Use these typical QA interview questions -- broken into basic, intermediate and advanced -- to progress from the screening interview to the final stages and land the job.
When hunting for a new job, it's crucial to prepare for interviews, whether candidates are highly experienced software quality engineers or junior testers.
Candidates will encounter various hiring processes, such as multiple interviews, personality and/or technical skill tests, and sometimes group projects or presentations. Of all the hiring process components, interviews are candidates' best opportunity to impress. Candidates will not receive a job offer unless they demonstrate they are the best for the role.
How to prepare for a QA interview
Preparation is the key to a successful interview, as it not only helps the candidate show off any relevant skills and experiences; it also showcases the candidate's approach to work and their interest in the organization. To be well prepared, candidates must conduct in-depth research into the organizations and roles for which they are applying. By understanding the organizations and the domains in which they compete, candidates can begin to anticipate not only the types of questions interviewers will ask, but also the potential pain points organizations want the candidates to address should they be hired.
Preparation is not just for candidates. Hiring teams should prepare for individual interviews and the hiring process to find the best candidate for the role. Preparation for hiring teams begins with the job description. Although no candidate will have all the qualifications, it is important to be as specific as possible and document "must-haves" vs. "nice-to-haves."
Preparation is the key to a successful interview. It not only helps the candidate show off any relevant skills and experiences, it also showcases the candidate's approach to work and interest in the organization.
The hiring team should consider the skills required to test software and the tech stack behind it, as well as the skills that best complement the current test team. For example, if current team members have strong technical knowledge, it might be worthwhile to prioritize a candidate with strong domain experience or more in-depth user experience skills. Spending the time to develop a thorough understanding of the role and the ideal candidate will help interviewers develop an effective set of interview questions.
I based the following list on my experience and several quality engineering peers' experiences, in addition to research on various quality assurance sites. I chose the most common interview questions and those that provide the most insight into a candidate's experience, knowledge, skill set and quality assurance point of view. I categorized the questions by difficulty -- basic, intermediate and in-depth -- and noted the interview stage and type of interviews in which they are likely to be asked.
5 basic QA interview questions
The hiring process for quality engineers and testers frequently includes multiple interviews. The first interview is usually for screening, which an HR representative or the quality engineering team lead conducts. The screening interview determines if the candidate is qualified and will continue in the hiring process. Here are some basic, commonly asked screening interview questions:
What is quality assurance?
This question determines if the candidate understands the purpose of quality assurance at a holistic level.
Answer: Quality assurance is the process of ensuring that the software under development meets the requirements and end user expectations.
What is the difference between quality assurance and software testing?
This question allows candidates to elaborate on their understanding of quality assurance.
Answer: Quality assurance is a process that is embedded throughout the software development lifecycle, whereas testing is the technical approach and techniques used to verify and validate the product. Quality assurance focuses on preventing bugs, whereas testing focuses on bug detection.
What is the difference between a test scenario and a test case?
This question assesses the candidate's basic testing knowledge.
Answer: A test scenario describes the conditions and criteria under test. The scenario usually covers acceptance criteria and might involve multiple test cases. A test case describes the steps to test a piece of functionality as well as the expected results.
What is the difference between verification and validation?
This question is especially important in regulated testing domains, including health- and safety-critical applications.
Answer: The verification process ensures that applications meet specifications, whereas validation ensures that the application is fit for purpose. Validation is often part of user acceptance testing
What is a defect and how do you document it?
This question provides insight into the candidate's thought processes around defects.
Answer: A defect occurs when test results do not match the expected results. To document a defect, the tester should first replicate it. The bug report should include a clear description of the defect, including the steps to reproduce it, the environment in which the tester found it, the expected and actual result, screenshots or videos, and an assessment of its severity.
4 intermediate QA interview questions
Once a candidate has passed the screening interview, the next interview or series of interviews delve into the candidate's knowledge of test methodology, including test strategy and test plans, Agile testing, test techniques and test types, such as manual and automated testing. Some questions to expect at this stage in the process are as follows:
What is the difference between a test strategy and a test plan?
This question ascertains the candidate's experience in a lead role.
Answer: The test strategy describes the test design and overall approach to structuring the test process. A test strategy includes the testing types (usually both manual and automation), the testing levels such as smoke, sanity and regression, and test techniques that should be applied. The purpose of the test strategy is overall test program management. The test plan details how to execute the test. It includes the scope of testing, the environment and data requirements, and the risks, issues, constraints and approach to defect management.
What test techniques should be applied during test case design?
In this question, the interviewer wants to understand the candidate's level of experience in incorporating test techniques into test cases.
Answer: These test techniques should be included in test case design: negative testing, boundary value analysis and equivalence partitioning. Negative testing ensures that the system doesn't do something it should not. An example is testing numbers in a field that should accept only alpha characters. Boundary value analysis tests the boundaries around input ranges, where defects are likely to occur. Equivalence partitioning divides data into classes that have the same expected results. These techniques are used to derive the greatest benefit from the fewest test cases.
What are the differences between load and stress testing?
This question is designed to assess the candidate's experience with non-functional testing.
Answer: Both load and stress testing are examples of non-functional tests. Load testing verifies that the application under test can handle the highest expected load without degradation in performance or crashes. Stress testing pushes the application above its required limit to determine its highest capacity. Stress testing is particularly important for applications such as retail, which have seasonal peak use.
What types of testing should be automated?
This question shows how a candidate builds a test automation strategy.
Advanced QA interview questions are for final interviews. They consist of behavioral questions that focus on the candidate's work experiences and situational questions that allow the candidate to respond to challenges. Approach behavioral questions using the STAR method in which the candidate describes a situation, the tasks the candidate was responsible for, the actions the candidate took and the results. Here are some examples of advanced questions:
Tell me about a time that a missed bug was found in production.
This shows how a candidate responds when issues arise.
Answer: Don't say that bugs haven't been missed. Describe the situation, tasks, actions and results. Focus on the bug's impact and the steps taken to mitigate it.
Describe a situation in which a release has a hard deadline, and all the tests in the test plan cannot be completed.
This assesses the candidate's flexibility and approach to risk-based testing.
Answer: In this situation, discuss risk analysis and how to select the most critical test cases to execute in the remaining time. It could be wise to suggest recruiting product owners and developers to run tests to ensure more complete test coverage.
What is your approach to test automation?
This shows the candidate's experience with developing test automation strategies.
Answer: Cost versus benefit should be a major consideration in all test automation projects. The test suite and test cases should be optimized to get the greatest value from the fewest test cases. Select test cases based on criticality. Follow the test automation pyramid with the bulk of the automation at the unit and component levels and the least at the UI level.
UI tests should incorporate the least amount of automation.
Can you achieve 100% automation?
Responses to this question demonstrate the candidate's philosophy on test automation.
Answer: Although it is possible to achieve 100% automation using techniques such as behavior-driven development, where requirements are translated directly into test scripts, it is not necessary or cost-effective to automate all edge cases and low-priority tests. Additionally, user experience testing should never be automated as it provides an assessment of how actual users will react to the application. This testing should account for uncertainty, so automation might be suboptimal.
Gerie Owen is a lead quality engineer at ZS. She is a conference presenter and author on technology and testing topics, and a certified Scrum master.
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