UI Testing with Puppeteer: Implement end-to-end testing and browser automation using JavaScript and Node.js

✍ Scribed by Dario Kondratiuk

• Publisher: Packt Publishing
• Year: 2021
• Tongue: English
• Leaves: 316
• Category: Library

✦ Synopsis

Write fail-safe automation tests, device emulation, and browser automation using Puppeteer's Google-powered API

Key Features

• Get up and running with Puppeteer and discover best practices for automation testing
• Automate your modern web applications using Jest and Mocha with Puppeteer
• Generate screenshots using Puppeteer and find out how they can be used for UI regression tests

Book Description

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.

What you will learn

• Understand browser automation fundamentals
• Explore end-to-end testing with Puppeteer and its best practices
• Apply CSS Selectors and XPath expressions to web automation
• Discover how you can leverage the power of web automation as a developer
• Emulate different use cases of Puppeteer such as network speed tests and geolocation
• Get to grips with techniques and best practices for web scraping and web content generation

Who this book is for

The book is for QA engineers, testing professionals, and frontend web developers alike who want to perform end-to-end testing using Google's developer tools. Web developers who want to learn how to use Puppeteer for generating content, scraping websites, and evaluating website performance will also find this book useful. Although knowledge of Node.js isn't necessary, basic JavaScript knowledge will assist with understanding the concepts covered.

Table of Contents

1. Getting started with Puppeteer
2. Automated Testing and Test runners
3. Navigating through a website
4. Interacting with a page
5. Waiting for elements and network calls
6. Executing and Injecting JavaScript
7. Generating Content with Puppeteer
8. Environments emulation
9. Scraping tools
10. Evaluating and Improving the Performance of a Website

✦ Table of Contents

Cover
Title page
Copyright and Credits
Dedicated
Contributors
Table of Contents
Preface
Chapter 1: Getting started with Puppeteer
What is browser automation?
Selenium and Puppeteer
Introducing Headless browsers
Available headless browsers
The Chromium DevTools Protocol
Introducing Puppeteer
The Puppeteer object model
Puppeteer use cases
Task Automation
Web Scraping
Content generation
End-to-end testing
Setting up the environment
Node.js
Visual Studio Code
Our first Puppeteer code
Installing Puppeteer
Hello world in Puppeteer
Asynchronous programming in JavaScript
Promise.all
Promise.race
Fulfilling our own promises
Summary
Chapter 2: Automated Testing and Test runners
Technical requirements
Introduction to Automated Testing
Unit tests
Service tests
End-to-end tests
Test runner features
Available test runners
Creating our first test project
Organizing our code
Introducing the Page Object Model
Summary
Chapter 3: Navigating through a website
Technical requirements
Introducing the tests sites for this chapter
Creating a Puppeteer browser
Using the Puppeteer.launch function
Headless
The user data directory
Executable Path
Default Viewport
Product
Browser Arguments
Mobile options
Options in practice
Navigating through a site
Timeouts
waitUntil
Referrer
Using the response object
Getting the response URL
Getting the response status code
Introduction to continuous integration
Summary
Chapter 4: Interacting with a page
Technical requirements
Introduction to HTML, the DOM, and CSS
HTML
The DOM
CSS Selectors
Finding elements
Finding elements using XPath
Interacting with Elements
Typing on input elements
Clicking on elements
Selecting options in drop-down lists
Keyboard and Mouse emulation
Debugging tests with Visual Studio Code
Summary
Chapter 5: Waiting for elements and network calls
Technical requirements
Waiting for the page to load
Waiting for elements
Await a wait function
Waiting for network calls
Arrange, Act, Await
Fire and forget
Promise.all
Waiting for page events
The close event
The popup event
Target created event
The console event
The dialog event
The headless recorder
Summary
Chapter 6: Executing and Injecting JavaScript
Technical requirements
Executing JavaScript code
Variable scopes in JavaScript
Manipulating handles with JavaScript code
Getting information from the elements
Acting on elements
Enforcing server rules
Finding elements using JavaScript
Waiting for functions
Exposing local functions
Running our checks with Checkly
Summary
Chapter 7: Generating Content with Puppeteer
Technical requirements
Taking screenshots
Using screenshots for regression tests
Generate PDF files
Creating HTML content
Summary
Chapter 8: Environments emulation
Technical requirements
Understanding the browser's market share
The browser's popularity over the years
Operative Systems market share
Screen resolution distribution
Emulating mobile devices
The Viewport
Pixel ratio
The touchscreen
The user agent
Emulating mobile devices with Puppeteer
Emulating network conditions
Emulating localization
Emulating geolocation
Emulating time zones
Emulating languages
Other emulations
Summary
Chapter 9: Scraping tools
Technical requirements
Introduction to web scraping
Does the site allow scrapers?
Creating scrapers
Running scrapers in parallel
How to avoid being detected as a bot
Dealing with authorization
Summary
Chapter 10: Evaluating and Improving the Performance of a Website
Technical requirements
The Issue of Performance
Getting started with Google Lighthouse
As part of Chrome DevTools
Using PageSpeed Insights
Using the command line
Using the node module
The performance category
Using Lighthouse for testing
Tracing Pages
Analyzing code coverage
Summary
Why subscribe?
About Packt
Other Books You May Enjoy
Index