10 Regression testing Interview Questions and Answers for qa engineers

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If you're preparing for qa engineer interviews, see also our comprehensive interview questions and answers for the following qa engineer specializations:

1. Can you explain the difference between regression testing and retesting?

Regression testing and retesting are two types of software testing, but they serve different purposes. Regression testing is performed when new changes are introduced to the software. It helps ensure that existing features and functionality of the software are not affected by the new changes. This type of testing is important as changes can have unintended consequences and may introduce new defects. For example, a recent change to a website's login page may have caused a previously working feature of the site - such as forgotten password functionality - to stop working.

On the other hand, retesting is performed after defects are identified and fixed. It ensures that the software after a fix still works as required. This is particularly important when multiple defects are identified, as fixing one may inadvertently cause another defect. Say a version of a banking application that caused problems with money transfers have been fixed. A retesting of the application is required to verify that beyond anything else, the money transfers now work as expected.

  • Regression testing checks if new changes introduced to the software affects its existing functionality.
  • Retesting checks if defects have been successfully fixed in the software.

2. How do you determine which test cases to include in a regression suite?

When determining which test cases to include in a regression suite, I follow a systematic approach that considers multiple factors:

  1. Business criticality: I prioritize test cases for features that are critical to the business and have the highest impact on user experience. For instance, if there is a bug that affects payment transactions or registration, it could lead to significant financial loss and damage to the company's reputation.
  2. Frequency of use: I consider how frequently a feature is used by end-users. This helps me to determine if there are high traffic areas that require more testing to ensure there are no bugs or glitches. For example, if a majority of the users go through a specific feature or module, such as the checkout process, it will be critical to include extensive testing coverage in the automation regression suite.
  3. Recent changes: Test cases that cover features that have undergone recent changes or enhancements are given priority. This ensures that the new implementation does not cause any regression issues in the existing functionalities.
  4. Sustainability: Sustainability is an important consideration when selecting test cases for the regression suite. I make a point of selecting test cases that can be easily maintained in the future, without requiring excessive time and effort. This way, I minimize the workload for future releases or testing cycles.
  5. Efficiency: I aim to select test cases that are efficient, both in terms of time and resources. I do not include redundant test cases, which leads to overlapping and time-consuming testing cycles. Instead, I choose reusable and modular test cases that are easily and quickly modifiable.

Overall, my approach to selecting test cases for the regression suite takes into account several factors, from the most critical features to the sustainability and efficiency of the test cases. By doing so, the test cases can be relevant and valuable for multiple future releases while providing a significant return on investment for the engineering team.

3. What tools and technologies have you used for regression testing?

During my experience as a QA tester, I have used several automation tools for regression testing to ensure the software functionality remains stable after code changes or new features have been introduced.

  1. Selenium - I have used Selenium WebDriver to create automated test scripts for web applications. In my previous role, we were able to achieve 95% test coverage using Selenium and reduce the regression test cycle by 50%.
  2. TestComplete - I have also used TestComplete for desktop application testing. With TestComplete, I was able to create automated tests quickly and perform tests across multiple operating systems through virtualization.
  3. Appium - For mobile testing, I have used Appium which allows us to run the same tests across multiple platforms like iOS and Android. With Appium, our team reduced the regression test cycle time by 30%.
  4. JIRA - Test case management and bug tracking tool. Used to manage and track the status of test cases and defects.

These tools have helped me increase the efficiency and effectiveness of regression testing in my previous roles. By using these tools, we were able to achieve maximum test coverage and detect defects quickly, which ultimately led to better software quality.

4. What steps do you take to ensure that regression bugs are caught early?

Regression bugs can be tricky, and they can cause damage if they manage to make it into the final product. That's why I take several steps to ensure that they are caught early, and that they don't make it into the released code.

  1. The first step I take is to create a comprehensive suite of regression test cases that cover all the functionality of the application. I make sure to include test cases that are likely to catch any regression bugs that may arise.

  2. Next, I make sure to run these test cases on a daily basis, in an automated fashion, using a Continuous Integration (CI) server. This ensures that any code changes are immediately tested against the regression test cases, and any issues are caught early in the development cycle.

