Sunday, 25 October 2015

What Do We Know About Regression Testing?

When it comes to software development process, even a small change can bring forth major unexpected changes in the functionality of the whole system. Here comes the role of the regression testing. Regression testing is done to check if the existing functionality is rendered unaltered even by the tweaks made to abolish the bugs. It also provides with proof that the eradicated bugs are not brought to life again.
Regression testing is done whenever any kind of changes are applied to the system, so as to check if the system is working properly as desired. Bigger the changes made, bigger will be the possibility of the software functionality to be affected. Basically regression testing has two steps:
1.    Conducting the already performed tests.
2.    Checking the results of the tests with the previously available results to check if the system is up and running and what new bugs have developed which needs to be eradicated to make the software function well.
The regression tests are performed from time to time in patches to save both time and money on the testing process by preventing the errors to pile up at the end.
Various software testers take different approaches towards the regression testing of software available to them. While a part of the tester prefers testing the whole system after a certain amount of development is done, another set prefers testing the software every time a small change is made in the source code. In a way the later method is better as particular software is capable of showing completely surprising changes in the system which can be sparsely related to the changes made to the system. Luckily, (thanks to the technology available these days) testers can now create a library of various tests with the previously available data from functional tests, unit tests, integration tests, build verification tests or any other tests which helps in verifying that the system is performing as desired.
With the advent of automatic testing of software, regression testing has been made easier. Now a days a set of tests can be scripted with the help of codes and with just a few clicks of the mouse, these tests can be performed on the software under examination to check the validity of the system and the status of the abolished bugs. Although this automation helps in stress removal from the testers, it has some shortcomings too. When you are performing the same test over and over again, there are chances that the regression test system will become a standstill. At times it may also happen that the developers trick the automated regression test system to overlook certain errors and in this way your system will end up overlooking most of the errors. So, even if the automation saves a lot of time and energy, from time to time, manual inputs are needed to keep the system up and running.

In order to get the most out of regression testing of software, testers have to strike a balance in between the automation of the process and the manual aspect of the test. Also, regression testing should be introduced at an early stage of the software development life cycle so that maximum test coverage of the software can be achieved and piling up of the system can be avoided. 


  1. Thanks for sharing your views.regression testing is an important part of STLC but should be done once the product is stable to save some time. It has benefits in early stages but would be possible if there is enough time or automation is available.

  2. Regression should be done post progression cycle. Automated tests should be run against all new builds promoted to test environment. Regression should only focus on areas impacted by changes done during development cycle. Manual testing + acceptance testing should be used for regression cycle.