“Regression Testing is a test type conducted to test that the changes made to the code did not impact the existing functionality of the software”.
Regression Testing a is a test activity aimed at evaluating the effect of changes done to the application under test (AUT). This type of test type falls under the change-related testing activity.
Change Related Testing consists of two types of test:
Confirmation Tests: This type of testing, also known as re-testing, confirms the bugs have been fixed.
Regression Tests: This type of testing tests the impacted areas in the software which may have been affected with the bug fixes in software or environment.
Why Perform Regression Testing
When a change is made to the application due to fixing of bugs, change in environment or database, it may unintentionally affect the conduct of other parts of the module or system. Such side-effects are known as regressions. Testers perform regression testing to detect those side-effects. Regression Testing becomes extremely important as the system grows.
About Regression Testing
Regression Testing is performed at all Test Levels such as component testing, maintenance testing etc.
It is performed at Test Execution phase of the Test Process. It can be done manually or using test execution tools.
Regression Testing is performed many times as the software is built gradually, thus it is best candidate for test automation.
Automation of regression testing should start early in the project.
Regression Testing is very important in IOT (Internet of Things) where the devices are added, removed and updated frequently.
Since retesting and regression testing incur high costs, static testing should be practiced by organisation as it is much cheaper as compared to dynamic testing.
Regression Tests are also prioritized for rapid feedback in iterative development life-cycles.
Due to testing principle, “Beware of Pesticide Paradox", few regression defects may be found if manual test cases or automated test scripts are not updated. Therefore, regression tests should be updated.
Regression in Continuous Integration Environment is done at multiple levels since the components are integrated one by one. So, it is effective to use test automation for regression test.
Regression Testing in Agile
Agile is an incremental and iterative software development model. In Agile, adding a new functionality, making changes to existing feature occurs frequently in small duration of time called “Sprints”. This leads to repeated changes to the program code. In such fast and iterative development model, retesting and regression testing are very important.
Benefits of Regression Testing in Agile
Stability of Product: Regression Test Cases in Agile ensures overall product stability while a new functionality is being developed in a Sprint. It helps the product owner to gauge the complete functionality of the product after the changes have been made. When it comes to real life system, there is a trade off between faster development, market and less regression bugs. It depends on the product owner to decide to minimize the regression by decreasing the scope of the user stories or value faster development.
Rapid Feedback: Regression Tests are executed in short intervals after small changes have been made to the code. The early feedback in agile, helps the developers to track and correct errors of the functionality easily as they have not moved further to other modules.
How to Develop Regression Tests in Agile
1. Regression Tests are created gradually as the Sprints are delivered so that the team can understand the important functionalities.
2. Functional Test Cases of previous Sprints are kept for reuse. These tests are later upgraded to regression tests.
3. The product owner will write the business functions which should be added in regression test suites in the user story. Thus, the testers should give test effort estimation considering the regression part as well.
Best Practices of Regression Testing in Agile
The early feedback mechanism in Agile, can be achieved by test automation. This means that the regression test cases should be written as automation test scripts and run on automated build environment.
The Regression Tests ensure overall stability of the product while Functional Test Cases focus on the current functionality being developed. The functional test cases should not be considered same as regression test cases.
Regression Tests should be constructed for enough coverage considering the business workflow and technical implementation. Using same functional tests developed over last sprints as regression tests for current sprint lead to test duplication, lot of time to view and analyze the results.
In this world of continuous development of web and mobile applications, expertise in regression testing to test new features, bug fixes are demanded. Regression testing is a must for Agile and DevOps. If you are looking to learn regression testing, improve your regression testing skills, reach out to busyQA.