Interview Questions And Answers On Selenium

What is Automation Testing?

Automation testing is a way of automating the browser application by performing or executing the test cases. Using automation tests, we can perform parallel execution, which we can't do with manual processes. The manual process requires more manpower and more effort to execute the test case. Rather, we can do it using various Automation tools, like Selenium, CodedUI, and QTP, which require less time. Using automation testing, we can execute various scenarios multiple times, but in the case of using manual processes or manual testing, there may be chances of leaving such scenarios. The results are more accurate with automation testing and save a lot of time.

Different Automation Testing Tools in the IT Industry

Nowadays, everyone prefers various Automation Tools like QTP, CodedUI, Selenium, etc. Using these tools, we can get very accurate results compared to of manual processes. Selenium is open source whereas CodedUI and QTP both are licensed tools. Selenium is easy and fast in execution compared to QTP and CodedUI.

Usage of Automation Testing

Using Selenium or any other Automation Tool, we can perform various tasks, like execution of test cases with accurate results, and navigating through various scenarios and screens multiple times. Executing the test cases on remote machines by launching various browsers remotely reduces the time and effort.

What is Selenium and its components?

Selenium is an open-source automation tool that is used to execute test cases on web applications. Selenium supports various programming languages which include C#.Net, Java, Perl, PHP, Javascript, etc. It supports various platforms to perform execution; some of the platforms are Windows, Linux, Mac OS, windows -10(For Edge browser), etc. It supports various browsers to execute the test cases such as Chrome browser, Internet Explorer, Firefox, Safari, Edge, etc.

The various components of Selenium are,

Selenium Core
Selenium RC
Selenium IDE
Selenium Grid
Selenium webdriver.

Among these, Selenium Core and Selenium RC (Remote Control) are part of Selenium version 1.0. Selenium IDE (Integrated Development Environment ), Grid, and Webdriver are part of Selenium 2.0. The popular ones in Selenium are Selenium Grid and Selenium Webdriver, as most of the top organizations are preferring these in their project development.

Why should I prefer Selenium over other Automation tools?

As I mentioned in my above answers, Selenium is an open source Automation tool, whereas CodedUI, QTP, or other tools are Licensed Versions. Selenium is very fast in execution compared to other tools. It supports execution on web applications as well as mobile applications like Android, IOS, etc.

What are the advantages of using Selenium?

You can refer to the above answers.

Using Selenium we can perform parallel execution with the help of hub and node configuration and it also supports execution of the test cases in remote machines which saves time and human effort.

How to find a control or element in Selenium?

We can have various elements or controls on a page like Textbox, radio button, dropdown, Button, Hyperlink, etc.

In Selenium after launching the browser we can perform various operations like clicking a button or selecting dropdown, selecting a checkbox or entering the value in a textbox, checking the radio button, etc based on our requirements.

For identifying the controls or elements, each element will have a unique property like Id, Name, Classname, Xpath, Tagname, CSS Selector, partial link text, etc.

Code for identifying the control

IWebDriver driver;
IWebElement element = driver.Navigate().GoToUrl("http://www.google.com");
element.FindElement(By.Id("Inputname"));
element.FindElement(By.Name("Inputname"));
element.FindElement(By.CssSelector("Inputname"));
element.FindElement(By.TagName("Inputname"));
element.FindElement(By.XPath("//Inputname"));
element.FindElement(By.LinkText("Inputname"));

These are a few examples of finding a control based on their unique properties.

Different versions of Selenium

As I have explained in my earlier questions above, there are three different versions of Selenium.

Selenium 1.0 was the very starting version of Selenium which was released in 2004. In this version, we have Selenium Core and Selenium RC.
Selenium 2.0 is the second version which was released in July 2011 and consists of Selenium IDE, Selenium Grid, and Selenium Webdriver. Most of the companies prefer to work on Selenium Grid and Selenium Web Driver. For more information, you can follow the official website(https://seleniumhq.wordpress.com/2011/07/08/selenium-2-0/)
Selenium 3.0 is the latest version which was released in June 2016 and it has the following advantages or features.

Firefox Browser version is supported by 47+. If we want to work with the older versions; i.e., less than 47 versions, there is no need to install the Gecko driver but working with more than 47+ either in Selenium 2.0 or Selenium 3.0 requires the Gecko driver to be installed and configured.