  3. I also make use of code reviews to catch any potential issues before they make it into the codebase. By having someone else review my code changes, I can be sure that any potential regressions are caught early on.

  4. I keep a log of any regression bugs that are found, along with their root cause and resolution. This helps me to identify patterns in the types of issues that crop up, and to make changes to the development process that will prevent similar issues from recurring in the future.

  5. Finally, I also work closely with the development team to identify any potential regression issues that may be introduced due to upcoming code changes. By being proactive about regression testing, we can catch any potential issues before they have a chance to cause problems for our users.

Through the use of these techniques, I have been able to catch regression bugs early and ensure that they don't make it into the final product. This has resulted in a higher quality product, fewer issues reported by customers, and a better overall user experience.

5. Have you ever introduced a regression bug? How did you identify and resolve it?

Yes, I have introduced a regression bug during my work. It was during the release of a new feature that I introduced a bug in a previous working feature. The bug was identified by one of our QA team members during the testing phase. Our team was able to quickly reproduce the bug and identify the root cause of the issue. To resolve the regression bug, we first rolled back the release to the previous version of the codebase. We then isolated and fixed the bug, and applied a fix to prevent the same issue from happening in the future. After the fix was applied, we ran a regression test suite that consisted of over 200 test cases to ensure that the issue had been resolved and did not affect any other areas of the application. The test suite passed successfully with no issues found. In hindsight, I took this as a valuable learning opportunity and reinforced the importance of thorough testing and code review. It also taught me the importance of impact analysis, especially when a new feature is being introduced.

6. How do you decide when to automate a regression test case? Can you walk me through an example of a recently automated test case?

When deciding which regression test cases to automate, there are several key factors that I take into consideration:

  1. Frequency of execution: Automated regression tests are ideal for test cases that are executed frequently, as automation saves time and effort compared to manual execution.
  2. Risk and complexity: Regression tests that have an elevated risk or are particularly complex benefit from automation as it provides consistency and reduces human error.
  3. Time and resource constraints: In situations where there are time or resource constraints, automation can be used to complete the regression testing much faster.

For example, in my previous role, we decided to automate a test case for an e-commerce website. The test case entailed adding a product to the shopping cart, proceeding to checkout, and verifying that the selected product is correctly listed in the order summary. This test case was executed multiple times every day, and it was quite time-consuming to execute manually. After careful consideration, we decided that automating this test case would save considerable time and effort in the long run.

Furthermore, the automated test case provided us with additional benefits. It provided a greater level of consistency compared to manual testing and significantly reduced the possibility of human error. Additionally, since the test case was automated, we could easily integrate it into our continuous testing strategy and run it as part of our regression suite. This allowed us to identify any potential regressions quickly.

After automating this test case, we analyzed the results and found that the new automated test case took 30% less time to execute, and there was a significant reduction in test case failure rates. Automating this test case provided us with a big ROI both in terms of time and quality.

7. What do you think are the biggest challenges in conducting regression testing?

Challenges in Conducting Regression Testing

  1. Test Case Selection:

    One of the biggest challenges in conducting regression testing is test case selection. If you include too few test cases, then there is a risk that some bugs may go undetected. However, if you include too many test cases, the testing process may take too long and incur unnecessary costs. In 2020, a study conducted by Capers Jones found that the number of test cases can impact software quality. According to the study, "for every ten percent increase in the number of test cases, the number of defects found increased by four percent”.

  2. Test Data Management:

    The test data used in regression testing must be comprehensive, varied, and up-to-date. Failing to use correct test data can affect the accuracy of the testing results. In 2021, a survey conducted by the World Quality Report found that 59% of respondents cited the lack of proper test data management as a significant challenge in regression testing.

  3. Automation vs Manual Testing:

    Deciding whether to conduct regression testing manually or automate the process is another challenge. While automation saves time and resources, there is a risk that some bugs may be missed. On the other hand, manual testing allows testers to identify irregularities that would be missed by automated tools. In 2022, a study conducted by Accenture found that automated testing identified 78% of the critical defects, while manual testing identified 100% of the critical defects.

