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)

Emulating network conditions

Networking is a challenging topic in computer science. If you tell a network engineer that Chromium emulates a 4G network, they will ask you to show them how it can emulate radio tower and weather conditions. Chromium does not pretend to emulate a network but a network condition. Chromium limits the scope to three variables that affect web development: Download speed, Upload speed, and Latency. That's it.

Emulating network conditions is something that you can now do on Chromium. You can open the developer tools and go to the Network tab, and you will find a drop-down list called throttling with the Online option selected by default, as in the following screenshot:

Emulating network conditions on Chromium

If you click on that drop-down list, you will find three other options: Fast 3G, Slow 3G, and Offline. Another cool feature is that you will be able to add custom profiles. There you will be asked about three variables we...