What is Regression Testing and How Do You Create Test Cases for It?

In the software development process, testing plays a vital role. One crucial type of testing is regression testing, which helps identify potential errors or undesired changes in program functionality after implementing modifications. In this article, we will explore the concept of regression testing and discuss how to create regression tests.

Regression testing focuses on identifying defects in the current functionality of a program that may arise due to recent code changes. Essentially, it ensures that all the program’s business programs continue to function correctly after implementing new updates or features. Typically, errors occur due to issues in the interaction between existing and new code within applications. The process of regression testing plays a critical role in maintaining product quality, and it is essential for testers to possess the knowledge and skills to analyze regression test coverage, create, and update regression test cases.

The creation of regression tests demands meticulous planning, wherein the test scope is clearly defined, followed by the development and execution of tests within that scope. Employing automation and maintaining a continuous update process significantly enhances the efficiency of this procedure. 

Let’s delve deeper into each aspect of regression testing:

1. Understanding Changes

Before embarking on the creation of regression tests, it is crucial to gain a comprehensive understanding of the changes or new features being introduced. This enables the identification of specific areas that need to be tested for regression.

2. Defining the Testing Scope

Defining the scope of your test directly impacts the quality of regression testing. Further, by prioritizing tests, a clearer understanding of their importance is achieved and allows you to eliminate redundant checks. It is important to keep in mind the Pareto rule, where 20% of the effort produces 80% of the results. The prioritization process should involve the entire team to ensure a comprehensive perspective on the priority of each test case, which may differ from the tester’s personal opinion.

3. Test Case Creation

The format for documenting regression tests differs from typical tests written using design techniques. In most cases, regression tests are not created from scratch; instead, they include test cases that have already been used to test new features within the regression model or test suite. Furthermore, regression tests are often prime candidates for automation, necessitating a deeper level of detailing and the use of specific rules and writing standards, such as Gherkin. It is also common to employ a system of tags that describe the module, business process, or sub-process to which a test case belongs. It is normal for a test case to have multiple tags representing different processes.

4. Test Execution

Regression testing commonly follows a two-tiered approach, of which two iterations of regression testing are performed:

• Selective Regression Testing:

Selective regression testing focuses on evaluating the functionality of a program when new features are added or when retesting previously reported bugs. This approach utilizes prioritization and the tag system to create a targeted regression test set that focuses on specific functions of an application. By leveraging these parameters, it becomes possible to identify potential regression errors in advance while minimizing the testing effort. Selective regression testing is commonly employed in agile development methodologies, particularly when multiple teams are responsible for different functionalities of the product.

• Full Regression Testing:

Full regression testing is predominantly performed after the completion of a collective release involving several or all teams. In this scenario, the entire set of regression tests is executed to ensure the system as a whole continues to function without errors. However, it is essential to execute the tests considering prioritization, starting with tests of the highest priority and progressively moving to lower priorities. This approach enables the early detection of critical and blocking errors, allowing for timely resolutions before the final release day.

5. Test Automation

Test automation is a valuable approach to enhance regression testing. By creating automated regression tests, it becomes possible to rerun tests whenever there are changes in the program, eliminating the need for manual execution of every test step. Automation not only accelerates the testing process but also enables more frequent releases of program updates. To learn more about building an effective test automation process, take a look at our previous article on automated testing processes.

6. Testing Updates

Regression testing is an ongoing process and does not occur only once. Following the release of a program or a new update, it is essential to continuously perform regression testing. Consequently, the tests must be kept up-to-date and ready for execution. Therefore, it is necessary to have a constant process of updating priorities and test coverage. The frequency of updating regression tests depends on the pace of the company’s development and the frequency of changes, which could be monthly, quarterly, or every six months. Maintaining updated regression tests ensures that the testing process aligns with the evolving nature of the software.

Regression testing serves a vital role in ensuring the seamless progression of the software development process. In today’s dynamic landscape, Agile and DevOps methodologies dominate the industry and place emphasis on rapid iterative development, causing the significance of regression testing to heighten. With the ability to perform up to 100 regression testing iterations daily, modern technology companies strive to safeguard themselves against potential issues and uphold optimal user experience.

It is imperative to acknowledge that regression testing must encompass the entire software life cycle. Its execution should not be confined solely to pre-release phases but should extend to every release. This holistic approach guarantees the program’s stability and dependability.

Should you find your regression testing process lacking efficiency or you’re interested in enhancing your testing process, our team of skilled testing experts stands ready to assist you in achieving your goals. Learn more about our QA Services and contact us to book an introductory consultation!

Alexander Meshkov

Delivery QA Director at First Line Software

Alexander Meshkov is QA Delivery Director at FLS. Alexander has over 10 years of experience in software testing, organization of the testing process, and test management. A frequent attendee and speaker of diverse testing conferences, actively engages in discussions and keeps up-to-date with the latest trends and advancements in the field.