Book Image

UI Testing with Puppeteer

By : Dario Kondratiuk
Book Image

UI Testing with Puppeteer

By: Dario Kondratiuk

Overview of this book

Puppeteer is an open source web automation library created by Google to perform tasks such as end-to-end testing, performance monitoring, and task automation with ease. Using real-world use cases, this book will take you on a pragmatic journey, helping you to learn Puppeteer and implement best practices to take your automation code to the next level! Starting with an introduction to headless browsers, this book will take you through the foundations of browser automation, showing you how far you can get using Puppeteer to automate Google Chrome and Mozilla Firefox. You’ll then learn the basics of end-to-end testing and understand how to create reliable tests. You’ll also get to grips with finding elements using CSS selectors and XPath expressions. As you progress through the chapters, the focus shifts to more advanced browser automation topics such as executing JavaScript code inside the browser. You’ll learn various use cases of Puppeteer, such as mobile devices or network speed testing, gauging your site’s performance, and using Puppeteer as a web scraping tool. By the end of this UI testing book, you’ll have learned how to make the most of Puppeteer’s API and be able to apply it in your real-world projects.
Table of Contents (12 chapters)

Getting started with Google Lighthouse

As we saw in the previous section, it's not easy to determine how fast "fast" is. Google came up with an idea. They built Lighthouse, "an open-source, automated tool for improving the quality of web pages. You can run it against any web page, public or requiring authentication. It has audits for performance, accessibility, progressive web apps, SEO and more" (

Lighthouse will grab the website you choose, apply a list of metrics and recommendations it finds important, and give you a score from 0 to 100. It will analyze the website under five categories:

  • Performance: The most popular category. Lighthouse will measure how optimized the website is, that is, how fast it gets ready for user interaction.
  • Accessibility: I would love to see developers paying more attention to this category. Here, Lighthouse will evaluate how accessible the website is...