content-Type: application/json" \
  -d '{
    "code": "function multiply(a, b) { return a * b; }",
    "framework": "jest"
  }'