Introduction
Regression testing is the act of testing the unchanged feature of an application, when there has been a recent modification to the program codebase, such as: Added feature, Deleted feature, and fixed/defect.
This testing is carried out to ensure that new code changes do not have side effects on the existing functionalities. It ensures the old functionalities work once the latest code changes are done.
In this blog, we will analyze regression testing, its types, use cases, examples, tools, and benefits.
Why Regression Testing?
There is a need to perform Regression testing whenever the application codebase is changed, and you need to determine if the modified code will affect other parts of the software application.
Regression testing may also be performed when a functionality or performance issue is fixed.
Regression testing is an essential part of the software development process. By ensuring that software changes do not cause existing functionality to break, regression testing helps to improve the quality of software and reduce the risk of defects.
Types of Regression Testing
Unit Regression Testing: This type of testing focuses only on the change or modified part of the software unit or component done by the engineering team.
Regional Regression Testing (RRT): Focuses on testing the changed code and also the other imparted components. If module A is modified and the modification also affects module D, then this test is carried out to identify the two modules and fix them.
Full Regression Testing: Testing the change unit and also the other remaining unchanged part of the software application, to make sure all features work as expected. This is mostly carried out when the root component of the application was modified.
Selective Regression Testing: Focuses on specific areas of the software that are affected by the changes.
Corrective Regression Testing: This testing is done when no modifications are made to the features. Such tests can be performed with existing cases.
Examples of Regression Testing
Smoke Test: A smoke test is a quick and shallow regression test that verifies the basic functionality of the software after changes. It ensures that the critical functionalities of the application are still operational and that the build is stable enough to proceed with further testing.
Functional Regression Testing: This type of regression testing focuses on validating the core functionalities of the software after modifications. It includes retesting the affected areas to ensure that the intended functionality has not been impacted and that the application is still able to perform its intended tasks.
Performance Regression Testing: Performance regression testing aims to ensure that the performance of the application has not degraded after changes. It involves measuring and comparing performance metrics, such as response times, throughput, and resource utilization, to ensure that the system's performance meets the required standards.
GUI Regression Testing: GUI regression testing involves verifying the graphical user interface after modifications. It ensures that the UI elements, layouts, and user interactions remain consistent and functional across different screens and resolutions, even after changes have been made to the underlying codebase.
Use Cases of Regression Testing
Software Updates: Whenever a new software update is released, regression testing is taken into consideration, to ensure that the existing functionalities continue to work.
Bug Patches: After fixing a bug, regression testing confirms that the fix has not introduced any new issues.
New Feature Development: When new features are added to the application, regression testing ensures that this new feature does not impart existing functionalities.
System Integration: When integrating multiple systems or components, regression testing ensures that the integration does not break existing features.
Environment Changes: When migrating a database from one to another, e.g. (MYSQL to ORACLE). regression testing ensures this new migration works as expected, delivering its intended purpose and performance.
When is Regression Testing Needed?
Regression testing is usually needed whenever there is a change in specifications and the application’s code structure, requiring a series of tests to ensure that the modifications don’t affect other related and non-related components of the application build.
This testing is also required whenever new features are integrated into the application build and bug fixes, defects, and other issues before deployment.
Regression testing is an essential part of the software development process. By ensuring that software changes do not cause existing functionality to break, regression testing helps to improve the quality of software and reduce the risk of defects.
Benefits of Regression Testing
The idea behind Regression Testing is to identify potential bugs introduced due to the changes in the new feature.
Conducting these tests benefits in many ways such as:
Increase chances of detecting bugs.
Help catch bugs early after feature integration.
Make sure that issues/defects fixed do not occur again.
Ensure the correctness and quality of the application.
Tools for Regression Testing
Regression testing can be significantly enhanced with the help of specialized tools and technologies. These tools automate and streamline the regression testing process, enabling testers to execute tests more efficiently and effectively.
Some popular tools for regression testing include:
selenium: This is an open-source tool used for automating web applications. Selenium can be used for browser-based regression testing.
TestComplete: TestComplete is a commercial functional testing tool that supports regression testing for various types of applications, including web, desktop, and mobile. It provides a graphical user interface for test creation, execution, and result analysis.
Rational Functional Tester (RFT): Rational Functional Tester is an automated functional testing tool by IBM. It supports regression testing for a wide range of applications, including web, desktop, and mobile. RFT provides a scripting interface for creating test scripts, and it integrates with other tools in the IBM Rational suite for comprehensive testing and reporting.
JUnit: JUnit is a unit testing framework for Java applications. It provides a set of annotations and assertions to define and execute test cases. JUnit can be used for regression testing by writing test cases that validate the expected behaviour of specific components or modules.
Conclusion
Regression testing plays a vital role in maintaining the stability, reliability, and quality of software applications. By conducting thorough regression tests and following best practices, organizations can minimize the impact of changes, ensure that critical functionalities are intact, and deliver software that meets or exceeds user expectations.
Regression testing helps facilitate the application development cycle by catching bugs early, saving the company money, and reducing the application's frequent crashes. Assuring that software applications remain stable and function as intended even after changes are made. Through various types of regression testing, such as functional, performance, and security regression testing, organizations can effectively validate the integrity of their software systems.