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25 Functional Testing Interview Question and Answers

Everyone trying to attain a job in the functional field is confused about the functional testing interview question and answers. The following article has information to help a person crack the interview. Usually, the interviewer expects confidence and correct answers from the employer or applicant. Therefore, the applicant should have in-built confidence. The applicant can know correct answers to about 25 functional testing interview questions and answers from the following article. In addition, there is information relating to manual testing interview questions and software testing interview questions. 

About functional testing

Initially, the applicant trying to crack the interview of functional testing should know what functional testing is. So basically, functional testing can be understood as a process of the application that is being tested concerning the requirement of the document. There are two ways to do functional testing, and those are:

  • Functional testing manually: manual testing involves a human performing all the processes of testing step by step.
  • Functional testing through the automatic process is done without any human assistance, and the automated process is often done with tools and software.

There is a similarity in both of the functional testing processes. Both processes include testing the application using inputs and verifying and determining the output or result after comparing the work with expected results. Functional testing has various phases that are done while testing an input. Functional testing is done to ensure that the current functionalities of the application or software are ready to use. Everyday work should match the software’s primary target and purpose of functional testing. Functional testing is done to improve the quality of the product.

Let’s take an example for functional testing:

Consider an end-to-end test for a customer who wants to add payment information to a retailer’s account. The developer and tester should conduct a trial in the format of to ensure that the secure type of data such as credit card number has been saved in a PCI compliant manner. After confirming that there is no fault and no mistake in any software and ensuring that the given software is as expected by the client, a tester will move forward and send the cleared and checked software to the client.

Types of functional testing

There are about 15 types of functional testing that are given below:

  • Unit testing: before testing the entire software, it is valid to check individual parts of the software and know if they work correctly. Unit testing contains the function of a unit and ensures that (one to a few) every input should result in the expected output. The unit test is done through the process of automation. 
  • Component testing: module testing is another name of component testing. The application’s part is checked in the process of component testing. The method of component testing is quite similar to unit testing. The component testing assesses a part of the software in isolation from the broader system. The difference between component testing and unit testing is that the testers or developers do the component testing in a format of a black box to ensure and verify that individual objects and parts of the software are proper. Developers do the other unit testing in the form of white box to check that program modules execute.
  • Smoke testing is a type of acceptance testing that provides an initial check that new software built should be critical functionality is stable. If the software passes the smoke test, then the software will be sent to test further. Build verification testing is another name for smoke testing. The smoke testing checks whether new or critical functionality meets the objective. If any software doesn’t pass the smoke test, the function says, “where there’s smoke there is fire,” so it’s stated that additional development work is required.
  • Sanity testing: it is a type of regression testing. Professionals QA performs sanity testing on new versions of stable builds to check if there is any new functionality or any bug fixes. With the same capacity of smoke testing, sanity testing also provides a gate check that software is ready for more testing. Sanity testing usually checks that area that has undergone a code change.
  • Regression testing: after passing a single functional test, it doesn’t mean that the entire test is passed. When a developer changes the code or changes a feature, the software runs a regression test to ensure that the functions are as expected. In the process of regression testing, a stable product is maintained after the changes are made.
  • Integration testing: it is often done in pairs with unit tests. At the time of integration testing, QA professionals go through and check whether the individual module of code work is going together as expected or not. Many modern applications run on microservices and self-contained applications that are designed to handle a specific task. The application won’t work as intended if the microservices will not communicate with each other. The integration testing is to be done to ensure these components together operate and communicate together seamlessly.
  • API testing: application programming connects different applications or systems, and they are gaining popularity because every consumer is expecting apps to interoperate. In API testing, a tester validates and ensures that API connections and responses function as intended; they also include handling data and user permissions.
  • UI testing: in the UI type of testing, QA professionals interact with the graphical interface of a problem software program. The UI testing includes the tests related to controls of the UI, for example, buttons, text input, and menus, for ensuring that the experience flow and features chosen are optimal for the user experience. 
  • System testing: With system testing, QA professionals test the entire software as a complete product. With system type functional testing, the tester validates and confirms the integrated and comprehensive software package to make sure that the software product meets the client’s requirements and expectations. In the process of system testing, a tester can review the functional aspect and performance of the app or website without knowing the way it was programmed. The system testing helps a team to develop test cases that are to be used for moving forward. End-to-end testing is another name of system testing.
  • White-box testing: all the details of software internal infrastructure like code and design are visible to the tester and developer, then the case is called white box testing. In the approach of white box testing, a system includes many functional testing types, including unit and system testing. The tester can assess all of the given features individually. 
  • Black box testing: contrary to white box testing, black box testing involves testing against a system where the internal code, paths, and infrastructure are not visible. The tester uses the black box testing method to ensure the expected output against specific inputs.
  • Acceptance testing: the goals set in business requirements should match the end-user software; this is the primary goal of acceptance testing. The acceptance type of testing involves reviewing feature-complete applications and having an end-to-end experience of the software.
  • Alpha testing: as a subset of acceptance testing, alpha testing evaluates the product using internal team members. Not involving the development and testing, the team members should know about the project.
  • Beta testing: after fixing all bugs and testing the product, beta testing occurs with a select group of end-users. Beta testing serves as a soft launch that enables the client to get feedback from the actual user that does not know the given app.
  • Production testing: after the product is public, the product will be in a live production environment where any users can interact with the product anyway. There is no need for the client to control everything from the testing environment to the product. 

