JavaScript Testing

Testing is a critical aspect of modern web development that ensures the reliability and functionality of your JavaScript code. Testing frameworks like Jest and Mocha provide developers with powerful tools to automate and streamline the testing process.

Example – Using Jest:

Jest is a popular testing framework developed by Facebook, known for its simplicity and ease of use. It offers features like test runners, assertions, and mocking to facilitate unit testing.

// Example test using Jest
// math.js
function add(a, b) {
return a + b;
}

// math.test.js
const { add } = require(‘./math.js’);

test(‘adds 1 + 2 to equal 3’, () => {
expect(add(1, 2)).toBe(3);
});

Unit testing involves testing individual units (functions, components) of your JavaScript code to ensure they work as expected. By writing unit tests, you can catch bugs early and refactor code with confidence.

Example – Using Mocha:

Mocha is a flexible and widely-used testing framework that can be paired with other libraries like Chai for assertions.

// Example test using Mocha and Chai
// math.js
function subtract(a, b) {
return a – b;
}

// math.test.js
const assert = require(‘chai’).assert;
const { subtract } = require(‘./math.js’);

describe(‘Math functions’, () => {
it(‘should return the difference of two numbers’, () => {
assert.equal(subtract(5, 3), 2);
});
});