Jest Tutorial – Installation and overview
Jest is a JavaScript testing framework that support almost all libraries like angular, vue, react and also works with node, typescript, babel.
Step1: Installation
npm install --save-dev jest
or
yarn add --dev jest
Step2: Add this in package.json to run test case execution mentioned below.
{ "scripts": { "test": "jest" } }
Step3: Create a js(JavaScript) file and export the required function.
filename: student.js
function fullName (first, middle, last) { return `${first} ${middle} ${last}`; }
module.exports = fullName;
Step4: Create another js file in which we will write tests to test the code in the js file created in step3.
filename: student.test.js
const student = require('./student'); test('fullname to equal I am a developer', () => { expect(sum('I', 'am a', 'developer')).toBe('I am a developer'); });
Step5: Run the test using yarn test or npm test which will show the result either pass or fail.
Sample Message afer running the test
PASS ./student.test.js
✓ fullname to equal I am a developer (5ms)
Official Website:
https://jestjs.io/