5 Regression Testing Interview Questions (With Answers)

Updated 23 March 2023

Testing is integral to the software development lifecycle to verify that an application functions as intended. Regression testing is a type of software testing that ensures that recent code changes do not affect an application's existing functionality. If you have an interview for a job as a test engineer, learning about different testing interview questions and knowing how to answer them can help you with your interview preparation. In this article, we list five regression testing interview questions along with example answers and provide some tips to help you in your interview.

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Regression Testing Interview Questions With Example Answers

Regression testing interview questions test a candidate's knowledge and understanding in areas such as the basics of regression testing, test planning, types of regression testing, test automation, metrics and reporting and Agile development. They may also ask questions related to your work experience to assess your communication and collaboration skills. Here are some example questions and answers you can refer to:

1. What is regression testing? Why is it important?

Interviewers may ask this question to assess your knowledge of the testing process and the importance of retesting after making changes to the software. The first step is to define what regression testing is. You can then highlight its importance by mentioning the necessity of preserving existing functionality.

Example answer: Developers make code changes to resolve bugs, add functionalities, optimise performance or improve an application's design and architecture. Although the code changes may be small, they can introduce bugs that affect the existing functionalities. While functional testing validates the recent code changes, it does not check whether they are compatible with an application's earlier version.

Regression testing is a testing technique that ensures that the code changes do not introduce new bugs or impact the existing functionality. It is advisable to conduct regression testing after every sprint to make sure new and existing features work properly. You can also automate the regression process using various tools and adding custom test cases to make it cost-effective and efficient.

2. Tell me about the different types of regression testing

Testers use various types of regression testing to verify different aspects of the software. Interviewers may ask about different regression testing techniques to determine your knowledge of various software testing concepts and practices. List some types of regression testing and your approach to selecting an appropriate type for each scenario.

Example answer: You can perform corrective regression testing when there are no changes in the product's requirements. This allows you to reuse existing test cases to make the testing process more manageable. With selective regression testing, you test the software by taking a smaller subset of test cases based on factors such as risk, priority and criticality. This is suitable when you have limited time and resources. Partial regression testing involves re-executing a subset of existing test cases to validate the software system changes. You can choose test cases by performing an impact analysis of the new changes.

Progressive regression testing is necessary when there are changes in the program's specifications. This requires you to build new test cases and reuse existing ones to test the software continuously, ensuring that newly added features do not affect the existing functionality. Complete regression testing involves retesting all the aspects of the software to check that it functions correctly. This is useful when developers make multiple code changes that can impact the core functionality of the software.

3. How do you handle changes in the requirements during regression testing?

Changes in the requirements during the software development process can impact regression testing. Interviewers may ask this question to assess your ability to handle changes in requirements and modify the testing suite. In your response, highlight the impact of changes on existing test cases and mention steps you take to ensure your test suite is up to date.

Example answer: Project requirements may change constantly because of missed requirements, defects, miscommunication or changes in trends. In order to test portions of the code that are stable and unlikely to change with needs, you can first create an automated testing workflow. This can save a significant amount of time and resources. Then work closely with developers to understand the scope of the requirements and how each one may affect existing functionalities. Once the feature is stable, you can prepare new test cases and perform progressive regression testing.

It is also necessary to advise developers and project managers that frequent requirement changes involve risk and prepare a contingency plan. It is important to document all the test cases for future reference. You can also track software testing metrics to assess testing efficiency and identify areas for improvement.

4. How do you approach creating regression test cases for a new feature?

Creating regression test cases for new features is an important aspect of regression testing. This question tests your ability to design effective test cases. When answering this question, detail the steps that help in understanding the new feature and creating comprehensive test cases.

Example answer: The first step is to get a clear understanding of the requirements by coordinating with the developers and project and product managers. This helps determine the purpose of the requirements and the functionality of the new features. Then create a list of test scenarios that cover all possible use cases for the new feature. Next, identify all existing functionalities or aspects that the recent code change may alter. Determine the input and the output for each test scenario and prioritise test cases based on their criticality or impact on the software.

You can also automate some parts of the testing process by identifying areas that need repeated testing. This involves selecting the type of regression testing based on the use case. It is a good idea to perform this regularly to ensure that the software functions as intended.

5. Discuss a situation when a third-party component caused a problem that you debugged. How did you resolve it?

Changes in third-party components can cause complex debugging problems. Interviewers may ask this question to assess your ability to diagnose and resolve problems related to third-party components. Outline your approach to resolving issues in this scenario. You can include steps such as isolating the problem, understanding the changes made to the component and making any necessary updates to the software to resolve the issue.

Example answer: I faced an issue when testing an in-house automated machine learning, or AutoML, software that the team developed. The software had several third-party components, such as data processing, model serving and deployment frameworks. There was an issue that resulted in the application crashing repeatedly. After rigorous testing, I found that it was due to an application programming interface, or API, version mismatch. I re-checked the API documentation and discovered that the vendor had updated their API version. It was incompatible with current AutoML software, so I updated the API versioning in the YAML file to fix the issue.

I also implemented a process to track changes made to the API and test the updated API in a controlled environment before deployment. I wrote documentation that included best practices to follow when using third-party components. One suggestion was to have a dedicated team or process to test and deploy updates, check for compatibility issues, maintain a repository of recent packages and communicate with the vendor periodically to stay up to date with the changes. Another suggestion was to use version control and dependency management tools to track dependencies effectively and ensure the compatibility of different components.

Tips To Prepare For A Regression Testing Interview

Here are some tips to consider when you prepare for your interview:

Review the basics of regression testing. Learn how regression testing works and how it differs from other testing techniques. You can watch tutorials or take courses to learn the basics.
Learn about the various types of regression testing. Be familiar with different regression testing techniques and learn which technique to use based on the scenario.
Be familiar with different tools. Learn about different regression tools available on the market. You can evaluate them based on factors such as the complexity of testing, scaling, functionality and automation capabilities.
Get practical experience. Download open-source projects and identify new features, bug fixes or enhancements. You can then build a regression test suite to validate these changes and suggest changes by commenting on a pull request.
Prepare for behavioural questions. Regression testing involves the collaborative effort of testers, developers and project managers. Interviewers may want to know how you approached challenges at your previous workplace and coordinated with other team members to find solutions.