Qualities for a functional testing job:

An applicant willing to work for functional testing then the following qualities should be present in them to get selected as an employee:

An applicant should be strong enough to solve and identify all the problems in the software and clear the issues to make them as expected. The logic should be used to examine all the issues, and no problem should be taken for granted. Every case should be given preference and should be solved.

Analytical behavior should be seen in the applicant. Functional testing aims to analyze the problems and give proper reasons to show that the software has a problem and a reasonable explanation about how to solve the problem. The functional testing process requires a lot of analysis that will be helpful and easy if the applicant already has analytical behavior in him.

Testing skills are mandatory for functional testing as the name says that an employee has to work in the testing field, and testing cannot be done without testing skills. Skills have an essential role in relating to the job that an individual does. If a person has testing skills, then he shouldn’t be joining any other fields, and if a person doesn’t have testing skills, he shouldn’t try for a testing job.

A functional tester is very important because it is able to analyze individual parts of an application in the context of the whole application. It examines a particular element, identifies points of integration between that element and other parts of the application, and then formulates a strategy to inspect these weaknesses. Applications are generally weaker where the different parts come together. A strong functional tester knows how to exploit these weaknesses to identify hidden bugs. A functional tester has the ability to assess the individual characteristics of an application.

Qualification of functional testing job

To work as a functional tester, a person should have a bachelor’s degree in the field related to discipline, and they should have experience in this field of work for a minimum of five years. Furthermore, with the given degree, a person should have the qualities of a tester, especially the analyzing and logical thinking quality. If a person has the qualities and qualifications, then the person can easily fit the work of a functional tester.

Following are the 25 functional testing interview questions and answers that can help an interviewee to crack the interview of any job related to functional testing. 

Functional testing interview questions for freshers

1. What can you tell about functional testing?

Answer: as the name itself says functional testing is a type of test that is done to check that the product of the software matches the client’s expectations. The role of functional testing is to verify whether the application is ready to be sent to the live environment or not. The functional tester should validate the application’s behavior according to the client’s document specifications. There are about 15 types of functional testing. Still, generally, 7 types of functional testing are given more preference: unit testing, integration testing, smoke testing, system testing, usability testing, user acceptance testing, and lastly, regression testing. In all of these testing types, customer satisfaction and precise software without any problems should be verified and given particularly.

