Testing Interview Questions and Answers

Q. What is Agile Testing and how is it different to traditional waterfall or the V model?

Agile Testing is testing practice that follows the principles of agile software development. Agile testing involves all members of an agile team with special skills and expertise to ensure business value is delivered at frequent intervals.

The big difference is that in Agile environment, testing is not a phase, it is an activity parallel to development.

In agile environment, small features of software are delivered frequently, so testing activity should be parallel to development activity. Testing time is short as we are only testing small features.

In the waterfall model, there is a testing phase at the end of the development so, testing is a big effort done after the whole application is developed. Testing time is long as we have to test the whole application.

Q: What is your approach when requirements change continuously?

This question can be asked if you are interviewed for an agile QA position where requirements are likely to change frequently during development. Although a complete change in requirement is possible, most of the time, it is the technical details that are subject to change. e.g. the intent of the requirement or behaviour of the feature is the same but implementation details can change

A: Some possible answers can be:

• Write generic test plans and test cases which focus on the intent of the requirement rather than its exact details
• Work very closely with the product owners or business analysts to understand the scope of change so testing can be updated
• Make sure the team understands the risks involved in changing requirements especially towards the end of sprint
• If you’re going to automate this feature, it is best to wait until the feature is stable and requirements are finalized
• Negotiate to see if the changes can be kept to a minimum and/or implement the changes in next sprint.
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Can you explain defect age and defect spoilage?

Defect age is also called a phase age or phage. One of the most important things to remember in testing is that the later we find a defect the more it costs to fix it. Defect age and defect spoilage metrics work with the same fundamental, i.e., how late you found the defect. So the first thing we need to define is what is the scale of the defect age according to phases. For instance, the following table defines the scale according to phases. So, for instance, requirement defects, if found in the design phase, have a scale of 1, and the same defect, if propagated until the production phase.
Once the scale is decided now we can find the defect spoilage. Defect spoilage is defects from the previous phase multiplied by the scale. For instance, in the following figure we have found 8 defects in the design phase from which 4 defects are propagated from the requirement phase. So we multiply the 4 defects with the scale defined in the previous table, so we get the value of 4. In the same fashion we calculate for all the phases. That's the spoilage.

Can you explain how the number of production defects is measured?

This is one of the most effective measures. The number of defects found in a production is recorded. The only issue with this measure is it can have latent and masked defects which can give us the wrong value regarding software quality.

Can you explain DRE?

DRE (Defect Removal Efficiency) is a powerful metric used to measure test effectiveness. From this metric we come to know how many bugs we found from the set of bugs which we could have found. The following is the formula for calculating DRE. We need two inputs for calculating this metric: the number of bugs found during development and the number of defects detected at the end user but the success of DRE depends on several factors. The following are some of them:

• Severity and distribution of bugs must be taken into account.
• Second, how do we confirm when the customer has found all the bugs. This is normally achieved by looking at the history of the customer.

Testing Interview Questions

1. What is functional system testing ?

Testing the end to end functionality of the system as a whole.

2. What is the benefits of Independent Testing

Independent testers see other and different defects and are unbiased.  

3. In a REACTIVE approach to testing when would you expect the bulk of the test design work to be begun?

After the software or system has been produced.

4. What are the different Methodologies in Agile Development Model?

There are currently seven different Agile methodologies that I am aware of:

1.  Extreme Programming (XP)
2.  Scrum
3.  Lean Software Development
4.  Feature-Driven Development
5.  Agile Unified Process
6.  Crystal
7.  Dynamic Systems Development Model (DSDM) 

5. Which activity in the fundamental test process includes evaluation of the testability of the requirements and system?

A Test analysis and design.

6. What is typically the MOST important reason to use risk to drive testing efforts?

  Because testing everything is not feasible.  

7. Which is the MOST important advantage of independence in testing?

An independent tester may be more effective at finding defects missed by the person who wrote the software.  

8. Which of the following are valid objectives for incident reports?

i. Provide developers and other parties with feedback about the problem to enable identification, isolation and correction as necessary.

ii. Provide ideas for test process improvement.

iii. Provide a vehicle for assessing tester competence.

iv. Provide testers with a means of tracking the quality of the system under test.

i. Provide developers and other parties with feedback about the problem to enable identification, isolation and correction as necessary,

ii.Provide ideas for test process improvement,

iv.Provide testers with a means of tracking the quality of the system under test

9. Consider the following techniques. Which are static and which are dynamic techniques?

i. Equivalence Partitioning.

ii. Use Case Testing.

iii.Data Flow Analysis.

iv.Exploratory Testing.

v. Decision Testing.

vi. Inspections.

Data Flow Analysis and Inspections are static, Equivalence Partitioning, Use Case Testing, Exploratory Testing and Decision Testing are dynamic.

10. Why are static testing and dynamic testing described as complementary?

Because they share the aim of identifying defects but differ in the types of defect they find.  

11. What are the phases of a formal review ?

In contrast to informal reviews, formal reviews follow a formal process. A typical formal review process consists of six main steps:

1.  Planning
2.  Kick-off
3.  Preparation
4.  Review meeting
5.  Rework
6.  Follow-up.  

12. What is the role of moderator in review process?

The moderator (or review leader) leads the review process. He or she deter-mines, in co-operation with the author, the type of review, approach and the composition of the review team. The moderator performs the entry check and the follow-up on the rework, in order to control the quality of the input and output of the review process. The moderator also schedules the meeting, disseminates documents before the meeting, coaches other team members, paces the meeting, leads possible discussions and stores the data that is collected.

