Wednesday, June 4, 2008

Software Testing Interview Questions Answers - Vol 1

Q: What is verification?
A: Verification ensures the product is designed to deliver all functionality to the customer; it typically involves reviews and meetings to evaluate documents, plans, code, requirements and specifications; this can be done with checklists, issues lists, walkthroughs and inspection meetings.

Q: What is validation?
A: Validation ensures that functionality, as defined in requirements, is the intended behavior of the product; validation typically involves actual testing and takes place after verifications are completed.

Q: What is a walk-through?
A: A walk-through is an informal meeting for evaluation or informational purposes.

Q: What is an inspection?
A: An inspection is a formal meeting, more formalized than a walk-through and typically consists of 3-10 people including a moderator, reader (the author of whatever is being reviewed) and a recorder (to make notes in the document). The subject of the inspection is typically a document, such as a requirements document or a test plan. The purpose of an inspection is to find problems and see what is missing, not to fix anything. The result of the meeting should be documented in a written report. Attendees should prepare for this type of meeting by reading through the document, before the meeting starts; most problems are found during this preparation. Preparation for inspections is difficult, but is one of the most cost-effective methods of ensuring quality, since bug prevention is more cost effective than bug detection.

Q: What is quality?
A: Quality software is software that is reasonably bug-free, delivered on time and within budget, meets requirements and expectations and is maintainable. However, quality is a subjective term. Quality depends on who the customer is and their overall influence in the scheme of things. Customers of a software development project include end-users, customer acceptance test engineers, testers, customer contract officers, customer management, the development organization's management, test engineers, testers, salespeople, software engineers, stockholders and accountants. Each type of customer will have his or her own slant on quality. The accounting department might define quality in terms of profits, while an end-user might define quality as user friendly and bug free.

Q: What is a good code?
A: A good code is code that works, is free of bugs and is readable and maintainable. Organizations usually have coding standards all developers should adhere to, but every programmer and software engineer has different ideas about what is best and what are too many or too few rules. We need to keep in mind that excessive use of rules can stifle both productivity and creativity. Peer reviews and code analysis tools can be used to check for problems and enforce standards.

Q: What is a good design?
A: Design could mean to many things, but often refers to functional design or internal design. Good functional design is indicated by software functionality can be traced back to customer and end-user requirements. Good internal design is indicated by software code whose overall structure is clear, understandable, easily modifiable and maintainable; is robust with sufficient error handling and status logging capability; and works correctly when implemented.

Q: What is software life cycle?
A: Software life cycle begins when a software product is first conceived and ends when it is no longer in use. It includes phases like initial concept, requirements analysis, functional design, internal design, documentation planning, test planning, coding, document preparation, integration, testing, maintenance, updates, re-testing and phase-out.

Q: Why are there so many software bugs?
A: Generally speaking, there are bugs in software because of unclear requirements, software complexity, programming errors, changes in requirements, errors made in bug tracking, time pressure, poorly documented code and/or bugs in tools used in software development.
There are unclear software requirements because there is miscommunication as to what the software should or shouldn't do.
i)Software complexity. All of the followings contribute to the exponential growth in software and system complexity: Windows interfaces, client-server and distributed applications, data communications, enormous relational databases and the sheer size of applications.
ii)Programming errors occur because programmers and software engineers, like everyone else, can make mistakes.
iii)As to changing requirements, in some fast-changing business environments, continuously modified requirements are a fact of life. Sometimes customers do not understand the effects of changes, or understand them but request them anyway. And the changes require redesign of the software, rescheduling of resources and some of the work already completed have to be redone or discarded and hardware requirements can be effected, too.
iv)Bug tracking can result in errors because the complexity of keeping track of changes can result in errors, too.
v)Time pressures can cause problems, because scheduling of software projects is not easy and it often requires a lot of guesswork and when deadlines loom and the crunch comes, mistakes will be made.
vi)Code documentation is tough to maintain and it is also tough to modify code that is poorly documented. The result is bugs. Sometimes there is no incentive for programmers and software engineers to document their code and write clearly documented, understandable code. Sometimes developers get kudos for quickly turning out code, or programmers and software engineers feel they have job security if everyone can understand the code they write, or they believe if the code was hard to write, it should be hard to read.
vii)Software development tools , including visual tools, class libraries, compilers, scripting tools, can introduce their own bugs. Other times the tools are poorly documented, which can create additional bugs.

