Your development team is ready to hire a new software tester. What QA interview questions can you ask in the job interview that (a) are not lame and (b) actually help you determine if this job applicant is qualified? If you have no idea what questions to ask the candidate, this article serves as a useful cheat sheet.
Your company is ready to hire a new QA tester. You need someone with the eye of an eagle, the nose of a bloodhound, and the curiosity of a child who wonders why Santa Claus looks a lot like Uncle Bob. So how do you find the right eagle-eyed, bloodhound person?
The same way you find errors when testing code: by asking the right questions.
It’s fine to ask interviewees the obvious questions first. It makes sense to confirm domain knowledge based on statements made in the job applicant’s résumé.
However, several people likely can check-off items on a “tools used” list. Ultimately, you want to know if the person is a good fit for your company’s tech culture – and whether you want to hang out with them at the next office happy hour.
If you make the right choice, then lucky you: You won’t have to read another résumé for a good, long time. Let’s explore the best QA interview questions and answers to help you prepare for that day.
1. What methodologies of QA testing have you used?
Have you worked in agile or waterfall conditions? Does the word “scrum” mean anything to you? Do you make it to the finish line when you sprint?
“The interview is where I learn if you’ve only had simple jobs,” says Egor Bulyhin, project manager and team lead at Smart IT. The interviewee may have been a QA tester for ten years, but that doesn’t mean the candidate has the depth and breadth of experience your demanding company requires.
Asking candidates to explain which methodology they prefer—and why—demonstrates how well they understand the benefits and drawbacks of each. Plus, it proves communication skills, and as we know, being able to clearly communicate is one of the few things that makes people superior to puppies.
2. Can you write test scripts? What testing software do you use?
Selenium. IBM Functional Tester. TestComplete. Katalon Studio. Functionize (especially Functionize). Your interviewee’s familiarity with a brand of test software may be the difference between them getting the job at your company and getting the fabulous opportunity to work somewhere else.
It’s fine if the job applicant knows more than one tool; if nothing else, it suggests they understand the pros and cons of each one. Even better: If the candidate lives and breathes the software your company uses, no one (especially not you) has to spend time training the newbie.
Though a lack of familiarity should not be a reason to escort the person off the premises. Tools change; you probably aren’t using the same software you were five years ago. It’s useful if the candidate knows your current tools – but in the long run, it’s more important to find someone who loves to learn new things.
3. What is your experience with automated and manual testing?
Here again, it’s helpful to choose someone who’s familiar with your current business processes – whatever they are – and also to incorporate the diversity of someone who has another mindset. If your company is adopting test automation, it’s good to know that this isn’t a foreign concept; on the other hand, experienced QA staff understand that QA needs humans to fill in the work where machines fail. QA testers can find hard-to-spot errors and communicate to the users who ultimately judge this product. (Suck it, Megatron.)
But the issue really is whether the job applicant has a hidebound approach – “we’ve always done it that way” – and if that suggests a reluctance to adopt new business practices or different tools.
4. What was the best catch you ever made?
This question gives your interviewee the opportunity to put on his bragging pants. Like the time when Colin Ma, who works at the OC Tech Alliance and is a former QA team leader, noticed that his system processed 8% fewer transactions than normal. He decided to investigate.
“After three days, I found the culprit. Under a certain condition, a payment processor would shift over account numbers, which usually caused the account to not exist,” Ma says. “We fixed the bug by correcting an IF statement in the code.”
Had Ma not found the error, it would have cost his company several hundred thousand dollars’ worth of fines. That knowledge alone is enough to turn your interviewee into a fellow co-worker.
5. What's the toughest bug you ever found and fixed?
It happens, even to you, the experienced, long-suffering QA team lead. You go toe-to-toe with software and you get knocked back. Errors: 1. Your ego: -1.
Asking this question gives your interviewee an opportunity to tell you what went wrong, how she responded to it, and how this particular problem never happened on her watch again. Here’s hoping she keeps her tale to “an amusing anecdote” and not “I accidentally executed code that wiped out a backup server and deleted 90% of Toy Story 2.”
This question is the opportunity for the potential QA hire to tell a story and cast herself as the scrappy underdog who eventually becomes the star. Besides: Storytelling can get nervous interviewees to relax somewhat, and to speak in their own voices.
6. How would you test a soda machine?
Naturally, you want to see how your interviewee engages with technical problems, including those that are new to her. Ask your candidate to test something arbitrary, such as a soda machine or a mobile phone app with which you’re both familiar.