In this version, we also have support for Microsoft’s Edge Browser, which is Microsoft’s own browser.
The following are the prerequisites to work with Edge Browser.
The client machine should be installed with the Windows 10 Operating system.
It supports Java greater than 8 versions to run Java code (hub).
Support for Safari (Apple OS) Browser is provided by Safari drivers (10.0 version+).
More than 9+ versions of IE are supported in Selenium 3.0.
Now Selenium 3.0 has become a W3C (World Wide Web Consortium) standard.
Selenium 3.0 removed Selenium Core but supports Selenium RC indirectly through back-end Webdriver.
For more information, you can refer to the Selenium Official website (http://www.seleniumhq.org/about/news.jsp) and you can refer to my previous articles (http://www.c-sharpcorner.com/article/introduction-to-selenium-3-0/).

What is the usage of Xpath in Selenium?

If the control or the element is not identified by its unique properties like id, name, class, tag name, etc then in this situation we need to use Xpath. For some elements, there will be no unique properties or there may be properties with the same name for multiple controls like id=inputname for textbox and button. In this case, we need to use XPath to identify the control. Xpath will be unique for each control. Once we inspect the webpage by clicking on F12, we can highlight the element and right-click ---> And click on Copy Xpath.

What is the absolute & relative path in Selenium?

In Xpath Absolute path can be created by using a single forward Slash like ('/'). If we want to take XPath of control then it takes it from the beginning of the element.

/html/body/table/tr/td[2]

Relative path can be created by using two forward slashes like ('//'). If we want to take the XPath of control, the relative path starts in the middle of any element.

//table/tr/td[2]

What is the benefit of using Selenium Grid?

Using Selenium Grid we will be able to execute the test cases in parallel and remotely in another machine by configuring a hub and a node.
We can configure a single hub and multiple nodes from other machines that are connected to the LAN Network.
Hub will act as a Server and distributes the test cases to different nodes which are configured to a particular hub.

What is a webdriver and its types?

Selenium webdriver is an object-oriented tool that consists of various classes and namespaces with which we can perform various actions on the web elements or controls.

To Execute the test cases, each browser has its own drivers to execute.
If we want to execute a test case in Chrome, we have a Chrome driver.
If we want to execute a test case in Internet Explorer, we have an Internet Explorer driver.
If we want to execute a test case in Safari, we have a Safari driver.
If we want to execute a test case in Firefox, we have a Gecko driver. (Supported only for version 47+)
If we want to execute a test case in Edge, we have an Edge driver.
Selenium even supports execution in mobile applications like IOS/Android drivers which can be downloaded from (http://www.seleniumhq.org/download/).

How to launch a browser in Selenium?

Using Selenium Automation Tool we can launch the browser in various browsers like Chrome, Firefox, Edge, Safari, Internet Explorer, etc. If we want to execute it first we need to download their respective driver from the official website.(http://www.seleniumhq.org/download/) unzip them and place them in some folder.

Example 1

To launch the browser in Internet Explorer, Chrome and Firefox drivers.

using OpenQA.Selenium;
using OpenQA.Selenium.Firefox;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.IE;
using Microsoft.VisualStudio.TestTools.UnitTesting;
[TestClass]
public class BrowserTests
{
    [TestMethod]
    public void IELaunch()
    {
        // Internet Explorer
        IWebDriver ieDriver = new InternetExplorerDriver("path of the driver");
        IWebElement ieElement = ieDriver.Navigate().GoToUrl("http://www.google.com");
        // Firefox
        IWebDriver firefoxDriver = new FirefoxDriver("path of the driver");
        IWebElement firefoxElement = firefoxDriver.Navigate().GoToUrl("http://www.google.com");
        // Chrome
        IWebDriver chromeDriver = new ChromeDriver("path of the driver");
        IWebElement chromeElement = chromeDriver.Navigate().GoToUrl("http://www.google.com");
    }
}

Different operations on an element in SeleniumWe can perform various operations or actions to a control like entering the value or clicking the button double click etc.

IWebDriver driver = new FirefoxDriver();
IWebElement element = driver.Navigate().GoToUrl("http://www.google.com");
element.FindElement(By.Id("cvcv")).SendKeys("Hello This is Selenium Interview QA"); // for performing sendkeys to a textbox.
element.FindElement(By.Name("cvcv")).Click();
element.FindElement(By.ClassName("cvcv")).DoubleClick();

What is the difference between findElement() and findElements () in Selenium?

