MCP Server E2e Testing Example

🚀 MCP Server E2E Testing Example

A minimal demonstration repository showcasing two modes of end-to-end (E2E) testing for a TypeScript MCP (Model Context Protocol) server using Vitest:

• Raw Method: Spawn the CLI via tsx and communicate (JSON-RPC) through stdio.
• SDK Method: Use the Client and InMemoryTransport of the official MCP SDK for in-memory RPC.

Repository URL: https://github.com/mkusaka/mcp-server-e2e-testing-example

🚀 Quick Start

Prerequisites

• Node.js ≥ 16
• pnpm installed globally
• Git

Installation

# Clone the repository
git clone https://github.com/mkusaka/mcp-server-e2e-testing-example.git
cd mcp-server-e2e-testing-example

# Install dependencies
pnpm install

✨ Features

This project demonstrates two different ways to conduct E2E tests on an MCP server:

• Raw Method: It spawns the CLI using tsx and communicates through stdio with JSON-RPC.
• SDK Method: Utilizes the official MCP SDK's Client and InMemoryTransport for in-memory RPC.

📦 Installation

# Clone the repository
git clone https://github.com/mkusaka/mcp-server-e2e-testing-example.git
cd mcp-server-e2e-testing-example

# Install dependencies
pnpm install

💻 Usage Examples

Basic Usage

1. Raw (spawn + stdio) Test

This test suite spawns the CLI (src/cli.ts) via npx tsx and sends JSON-RPC through stdin/stdout.

pnpm vitest run tests/e2e/raw.spec.ts

2. SDK (In-memory) Test

This test suite uses the Client + InMemoryTransport of the MCP SDK to call the same server logic without spawning a child process.

pnpm vitest run tests/e2e/sdk.spec.ts

Advanced Usage

You can add the following scripts to package.json if needed:

{
  "scripts": {
    "test:raw": "vitest run tests/e2e/raw.spec.ts",
    "test:sdk": "vitest run tests/e2e/sdk.spec.ts",
    "test": "vitest run"
  }
}

• pnpm run test:raw - Run only the raw/stdio tests.
• pnpm run test:sdk - Run only the in-memory SDK tests.
• pnpm run test - Run all tests.

📚 Documentation

Repository Layout

.
├── LICENSE
├── README.md
├── package.json
├── pnpm-lock.yaml
├── src
│   ├── cli.ts         # CLI entry point (tsx + stdio transport)
│   └── server.ts      # createServer() factory (resources, prompts, tools)
├── tests
│   └── e2e
│       ├── raw.spec.ts  # spawn-based E2E tests
│       └── sdk.spec.ts  # SDK/InMemoryTransport-based E2E tests
└── tsconfig.json

Publishing and Usage

This repository is intended as an example/template. Feel free to:

• Adapt the src/server.ts factory to your own MCP server.
• Extend raw.spec.ts and sdk.spec.ts to include more test cases.
• Integrate it into your CI pipeline.

📄 License

This project is released under the MIT License.