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! How do I write my first test in Jest?

To write your first test, create a file named sum.test.js. Inside, you can write a simple test like this:

const sum = (a, b) => a + b;

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

This test checks if the sum function works correctly. Would you like to learn about running the tests?

Yes, how do I run the tests I wrote?

You can run your tests by adding a script in your package.json like this:

"scripts": {
  "test": "jest"
}

Then, run the command npm test in your terminal. Jest will automatically find and run your test files. Do you need help with anything else?

What are some best practices for writing tests in Jest?

Some best practices include writing clear and descriptive test names, keeping tests isolated, and using setup and teardown methods for shared state. Also, consider testing edge cases and using mocks for external dependencies. Would you like more details on any of these?