Nest: How to test Nest with supertest ?

[ThomRick]

Hey !
I don't know how to test Nest api routes with supertest.
Someone already try this ?

[kamilmysliwiec]

Hi @ThomRick,
The same way as with express. It is possible to pass custom express instance as a second argument of NestFactory.create method.

import * as request from 'supertest';
import * as express from 'express';
import { NestFactory } from '@nestjs/core';

const instance = express();

@Controller() 
class UsersController {
    @Get('user')
    getUser(req, res) {
        res.status(200).json([]);
    }
}

@Module({
    modules: [],
    controllers: [UsersController],
})
export class ApplicationModule {}

const app = NestFactory.create(ApplicationModule, instance);
app.listen(3000, () => console.log('Application is listening on port 3000.'));

///////////// Test
request(instance)
  .get('/user')
  .expect('Content-Type', /json/)
  .expect(200)
  .end(function(err, res) {
    if (err) throw err;
  });

[ThomRick]

Hey @kamilmysliwiec,

The thing is I don't know why you have to call the listen() function ?

I wrote this test file that work fine:

import {NestFactory} from '@nestjs/core';
import {RegistrationModule} from './registration.module';
import * as request from 'supertest';
import {expect} from 'chai';
import {ExpressAdapter} from '@nestjs/core/adapters/express-adapter';
import {Application} from 'express';
import {INestApplication} from '@nestjs/common/interfaces/nest-application.interface';

describe('RegistrationModule', () => {
  let instance: Application;

  before(() => {
    instance = ExpressAdapter.create();
    const application: INestApplication = NestFactory.create(RegistrationModule, instance);
    application.listen(8080, () => console.log('Application listening at port 8080'));
  });

  it('should expose GET /api/registrations endpoint', done => {
    request(instance)
      .get('/api/registrations')
      .end((error, response) => {
        expect(response.status).to.not.be.equal(404);
        done();
      });
  });

  it('should expose POST /api/registrations endpoint', done => {
    request(instance)
      .post('/api/registrations')
      .end((error, response) => {
        expect(response.status).to.not.be.equal(404);
        done();
      });
  })
});

But I couldn't write the test init like this:

beforeEach(() => {
    instance = ExpressAdapter.create();
    const application: INestApplication = NestFactory.create(RegistrationModule, instance);
    application.listen(8080, () => console.log('Application listening at port 8080'));
  });

Because it throws this exception:

Uncaught Error: listen EADDRINUSE :::8080
      at Object.exports._errnoException (util.js:1050:11)
      at exports._exceptionWithHostPort (util.js:1073:20)
      at Server.setupListenHandle [as _listen2] (net.js:1259:14)
      at listenInCluster (net.js:1307:12)
      at Server.listen (net.js:1406:7)
      at Function.listen (node_modules/@nestjs/core/node_modules/express/lib/application.js:617:24)
      at NestApplication.listen (node_modules/@nestjs/core/nest-application.js:26:29)
      at exceptions_zone_1.ExceptionsZone.run (node_modules/@nestjs/core/nest-factory.js:47:35)
      at Function.run (node_modules/@nestjs/core/errors/exceptions-zone.js:8:13)
      at Proxy.args (node_modules/@nestjs/core/nest-factory.js:46:70)
      at Context.beforeEach (src/application/modules/registration/registration.module.spec.ts:15:17)

So I though to close the server and I had looking for what return listen() function ==> nothing... not as express that it return the http.Server.
So impossible to close the server...

I didn't try yet to execute more than one test file but I smell a problem with the listen()...

[kamilmysliwiec]

Hi @ThomRick,
Update your packages into 2.1.0 version. Now listen() method should returns http server. Futhermore, I added close() methods in INestApplication and INestMicroservice.

[lock[bot]]

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