CODEWITHSUNDEEP
javascriptexpresstestingjestjs
shamon shamsudeen
shamon shamsudeen

Reputation: 5858

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

Here are my HTTP routes 

 app.get('/', (req, res) => {
    res.status(200).send('Hello World!')
})

app.post('/sample', (req, res) => {
    res.status(200).json({
        x:1,y:2
    });
})

I would like to test for the following

1) GET request working fine.

2)the /sample response contains the properties and x and y

const request = require('supertest');
const app = require('../app');

describe('Test the root path', () => {
    test('It should response the GET method', () => {
        return request(app).get('/').expect(200);
    });
})

describe('Test the post path', () => {
    test('It should response the POST method', (done) => {
        return request(app).post('/sample').expect(200).end(err,data=>{
            expect(data.body.x).toEqual('1');

        });
    });
})

But I got the following error on running the test

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

return request(app).get('/').expect(200);

Upvotes: 10

Views: 17991

Answers (4)

Chris Halcrow
Chris Halcrow

Reputation: 31960

As a general tip to debug this error, add --detectOpenHandles to your npm script that runs Jest e.g.

   "scripts": {
    ...
    "test": "jest --detectOpenHandles"
    }

This should tell you exactly which part of the code is causing the issue (probably some type of server connection, particularly if its async).

In general, if you can move the connection code to a separate function in a file outside of your tests, then import and call it in your tests, this will also fix the issue.

Upvotes: -2

David Okwii
David Okwii

Reputation: 7840

This trick worked;

afterAll(async () => {
    await new Promise(resolve => setTimeout(() => resolve(), 500)); // avoid jest open handle error
});

As described in this github issue.

Upvotes: 9

Nenoj
Nenoj

Reputation: 197

you need to call done() in the end() method

const request = require("supertest");
const app = require("../app");

let server = request(app);

it("should return 404", done =>
    server
        .get("/")
        .expect(404)
        .end(done);
});

Upvotes: 11

Shraddha Goel
Shraddha Goel

Reputation: 897

Hi You can use the toEqual function as well

describe('Test the post path', () => {
    test('It should response the POST method', () => {
        return request(app).post('/sample').expect(200).toEqual({ x:1,y:2
        });
    });
})

There are lots of methods can be used instead.You can go throw the official documentation which covers every jest function https://jestjs.io/docs/en/expect

Upvotes: -1

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