Q: How do you introduce a New Software QA Process?
A: It depends on the size of the organization and the risks involved. For large organizations with high-risk projects, a serious management buy-in is required and a formalized QA process is necessary. For medium size organizations with lower risk projects, management and organizational buy-in and a slower, step-by-step process is required. Generally speaking, QA processes should be balanced with productivity, in order to keep any bureaucracy from getting out of hand. For smaller groups or projects, an ad-hoc process is more appropriate. A lot depends on team leads and managers, feedback to developers and good communication is essential among customers, managers, developers, test engineers and testers. Regardless the size of the company, the greatest value for effort is in managing requirement processes, where the goal is requirements that are clear, complete and testable.

Q: Give me five common problems that occur during software development.
A: Poorly written requirements, unrealistic schedules, inadequate testing, adding new features after development is underway and poor communication.
i)Requirements are poorly written when requirements are unclear, incomplete, too general, or not testable; therefore there will be problems.
ii)The schedule is unrealistic if too much work is crammed in too little time.
iii)Software testing is inadequate if none knows whether or not the software is any good until customers complain or the system crashes.
iv) It's extremely common that new features are added after development is underway.
Miscommunication either means the developers don't know what is needed, or customers have unrealistic expectations and therefore problems are guaranteed.

Q: Give me five solutions to problems that occur during software development.
A: Solid requirements, realistic schedules, adequate testing, firm requirements and good communication.
i) Ensure the requirements are solid, clear, complete, detailed, cohesive, attainable and testable. All players should agree to requirements. Use prototypes to help nail down requirements.
ii) Have schedules that are realistic. Allow adequate time for planning, design, testing, bug fixing, re-testing, changes and documentation. Personnel should be able to complete the project without burning out.
iii) Do testing that is adequate. Start testing early on, re-test after fixes or changes, and plan for sufficient time for both testing and bug fixing.
iv) Avoid new features. Stick to initial requirements as much as possible. Be prepared to defend design against changes and additions, once development has begun and be prepared to explain consequences. If changes are necessary, ensure they're adequately reflected in related schedule changes. Use prototypes early on so customers' expectations are clarified and customers can see what to expect; this will minimize changes later on.
v) Communicate. Require walk-throughs and inspections when appropriate; make extensive use of e-mail, networked bug-tracking tools, tools of change management. Ensure documentation is available and up-to-date. Use documentation that is electronic, not paper. Promote teamwork and cooperation.

Q: Do automated testing tools make testing easier?
A: Yes and no. For larger projects, or ongoing long-term projects, they can be valuable. But for small projects, the time needed to learn and implement them is usually not worthwhile. A common type of automated tool is the record/playback type. For example, a test engineer clicks through all combinations of menu choices, dialog box choices, buttons, etc. in a GUI and has an automated testing tool record and log the results. The recording is typically in the form of text, based on a scripting language that the testing tool can interpret. If a change is made (e.g. new buttons are added, or some underlying code in the application is changed), the application is then re-tested by just playing back the recorded actions and compared to the logged results in order to check effects of the change. One problem with such tools is that if there are continual changes to the product being tested, the recordings have to be changed so often that it becomes a very time-consuming task to continuously update the scripts. Another problem with such tools is the interpretation of the results (screens, data, logs, etc.) that can be a time-consuming task.

