Top Selenium Interview Questions and Answers
Here are the top 35 sample Selenium interview questions and their answers. These sample questions are framed by experts from Cedar Pro who train for Selenium Training to give you an idea of the type of questions asked in interviews. We have taken full care to give accurate answers to all the questions. Selenium is an open-source tool used for Automation Testing, which allows you to test web applications across a range of browsers. It was introduced once Manual Testing started to pose several challenges, and there was a high demand for a method that automates the testing process. This Selenium Interview Questions blog has a compiled list of most of the questions that are asked during Selenium job interviews. These Selenium interview questions are mentioned below:
Top Answers to Selenium Interview Questions
Basic Interview Questions
Automation testing is the process of automating the manual testing of the application under test (AUT) or the system under test (SUT). It includes the involvement of testing tools that help us create test scripts, which can be used repeatedly without any human intervention.
Selenium RC is called Selenium 2.0, and the integration of Selenium RC and WebDriver as a single tool has formed Selenium 3.0.
Selenium uses locators to find and match the elements of a web page that it needs to interact with. There are different types of locators to identify various web elements on a web page:
• UI element
For testing web-based applications, Selenium can be used.
The test types supported by Selenium are:
• Functional testing: It verifies that each function of a software application performs in accordance with specific requirements. This testing primarily involves black-box testing, and it is not concerned about the source code of the application.
• Regression testing: It is nothing but a full or partial selection of the already executed test cases to re-executed to ensure whether the existing functionalities work fine.
While DOM is the recognized standard way for navigating through an HTML element tree, XPath is the navigation tool used to locate a web element based on its XML path.
XML stands for ‘Extensible Markup Language’ and is used to store, organize, and transport arbitrary data. It stores data in a key–value pair that is very much similar to HTML tags. Both being markup languages and falling under the same umbrella, XPath can be used to locate HTML elements.
The fundamental concept behind locating elements using XPath is traversing between various elements across the entire page and thus enabling a user to find an element with the reference of another element.
• Single Slash (/): Single slash is used to create an XPath with an absolute path. In this case, the XPath would start selection from the document’s start node.
• Double Slash (//): Double slash is used to create an XPath with a relative path. In this case, the XPath would start selection from anywhere within the document.
Selenium should be used for test automation as it:
• Is a free and open-source tool
• Has a large user base and community support
• Has cross-browser compatibility (Firefox, Chrome, Internet Explorer, Safari, etc.)
• Has great platform compatibility (Windows, Mac OS, Linux, etc.)
• Supports multiple programming languages (Java, C#, Ruby, Python, Perl, etc.)
• Has fresh and regular repository developments
• Supports distributed testing
Yes, Selenium has a few limitations:
• Testing of only web applications is possible using Selenium.
• Testing of mobile applications or desktop applications is not possible.
• Captcha and barcode readers cannot be tested using Selenium.
• A third-party tool like TestNG or JUnit should be used to generate reports.
• As Selenium is a free tool, there is no ready vendor support through which users can find various helping communities.
• Prior programming language knowledge is expected from users.
An object repository allows testers to accumulate web elements of the application under test (AUT), along with their locator values, in one or more centralized locations as restricted to hard-coding them within the test scripts.
Intermediate Interview Questions
In Java, a special form of syntactic metadata can be added to Java source code, which is known as ‘annotations’. Variables, parameters, packages, methods, and classes are annotated. Some of the JUnit annotations are:
JUnit annotations linked with Selenium are:
• @Test: The @Test annotation finds a method to be a test method. When used before a test method, it is mentioned as ‘@Test’; it informs the JUnit framework that the following method is a test method.
• @Before: The @Before annotation is used to find the method that is executed before executing the test method. This method can be used to set up the test environment.
• @After: The @After annotation is a method that is executed after executing the test method. This method can be used to do a teardown, i.e., it is a method used to delete all temporary data, set-up default values, clean up the test environment, etc.
• @BeforeClass: The @BeforeClass method is used only once before the start of all tests. Basically, this is used to perform cumbersome activities, like connecting to a database.
• @AfterClass: The @AfterClass method is used only once after executing all tests. Basically, this is used to carry out clean-up activities, like disconnecting from a database.
Selenium is more widely used than QTP since:
• Selenium is an open-source tool, whereas QTP is a profitable tool
• Selenium is used specifically for testing web-based applications, while QTP can be used for testing client–server applications too
• Selenium supports multiple browsers like Firefox, IE, Opera, Safari, etc. and has multiple operating systems compatibility too. Selenium-supported OS platforms are Windows, Mac, Linux, etc. On the other hand, QTP is limited to Internet Explorer on Windows
• Selenium supports multi-programming language compatibility. Languages supported by Selenium are Python, Ruby, Perl, etc. But, QTP supports only VBScript
The ‘Same-origin Policy’ is introduced for security reasons.
• It ensures that the content of our site will never be accessible by a script from another site.
• As per the policy, any code loaded within the browser can only operate within that website’s domain.
To avoid this same-origin policy, the proxy injection method is used. In the proxy injection mode, Selenium Server tricks the browser to be a real HTTP URL, i.e., it acts as a client-configured HTTP proxy, which sits between the browser and the application under test (AUT) and then masks the AUT under a fictional URL.
A data-driven framework in Selenium is an approach of separating a ‘dataset’ from the actual ‘test case’ (code). This framework is completely dependent on the input test data. The test data is inserted from the external sources, such as from an Excel file, a CSV file, or from any database. It also allows us to easily control how much data needs to be tested. We can easily increase the number of test parameters by adding more username and password fields to the Excel file (or other sources).
