Software Regression Testing: Ensuring Software Fixes Don't Become Problems

The existing software requires changes due to fixing defects, enhancements etc. Regression testing is done to ensure that enhancement, defect fixes or any other changes made to the software have not broken any existing functionality.

Regression testing is very important wherever there is iterative development of software. In iterative development, the developer adds another module with some functionality to the existing running module and one should make sure that addition of this module does not break the existing functionality. Regression testing is performed with the goal of discovering regression bugs.

Whenever there are any changes in the software regression testing is performed. This ensures that the changes have not introduced any new bugs or affecting the previous functionality of the software without the new module. By doing this test one makes sure that functions that were performing satisfactorily continues to perform well with the addition of the new module. Many a times software change cause malfunctioning of the existing software. Regression testing helps in locating and eliminating the problem.

Regression is also known as verification testing and is used after a software programmer has either fixed a problem or added source code to the program. In certain cases, the addition of source code to a program will initiate new errors. This type of regression testing is a type of quality control to ensure that that new changed code is still in compliance with the original requirements and also that the unchanged code is not affected by any corrections made to the software. A very common way of regression testing is to just rerun tests that were previously run to check for new or reemerging problems.

Regression testing is the method of verification. It verifies whether the bugs are fixed and the newly added features have not created any problem in previous working version of software. Regression means retesting the unchanged parts of the application. Test cases are re-executed in order to check whether previous functionality of application is working fine and new changes have not introduced any new bugs. When an additional program module is added to the existing running program it might cause new errors. The regression testing tracks it and the bug can be fixed.

In any software development, you will come across errors and bugs reemerging after certain codes in the application are rewritten for fixing any bugs. There could be many reasons for this. Most of them are due to human errors. Some of the reasons for such errors are wrong coding, incorrect logic or not understanding the customer’s requirements.

Some of the types of regression testing are as follows.

	local – this occurs when the changes made to the software bring in new bugs
	Unmasked – this happens when a change in the software brings previous bugs
	remote – occurs when a change to one part of software causes malfunctioning to another part of the same software

Regression testing is not only useful in correcting a problem in the program, but also to track the output.