2. What are the major differences between nonfunctional testing type and functional testing type?


Nonfunctional testingFunctional testing
This is a process of testing that is done in order to determine the performance of the system as per the expectations of the client.This is performed to check the behavior of the system as per the functional requirements of the client.
With effective and efficient tools that are required, nonfunctional testing is done after the process of functional testingThere are two tools for functional testing and they are manual testing tools and automation testing tool.
It is difficult to perform manual testing as the reliability, speed, scalability and other parameters are the input in nonfunctional testing.It is easy to do manual testing as the given input of functional testing is client requirements.
There are following types in nonfunctional testing:Load, volume and stress testTesting of performanceTesting of securityTesting of compatibility.Following are the types in functional testing:Testing unitSmoke testingIntegration testingUser acceptance testingRegression testingSanity testing

3. What is the exact meaning of the bug cycle?

Answer: bug cycle is known as unwanted error, flaw, mistake, etc. That is inside the application. The bug cycle prevents the product from becoming the desired output. Whenever a bug is found or a defect encountered in an application while the time of testing from the entire logging process is done till it is revolved. A bug will move through a fixed life cycle that is known as a bug life cycle. 

The whole process of the bug cycle starts from the encounter of the bug or issue. First, the bug will be reported in a tool named bug tracking. Then the bug will be handed over to the developer, and the bug’s status will be ‘open’. The developer will now review the given bug and start working on the bug.

4. Explain about data- driven testing with its advantages?

Answer: The testing named as data-driven is a methodology where the test script with the test cases are run continuously by using few new data sources like an XML file, CVS File for the values of input and actual output will be compared to the expected software in the process of verification. For instance, a test studio is a tool used for data-driven testing.

Advantages of data-driven:

Repeatability in output

Separation of test logic from test data

The reduction in the number of test cases

5. Explain about automation testing and the tools of automation.

Answer: it is a testing methodology that uses automation tools to execute a few test cases to increase coverage of tests and increase test execution speed. The automation testing is conducted by pre-scripted tests and does not require any human interaction. 

Following are the tools of automation testing that do not require any human interaction:

  • Tellurium
  • Selenium
  • SoapUI
  • Watir

6. How many types of test techniques are used in the process of functional testing?

Answer: there are about two types of test techniques while using functional testing and they are defined below:

Business process type testing: the business process perspective involves this type of functional testing. The business process type testing requires knowledge of business processes for performing tests.

Requirement-based testing: This form’s functional testing is done to prioritize the requirements based on risk criteria. The requirements-based testing makes sure that all the critical test paths are included in the testing process.

7. What is meant by accessibility testing?

Answer: it is a type of usability testing in which the testing is done to ensure that differently-abled people easily handle the software. If someone has a problem in hearing or if a person has color blindness, then it shouldn’t be difficult for them to use the software. In today’s life, the internet is acquiring a significant place in the life of growth. The internet is in the form of e-commerce sites, e-learning, and e- payments. For a change in life, everyone should use technology, especially people dealing with some natural problems.

8. Explain the team of sanity testing?

Answer: sanity testing is done after checking new functionality or defects that are yet to be fixed. Insanity testing the goal is stated as checking functionality roughly that is as expected and to know that the bug is fixed and to check if there is any effect of a fixed bug on the application under test. 

9. What do you know about user acceptance testing?

Answer: it is usually performed after the software is tested correctly. In the user acceptance testing, the client uses the software to check if there is no problem and every work is done and going perfectly, and everything is as expected.

10. What is the reason for performing smoke testing?

Answer: the performance of smoke testing is done after the application received build. The critical path is tested in depth to make sure that the build is valid enough for further testing.

11. What is the role of validation and verification in the testing of software?

Answer: the verification is done to confirm that product development is going on as per the specifications mentioned. The following activities come under verification:

Reviews, inspections, walkthrough, and demos

The validation is done to confirm that the developed product doesn’t have any bugs and if the product is working as expected by the client. Validations include the following activities:

Non- functional testing and functional testing

12. What is meant by black box testing?

Answer: black box testing is a software testing approach that wants testers to assess the software as per the business requirements. Here the software is taken as a black box and checked as per the user’s point of view.

