JavaScript testing fundamentals: from why tests matter to writing your first assertions with Jest and Vitest. Covers unit, integration, and E2E strategies.
Tutorial series
Testing Javascript
9 tutorials — follow in order for the best learning path.
- JavaScript Testing: Getting Started
- Unit testing with Jest: a hands-on guide to JavaScript test automation
A practical guide to unit testing with Jest — the most popular JavaScript testing framework. Covers matchers, setup, async testing, mocking, and best practices.
- Unit Testing with Vitest: A Fast, Modern Test Runner
Learn unit testing with Vitest, the Vite-powered test runner for JavaScript. Covers setup, matchers, mocking, async testing, snapshots, and coverage.
- Testing asynchronous code with Jest and Vitest
Learn testing asynchronous JavaScript code with Jest and Vitest. Covers promises, async/await, timers, callbacks, and concurrent operations with real examples.
- Mocking Modules and Dependencies
Learn mocking modules in Jest and Vitest — replaces dependencies with controlled test doubles so your unit tests stay fast, reliable, and isolated.
- Testing DOM code with jsdom in Node.js: a tutorial
Learn testing DOM code in Node.js with jsdom. Covers setup with Jest, querying and mutating elements, testing events, form validation, fixtures, and pitfalls.
- End-to-end testing with Playwright in JavaScript
Learn end-to-end testing with Playwright for JavaScript, from basic assertions to advanced browser automation for modern web applications.
- Code Coverage and CI Integration
Learn how to measure code coverage, interpret coverage reports, and integrate testing into your CI pipeline for reliable JavaScript projects.
- Snapshot Testing in Jest and Vitest: Patterns and Best Practices
Master snapshot testing in JavaScript with Jest and Vitest. Learn when to use snapshots, how to manage them, and best practices for effective test maintenance.