Top 70 Plus Functional Testing Interview Questions with Answers

Functional testing is essential in software quality assurance, ensuring applications perform as specified. As software's role in business and daily life grows, the demand for skilled functional testers increases. These professionals verify that software functions correctly, providing a seamless user experience.

To succeed in a functional testing interview, candidates must understand various testing methodologies, techniques, and tools. They need to demonstrate their ability to identify and resolve issues efficiently. This article offers a concise set of common functional testing interview questions and answers to help aspiring testers showcase their expertise. Whether you're new to the field or seeking to refine your skills, this guide will assist you in preparing for interviews and securing a role in functional testing.

Functional Testing Interview Questions for Freshers

Here in this section, we explore common interview questions about Functional Testing. Functional Testing checks that software does what it's supposed to do according to its requirements. The questions cover everything from the basics of how functional testing works to more detailed situations that test your ability to use it in real jobs.

1. What is Functional Testing?

Functional testing is a type of black-box testing that verifies that each function of the software application operates in conformance with the requirement specification. This type of testing involves checking user interfaces, APIs, databases, security, and other functionality to ensure that the software behaves as expected.

2. Why is Functional Testing Important?

Functional testing is crucial because it ensures that the software system operates according to the specified requirements and meets the needs of the end users. It helps identify any discrepancies between the actual and expected output, thereby improving the overall quality and reliability of the software.

3. What is the Purpose of Functional Testing?

The primary purpose of functional testing is to validate the software's functionality against the specified requirements. It ensures that the software performs its intended functions correctly and provides the expected results. This type of testing helps detect functional errors and issues early in the development cycle, reducing the risk of defects in the final product.

4. What Kind of Testing Covers Functional Testing?

Functional testing includes several types of testing such as:

• Unit Testing: Testing individual components or units of code.
• Integration Testing: Testing the interaction between integrated units or components.
• System Testing: Testing the complete and integrated software system.
• Acceptance Testing: Validating the software against user requirements to determine if it is ready for release.

5. What Do You Test in Functional Testing?

In functional testing, you test:

• User interfaces to ensure they work correctly.
• APIs to verify they return the correct responses.
• Databases to check data integrity and storage.
• Security features to ensure proper access controls.
• Overall workflow to ensure that all functional requirements are met.

6. What Are the Important Steps That Are Covered in Functional Testing?

The important steps in functional testing include:

1. Requirement Analysis: Understanding the functional requirements.
2. Test Planning: Creating a test plan with objectives, scope, and resources.
3. Test Case Design: Writing test cases based on functional specifications.
4. Test Environment Setup: Preparing the test environment.
5. Test Execution: Running the test cases and documenting the results.
6. Defect Reporting: Logging and tracking defects found during testing.
7. Retesting and Regression Testing: Re-testing fixed defects and conducting regression tests to ensure no new issues were introduced.

7. What Is the Use of a Traceability Matrix?

A traceability matrix is used to ensure that all requirements defined for a system are tested in the test protocols. It maps and traces user requirements with the test cases, ensuring that each requirement has been covered by a test case. This helps in identifying missing functionalities or gaps in testing.

8. What Is the Difference Between Functional and Non-Functional Testing?

Functional testing focuses on verifying that the software performs its intended functions correctly, based on the requirement specifications. Non-functional testing, on the other hand, evaluates aspects such as performance, usability, reliability, and scalability, which are not related to specific behaviors or functions of the software.

9. What Are the Different Test Levels?

The different test levels include:

• Unit Testing: Testing individual components or units.
• Integration Testing: Testing interactions between integrated units.
• System Testing: Testing the complete and integrated system.
• Acceptance Testing: Validating the system against user requirements to determine readiness for deployment.

10. What Is the Use of Acceptance Testing?

Acceptance testing is used to determine whether the software is ready for release. It involves validating the software against user requirements and checking if it meets the acceptance criteria set by the end users or stakeholders. This type of testing ensures that the software is functional, reliable, and ready for deployment

11. What Is Adhoc Testing?

Adhoc testing is an informal and unstructured testing approach where the tester aims to find defects without any specific plans or documentation. It relies on the tester's intuition, experience, and understanding of the application. This type of testing is usually conducted when there is limited time and requires a quick evaluation of the software's functionality.

