👀 Views: 81 💬 Answers: 1 📅 Created: 2025-06-07

jest socket.io testing JavaScript

I'm prototyping a solution and I'm migrating some code and I need help solving I'm collaborating on a project where I'm working through a tutorial and I'm currently writing tests for a Node.js application that uses Socket.io for real-time communication... My goal is to ensure that my WebSocket events are being emitted and received correctly, but I'm running into issues with Jest not being able to properly mock the Socket.io server and client. I've set up a simple Socket.io server like this: ```javascript const express = require('express'); const http = require('http'); const socketIo = require('socket.io'); const app = express(); const server = http.createServer(app); const io = socketIo(server); io.on('connection', (socket) => { socket.on('message', (msg) => { socket.emit('message', `Received: ${msg}`); }); }); server.listen(3000, () => console.log('Listening on port 3000')); ``` And here's the test case I've written using Jest: ```javascript const io = require('socket.io-client'); const server = require('./server'); // Path to your server file describe('WebSocket tests', () => { let socket; beforeAll((done) => { server.listen(3001, () => { socket = io('http://localhost:3001'); socket.on('connect', done); }); }); afterAll(() => { socket.disconnect(); server.close(); }); test('should respond to message event', (done) => { socket.emit('message', 'Hello'); socket.on('message', (response) => { expect(response).toBe('Received: Hello'); done(); }); }); }); ``` When I run the test, I get the following behavior: ``` behavior: Timeout of 5000ms exceeded. Ensure the done() callback is being called in this test. ``` I've confirmed that the server is running and the client connects successfully, but the message handler isn't being triggered as expected. I suspect it might be related to the server and client being on different ports (3000 and 3001), but I've tried changing the ports and it didn't resolve the scenario. Any guidance on how I can correctly test the WebSocket events in this setup would be greatly appreciated! The stack includes Javascript and several other technologies. Is this even possible? I'm coming from a different tech stack and learning Javascript. Any ideas how to fix this? My team is using Javascript for this REST API. What would be the recommended way to handle this? I'm working with Javascript in a Docker container on Windows 11. Cheers for any assistance! I'm working in a Linux environment. What's the correct way to implement this? My development environment is macOS. Any pointers in the right direction? Am I missing something obvious?