Beginner's Guide to Using Selenium for Automated Testing

Selenium is an open-source automation tool used for testing web applications across different browsers and platforms. It mimics real user interactions like clicking, typing, and navigating to verify if everything on a webpage works as expected.

Why use Selenium?

Selenium is widely used in the industry for functional and regression testing.

• It’s free and open source.

• Supports multiple programming languages (Java, Python, C#, etc.)

• Works on multiple browsers (Chrome, Firefox, Edge, etc.)

• Cross-platform support (Windows, macOS, Linux)

• Integrates well with tools like TestNG, Maven, Jenkins, etc.

Selenium components:

• Selenium IDE – A simple record-and-playback tool for beginners

• Selenium Grid – Allows running tests on different machines/browser combinations in parallel

• Selenium WebDriver - The most used part; it’s controls the browser directly.

🧠 Why we write WebDriver driver = new ChromeDriver(); in Selenium

Selenium WebDriver → Browser Driver (like ChromeDriver) → Real Browser

✅ 1. WebDriver is an Interface

• WebDriver is a built-in Selenium interface that defines all the browser automation methods like .get(). click(), .sendKeys() etc.

• It provides a standard way to write automation code for different browsers.

✅ 2. ChromeDriver is a Class

• ChromeDriver is a class that implements the WebDriver interface.

• It contains the actual code to control the Chrome browser.

✅ 3. Why use Interface as Reference?

• WebDriver driver = new ChromeDriver(); is written this way to follow the Java best practice: "Program to an interface, not an implementation."

• This makes your code flexible and easily maintainable.

✅ 4. Easily Switch Between Browsers

• By using the WebDriver interface, you can switch to other browsers by changing just one line:

    javaCopyEditWebDriver driver = new FirefoxDriver(); // For Firefox
    WebDriver driver = new EdgeDriver();    // For Edge
  

• The rest of the automation code stays the same!

✅ 5. Creates Browser Instance

• new ChromeDriver() launches a new Chrome browser window.

• Combined with WebDriver driver, it initializes and opens the browser for automation.