12. What is Meant by Equivalence Partitioning?

Equivalence partitioning is a software testing technique that divides input data into equivalent classes or partitions. Test cases are designed to cover each partition at least once, reducing the number of test cases needed while still covering a wide range of scenarios. This technique helps in identifying classes of inputs that are expected to produce similar results, making testing more efficient.

13. What is Boundary Value Analysis?

Boundary Value Analysis (BVA) is a testing technique that focuses on the values at the boundaries of input domains. Since defects often occur at the edges of input ranges, BVA involves creating test cases for the values at, just below, and just above the boundaries. This helps in identifying potential edge-case issues that may not be caught with other testing techniques.

14. When to Do Smoke Testing?

Smoke testing is performed after a new build is received and before it undergoes more rigorous testing. It is a preliminary test to check whether the critical functionalities of the application are working. The main goal of smoke testing is to ensure that the build is stable enough for further testing. It is usually done early in the testing cycle to catch major issues early on.

15. Why Do We Need to Conduct End-to-End Testing?

End-to-end testing is necessary to verify the complete flow of an application from start to finish, ensuring that all integrated components work together as expected. This type of testing validates the system's overall functionality and identifies any issues that may arise in the real-world usage of the application. It helps in detecting defects that may not be apparent during unit or integration testing.

16. What Do You Understand by Sanity Testing?

Sanity testing is a subset of regression testing focused on verifying specific functionalities or bug fixes. It is conducted to ensure that changes or fixes in the code have not affected existing functionalities. Sanity testing is usually performed after receiving a new build to quickly determine if the critical functionalities are working as intended, allowing testers to proceed with more detailed testing.

17. What is the Difference Between Severity and Priority?

• Severity refers to the impact of a defect on the system's functionality. It indicates how serious the defect is and how much it affects the software's operation.
• Priority refers to the order in which a defect should be fixed. It indicates the urgency of fixing the defect based on business needs or customer requirements.

18. What is RTM?

RTM, or Requirements Traceability Matrix, is a document that maps and traces user requirements with the test cases. It ensures that all requirements are covered by test cases and helps in identifying any gaps. RTM is used to track the progress of testing and ensure that all specified requirements have been tested.

19. What is Data-Driven Testing?

Data-driven testing is a testing methodology where test scripts are executed using multiple sets of data inputs. This technique allows testers to create a single test script that can run with various data inputs, making it easier to validate how the application handles different data scenarios. It is commonly used in automation testing to increase test coverage and efficiency.

20. What is Mutation Testing?

Mutation testing is a technique used to evaluate the quality of test cases. It involves making small changes (mutations) to the code and running the test cases to see if they can detect the changes. The goal is to ensure that the test cases are robust enough to catch defects. If the test cases fail to detect the mutations, it indicates that the test cases need improvement.

21. Why Is It Impossible to Test a Program Thoroughly?

It is impossible to test a program thoroughly because the number of possible inputs, paths, and scenarios in a software application is virtually infinite. Testing every possible combination is impractical due to time, resource, and cost constraints. Additionally, complex software systems often interact with other systems and components, adding more variables that make complete testing infeasible.

22. How Can You Test a Product if the Requirement Is Yet to Freeze?

When requirements are not finalized, testing can be approached by:

1. Using Prototypes: Test early versions or mock-ups of the product.
2. Exploratory Testing: Conducting informal, ad-hoc testing based on experience and intuition.
3. Focusing on Core Functionality: Testing the most critical and stable parts of the application.
4. Collaborating with Stakeholders: Regularly communicating with developers, product managers, and users to understand evolving requirements.

23. What Are Important Points You Need to Remember While Considering Writing Test Cases?

When writing test cases, consider the following:

1. Clarity: Test cases should be clear and concise.
2. Coverage: Ensure all functional requirements are covered.
3. Reusability: Write reusable test cases for future testing cycles.
4. Traceability: Link test cases to requirements using a traceability matrix.
5. Maintainability: Keep test cases easy to maintain and update.
6. Preconditions: Clearly define any setup or preconditions needed before execution.
7. Expected Results: Clearly specify the expected outcomes.

