Supertest: Error: listen EADDRINUSE: address already in use :::3000

Created on 27 Mar 2019 · 32Comments · Source: visionmedia/supertest

Hey guys, so I have been just trying to start testing my Koa server using Supertest.

I am getting the error: Error: listen EADDRINUSE: address already in use :::3000

I have tried closing everything down on that port and run it but I'm still getting the issue.

Here is my app:

require('dotenv').config();
const Koa = require('koa');
const app = new Koa();
const router = require('./router');
const PORT = process.env.NODE_PORT || 3001;
const ENV = process.env.NODE_ENV || 'Development';
const logger = require('koa-logger');

app.use(logger());
app.use(router.routes());

app.listen(PORT, (err) => {
    if (err) console.error('❌ Unable to connect the server: ', err);
    console.log(`🌍 Server listening on port ${PORT} - ${ENV} environment`);
  });

    module.exports = app;

my router:

const Router = require('koa-router');
const router = new Router();

router.get('/', ctx => ctx.body = 'Sending some JSON');
  module.exports = router;

finally the test:

const server = require('../index');
const request = require('supertest').agent(server.listen());

afterEach(() => {
  server.close();
});

describe('routes: index', ()=> {
  it('should reach endpoint', async () => {
    const response = await request(server).get('/');

    expect(response.status).toEqual(200);
    expect(response.body).toEqual('Sending some JSON');
  });
});

my server isn't even running on port 3000 it is running on 8080
however, just to make sure I will run my server on 3000 and it starts up no problem. I then try to run the test, I get the error again with the server running on 3000 and the server not. Kinda stuck

Source

ctfrancia

Most helpful comment

lsof -i:3000 
kill -9 [PID]

dionisoros on 5 Nov 2019

👍82 ❤25 🎉18 😄14 🚀4

All 32 comments

Could you send us the output of:
lsof -i:3000

rimiti on 27 Mar 2019

👍20 🎉8 🚀3

Hi @rimiti I don't get any output

ctfrancia on 27 Mar 2019

UPDATE so the reason was because in my app.test.js file I had a series of tests that were not closing after completion because I was running tests like:

const app = require('../index');

describe('server working', () => {

  it('should exist', async (done)=> {
    expect(app).toBeDefined();
    done();
  });

  it('should be an object', async (done)=>{
    expect(typeof app).toBe("object");
    done();
  });
});

and I am _still_ getting the error:

Jest did not exit one second after the test run has completed.

This usually means that there are asynchronous operations that weren't stopped in your tests. Consider running Jest with --detectOpenHandles to troubleshoot this issue.

ctfrancia on 27 Mar 2019

I had that exact error message, try this out:

Expected: I can use app.listen(PORT, ()=>{})

Code: index.js exports "app", app.listen(PORT, ()=>{}) is uncommented

Output: npm test => "Jest did not exit one second after the test run has completed.
This usually means that there are asynchronous operations that weren't stopped in your tests. Consider running Jest with --detectOpenHandles to troubleshoot this issue."

Workaround: comment/delete app.listen(PORT) and listen to the port on another file (example: require "app" from index.js in app.js and listen to a port in app.js)

aech12 on 22 Jul 2019

👍8 😕7 🎉4 ❤2

what's weird is that the documentation claims "if the server is not already listening for connections then it is bound to an ephemeral port for you so there is no need to keep track of ports."

aech12 on 22 Jul 2019

👍5 👎1

Ok thanks a lot, I will be checking that out for sure!

ctfrancia on 22 Jul 2019

Looks like you have to do two things:
1) ensure that the app has not yet been started (i.e. put the app.listen in an if statement that asserts it's not in test mode first)
2) pass koa.callback() into supertest as follows:

request(app.callback())

dgreene1 on 13 Aug 2019

👍4

lsof -i:3000 
kill -9 [PID]

dionisoros on 5 Nov 2019

👍82 ❤25 🎉18 😄14 🚀4

You are actually running the main server in the terminal. Stop the server so the debugger can run on the same PORT

Atabic on 9 Jan 2020

👍8 🎉3 👎3

So I had this issue as well.
What you want to do is that you don't want to start your server. In your main server express file you should export the server. But do NOT call the listen method.

So modify your code so that when you're testing (for example by setting an environment variable and looking for that), you're not calling the listen() method. This should resolve it and let you run your tests in parallel.

spock123 on 19 Jan 2020

👍11 ❤6 🎉6

Thanks a lot @aech12 and @spock123 you saved my day!

avencat on 17 Feb 2020

😄2

Cheers from brazil, thank you all for the support!

Robertosousa86 on 20 Feb 2020

lsof -i:3000 
kill -9 [PID]

What is PID here? New comer please help. Thank you.

HashemDeveloper on 4 Mar 2020

@HashemDeveloper when you run lsof -i:3000, you will get some information related to the port. the second column in the returned table says PID, that's what you have to type instead of [PID] when run kill -9

cguidog on 4 Mar 2020

👍9 🚀1

@HashemDeveloper when you run lsof -i:3000, you will get some information related to the port. the second column in the returned table says PID, that's what you have to type instead of [PID] when run kill -9

I actually figured that out by try and error. Thank you for the reply though.

HashemDeveloper on 9 Mar 2020

im new to web development and i get the same error and dont know exactly what to do can someone please dumb it down for me