Test Code Generator MCP Server

An MCP server that generates Vitest test code based on boundary value analysis and equivalence partitioning from JSON specifications.

Features

• Boundary Value Analysis: Automatically generates boundary values and their adjacent values for continuous ranges
• Multiple Range Support: Handles discontinuous valid ranges (e.g., 0-10, 20-30, 40-50)
• Equivalence Partitioning: Includes all valid and invalid values from categorical data
• Pairwise Testing: Generates efficient test combinations using pairwise method
• Vitest Format: Generates clean test code using test.each pattern
• Specification Guide: Provides prompts to help create JSON specifications
• Language-Optimized: All processing and output in English for optimal LLM performance

Quick Start

Using npx (No installation required)

# Run directly with npx
npx @test-generator/mcp-vitest

# Configure Claude Desktop as shown below

See QUICKSTART.md for detailed setup instructions.

Installation

Using npx (Recommended)

npx testing-mcp-vitest

Local Installation

# Clone repository
git clone <repository-url>
cd test-code-generator-mcp

# Install dependencies
npm install

# Build
npm run build

Usage

Claude Desktop Configuration

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "test-generator": {
      "command": "npx",
      "args": ["testing-mcp-vitest"]
    }
  }
}

Config file locations:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

Available Tools

1. generate-test-code

Generates test code from JSON specification.

2. Prompts

• create-test-spec: Explains how to create test specifications
• boundary-value-example: Provides boundary value analysis examples
• equivalence-class-example: Provides equivalence partitioning examples

Specification Format

Basic structure with single range:

{
  "type": "model",
  "name": "UserRegistration",
  "columns": [
    {
      "name": "age",
      "type": "number",
      "valueType": "continues",
      "values": {
        "min": 18,
        "max": 120
      }
    },
    {
      "name": "userType",
      "type": "string",
      "valueType": "category",
      "values": {
        "valid": ["admin", "user", "guest"],
        "invalid": ["superuser", "root", ""]
      }
    }
  ]
}

Multiple ranges example:

{
  "name": "workHours",
  "type": "number",
  "valueType": "continues",
  "values": {
    "ranges": [
      { "min": 9, "max": 12 },   // Morning shift
      { "min": 14, "max": 18 }   // Afternoon shift
    ]
  }
}

Generated Test Code Example

import { describe, test, expect } from 'vitest';

describe('Tests for UserRegistration', () => {
  // Valid cases
  test.each([
    { inputs: { age: 18, userType: "admin" }, description: 'Combination 1: Valid case' },
    { inputs: { age: 69, userType: "user" }, description: 'Combination 2: Valid case' },
    { inputs: { age: 120, userType: "guest" }, description: 'Combination 3: Valid case' },
    // ... more test cases
  ])('Valid case: $description', ({ inputs }) => {
    // TODO: Import the function or model to test
    // import { UserRegistration } from './path/to/UserRegistration';

    // TODO: Execute the test subject
    // const result = UserRegistration(inputs);

    // TODO: Check expected values
    // expect(result).toBeDefined();
    // expect(result.error).toBeUndefined();
  });

  // Invalid cases
  test.each([
    { inputs: { age: 17, userType: "admin" }, description: 'Combination 4: Invalid case' },
    { inputs: { age: 121, userType: "user" }, description: 'Combination 5: Invalid case' },
    { inputs: { age: 50, userType: "superuser" }, description: 'Combination 6: Invalid case' },
    { inputs: { age: 50, userType: "root" }, description: 'Combination 7: Invalid case' },
    { inputs: { age: 50, userType: "" }, description: 'Combination 8: Invalid case' },
    // ... more test cases
  ])('Invalid case: $description', ({ inputs }) => {
    // TODO: Import the function or model to test
    // import { UserRegistration } from './path/to/UserRegistration';

    // TODO: Verify that an error occurs
    // expect(() => UserRegistration(inputs)).toThrow();
    // or
    // const result = UserRegistration(inputs);
    // expect(result.error).toBeDefined();
  });
});

Key Features

Full Coverage

• All valid and invalid equivalence class values are included in test cases
• Boundary values include: min-1, min, min+1, middle, max-1, max, max+1
• For multiple ranges, includes gap values between ranges

Efficient Combinations

• 3 or fewer parameters: generates all combinations
• 4 or more parameters: uses pairwise method for efficiency

Multiple Range Support

Useful for:

• Working hours (9-12, 14-18)
• Valid scores (0-40 passing, 60-100 honors)
• Temperature ranges (different valid ranges for different conditions)
• Time slots (morning, afternoon, evening sessions)

Examples

See the examples/ directory for more specification examples:

• user-registration.json - Basic model validation
• calculate-discount.json - Business logic with multiple parameters
• multi-range-validation.json - Complex scheduling with multiple ranges
• japanese-postal-code.json - Regional validation patterns

Development

# Development mode
npm run dev

# Build
npm run build

# Production mode
npm start

# Debug mode
DEBUG=1 npm start

Publishing to npm

# Build and publish
npm publish

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

MIT - see LICENSE for details

Support

• GitHub Issues: [Report bugs or request features](/issues)
• Discussions: [Ask questions or share ideas](/discussions)