24. How Many Test Cases Can You Execute in a Day?

The number of test cases executed in a day depends on several factors, including:

• Complexity of the test cases.
• Stability of the application.
• Test environment setup.
• Manual or automated testing. Typically, a tester might execute anywhere from 10 to 50 test cases per day, but this can vary widely.

25. What Is Stress Testing?

Stress testing involves evaluating how a system performs under extreme conditions, such as high load, limited resources, or intense activity. The goal is to identify the system's breaking point and ensure it can handle peak loads without crashing or experiencing significant performance degradation.

26. What Is Load Testing?

Load testing assesses the system's performance under expected user load. It measures response times, throughput, and stability when the system is subjected to typical or slightly above typical usage conditions. The aim is to ensure the system can handle anticipated traffic and perform efficiently.

27. What Is Configuration Management?

Configuration management involves systematically managing changes to software, hardware, and documentation. It ensures that all components of a system are identified, tracked, and maintained consistently. Configuration management helps in maintaining the integrity and traceability of the system throughout its lifecycle.

28. What Are the Important Factors to Be Considered in Risk-Based Testing?

In risk-based testing, consider the following factors:

1. Business Impact: Prioritize testing areas that have a significant impact on the business.
2. Likelihood of Failure: Focus on parts of the system with a higher probability of defects.
3. Severity of Defects: Emphasize testing on areas where defects could cause severe consequences.
4. Complexity: Target complex functionalities that are more prone to errors.
5. Regulatory Requirements: Ensure compliance with any legal or regulatory standards.

29. What Is Non-Functional Testing?

Non-functional testing evaluates aspects of the software that do not relate to specific functions or behaviors. It includes testing for performance, scalability, security, usability, and reliability. The goal is to ensure the software meets predefined criteria for these attributes, providing a satisfactory user experience.

30. What Are the Main Advantages of Automation Testing?

Automation testing offers several advantages:

1. Efficiency: Executes tests faster and more accurately than manual testing.
2. Repeatability: Allows repetitive execution of tests with consistent results.
3. Coverage: Enables testing of a larger set of cases, increasing test coverage.
4. Early Detection: Identifies defects early in the development cycle.
5. Cost-Effective: Reduces long-term testing costs despite initial setup investments.
6. Continuous Testing: Supports continuous integration and continuous delivery (CI/CD) pipelines, facilitating frequent testing and faster releases

31. What Is Covered, and What Are the Different Coverage Techniques?

Coverage in testing refers to the extent to which the test cases cover the software's code, functionality, or requirements. Different coverage techniques include:

• Statement Coverage: Ensures that each line of code is executed at least once.
• Branch Coverage: Ensures that every possible branch (true/false) of each decision point is executed.
• Path Coverage: Ensures that all possible paths through the code are executed.
• Function Coverage: Ensures that every function or method in the code is called.
• Condition Coverage: Ensures that each condition in a decision point is tested for all possible outcomes.

32. What Is a Bug Report?

A bug report is a document that communicates detailed information about a defect or issue found in the software. It typically includes:

• Bug ID: A unique identifier for the bug.
• Title: A brief summary of the bug.
• Description: A detailed explanation of the bug, including steps to reproduce it.
• Severity: The impact of the bug on the system's functionality.
• Priority: The urgency of fixing the bug.
• Environment: Information about the system configuration where the bug was found.
• Attachments: Any screenshots, logs, or other files that help illustrate the bug.

33. What Is GUI Testing?

GUI testing involves testing the graphical user interface of an application to ensure it meets specifications and provides a positive user experience. This includes checking elements like buttons, menus, icons, and dialogs for:

• Functionality: Ensuring they work as intended.
• Usability: Ensuring they are user-friendly and intuitive.
• Consistency: Ensuring they adhere to design standards and guidelines.
• Layout: Ensuring proper alignment, spacing, and visual appeal.