Soda machines are interesting test cases, because the sum is made up of multiple parts: an alphanumeric keypad, a refrigerator, a dollar bill validator, a soda dispensary, an advertising display, etc. Also, a repairperson approaches the machine differently than does a customer who wants a pause that refreshes. QA testers who think well on their feet will consider these different functions and user needs. And it tells you, the interviewer, how the job candidate approaches the issues, from security testing to user interfaces.
Even if in the back of her mind, all she’s thinking about is how much she needs a soda.
7. How do you write a test case?
Of course you want someone who can write a test case as easily as they can drink quarantinis. But not every interviewee gets an A+ and a gold star, particularly those who are new to a software testing career.
Don’t expect the applicant to have the answer, Bulyhin says. But the discussion can show what the interviewee considers important. “You should see attentiveness, clear articulation of thoughts, and how comfortable they would be when working.”
It isn’t their answers that matter as much as their questions. “What I look for here is for the potential QA tester to ask a question,” says Shayne Sherman, CEO of TechLoris. “I want them to ask what platforms we support. Anyone who has done any QA on web applications knows that there are significant differences between the different browsers and devices. QA shouldn't sign off on any test case until it has been tested on all [supported] device/OS/Browser combinations.”
So even if QA newbies flub that part of the interview, they might still walk away with an offer...as long as they flub it the right way.
8. How do you organize your work?
You can ask this in several ways. “Do you use checklists? Do you add to the checklist as you go? How do you arrange your priorities? Do you start with requirements? (Please tell me you start with requirements.)” There are yet more questions that provide a window into the way your interviewee works without having to resort to carpentry or trepanation.
“QA is a repetitive process that requires maximum attention,” says Alexandra Marin, director of design at CodeCrew. As Marin sees it, the more organized a person is from the get-go, the more productive they are.
9. How much time is enough time to test for a release?
Of course, any tester wants as much time as possible. But the luxury of time exists only in a perfect world, and you don’t see this world populated only by Hemsworth Brothers, do you? Still, it’s an opportunity to set and learn expectations about how much time they are used to, and what time or process they prefer.
Ask your interviewees to speak to their experiences about getting a job done under pressure—and to explain the other steps they would have included if the team was given a few more days.
If they resist the urge to sigh dramatically, so much the better.
10. How important is it for QA to take part in development planning sessions?
QA teams can work in many ways. Some are part of a larger development team, where data center operations gets together with programmers for regular meetings (or for beer). Others are used to communicating largely among themselves. Similarly, some QA teams come in long after the application design process is complete, while others get involved from Day One. That isn’t to suggest that one process is better than another, but both the interviewer and manager should know what the other person expects and desires.
A candidate who forgoes planning sessions in favor of some much-needed bug hunting might be focused on the task at hand—and nothing else. Is that good or bad? The answer is up to you. One QA tester may expect to be part of sprint/development planning sessions to better understand the context of each task, and thus to assess each feature’s risks and complexity. Another might feel that it’d be more productive to invite goats to a Zoom meeting.
As you know, planning sessions are a good way to get in front of theoretical problems before they become actual problems. We hope your interviewee knows it too.
11. What is the difference between Quality Assurance, Quality Control and Testing?
Quality assurance deals with creating a strategy to define and implement quality standards. Quality control, on the other hand, uses the method established by Quality Assurance to find problems and improve the software. Testing is the actual process of finding bugs and defects.
Check if your interviewee understands the nuances of these processes and is aware of the different people or teams in the organization that are usually tasked with each responsibility.
12. When Should QA start?
The best time to start QA is at the very beginning of the project. Setting the quality standards at the earliest opportunity guarantees a smoother experience through development and testing.
Your interviewee should be able to appreciate the value of starting QA early and how costly in terms of time and effort delays can be. An understanding of what can hurt a project translates into better implementation of best practices.
13. How much testing is considered sufficient?
It is impossible to exhaustively test an application. Testers need to pick test cases that the most likely to test the apparent vulnerabilities of the code. In order to stay efficient, the focus on testing should be on common problem areas and important features and functionality.
The interviewee should be able to define a good balance between exhaustive and efficient testing. It’s essential to acknowledge that the testing process needs to have a definitely end goal.
14. What is the difference between validation and verification?
Verification takes place during the development phase to ascertain if all the specified requirements of the phase are being met. Validation takes place when the development is complete and is used to understand if the entire product meets the requirements.
It is crucial for the interviewee to understand this very important distinction. Look for in-depth technical knowledge about both processes.
