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Selenium

tldr; Instead of using mouse and keyboard to control browser, you call a Selenium function.

Selenium is a software project that allows you to automate web applications using various browsers

Components of Selenium​

ELI5 description

  • Web Driver - jar file with bunch of classes to automate browser
  • Selenium IDE - records actions you perform on browser and creates an automation script
  • Selenium Grid - Run tests remotely

Selenium components

Selenium IDE hands on​

[!NOTE] Scripts created by this plugin is pretty terrible Not necessarily because it's bad engineering It's genuinely a hard problem

[!NOTE] Generated code is using JUnit 4

Selenium Web Driver hands on​

Pre-requisites​

  • Java 21
  • Gradle 8
  • Firefox
  • VSCode with Extension Pack for Java (or any other Java IDE)

Simple Selenium Demo​

Webdriver classic, WebDriver BiDi​

Dec 21, 2024 9:12:29 AM org.openqa.selenium.firefox.FirefoxDriver <init>
WARNING: CDP support for Firefox is deprecated and will be removed in future versions. Please switch to WebDriver BiDi.

WebDriver classic architecture​

webdriver classic architecture

WebDriver BiDi architecture​

webdriver bidi architecture

Enable BiDi​

Chrome​

var options = new ChromeOptions();
options.setCapability("webSocketUrl", true);
browser = new ChromeDriver(options);

Firefox​

var options = new FirefoxOptions();
options.setCapability("webSocketUrl", true);
browser = new FirefoxDriver(options);

Remove extensions​

[!NOTE] While most Selenium commands are included in the specification, some things are browser specific

On Chrome​

var options = new ChromeOptions();
options.addArguments("--disable-extensions");
browser = new ChromeDriver(options);

On Firefox​

var options = new FirefoxOptions();
options.addArguments("--safe-mode");
browser = new FirefoxDriver(options);

[!NOTE] --safe-mode flag in Firefox disables multiple features including extensions Such as Hardware Acceleration & Themes etc

Common Exceptions​

ELI5 description;

  • NoSuchElementException - Element you are looking for is not in the webpage. If selector is correct, see if it's inside an iframe
  • StaleElementReferenceException - Element was there but not right now
  • ElementClickInterceptedException - Popup probably covering the element or not in the view

[!TIP] Looking for info? Search in documentation first Then try GPTing it or try Stackoverflow

Page object model design pattern​

Why page object model​

  • Re-usability
  • Ease of maintenance
  • Better readability and clarity
  • Create pages from form and form output
public class Page {
  private WebDriver browser;

  @FindBy(id = "identifier")
  private WebElement elementName;

  Page(WebDriver browser) {
    this.browser = browser;
    PageFactory.initElements(browser, this);
  }

  public void doSomething(String value) {
    this.elementName.sendKeys(value);
  }
}

Headless mode

changes

Chrome​

var options = new ChromeOptions();
options.addArguments("--headless=new");
browser = new ChromeDriver(options);

Firefox​

var options = new FirefoxOptions();
options.addArguments("--headless");
browser = new FirefoxDriver(options);

Questions?