How do you regression test software changes without introducing new defects?

1 Define the scope and objectives of regression testing

Before you start regression testing, you need to define the scope and objectives of your testing activities. This means identifying what features, functions, or components of the software are affected by the changes, and what are the expected outcomes or results of the changes. You also need to determine what level of testing is required, such as unit, integration, system, or acceptance testing, and what criteria or metrics will be used to measure the success or failure of the testing. By defining the scope and objectives of regression testing, you can focus your efforts on the most relevant and critical aspects of the software, and avoid wasting time or resources on unnecessary or redundant tests.

2 Choose the right regression testing technique

Depending on the scope and objectives of your regression testing, you can choose from different techniques that suit your needs and context. Retest all involves retesting the entire software or application after every change, regardless of the impact or relevance of the change. This technique is thorough and comprehensive, but also very costly and time-consuming, and may not be feasible for large or complex software systems. Selective retest involves retesting only the parts of the software that are directly or indirectly affected by the changes, while test case prioritization involves retesting the most important or high-risk test cases first. Test case minimization is helpful for reducing the test effort and cost, as it involves retesting the minimum number of test cases that can cover the maximum functionality or requirements of the software. All of these techniques require more analysis and maintenance to identify and select affected parts, as well as more planning and evaluation to prioritize test cases.

3 Use automation tools and frameworks

Regression testing software changes without introducing new defects can be achieved through automation tools and frameworks. This method can execute test cases faster, more consistently, and more accurately than manual testing. Automation tools and frameworks can also create and maintain reusable and scalable test scripts, integrate and coordinate the test execution with other tools or systems, generate and report the test results and metrics, and perform parallel or distributed testing. However, these tools and frameworks have some limitations and challenges such as high initial investment, dependency or compatibility issues with the software environment, platform, or technology, maintenance or update issues due to changes in the software or automation tools, and false positives or negatives due to errors or bugs in the automation tools. It is important to select an automation tool that is suitable for your software system, regression testing technique, and testing goals.

4 Review and update the test cases and data

Another important step to regression test software changes without introducing new defects is to review and update the test cases and data according to the changes in the software. This means checking and verifying that the test cases and data are still valid, relevant, and complete, and that they reflect the current requirements and specifications of the software. You also need to add, modify, or delete the test cases and data as needed, to cover the new, changed, or deleted functionality or features of the software. By reviewing and updating the test cases and data, you can ensure that they are accurate and consistent, and that they can detect and prevent any defects or errors in the software.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?