Fe Testgen

You run an MCP server that automatically generates and fixes frontend tests from code diffs, exposing either HTTP streaming or stdio interfaces. It supports Vitest/Jest, runs with isolated workers, and integrates into CI or automation tools to provide a one-command test completion workflow.

How to use

You interact with the MCP server using a client that connects via HTTP or stdio. The server can automatically detect project diffs, generate a test matrix, create tests, run them, and fix failing cases. You can run the server in HTTP streaming mode or in stdio mode, with the ability to pass your API key and transport preferences.

How to install

Prerequisites: Node.js 18 or newer. It is recommended to use Node.js 20+. Ensure you have network access to install dependencies.

1. Install dependencies for the MCP server.

2. Build the project.

3. Start the server in HTTP streaming mode by default or in stdio mode when requested.

The following steps show a typical workflow you can copy and run.

npm install
npm run build
npm start                       # Automatically selects HTTP Streaming or stdio mode
OPENAI_API_KEY=sk-xxx npm start -- --transport stdio

Configuration and endpoints

The server exposes two main endpoints you can connect to from your MCP client or editor integrations.

HTTP endpoint (default)

http://localhost:3000/mcp

SSE endpoint for streaming events

http://localhost:3000/sse

If you want to run in stdio mode explicitly, pass your OpenAI key and request stdio transport.

OPENAI_API_KEY=YOUR_KEY npm start -- --transport stdio

Other notes and troubleshooting

To avoid interference from HTTP logging, you can disable file and console logging when needed, or enable them in development as appropriate.

If you encounter File is not defined errors related to undici, ensure you are on Node.js 18+ and rebuild the project.

Available tools

fetch-commit-changes

Fetches differences from a local or remote Git repository for the target project to determine what needs test generation.

fetch-diff-from-repo

Retrieves the code diff from a repository to analyze changes for test generation.

analyze-test-matrix

Analyzes the detected changes to build a test matrix that covers relevant scenarios.

analyze-test-matrix-worker

Worker variant that performs test matrix analysis in isolation to prevent long-running tasks from blocking others.

generate-tests

Generates test cases based on the analyzed diff and the test matrix.

generate-tests-worker

Worker variant that generates tests in isolation for parallelism and reliability.

generate-tests-from-raw-diff

Creates test files directly from a raw diff input when diffs are provided without a full repo context.

write-test-file

Writes the generated test files to disk so they can be executed by the test runner.

run-tests

Runs Vitest or Jest against the generated tests and reports results.

fix-failing-tests

Automatically fixes tests based on failure logs to improve pass rates.

test-generation-workflow

End-to-end workflow that goes from diff to generated tests to execution and automatic fixes.