# Jest

A popular JavaScript test framework.

## What is **Jest**?

**Jest** is a popular JavaScript test framework with assertions, mocks and snapshot testing built in.

```javascript
test('adds tax', () => {
  expect(withTax(100)).toBe(108);
});
```

Level: Apprentice · [More JavaScript terms at this level](https://www.ask-codey.com/glossary/subjects/javascript/apprentice)

Updated: October 12, 2026

Source: https://www.ask-codey.com/glossary/jest