13. What do you understand by test plan and what comes under it?

Answer: the test plan stores the testing activities to check the quality of the product. The test plan takes data from requirements, use case documents and product description.

Following are the documents including in the test plan:

  • Test scope
  • Environment
  • Deliverables
  • Reason for testing
  • Testing the flame

14. Explain about test coverage.

Answer: a quality metric that shows the amount of testing that is completed is called test coverage. The test coverage shows the amount of tested product in percentage. The test coverage goes under the functional testing and non- functional activities. Test coverage is used to know the exact percentage of a product that has done a testing process.

15. What are the three ways to validate integration?

Answer: unit testing is also known as module testing or component testing. The integration testing checks how good units (more than two) are contacting each other. Following are three types of validate integration:

Top down approach
Big bang approach
And Bottom up approach.

16. State minor differences between a test stub and test driver.

Answer: a test stub can be said as a dummy program that deals with an application to complete its process in functionality. The test stub uses a top down approach in order to test the product.

A test driver can be said as a code that is used for a software component under test. The test driver uses a bottom up approach in order to test the product.

17. What do you know about agile testing and about its importance?

Answer: agile testing can be known as a testing process of software that corrects the software by the view of a customer. The agile testing is quite favorable because it does not need any team to do the coding completion. The process of agile testing requires customer interactions. 

18. Can a person check the program thoroughly? If not then why?

Answer: no, a program cannot be checked thoroughly. We have the following principal reasons that don’t allow a program to be checked entirely.

Too many outputs, path combinations and many outputs are required for a software program.

Different interpretations may lead and the software can be subjective.

19. How can you differentiate between defect, error and bug?

Answer: when a code finds a slip then it is an error. When the error gets spotted by a manual tester then it becomes a defect. When the development team agrees a defect then it is called a bug. If any built code is missed while required then it is called functional failure.

20. State similarities between priority and severity?

Answer: the similarities can be understood by following definitions:

Priority: here the point of view of a user is declined and it decides about the order of fixing bugs.

Severity: here the application’s point of view is accepted and severity shows the depth of a bug.

21. How can a person perform automated testing?

Answer: it is a process of executing tests automatically. Automated testing can be done to avoid human intervention. Different tools of automation like selenium, QTP and WinRunner can be used to test. By these tools a person can create their test scripts and verify the application automatically.

22. Give a short explanation on the silk test.

Answer: performance of regression and functionality testing can be done by developing silk tools. The silk test can be used while testing Java, web, and window-based work. In addition, a silk test can help a person while preparing the plan for the test.

23. Name benefits of test reports.

Answer: following are the benefits of test reports:

Test reports can know the current status and quality of a product
The stakeholders and customers can take action with the help of test reports
The test reports will help in analyzing different phases of the project.

24. How many types of defects are seen and what are they?

Answer: there are about three types of defects and they are missing, wrong and extra. 

25. What do you know about exploratory testing?

Answer: continue testing design and execution to it is known as exploratory testing. The domain knowledge and experience in testing are used in experimental testing. 


Functional testing is an integral part of any software testing mechanism. It ensures that a system is working exactly as it should, in real time. Since functional testing is done from the user’s point of view, it helps to deliver a high quality product that satisfies the customers and provides a very satisfying user experience. Of course, this makes life easier for developers and company staff.

Finally, in the functional test, the functionality of the module is tested and the structure is not taken into account. This is done from the user’s point of view. This test ensures that the system is doing what users expect of it. And this kind of testing means testing the functionality and verifying the output according to the requirements documents. to get selected for the job related to functional testing, whether it be manual testing, software testing, or even functional testing. A person should have the knowledge and brief information related to the content. With the help of the following 25 interview questions, an applicant can increase their knowledge skills and understand the functional interview and about testing.

More Resources : jobs in Kakinada today | jobs in Bhubaneswar for freshers graduates | business development associate interview questions | logical questions for interview

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