Selenium Interview Questions, Preparing for a Selenium SDET (Software Development Engineer in Test) role requires a solid understanding of Selenium WebDriver and various testing concepts. Below are 50 common Selenium interview questions with their answers and explanations to help students prepare for their interviews:
Selenium Interview Questions
1. What is Selenium
Answer: Selenium is an open-source automation testing framework used to automate web browsers for testing web applications. It supports multiple programming languages like Java, Python, C#, etc.
2. Explain the difference between Selenium IDE, Selenium WebDriver, and Selenium Grid.
Answer:
- Selenium IDE: A record and playback tool for creating Selenium test scripts in Firefox.
- Selenium WebDriver: A powerful API to interact with web elements and automate browsers programmatically.
- Selenium Grid: A tool to run tests in parallel on multiple machines or browsers.
3. What browsers does Selenium WebDriver support?
Answer: Selenium WebDriver supports various browsers, including Chrome, Firefox, Internet Explorer, Safari, Edge, and more.
4. How do you handle dynamic elements in Selenium WebDriver?
Answer: Use techniques like explicit waits (WebDriverWait), implicit waits (driver.manage().timeouts().implicitlyWait()), or expected conditions to handle dynamic elements.
5. How do you perform mouse hover actions in Selenium WebDriver?
Answer: Use the Actions class to perform mouse hover actions:
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.interactions.Actions;
Actions actions = new Actions(driver);
WebElement element = driver.findElement(By.id("element_id"));
actions.moveToElement(element).perform();
6. What is the difference between driver.close() and driver.quit()?
Answer: driver.close() closes the current browser window, while driver.quit() exits the WebDriver and closes all associated browser windows.
7. How do you handle alerts, prompts, and confirmations in Selenium WebDriver?
Answer: Use Alert class methods like accept(), dismiss(), and send_keys() to handle JavaScript alerts, prompts, and confirmations.
8. How do you handle frames and iframes in Selenium WebDriver?
Answer: Use driver.switch_to.frame() method to switch to frames or iframes, and driver.switch_to.default_content() to switch back to the default content.
9. What are implicit and explicit waits in Selenium WebDriver?
Answer:
- Implicit wait sets a global timeout for the driver to wait for an element to appear before throwing an exception.
- Explicit wait uses
WebDriverWaitwithExpectedConditionsto wait for specific conditions before proceeding with the test.
10. How do you handle dropdowns in Selenium WebDriver?
Answer: Use Select class to interact with dropdowns. For example:
import org.openqa.selenium.support.ui.Select;
Select dropdown = new Select(driver.findElement(By.id("dropdown_id")));
dropdown.selectByVisibleText("Option Text");
11. How do you handle SSL certificate errors in Selenium WebDriver?
Answer: Use the --ignore-certificate-errors argument for ChromeOptions to handle SSL certificate errors in Java:
import org.openqa.selenium.chrome.ChromeOptions;
ChromeOptions options = new ChromeOptions();
options.addArguments("--ignore-certificate-errors");
WebDriver driver = new ChromeDriver(options);
12. How do you take screenshots in Selenium WebDriver?
Answer: Use TakesScreenshot interface to take screenshots in Java:
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
TakesScreenshot screenshotDriver = (TakesScreenshot) driver;
File screenshotFile = screenshotDriver.getScreenshotAs(OutputType.FILE);
13. What is TestNG, and why is it used with Selenium?
Answer: TestNG is a testing framework for Java. It is used with Selenium for better test management, parallel test execution, and generating test reports.
14. How do you handle multiple windows or tabs in Selenium WebDriver?
Answer: Use driver.getWindowHandles() to get a list of window handles, and then use driver.switchTo().window() to switch between them in Java:
Set<String> windowHandles = driver.getWindowHandles();
for (String windowHandle : windowHandles) {
driver.switchTo().window(windowHandle);
// Perform actions on the window
}
15. What are data-driven testing and how can you achieve it in Selenium WebDriver?
Answer: Data-driven testing involves running the same test with different sets of data. You can achieve it using data providers in TestNG or by reading data from external sources (e.g., Excel, CSV).
16. Explain Page Object Model (POM) and its advantages.
Answer: Page Object Model is a design pattern where each web page is represented as a separate class, encapsulating its elements and actions. It improves code maintainability, reusability, and readability.
17. How do you handle browser cookies in Selenium WebDriver?
Answer: Use driver.manage().getCookies() to get cookies, driver.manage().addCookie() to add cookies, and driver.manage().deleteAllCookies() to delete all cookies in Java.
18. How can you handle AJAX calls in Selenium WebDriver?
Answer: Use explicit waits with ExpectedConditions to wait for AJAX calls to complete before interacting with elements affected by AJAX in Java.
19. How do you handle file uploads in Selenium WebDriver?
Answer: Use send_keys() on the file input element to specify the file path for file uploads.
WebElement fileInput = driver.findElement(By.id("fileInput"));
fileInput.sendKeys("/path/to/file");
20. What is the Page Load Strategy in Selenium WebDriver?
Answer: The Page Load Strategy defines how WebDriver waits for a page to load. Strategies include normal, eager, and none.
21. How do you perform keyboard actions like typing and pressing keys in Selenium WebDriver?
Answer:
Use sendKeys() method to type text and the Keys class for keyboard actions like ENTER, TAB, etc. in Java:
import org.openqa.selenium.Keys;
WebElement inputField = driver.findElement(By.id("inputField"));
inputField.sendKeys("Hello, world!");
inputField.sendKeys(Keys.ENTER);
22. How can you handle SSL certificate authentication pop-ups in Selenium WebDriver?
Answer: Use the --allow-insecure-localhost argument for ChromeDriver or set an --untrusted-cert preference for FirefoxDriver.
23. Explain the use of GeckoDriver in Selenium WebDriver.
Answer: GeckoDriver is required to run Selenium tests in Firefox browser since Selenium 3.0, as it provides the necessary bindings for Firefox.
24. How do you perform headless browser testing using Selenium WebDriver?
Answer: Use the --headless option for Chrome or Firefox drivers to run tests without launching a visible browser.