How do I write unit tests in JavaScript?

How do I write unit tests in JavaScript?

To write unit tests in JavaScript, you can use frameworks like Jest or Mocha. Would you like a step-by-step guide?

Yes, please provide a step-by-step guide using Jest.

First, install Jest using npm: npm install --save-dev jest. Then, create a test file, for example, sum.test.js. In this file, write your test cases using test() or it() functions.

Can you show me an example of a simple test?

Sure! Here's a simple test for a function that adds two numbers:

function sum(a, b) {
  return a + b;
}

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

What if I want to test asynchronous code?

For asynchronous code, you can use async/await in your tests. Just make your test function async and return a promise.