34. What Are the Standard Rules of an API Test Design?

Standard rules for API test design include:

• Validation of Response: Check the API response against expected results.
• Error Handling: Test how the API handles invalid inputs and errors.
• Security: Ensure the API is secure, including authentication and authorization.
• Performance: Measure the API's performance, including response time and throughput.
• Compatibility: Test the API across different environments and platforms.
• Documentation: Ensure the API documentation is accurate and comprehensive.

35. What Are the Advantages of Manual Testing?

Advantages of manual testing include:

• Flexibility: Easily adapt to changes in test cases or requirements.
• Human Insight: Allows testers to use intuition and experience to find defects.
• Exploratory Testing: Facilitates exploratory testing to uncover unexpected issues.
• Cost-Effective for Small Projects: No need for investment in automation tools and scripts.
• Immediate Feedback: Provides immediate feedback on user experience and usability.

36. What Is the Test Harness?

A test harness is a collection of software and test data configured to test a program unit by running it under varying conditions and monitoring its behavior and outputs. It typically includes:

• Drivers: Components that call the functions being tested.
• Stubs: Simulated components that replace missing parts of the software.
• Test Scripts: Automated scripts that execute the tests.
• Reporting Tools: Tools that capture and report test results.

37. What Is Test Closure?

Test closure refers to the final phase of the testing process, where the following activities are performed:

• Test Summary Report: Creating a summary of the testing activities and results.
• Defect Report: Finalizing the status of all defects.
• Documentation: Archiving test artifacts and documentation.
• Lessons Learned: Analyzing and documenting lessons learned for future projects.
• Sign-off: Obtaining formal approval from stakeholders that testing is complete.

38. What Is a Critical Bug in Functional Testing?

A critical bug in functional testing is a severe defect that significantly impacts the core functionality of the software. It can cause the system to crash, lose data, or produce incorrect results, making the software unusable. Such bugs need immediate attention and resolution to ensure the system's reliability and usability.

39. What Is Baseline Testing?

Baseline testing involves comparing the current performance of a system or application against a defined baseline. The baseline is a set of metrics or benchmarks established from previous tests or industry standards. Baseline testing helps identify changes in performance, detect regressions, and ensure that new versions of the software maintain or improve upon the established benchmarks.

40. What Is Defect Cascading?

Defect cascading occurs when a defect in one part of the software triggers additional defects in other parts. As the initial defect propagates through the system, it causes a chain reaction of failures, making the overall impact more severe. Detecting and fixing the initial defect early can prevent these cascading failures and reduce the overall number of defects in the system

41. Name All the Basic Components of the Defect Report Format.

The basic components of a defect report typically include:

• Defect ID: A unique identifier for the defect.
• Title/Summary: A brief description of the defect.
• Description: Detailed information about the defect, including steps to reproduce it.
• Severity: The impact of the defect on the system’s functionality.
• Priority: The urgency of fixing the defect.
• Status: The current state of the defect (e.g., new, assigned, fixed, closed).
• Environment: Information about the software and hardware configuration where the defect was found.
• Assigned To: The person responsible for fixing the defect.
• Attachments: Any supporting documents, screenshots, or logs.
• Date Raised: The date when the defect was reported.
• Reporter: The person who identified and reported the defect.

42. What Is a Testbed?

A testbed is a controlled environment configured for testing software. It includes hardware, software, network configurations, tools, and other resources needed to execute test cases. The testbed replicates the production environment to ensure that testing results are accurate and reliable.

43. What Is Defect Removal Efficiency?

Defect Removal Efficiency (DRE) is a metric used to measure the effectiveness of the defect detection and removal process. It is calculated as the ratio of defects found and fixed during testing to the total number of defects (including those found in production).

44. What Is the Difference Between Bug Release and Bug Leakage?

• Bug Release: Occurs when a known bug is intentionally released in the software due to its low severity or impact, often accompanied by a note in the release documentation.
• Bug Leakage: Refers to bugs that were not detected during testing but are found by end-users after the software is released into production.

45. What Is Agile Testing, and Why Is It Important?

Agile testing is a software testing practice that follows the principles of Agile development, which emphasizes iterative and incremental delivery of software. Agile testing is important because it:

• Promotes continuous feedback and improvement.
• Allows for early detection and resolution of defects.
• Enhances collaboration between testers, developers, and stakeholders.
• Supports rapid changes and adaptability to evolving requirements.