If we want to find a particular element; i.e., a single button textbox or dropdown, or any other control then we find it by the FindElement() method like below

IWebDriver driver = new ChromeDriver("path of the driver");
IWebElement element = driver.Navigate().GoToUrl("http://www.google.com");
element.FindElement(By.XPath("//html/body/input[2]")); // If it is single, find using FindElement()
List<IWebElement> elements = driver.Navigate().GoToUrl("http://www.google.com");
elements.FindElements(By.XPath("//html/body/a")); // If it is a collection, use FindElements()

What is the difference between Quit() and Close()?

Both are the methods of an IwebDriver interface.

driver.close() is used when we want to close the particular windows or current window in which we perform the execution of test cases.
driver.quit() is used when we want to close all the browser windows that were launched or opened by the current web driver.

Which programs are supported in Selenium?

JAVA, C#, PHP, Perl, JavaScript, etc.

What are the platforms supported in Selenium?

Windows(including Windows-10 for Edge browser), Linux, MacOS, etc.

What is Assertion and what different types of Assertions are used in Selenium?

Assertion is used to verify or to check whether the given value is present on the webpage or not, we have various types of Assertions like

Assert Text: Assert text is used to Assert the value Available in the textbox.
AssertElementPresent: AssertElementPresent is used to verify whether the element is displayed on the webpage or hidden state.
AssertBodyText: It is used to verify whether the given input exists on the webpage.
AssertId: It is used to verify / Assert the id of an element.
Assert Title: It is used to verify the title of the webpage.

What is a hub and node?

As we discussed earlier, Hub acts as a Server or middle point. We can configure multiple nodes to a hub. Hub distributes the test cases we want to execute on various nodes.

What is a jar file and how do we configure the hub and node?

The jar file is a Java Execute file that is used for creating the hub.
The following is the process for configuring the hub and Node.
Before configuring the hub, we need to have Java runtime installed on our machine. Without Java runtime, we cannot configure the hub.
Once Java runtime is installed on your machine, you can download the Jar file from the official website.
Java -jar "Name of the jar file" - role hub, this command will configure hub.
Java - jar "name of the jar file" -role hub - node http://192.168.1.1:4444 -browser:browsername="chrome" Version=ANY -DwebDriver.chrome.driver="path of the chrome driver"
The above command will configure the node.

Different types of exceptions are thrown in Selenium

NoSuchElementException
StaleElementReferenceException
ElementNotVisibleException
TimeoutException
ElementNotSelectableException

For more Exceptions in selenium, you can go here.

How do we perform sample unit tests in Selenium?

using OpenQA.Selenium;
using OpenQA.Selenium.Firefox; // or Chrome, InternetExplorer
[TestMethod]
public void LaunchBrowser()
{
    IWebDriver driver = new FirefoxDriver(); // or ChromeDriver(), InternetExplorerDriver("path of the driver file");
    driver.Navigate().GoToUrl("http://www.google.com");
    IWebElement element = driver.FindElement(By.Id("input"));
    element.Click();
}

To execute the above unit test, right-click on the above method, launch the browser, and either you can debug the test or Run.

What is the latest version of Selenium and what are its features?

Selenium 3.0 is the latest version available in the market which was released in June 2016. Please refer to my previous article which is on Selenium 3.0.

What are the parameters or arguments in Selenium?

Host: Host is the IP address of the node/client machine where we want to execute the test case.
Port Number: The default port number is 4444, if we don't assign any port number it takes by default 4444 or we can set other port numbers like 5555, 5556, etc.
Browser: It defines where we need to execute the test case on which browser (for example Chrome, Firefox, IE, Edge), etc.
URL: It defines the URL of the webpage.

How to specify the wait time for a control?

WebDriver driver = new FirefoxDriver();
driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
// Alternatively
Thread.sleep(2000); // 2000 milliseconds (2 seconds)

Does Selenium support testing on mobile-based applications?

Selenium supports mobile application testing, like iOS, Android, etc.

Can we handle Windows-based pop-ups using Selenium?

Yes, Selenium supports both Windows and Web pop-ups.

driver.switchTo().alert();

What is the use of the GetAttribute() method in Selenium?

If we want to access the properties of a control or element such as id, name, class, Tagname, etc, we use the GetAttribute() method.

element.getAttribute("id");
element.getAttribute("class");

How to click on the Login button using Selenium?

webElement.click() 
// or 
webElement.submit()

How to maximize the window in Selenium?

After launching the browser, if we want to maximize the page we use the below code.

driver.manage().window().maximize();

By default, IE and Firefox are maximized, but for Chrome, we need to maximize that using the above code.

You can enhance your knowledge more, by reading the following articles.