One of the test automation tools is Selenium. It is widely used worldwide as a tool for automating web application testing. In this book, we use Selenium WebDriver to automatically run the browser. As for the browser, we use Mozilla Firefox and Google Chrome. Selenium is a very useful tool, but it's not a simple tool that allows us to use it once we learn it. Practice is necessary, but to practice it is undesirable to use a real website that runs on the Internet.