15. Why do developers make poor testers?
There is a concrete difference in the mentality between developers and testers. Developers might try to check the quote to see if it works, whereas testers check for things that do not work. Developers can also tend to have bias, being the creators of the code. Finally, testing involves advanced techniques that fall more in the wheelhouse of testers.
This does not preclude developers from testing software. However, the best-case scenario involves leaving the bulk of the testing to experience testers. Of course, constructive input from developers can make the process easier.
16. What is the QA Testing Life Cycle?
It starts with requirement analysis and test planning. Next, the appropriate test cases are developed. The test environment is then set up and the tests are executed. Finally, the test is closed when all bugs are eliminated.
While the specific steps might not be an exact match, look for the interviewee to understand the basic concepts of the life cycle and how each step is supposed to work.
17. What is data driven testing?
Data driven testing uses input values by comparing them to data stored directly in data files, including excel sheets or CSV files. Expect your interviewee to understand the process in detail and mention the benefits of automating data driven tests for the best results.
18. What does the test strategy include?
The test strategy is a high-level plan that sets the definition of the overall testing approach for the whole project. It usually includes the scope, schedule, and vital resources for test planning and testing priorities.
Expect your interviewee to understand the different ingredients of an effective test strategy and its importance in informing the testing approach for the entire project.
19. What are the three different testing approaches?
Testing approaches can be broken down into white box, black box, and grey box testing. White box testing focuses on the code structure and is usually done by testers with coding skills. Black box testing instead relies on specifications and requirements. Grey box testing involves testers who have a relatively small degree of knowledge about the software.
Look for your interviewee to understand the nuances of these different testing approaches and common scenarios where each would be applicable.
20. How do you efficiently manage time and meet deadlines in testing?
The best approach is to prioritize the most basic test cases to ensure all the most crucial aspects of the software are tested. Another judicious idea is to rely on customer feedback to understand the most important areas of the software during real world use and focus on those areas.
Time management and an efficient workflow are crucial elements of QA and the interviewee should have a clear idea about these novel approaches.
21. How does stress testing differ from load testing?
Stress testing involves raising the load on the system is increased beyond the normal, expected range. Load testing, on the other hand, testing that involves a steady, consistently high load which is still within expectations.
While this is a subtle difference, the interviewee should be able to spell out possible scenarios where each approach might be useful and what each method of testing might be used to diagnose.
22. What is functional vs. Non-functional testing?
Functional testing deals with whether the software under test fulfills its functional requirements, whether its end users get the functionality they need out of it. Non-functional testing hinges on other attributes like scalability, security, and performance.
Once again, a pivotal conceptual distinction that informs testing approaches and something that an interviewee should have a strong understanding of.
23. What is retesting vs. Regression testing?
Retesting is carried out after a bug fix to see if the fix actually worked. Regression testing, on the other hand, is a testing procedure that tests the impact of bug fixes on the rest of the software.
Regression testing helps to keep bug fixes clean and impact-free. Ideal candidates should be able to elaborate on the basics of regression testing and the inherent techniques.
24. What are some of the common mistakes that you watch out for?
Your interviewee should be able to approach QA from a proactive and preventive standpoint. With this premise, look for an answer that includes improper allocation of resources, scheduling issues, lack of attention to detail, and deviation from the overall test strategy established at the outset.
25. What is monkey testing?
Monkey testing uses randomly generated inputs to test the behavior of the system. It is meant to replicate scenarios where real users might provide random inputs to the application. Monkey testing can be automated and is useful during load or stress tests.
Expect your interviewee to be able to explain the importance of monkey testing and understand basic concepts like dumb and smart monkeys.
26. How do you figure out how much testing is needed for a software?
How much testing a software needs depends on its complexity. This helps determine the level of testing required.
The interviewee should be able to provide a basic explanation of the concept of cyclomatic complexity and preferably display knowledge of nodes, edges, and calculating cyclomatic complexity for a piece of software.
27. What do you think is an ideal progression of testing techniques?
A good answer is a plan that starts with unit testing and concludes with acceptance testing. Depending on the interviewee, intermediate steps would include concrete testing techniques such as system testing and integration testing.
A thorough knowledge of different testing techniques and their nuances is a salient quality for an ideal candidate.
Good luck with those QA interview questions. And remember that the answers will lead you to your next QA hire.
One possible set of questions for job candidates is how they go about writing test cases. You might as well bone up on those processes by reading our white paper on test case best practices.