Selenium is an open-source tool used for automating web applications across different browsers. Its primary components include Selenium WebDriver (for browser automation), Selenium IDE (for record and playback functionality), and Selenium Grid (for running tests in parallel across multiple browsers and machines).
Selenium is free, supports multiple programming languages (like Java, Python, and C#), and is compatible with different browsers. It allows cross-browser testing, integrates with CI/CD tools like Jenkins, and supports parallel execution with Selenium Grid.
Locators in Selenium are used to identify elements on a web page. Common locators include ID, Name, Class Name, XPath, CSS Selector, and Link Text. These locators help Selenium identify and interact with web elements during test execution.
Selenium 4.0 introduces several new features, including native support for Chrome DevTools, relative locators (like “above,” “below,” “near”), and an improved Selenium Grid architecture that simplifies cross-browser and parallel testing.
Dynamic web elements can be handled using explicit waits, which wait for a specific condition to occur before proceeding. Other strategies include using relative XPath to locate elements and polling intervals to check for element availability.
The Page Object Model (POM) is a design pattern used in Selenium to create object repositories for web elements. In POM, every web page in the application is represented as a class, and elements on the page are defined as variables. This improves code reusability and maintenance.
Selenium allows testers to handle multiple browser windows or tabs using the getWindowHandles() method. This method returns a set of window handles, which can be iterated to switch between different windows using switchTo().window().
Implicit wait is a global wait that applies to all elements, telling WebDriver to wait a specified time before throwing an exception. Explicit wait, on the other hand, waits for a specific condition to be true before interacting with the element. It is more flexible and targeted compared to implicit wait.
Pop-ups and JavaScript alerts are handled using the driver.switchTo().alert() method. This method provides options to either accept (accept()) or dismiss (dismiss()) the alert. For input pop-ups, Selenium allows interaction using sendKeys() to enter text into the alert.
Screenshots can be captured using the TakesScreenshot interface in Selenium. The getScreenshotAs() method is used to take the screenshot and store it as a file. This is useful for debugging and logging failed tests.
JavaScript execution is done using the JavascriptExecutor interface. The executeScript() method allows testers to run JavaScript directly in the browser. This can be used to perform actions like scrolling, clicking, or interacting with elements that may not be accessible through standard WebDriver commands.
The findElement() method returns the first matching web element based on the locator, while findElements() returns a list of all matching elements. If no element is found, findElement() throws an exception, while findElements() returns an empty list.
Drag-and-drop actions in Selenium are performed using the Actions class. The dragAndDrop() method is used to click and hold an element, move it to a target location, and then release it. This is useful for testing complex user interactions like drag-and-drop.
Selenium Grid is used for running tests in parallel on multiple machines and browsers. It follows a hub-node architecture, where the hub is the central point controlling the test distribution, and nodes are machines where the tests are executed. This allows for efficient cross-browser and parallel testing.
Frames are handled using the switchTo().frame() method. Selenium can switch between frames by index, name, or web element. Once inside a frame, the test script can interact with elements inside it. After interacting, you can switch back to the main document using switchTo().defaultContent().
TestNG is a testing framework used for managing and organizing test cases. It provides features like annotations, test prioritization, parallel test execution, and reporting. When integrated with Selenium, TestNG helps structure tests, generate reports, and manage test dependencies.
Exception handling is done using try-catch blocks in Selenium. Common exceptions include NoSuchElementException, TimeoutException, and StaleElementReferenceException. Explicit waits are often used to avoid such exceptions by waiting for elements to be available before interacting with them.
Selenium provides three types of waits: implicit wait, explicit wait, and fluent wait. Implicit wait applies a global time to wait for elements, explicit wait waits for a specific condition, and fluent wait repeatedly checks for a condition and handles exceptions during the wait.
Cross-browser testing in Selenium is done by configuring different browser drivers like ChromeDriver, FirefoxDriver, or EdgeDriver. Tests can be run across multiple browsers by specifying the browser type in the test configuration and using Selenium Grid for parallel execution.
Selenium can be integrated with CI tools like Jenkins by creating build jobs that trigger test execution automatically after each code commit. The tests can be run on multiple environments, and Jenkins can generate detailed reports of the test results. This helps automate the testing process in a CI/CD pipeline.