  4. Time Constraints:

    Regression testing can be time-consuming due to the number of tests involved. However, in some cases, there may be time constraints that require more testing to be done in a shorter period. This can lead to incomplete testing and, in turn, put the quality of the software at risk. In a 2023 survey conducted by the QA Financial, 68% of respondents cited time constraints as a significant challenge in regression testing.

  5. Changing Requirements:

    Software requirements can change over time, which can impact the testing process. Regression testing must, therefore, be updated to reflect these changes. Failure to update the test cases can result in inaccurate testing results. According to a 2024 study conducted by Gartner, 70% of organizations that don't update their test cases frequently end up with inaccurate testing results.

8. What experience do you have in analyzing test results and reporting issues to the development team?

During my previous job, I was working as a Quality Assurance Engineer at XYZ Company. One of my responsibilities was to analyze test results and report issues to the development team.

  1. First, I would carefully review the test results to identify any patterns or potential issues. This included both automated and manual testing.
  2. Next, I would create detailed bug reports using JIRA, including steps to reproduce the issues and any relevant screenshots or logs.
  3. After creating the bug reports, I would prioritize them based on severity and impact on the product.
  4. Then, I would communicate these issues to the development team through daily standup meetings or one-on-one discussions.
  5. Throughout the development process, I would also perform regression testing to ensure that previously fixed issues did not resurface.
  6. As a result of these efforts, the overall defect density of our product decreased by 15% over the course of one year.

In addition, I worked closely with the development team to implement new processes for tracking and resolving issues, such as using test-driven development and in-depth root cause analysis.

9. How do you ensure that test data is relevant and useful for regression testing?

As a regression testing expert, I always ensure that test data is relevant and useful by following a thorough process:

  1. Reviewing the test plan: Before testing begins, I carefully review the test plan to ensure that it outlines the test cases that need to be run.
  2. Identifying the critical data: I then identify the critical data set that will be used during the regression testing.
  3. Prioritizing the data: The critical data set is then prioritized based on its importance to the overall system. This ensures that the most relevant and useful data is used first.
  4. Automating the tests: By automating the tests with tools like Selenium, we can easily use the relevant and useful data without worrying about human errors or bias.
  5. Analyzing the results: After each regression testing run, I analyze the results to determine if any issues were found. If there are any issues, I carefully review the data set used to ensure that it was sufficient for the tests to detect the issue.
  6. Updating the test data: Based on the analysis of the results, I update the test data to ensure that it is relevant and useful for future regression testing runs.

Using this process, I have been able to increase the efficiency of regression testing by 30% and reduce the number of defects found after release by 20%. These concrete results demonstrate the effectiveness of my approach to ensuring that test data is relevant and useful for regression testing.

10. Can you describe a situation where you had to prioritize regression testing with other testing efforts?

During my time at XYZ Company, we were working on a major software release that had multiple new features and enhancements. As the sole QA engineer on the team, I had to balance regression testing with other testing efforts to ensure a timely release.

First, I created a test plan that prioritized regression testing for critical functionalities and new features that had dependencies on existing functionalities. I communicated this plan to the team, and we collectively decided to focus on testing these areas first before moving on to other testing efforts.

As a result, we were able to catch several critical defects in the initial regression testing phase, including a bug in a new feature that would have broken an existing functionality if not caught in time. This led to a more streamlined testing process overall and a smoother release.

  1. Created a test plan prioritizing regression testing for critical functionalities and new features with dependencies on existing functionalities
  2. Communicated the plan to the team
  3. Caught critical defects in initial regression phase
  4. More streamlined testing process overall and a smoother release

Conclusion

Congratulations on making it through these 10 regression testing interview questions and answers! The next step to landing your dream job as a remote QA engineer is to write a killer cover letter. Don't worry if you're not sure where to start - we've got you covered with our ultimate guide to writing a cover letter. Another crucial step is to create an impressive resume that showcases your experience and skills as a QA engineer. But don't worry, our guide to writing a resume for QA engineers can walk you through every step of the process to create a standout CV that catches the attention of recruiters. And if you're ready to start your job search, look no further than Remote Rocketship's remote QA engineer job board. With our curated list of job openings, you'll have access to the best remote opportunities in the industry. Good luck!

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