46. What Will You Do as a Tester When Encountering a Bug?

When encountering a bug, a tester should:

1. Document the Bug: Record detailed information about the bug, including steps to reproduce, expected and actual results, environment details, and any relevant screenshots or logs.
2. Report the Bug: Create a defect report and submit it to the bug tracking system.
3. Communicate: Inform the development team and stakeholders about the bug.
4. Follow-Up: Track the bug’s progress, retest after it is fixed, and update the status accordingly.

47. What Are the Different Types of Debugging Categories?

The different types of debugging categories include:

• Manual Debugging: Analyzing code manually to find and fix defects.
• Automated Debugging: Using automated tools to detect and fix bugs.
• Static Debugging: Reviewing code without executing it, often through code reviews or static analysis tools.
• Dynamic Debugging: Identifying bugs by executing the code and observing its behavior, often with the help of debuggers.

48. What Is the Test Deliverable?

Test deliverables are the artifacts produced during the testing lifecycle. These include:

• Test Plan: Document outlining the testing strategy and objectives.
• Test Cases: Detailed test scenarios and steps to be executed.
• Test Scripts: Automated test scripts for execution.
• Test Data: Data sets used during testing.
• Test Summary Report: Overview of testing activities and results.
• Defect Reports: Records of identified defects.
• Traceability Matrix: Mapping of requirements to test cases.
• Test Logs: Records of test execution details and outcomes.

49. What Are the Common Risks That Lead to Project Failure?

Common risks leading to project failure include:

• Inadequate Requirements: Poorly defined or changing requirements.
• Lack of Communication: Insufficient communication among team members and stakeholders.
• Resource Constraints: Limited availability of necessary resources, including personnel, tools, and budget.
• Technical Challenges: Complexities and technical issues during development.
• Poor Project Management: Ineffective planning, scheduling, and monitoring of project activities.
• Quality Issues: Defects and performance issues in the software.

50. What Are the Significant Differences Between Test Matrix and Traceability Matrix?

• Test Matrix: A tool used to capture the status and progress of test activities, including test case execution, pass/fail status, and test coverage.
• Traceability Matrix: A document that maps requirements to test cases to ensure that all requirements are covered by testing.

51. What Are Positive and Negative Testing?

• Positive Testing: Validates that the system works as expected with valid input data.
• Negative Testing: Ensures that the system handles invalid or unexpected input gracefully and does not produce erroneous results.

52. What Is the Big Bang Approach?

The Big Bang approach is an integration testing method where all components or modules are integrated simultaneously, and the entire system is tested as a whole. It is typically used when the individual modules have been tested independently, and the focus is on testing the interactions between modules.

53. What Is the Meaning of a Fault?

A fault, also known as a defect or bug, is an error or flaw in the software code that causes the system to produce incorrect or unexpected results.

54. What Is Bug Leakage in Functional Testing?

Bug leakage occurs when defects are not detected during the testing phase but are found by end-users after the software has been released into production. It indicates gaps in the testing process.

55. What Is TDD?

Test-Driven Development (TDD) is a software development approach where tests are written before the code is developed. In TDD, developers write a test case for a new function, write the minimum code necessary to pass the test, and then refactor the code while ensuring that all tests continue to pass.

56. What Is the Difference Between Latent and Masked Defects?

• Latent Defects: Defects that are present in the system but have not yet been discovered because they have not caused any failures.
• Masked Defects: Defects that are hidden by other defects. They are not discovered until the masking defect is resolved.

57. What Is Random/Monkey Testing?

Random or Monkey Testing is an informal testing technique where the tester inputs random data into the system to check for crashes or unexpected behavior. It is used to identify edge cases and ensure the system’s robustness.

58. What Is Context-Driven Testing?

Context-driven testing is an approach that emphasizes adapting testing practices to the specific context of the project. It acknowledges that different projects have unique requirements, constraints, and goals, and testing strategies should be tailored accordingly.

