What is Jest and how do I get started with it?

What is Jest and how do I get started with it?

Jest is a JavaScript testing framework developed by Facebook. It's used for testing React applications and other JavaScript code. To get started, you can install it via npm with the command npm install --save-dev jest. Would you like to know how to write your first test?

Yes, please show me how to write a simple test.

Sure! Here's a simple test example. Create a file named sum.js with a function that adds two numbers. Then, create a test file sum.test.js where you can write your test cases using Jest's test function.

What does a test case look like in Jest?

A test case in Jest looks like this:

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

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

This checks if the sum function correctly adds 1 and 2.

How do I run the tests?

You can run your tests by executing the command npx jest in your terminal. Jest will automatically find and run all files with .test.js in their names.