In this lesson, we will use Chai's request method to test our Node application's API responses.

By the end of this lesson, you will know how to:

- install the prerequisites to use mocha and chai in your application

- test for HTTP status response codes

- test for a string of text on a page

- test for a json response and validate the properties of the object

- write tests that not only verify the response of your application, but the behavior as well

const mockRouter = require('./routes/mock');  app.use('/mock', mockRouter);

 

// routers/mock.jsconst express = require('express');const router = express.Router();router  .get('/', (req, res, next) => {    res.status(200)       .json({ title: 'Mock test' })  })  .post('/', (req, res, next) => {    const { v1, v2 } = req.body;    if (isNaN(Number(v1)) || isNaN(Number(v2))) {      res.status(400)         .json({ 'msg': 'You should provide numbers' });    } else {      const result = Number(v1) + Number(v2);      res.status(200)         .json({ result });    }  });module.exports = router;

 

// test/mock_test.jsconst chai = require('chai');const chaiHttp = require('chai-http');const should = chai.should();const server = require('../../src/app');chai.use(chaiHttp);describe('/mock GET', () => {  it('should return json', (done) => {    chai.request(server)        .get('/mock')        .end((err, res) => {          res.should.have.status(200);          res.body.should.have.property('title')             .and             .that             .equal('Mock test');          done();        })  });  it('should return right value', (done) => {    chai.request(server)        .post('/mock')        .set('content-type', 'application/json')        .send({          v1: 2,          v2: 3              })        .end((err, res) => {            res.should.have.status(200);            res.body.should.have.property('result').that.equals(5);            done();        });  });  it('should return 400 error', (done) => {    chai.request(server)        .post('/mock')        .set('content-type', 'application/json')        .send({                v1: 'tow',                v2: 'three'              })        .end((err, res) => {          res.should.have.status(400);          res.body.should.have.property('msg').that.contains('provide numbers');          done();        });  });});