13. What is an equivalence partition (also known as an equivalence class)?

An input or output range of values such that only one value in the range becomes a test case.  

14. When should configuration management procedures be implemented?

During test planning.

15. A Type of functional Testing, which investigates the functions relating to detection of threats, such as virus from malicious outsiders.

Security Testing  

16. Testing where in we subject the target of the test , to varying workloads to measure and evaluate the performance behaviors and ability of the target and of the test to continue to function properly under these different workloads. Load Testing

17. Testing activity which is performed to expose defects in the interfaces and in the interaction between integrated components is:

Integration Level Testing  

18. What are the Structure-based (white-box) testing techniques ?

Structure-based testing techniques (which are also dynamic rather than static) use the internal structure of the software to derive test cases. They are com-monly called 'white-box' or 'glass-box' techniques (implying you can see into the system) since they require knowledge of how the software is implemented, that is, how it works. For example, a structural technique may be concerned with exercising loops in the software. Different test cases may

19. What is the KEY difference between preventative and reactive approaches to testing? 

Preventative tests are designed early; reactive tests are designed after the software has been produced.

20. What is the purpose of exit criteria? 

To define when a test level is complete.

21. What determines the level of risk? 

  The likelihood of an adverse event and the impact of the event

22. What is the MAIN objective when reviewing a software deliverable?

To identify defects in any software work product.

23. Which of the following defines the expected results of a test? Test case specification or test design specification.

Test case specification.

24. Which is a benefit of test independence?

It avoids author bias in defining effective tests.  

25. As part of which test process do you determine the exit criteria?

Test planning.  

26. Rapid Application Development ?

Rapid Application Development (RAD) is formally a parallel development of functions and subsequent integration. Components/functions are developed in parallel as if they were mini projects, the developments are time-boxed, delivered, and then assembled into a working prototype. This can very quickly give the customer something to see and use and to provide feedback regarding the delivery and their requirements. Rapid change and development of the product is possible using this methodology. However the product specification will need to be developed for the product at some point, and the project will need to be placed under more formal controls prior to going into production.

27. What is the difference between Testing Techniques and Testing Tools?

Testing technique: - Is a process for ensuring that some aspects of the application system or unit functions properly there may be few techniques but many tools.

Testing Tools: - Is a vehicle for performing a test process. The tool is a resource to the tester, but itself is insufficient to conduct testing . 

28. We use the output of the requirement analysis, the requirement specification as the input for writing ...

User Acceptance Test Cases  

29. Repeated Testing of an already tested program, after modification, to discover any defects introduced or uncovered as a result of the changes in the software being tested or in another related or unrelated software component:

Regression Testing

30. What is component testing ?

Component testing, also known as unit, module and program testing, searches for defects in, and verifies the functioning of software (e.g. modules, programs, objects, classes, etc.) that are separately testable. Component testing may be done in isolation from the rest of the system depend-ing on the context of the development life cycle and the system. Most often stubs and drivers are used to replace the missing software and simulate the interface between the software components in a simple manner. A stub is called from the software component to be tested; a driver calls a component to be tested.

31. When should be performed Regression testing ?

After the software has changed or when the environment has changed

32. When should testing be stopped?

It depends on the risks for the system being tested

33. What is the purpose of a test completion criterion?

To determine when to stop testing  

34. What can static analysis NOT find?

For example memory leaks  

35. What is the difference between re-testing and regression testing?

Re-testing ensures the original fault has been removed; regression testing looks for unexpected sideeffects  

36. What are the Experience-based testing techniques ?

In experience-based techniques, people's knowledge, skills and background are a prime contributor to the test conditions and test cases. The experience of both technical and business people is important, as they bring different perspectives to the test analysis and design process. Due to previous experience with similar systems, they may have insights into what could go wrong, which is very useful for testing.  

37."How much testing is enough?"

The answer depends on the risk for your industry, contract and special requirements. 51. When should testing be stopped? It depends on the risks for the system being tested.  

38. What is the difference between re-testing and regression testing?

  Re-testing ensures the original fault has been removed; regression testing looks for unexpected side-effects.  

39. Why we use decision tables?.

The techniques of equivalence partitioning and boundary value analysis are often applied to specific situations or inputs. However, if different combinations of inputs result in different actions being taken, this can be more difficult to show using equivalence partitioning and boundary value analysis, which tend to be more focused on the user interface. The other two specification-based tech-niques, decision tables and state transition testing are more focused on business logic or business rules. A decision table is a good way to deal with combinations of things (e.g. inputs). This technique is sometimes also referred to as a 'cause-effect' table. The reason for this is that there is an associated logic diagramming technique called 'cause-effect graphing' which was sometimes used to help derive the decision table

40. Faults found should be originally documented by who?

By testers.  

41. Why does the boundary value analysis provide good test cases?

Because errors are frequently made during programming of the different cases near the 'edges' of the range of values.  

42. What makes an inspection different from other review types?

It is led by a trained leader, uses formal entry and exit criteria and checklists.

43. Why can be tester dependent on configuration management?

Because configuration management assures that we know the exact version of the testware and the test object.

44. What is a V-Model ?

A software development model that illustrates how testing activities integrate with software development phases

45. What is maintenance testing?

Triggered by modifications, migration or retirement of existing software  

46. What is test coverage?

Test coverage measures in some specific way the amount of testing performed by a set of tests (derived in some other way, e.g. using specification-based techniques). Wherever we can count things and can tell whether or not each of those things has been tested by some test, then we can measure coverage.  

47. What is Alpha testing?

Pre-release testing by end user representatives at the developer's site.

48. What is a failure?

Failure is a departure from specified behaviour.