A keyword-driven framework is an extension to the data-driven testing framework in the sense that it not only isolates the test data from the scripts but also keeps the particular section of the code belonging to the test script in an external data file. These sets of code are known as keywords, and hence the framework is so named. Keywords are self-guiding and work based on what actions need to be performed on the application.
If the file is on the same machine or in a mapped network drive, it is really straightforward: We have to just type the ‘path’ of the file in the FileUpload control.
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• getwindowhandles(): It is used to get the address of all open browsers, and its return data type is Set<String>.
• getwindowhandle(): It is used to get the address of the current browser where the control is, and its return type is a string data type.
Selenese is a set of commands in Selenium used for running a test.Three types of Selenese are as follows:
• Actions: They are used for performing interactions and operations with the target elements.
• Accessors: They are used for storing values in a variable.
• Assertions: They are used as a checkpoint.
To insert a breakpoint:
• First, we’ll have to select ‘Toggle Breakpoint’ by right-clicking on the command in Selenium IDE
• Then, press ‘B’ on the keyboard and select the command
• The same step should be repeated for deselecting a breakpoint
Advanced Interview Questions
There are two types of waits available in WebDriver:
• Implicit wait: These waits are used to provide a default waiting time (say, 30 seconds) between the consecutive test steps across the entire test script. Hence, the subsequent test step would only be executed only when the 30 seconds are over after executing the previous test step.
• Explicit wait: These waits are used to halt the execution until a particular condition is met or the maximum time has elapsed.
Explicit waits are instantiated for a particular instance only, whereas implicit waits are not.
An iframe (an acronym for ‘inline frame’) is used to insert another document within the current HTML document.
Selecting iframe by ID:
Locating iframe using the tagName:
Locating iframe using index:
• frame(“Name of the Frame”)
• frame(WebElement element)
Select Parent Window
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Different types of frameworks are as follows:
• Module-based Testing Framework: This framework divides the entire application under test (AUT) into a number of logical and isolated modules. For each module, we create a separate and independent test script. Thus when these test scripts are taken together, it builds a larger test script representing more than one module.
• Library Architecture Testing Framework: Instead of dividing AUT into test scripts, with this framework, we segregate the application into functions or rather common functions that can be used by the other parts of the application as well. Thus, we create a common library constituting of common functions for AUT. Therefore, these libraries can be called from the test scripts whenever required.
• Data-driven Testing Framework: The data-driven testing framework helps us segregate the test script logic and the test data from each other. It lets us store the test data into an external database. The data is conventionally stored in ‘key–value’ pairs. Keys can be used to access and populate the data within the test scripts.
• Keyword-driven Testing Framework: The keyword-driven testing framework is an extension to the data-driven testing framework in the sense that it not only segregates the test data from the scripts but also keeps a certain set of codes belonging to the test script in an external data file.
• Hybrid Testing Framework: A hybrid testing framework is a combination of more than one of the above-mentioned frameworks. The best thing about such a setup is that it leverages the benefits of all kinds of associated frameworks.
• Behavior-driven Development Framework: The behavior-driven development framework allows the automation of functional validations in an easily readable and understandable format to Business Analysts, Developers, Testers, etc.
Quick Test Professional (QTP)
|Browser compatibility||It supports almost all popular browsers: Firefox, Chrome, Safari, Internet Explorer, Opera, etc.||QTP supports Internet Explorer, Firefox, and Chrome. It only supports Windows operating system|
|Distribution||It is distributed as an open-source tool and is freely available||It is distributed as a licensed tool and is commercialized|
|Application under test (AUT)||It supports the testing of web-based applications only||It supports the testing of both web-based and Windows-based applications|
|Object repository||Object repository needs to be created as a separate entity in Selenium||QTP automatically creates and maintains the object repository|
|Language support||It supports multiple programming languages like Java, C#, Ruby, Python, Perl, etc.||It supports only VBScript|
|Vendor support||As Selenium is a free tool, users would not get the vendor’s support in troubleshooting issues||Users can easily get the vendor’s support if they face any issues|
Breakpoints: Breakpoints are used to stall the execution of the test. The execution will stop whenever a breakpoint is implemented, and this will help us check whether the code is working properly or not.
Start points: Start points are the points from where the execution should begin. Start points can be used when we want to run the test script from the middle of the code or after a breakpoint.
While working with Selenium, we need session handling. This is because, during test execution, Selenium WebDriver has to interact with the browser all the time to execute the given commands. It is also possible that, before the current execution completes, someone else starts the execution of another script in the same machine and in the same type of browser. So to avoid such a situation, we need session handling.
The types of Listeners in TestNG are:
Selenium solely supports web application testing. It does not support the testing of Windows-based applications or mobile applications. To handle Windows-based popups, third-party intervention is required. AutoIt and Robot Class are examples of third-party tools that we can use alongside Selenium to handle Windows-based popups.
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For the database testing in Selenium WebDriver, we need the JDBC (Java Database Connectivity) API. It allows us to execute SQL statements.
We can use isElementPresent (string locator) to find an object in Selenium. It takes a locator as the argument and, if found, returns a Boolean.
XPath is used to define web elements on a web page. The major advantage of XPath is it helps us in identifying the elements dynamically.
There are two types of XPath:
• Absolute XPath
• Relative XPath
Selenium is a popular open-source software that is used to automate web-based applications. It is a set of multiple software tools, and each tool has a different approach to automated testing.
Selenium has four major components, namely:
• Selenium Integrated Development Environment
• Selenium Remote Control
• Selenium WebDriver
• Selenium Grid
Selenium Grid creates a test suite that works by forwarding test cases to the hub, and from there, the test cases are redirected to Selenium WebDriver. WebDriver will then execute them in the browser. The test suite allows for running tests in parallel.