Q: What makes a good test engineer?
A: A Test Engineer
Has a "test to break" attitude,
Takes the point of view of the customer,
Has a strong desire for quality,
Has an attention to detail, He's also
Tactful and diplomatic and
Has good a communication skill, both oral and written. And he
Has previous software development experience, too.
Good test engineers have a "test to break" attitude, they take the point of view of the customer, have a strong desire for quality and an attention to detail. Tact and diplomacy are useful in maintaining a cooperative relationship with developers and an ability to communicate with both technical and non-technical people. Previous software development experience is also helpful as it provides a deeper understanding of the software development process, gives the test engineer an appreciation for the developers' point of view and reduces the learning curve in automated test tool programming.

Q: What makes a good QA engineer?
A: The same qualities a good test engineer has are useful for a QA engineer.

Q: What makes a good QA/Test Manager?
A: QA/Test Managers are familiar with the software development process; able to maintain enthusiasm of their team and promote a positive atmosphere; able to promote teamwork to increase productivity; able to promote cooperation between Software and Test/QA Engineers, have the people skills needed to promote improvements in QA processes, have the ability to withstand pressures and say *no* to other managers when quality is insufficient or QA processes are not being adhered to; able to communicate with technical and non-technical people; as well as able to run meetings and keep them focused.
Q: What is the role of documentation in QA?
A: Documentation plays a critical role in QA. QA practices should be documented, so that they are repeatable. Specifications, designs, business rules, inspection reports, configurations, code changes, test plans, test cases, bug reports, user manuals should all be documented. Ideally, there should be a system for easily finding and obtaining of documents and determining what document will have a particular piece of information. Use documentation change management, if possible.
Q: What about requirements?
A: Requirement specifications are important and one of the most reliable methods of insuring problems in a complex software project is to have poorly documented requirement specifications. Requirements are the details describing an application's externally perceived functionality and properties. Requirements should be clear, complete, reasonably detailed, cohesive, attainable and testable. A non-testable requirement would be, for example, "user-friendly", which is too subjective. A testable requirement would be something such as, "the product shall allow the user to enter their previously-assigned password to access the application". Care should be taken to involve all of a project's significant customers in the requirements process. Customers could be in-house or external and could include end-users, customer acceptance test engineers, testers, customer contract officers, customer management, future software maintenance engineers, salespeople and anyone who could later derail the project. If his/her expectations aren't met, they should be included as a customer, if possible. In some organizations, requirements may end up in high-level project plans, functional specification documents, design documents, or other documents at various levels of detail. No matter what they are called, some type of documentation with detailed requirements will be needed by test engineers in order to properly plan and execute tests. Without such documentation there will be no clear-cut way to determine if a software application is performing correctly.
Q: What is a test plan?
A: A software project test plan is a document that describes the objectives, scope, approach and focus of a software testing effort. The process of preparing a test plan is a useful way to think through the efforts needed to validate the acceptability of a software product. The completed document will help people outside the test group understand the why and how of product validation. It should be thorough enough to be useful, but not so thorough that none outside the test group will be able to read it.
Q: What is a test case?
A: A test case is a document that describes an input, action, or event and its expected result, in order to determine if a feature of an application is working correctly. A test case should contain particulars such as a...
Test case identifier;
Test case name;
Objective;
Test conditions/setup;
Input data requirements/steps, and
Expected results.
Please note, the process of developing test cases can help find problems in the requirements or design of an application, since it requires you to completely think through the operation of the application. For this reason, it is useful to prepare test cases early in the development cycle, if possible.
Q: What should be done after a bug is found?
A: When a bug is found, it needs to be communicated and assigned to developers that can fix it. After the problem is resolved, fixes should be re-tested. Additionally, determinations should be made regarding requirements, software, hardware, safety impact, etc., for regression testing to check the fixes didn't create other problems elsewhere. If a problem-tracking system is in place, it should encapsulate these determinations. A variety of commercial, problem-tracking/management software tools are available. These tools, with the detailed input of software test engineers, will give the team complete information so developers can understand the bug, get an idea of its severity, reproduce it and fix it.
Q: What is configuration management?
A: Configuration management (CM) covers the tools and processes used to control, coordinate and track code, requirements, documentation, problems, change requests, designs, tools, compilers, libraries, patches, changes made to them and who makes the changes.