59. What Is the PDCA Cycle in Software Testing?

The PDCA (Plan-Do-Check-Act) cycle is a continuous improvement model used in software testing:

• Plan: Define objectives, plan tests, and prepare test cases.
• Do: Execute the test plan and perform testing.
• Check: Evaluate test results and identify defects.
• Act: Implement improvements based on test results and feedback.

60. What Are the Entry Criteria in Software Testing?

Entry criteria are the conditions that must be met before testing can begin. These may include:

• Requirements documentation is complete and approved.
• Test environment is set up and ready.
• Test cases are developed and reviewed.
• Necessary resources (tools, data, personnel) are available.

61. What Is Exit Criteria in Software Testing?

Exit criteria are the conditions that must be met before testing can be considered complete. These may include:

• All planned test cases have been executed.
• All critical defects have been resolved.
• Test coverage meets predefined thresholds.
• Test summary reports are prepared and reviewed.
• Stakeholder approval is obtained.

62. Can System Testing Be Done at Any Stage?

System testing is typically done after integration testing and before acceptance testing. It focuses on testing the complete and integrated system to ensure it meets the specified requirements. While it is ideally performed at a specific stage, system testing can be done iteratively in agile development environments.

63. What Is Meant by Alpha, Beta, and Gamma Testing?

• Alpha Testing: Conducted internally by the development team or QA team in a controlled environment. It aims to identify bugs before releasing the product to external users.
• Beta Testing: Conducted by a select group of external users in a real-world environment. It helps gather feedback and identify defects not found during alpha testing.
• Gamma Testing: A final round of testing conducted just before the product release. It focuses on minor fixes and ensures the product is ready for production.

64. What Can Be Understood from End-To-End Testing?

End-to-end testing involves testing the complete flow of an application from start to finish. It ensures that all integrated components and systems work together as expected and validates the entire process flow to identify any issues in the application’s functionality, data integrity, and interactions.

65. What Is Use Case Testing?

Use case testing is a technique where test cases are designed based on use cases. Use cases describe the interactions between users and the system to achieve specific goals. This approach ensures that all user scenarios are tested, covering both functional and non-functional aspects of the system.

66. What Is A/B Testing?

A/B testing, also known as split testing, involves comparing two versions of a web page, application, or feature to determine which one performs better. Users are randomly assigned to one of the two versions, and their interactions are analyzed to identify the more effective version based on predefined metrics.

67. What Is the Defect Life Cycle?

The defect life cycle, also known as the bug life cycle, describes the stages a defect goes through from identification to resolution. Typical stages include:

• New: The defect is reported.
• Assigned: The defect is assigned to a developer for fixing.
• Open: The developer starts working on the defect.
• Fixed: The defect is resolved by the developer.
• Retest: The tester verifies the fix.
• Closed: The defect is confirmed as fixed and closed.
• Reopened: If the defect is not fixed, it is reopened for further investigation.

68. What Is Configuration Testing?

Configuration testing involves evaluating the software’s performance and functionality on different hardware, software, and network configurations. It ensures compatibility and identifies issues related to varying environments, such as different operating systems, browsers, devices, and network conditions.

69. What Determines the Level of Risk?

The level of risk is determined by two main factors:

• Probability: The likelihood that a particular event or defect will occur.
• Impact: The potential consequences or severity of the event or defect on the system or business.

70. What Do You Mean by Defect Triage?

Defect triage is the process of reviewing, prioritizing, and assigning defects based on their severity, impact, and urgency. During triage meetings, stakeholders (testers, developers, product managers) discuss each defect to decide its priority and the necessary actions for resolution.

71. What Is a Stub?

A stub is a temporary implementation of a component or module used in integration testing. It simulates the behavior of missing or incomplete components by providing predefined responses to calls made during testing. Stubs are used to isolate the module being tested and ensure it functions correctly without dependencies on other components

Conclusion

Getting ready for a functional testing interview can seem tough, but knowing the questions can really help. This interview preparation blog post covers a top and most asked of questions you might face, from simple definitions to more complex scenarios that test your skills on Functional testing. It's perfect for anyone starting out or looking to sharpen their knowledge in functional testing. As you prepare, remember that each interview is your chance to show how well you understand functional testing and solve problems.

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