Jest: test is not exiting unless 'done' parameter is passed to afterAll() without being explicitly called

[tito300]

🐛 Bug Report

I've been trying for the last 2 days to figure out why the test is not existing despite following all the steps with no luck until by accident I left the 'done' parameter in afterAll() without actually explicitly calling it from inside. like this: afterAll((done)=>{ mongoose.disconnect() }). This made it exit and work properly but when I explicitly call donefrom the function using promises (async/await or then) or as a callback to mongoose.disconnect() such as afterAll(async (done)=> { await mongoose.disconnect(); done()})it does not exit and keeps hanging. when using --detectOpenHandles it tells me that app.listen(3001) is the potential open handler which I explicitly closed. I can't figure if this is a problem in my code or a bug. The way I was able to fix the problem above by passing done param without using it seemed more of a hack (or bug) than a real solution. is done supposed to do anything if it is passed only(without being called)?

To Reproduce

`` const request = require('supertest');
const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/debugging');
const app = require('../app');
let server = '';

describe('GET /products/:name', ()=>{

beforeEach(()=> { server = app.listen(3001)})
afterEach(()=> { server.close() })
// afterEach((done)=> { server.close(done) })  <-- this does not work also
afterAll((done) => { 
   mongoose.disconnect();
//  done();                    <--- does not work even when using await on mongoose  
// mongoose.disconnect(done);  <--- does not work also
})

it('should return a 404 status', async ()=>{
    const res = await request(server).get('/name');
    expect(res.status).toBe(404); 
})

})

when I explicitly call done() in afterAll I get this:

Jest has detected the following 1 open handle potentially keeping Jest from exiting:

● TCPSERVERWRAP

   8 |
   9 |
> 10 |     beforeEach(()=> { server = app.listen(3001)})
     |                                    ^
  11 |     afterEach(()=> { server.close() })
  12 |     // afterEach((done)=> { server.close(done) })  <-- this does not work also
  13 |     afterAll((done) => {

  at Function.listen (node_modules/express/lib/application.js:618:24)
  at Object.listen (tests/routes.test.js:10:36)

```

Expected behavior

To be able to exit process when calling done after disconnecting from server and db.

Link to repl or repo (highly encouraged)

to reproduce behaivor here is a sample rep here. note that the sample I provide is a working. Just try to call done using any method and the test will hang. also try removing the done param from afterAll() and the test will also hang.

[rickhanlonii]

Hey @tito300 this is happening because mongoose.disconnect() is a promise and you need to wait until the disconnect promise is resolved. It looks like you tried this a few ways but none of them were correct.

What did work (providing the done arguments without calling) only works because it's basically forcing Jest to wait for a done that is never called, so the open handle detection never runs

Here's why a few of your attempts were wrong:

This will call done before the promise resolves (i.e. before it's done)

afterAll((done) => { 
    mongoose.disconnect(); // 1 - start the disconnect
    done();  // 2 - call done
    // 3 - sometime later the disconnect actually happens
})

This will pass done to disconnect, which would work if disconnect accepted a callback (it does not)

afterAll((done) => { 
    mongoose.disconnect(done); 
})

Two ways that should work are:

// pass done to .then
afterAll(done => { 
    mongoose.disconnect().then(done); 
})

// return the promise
afterAll(() => { 
    return mongoose.disconnect();
})

Give these a try and let me know if they work!

[dNitro]

Same issue here. The async handlings proposed by @rickhanlonii did not work :(