This post is a short tutorial how to install and use Jest testing framework to test React component

React is a JavaScript library for building user interfaces and Jest is a testing framework to test the React components.

To install Jest, use:

npm install --save-dev jest

Update package.json

“Scripts”: {
 ....
 “test” : “jest”
 ....
 }

example:

 "scripts": {
   "start": "react-scripts start",
   "build": "react-scripts build",
   "test": "jest",
   "eject": "react-scripts eject"
  }

Crate files for testin, like:

function sum(a, b) {
  return a + b;
}
module.exports = sum;

File below contains simple test for sum function above:

const sum = require('./sum');

test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

Run: npm test

This is how to set some basic test setup for Jest and React.

Reference:

  1. Jest - JavaScript Testing Framework
  2. React

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