server.close is not a function

Question

I have a jest supertest setup for my testing , I am trying to close server after tests are done but it is throwing error, it is saying server.close() is not a function. what is wrong here? is it issue with express or jest or supertest I am not able to figure it out I am new to testing please help me. server.js file:

const next = require('next');
const express = require('express');
const winston = require("winston");
const config = require("config");
const passport = require('passport');
const flash    = require('connect-flash');
const path = require('path');
var cookieSession = require('cookie-session');
const cookieParser = require('cookie-parser');

var app = express();



const dev = process.env.NODE_ENV !== 'production';
const nextApp = next({dev});
const port =  process.env.PORT || config.get("port");
const handleRequest = nextApp.getRequestHandler();


nextApp.prepare().then(() => {



    require("./server/startup/cors")(app);
    require("./server/startup/db")();

    app.use(cookieParser('ilovescotchscotchyscotchscotch'));
    app.use(express.json());



    app.use(cookieSession({
        name: 'MyAppName',
        keys: ['very secret key'],
        maxAge: 30 * 24 * 60 * 60 * 1000 // 30 days
      }));
      app.use(passport.initialize());
      app.use(passport.session());
      app.use(flash());



      require('./server/services/passport')(passport);



      require("./server/startup/logging")();
      require("./server/startup/routes")(app);
    require("./server/startup/prod")(app);




    app.get('*', (req, res) => {
        return handleRequest(req, res);
    });






})

app.listen(port, () => console.log(`Listening at port ${port}`));

module.exports = app;

Here is my test file:

const request = require('supertest');

const {User} = require('./../../server/models/user');
const mongoose = require('mongoose');

let server ;

beforeEach(() => { server = require('./../../server'); });
  afterEach(async () => { 
    await server.close(); 

  });


    describe('POST /api/signup', () => {
        it('should signin successfully',  () => {

        })
    });

This is my error :

TypeError: server.close is not a function

       9 | beforeEach(() => { server = require('./../../server'); });
      10 |   afterEach(async () => {    > 11 |     await server.close();
         |                  ^
      12 |
      13 |   });

what is happening here? Am I doing something fundamentally wrong here?

Answer 1

In order to close the server, you must obtain the instance that is returned from the listen function. In your example, it appears that you call that function here:

app.listen(port, () => console.log(`Listening at port ${port}`));

So, you would need to get the instance returned and close that. E.g.

let appServer = app.listen(port, () => console.log(`Listening at port ${port}`));
...
appServer.close()

Answer 2

At the end of your index.js, you want to export the listener, not app, so...

app.listen(port, () => console.log(`Listening at port ${port}`));
module.exports = app;

becomes...

const server = app.listen(port, () => console.log(`Listening at port ${port}`));
module.exports = server;

Should work from there.