chai: expect object to have array of objects like (in format)

Question

I'm trying to write a test for an node.js application using TDD but I can't figure out how to write a chai expect test for my Products Route get() function.

// productsController.js

let items = [
   {
        id: 1,
        name: 'Product 1',
        description: 'Product1 description',
       price: 19.00
   }
];

module.exports = {
    get(_, res) {
        res.json({items});
    }
};

I've read the docs a few times but i can't quite seem to figure out how I can test if the response object is expected to contain a key items where the value is a array of 'products' with the schema like the mentioned above.

What I've tried:

// products.test.js

const { get, getById } = require('../../routes/productsController');

const res = {
    jsonCalledWith: {},
    json(arg) {
        this.jsonCalledWith = arg
    }
}

describe('Products Route', function() {
    describe('get() function', function() {
        it('should return an array of products ', function() {
            get(req, res);
            expect(res.jsonCalledWith).to.be.have.key('items').that.contains.something.like({
                id: 1,
                name: 'name',
                description: 'description',
                price: 18.99     
            });
        });
    });
});

However, I get this error: AssertionError: expected { Object (items) } to be an array

Does anyone know how can I write this test successfully?

Answer 1

I figured it out!

// products.test.js

const chai = require('chai');
chai.use(require('chai-json-schema'));
const expect = chai.expect;

const { get } = require('../../routes/productsController');

let req = {
    body: {},
    params: {},
};

const res = {
    jsonCalledWith: {},
    json(arg) {
        this.jsonCalledWith = arg
    }
}

let productSchema = {
    title: 'productSchema',
    type: 'object',
    required: ['id', 'name', 'description', 'price'],
    properties: {
      id: {
        type: 'number',
      },
      name: {
        type: 'string'
      },
      description: {
        type: 'string',
      },
      price: {
        type: 'number',
      },
    }
  };

describe('Products Route', function() {
    describe('get() function', function() {
        it('should return an array of products ', function() {
            get(req, res);
            expect(res.jsonCalledWith).to.be.have.key('items');
            expect(res.jsonCalledWith.items).to.be.an('array');
            res.jsonCalledWith.items.forEach(product => expect(product).to.be.jsonSchema(productSchema));
        });
    });
});

Turns out the plug-in chai-json-schema allows the validation of json objects to meet a predefined schema.

Answer 2

I think you are receiving the error because the expected output is an array, to accomplish your tests you need:

it('Check route list all users', (done) => {
        api.get('/usuarios')
            .set('Accept', 'application/json; charset=utf-8')
            .expect(200)
            .end((err, res) => {
                expect(res.body).to.be.an('array');
                expect(res.body.length).to.equal(1);
                done();
            });
});

This is an example that returns an array as a json response.

Here is the same test for a object User instance from the route:

it('Check get by id return 200', (done) => {
            api.get('/usuarios/1')
            .set('Accept', 'application/json; charset=utf-8')
            .expect(200)
            .end((err, res) =>{
                expect(res.body).to.have.property('nome');
                expect(res.body.nome).to.equal('abc');
                expect(res.body).to.have.property('email');
                expect(res.body.email).to.equal('a@a.com');
                expect(res.body).to.have.property('criacao');
                expect(res.body.criacao).to.not.equal(null);
                expect(res.body).to.have.property('atualizado');
                expect(res.body.atualizado).to.not.equal(null);
                expect(res.body).to.have.property('datanascimento');
                expect(res.body.datanascimento).to.not.equal(null);
                expect(res.body).to.have.property('username');
                expect(res.body.username).to.equal('abcdef');
                expect(res.body).to.have.property('statusmsg');
                expect(res.body.statusmsg).to.equal('status');
                expect(res.body).to.have.property('genero');
                expect(res.body.genero).to.equal('M');
                expect(res.body).to.have.property('descricao');
                expect(res.body.descricao).to.equal('descricao');
                done();
            });
    });

Im my example I use mocha and chai and supertest .

Hope it helps, if you need more clarifications, please let me know.