How to test Node js apps using Mocha Chai and Sinonjs

Question

Can you tell me How to test Node.js apps using Mocha Chai and Sinonjs?

Answer 1

You can test Node.js apps using Mocha, Chai, and Sinon.js for unit and integration testing.

Steps:

1. Install Dependencies

npm install mocha chai sinon --save-dev

2. Create a Sample Function (app.js)

function add(a, b) {

    return a + b;

}

module.exports = { add };

3. Write Test Cases (test/app.test.js)

const { expect } = require('chai');

const sinon = require('sinon');

const { add } = require('../app');

describe('Math Functions', () => {

    it('should return sum of two numbers', () => {

        expect(add(2, 3)).to.equal(5);

    });

    it('should spy on a function call', () => {

        const spy = sinon.spy(add);

        spy(1, 2);

        expect(spy.calledOnce).to.be.true;

    });

});

4. Run Tests

npx mocha test/app.test.js