Q: What if the software is so buggy it can't be tested at all?
A: In this situation the best bet is to have test engineers go through the process of reporting whatever bugs or problems initially show up, with the focus being on critical bugs. Since this type of problem can severely affect schedules and indicates deeper problems in the software development process, such as insufficient unit testing, insufficient integration testing, poor design, improper build or release procedures, managers should be notified and provided with some documentation as evidence of the problem.

Q: How do you know when to stop testing?
A: This can be difficult to determine. Many modern software applications are so complex and run in such an interdependent environment, that complete testing can never be done. Common factors in deciding when to stop are...
i) Deadlines, e.g. release deadlines, testing deadlines;
ii) Test cases completed with certain percentage passed;
iii) Test budget has been depleted;
iv) Coverage of code, functionality, or requirements reaches a specified point;
v) Bug rate falls below a certain level; or
vi) Beta or alpha testing period ends.

Q: What if there isn't enough time for thorough testing?
A: Since it's rarely possible to test every possible aspect of an application, every possible combination of events, every dependency, or everything that could go wrong, risk analysis is appropriate to most software development projects. Use risk analysis to determine where testing should be focused. This requires judgment skills, common sense and experience. The checklist should include answers to the following questions:
i) Which functionality is most important to the project's intended purpose?
ii) Which functionality is most visible to the user?
iii) Which functionality has the largest safety impact?
iv) Which functionality has the largest financial impact on users?
v) Which aspects of the application are most important to the customer?
vi) Which aspects of the application can be tested early in the development cycle?
vii) Which parts of the code are most complex and thus most subject to errors?
viii) Which parts of the application were developed in rush or panic mode?
ix) Which aspects of similar/related previous projects caused problems?
x) Which aspects of similar/related previous projects had large maintenance expenses?
xi) Which parts of the requirements and design are unclear or poorly thought out?
xii) What do the developers think are the highest-risk aspects of the application?
xiii) What kinds of problems would cause the worst publicity?
xiv) What kinds of problems would cause the most customer service complaints?
xv) What kinds of tests could easily cover multiple functionalities?
xvi) Which tests will have the best high-risk-coverage to time-required ratio?

Q: What if the project isn't big enough to justify extensive testing?
A: Consider the impact of project errors, not the size of the project. However, if extensive testing is still not justified, risk analysis is again needed and the considerations listed under "What if there isn't enough time for thorough testing?" do apply. The test engineer then should do "ad hoc" testing, or write up a limited test plan based on the risk analysis.

Q: What if the application has functionality that wasn't in the requirements?
A: It may take serious effort to determine if an application has significant unexpected or hidden functionality, which it would indicate deeper problems in the software development process. If the functionality isn't necessary to the purpose of the application, it should be removed, as it may have unknown impacts or dependencies that were not taken into account by the designer or the customer. If not removed, design information will be needed to determine added testing needs or regression testing needs. Management should be made aware of any significant added risks as a result of the unexpected functionality. If the functionality only affects areas, such as minor improvements in the user interface, it may not be a significant risk.

Q: How can software QA processes be implemented without stifling productivity?
A: Implement QA processes slowly over time. Use consensus to reach agreement on processes and adjust and experiment as an organization grows and matures. Productivity will be improved instead of stifled. Problem prevention will lessen the need for problem detection. Panics and burnout will decrease and there will be improved focus and less wasted effort. At the same time, attempts should be made to keep processes simple and efficient, minimize paperwork, promote computer-based processes and automated tracking and reporting, minimize time required in meetings and promote training as part of the QA process. However, no one, especially talented technical types, like bureaucracy and in the short run things may slow down a bit. A typical scenario would be that more days of planning and development will be needed, but less time will be required for late-night bug fixing and calming of irate customers.

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