Code coverage in 2 minutes with NYC

#testing #javascript #codenewbie

In my previous posts about testing, I don’t have a clear picture of how much of my code is protected with tests? NYC comes to help me know the real status of my testing.

NYC is an npm package for getting stats about the test coverage working hand to hand with Mocha and the setup is so easy. My example is setup NYC to read the results from Mocha and it shows the % of cover.

I’m using the same project for testing if you want you to check the changes in the repo Github or continue reading.

Install NYC

Install the package NYC using npm, it will help to get the report of our test coverage with Mocha.

npm install NYC --save-dev

Running coverage

NYC is already installed, then run the command to see the report.

NYC npm run test

NYC it will generate a report table with stats about the code, functions and test cover by our tests.

We can see the branches, lines, functions with and without test, files and the percentage of covered, if you check the test ads.spec.js it only contains the first switch case, and the report notify the lines 11,18,25 are not covered, If I want to get 100% of cover, I will complete my pending cases.

Completing the cases

Edit the ads.spec.js file and include the pending cases and the default.

const assert = require('assert');
const { getIVABanner } = require('../src/ads');describe('Ads for taxes', () => {
    it('Get green banner for 15% IVA', () => {
        const actual = getIVABanner(15);
        const expect = {
            img: '/bar.jpg',
            size: '15%',
            border: 3,
            color: 'green'
        }
        assert.deepEqual(actual, expect)
    }) it('Get green banner for 20% IVA', () => {
        const actual = getIVABanner(20);
        const expect = {
            img: '/bar.jpg',
            size: '20%',
            border: 5,
            color: 'yellow'
        }
        assert.deepEqual(actual, expect)
    })
    it('Get green banner for 30% IVA', () => {
        const actual = getIVABanner(30);
        const expect = {
            img: '/bar.jpg',
            size: '30%',
            border: 5,
            color: 'red'
        }
        assert.deepEqual(actual, expect)
    })
    it('Get default ', () => {
        const actual = getIVABanner();
        const expect = {
            img: '/bar.jpg',
            size: '100%',
            border: 5,
            color: 'red'
        }
        assert.deepEqual(actual, expect)
    })
})