What is Regression Testing?
Fixing one defect makes dependencies susceptible to defects.
Once a release has gone through the development phase, software testers perform a functionality check to verify the correctness of the latest update or change made to the code.
Fixing a bug caught in any part of the application enhances the likelihood of bugs finding their way to other portions of the code, including those that are not directly related to the affected portion.
In order to ensure overall product quality it becomes imperative to ensure that fixing one thing has not led to breaking up another.
Regression testing is the retesting of a software system to confirm whether existing functionalities have been affected due to changes made to few parts of the code and ensuring that they are still working as they were before introduction of the new change.
Why Regression Testing and When to do it?
Regression testing is most useful when conducted during system testing
Ideally every release mandates that the code be checked for unexpected new problems, called regressions. Apart from a high code quality regression test would also ensure that the time spent on bug fixing is distributed and well managed.
At MetaDesign Solutions, we understand that neglected regressions from previous stages can pile up, increase at an exponential rate and have a cascading negative effect making testing an unmanageable task once the regressions become noticeable, which it eventually always will.
Regression testing is a normal and vital part of the Software Testing Life Cycle. Already developed test cases from the testers test bucket are executed against the new software version to make sure that the results are unchanged; positive cases are still giving positive results and negative test cases are still negative.
Regression testing can be performed during any phase of testing be it Unit, Integration, System, or Acceptance. But when the code is being checked for compliance with an integrated system as a whole, testing for regressions proves most beneficial. The time and resources applied for regression testing can be economized during system testing as it also evaluates the program with respect to certain specified requirements. Testers at MetaDesign Solutions are strong believers in performing frequent regression tests thus ensuring improved effectiveness.
By now you have already understood that software development would no be possible without regression testing. A thorough regression test requires a number of test cases to run repetitively, which software companies generally prefer to automate for obvious reasons. It is most suitable to conduct a retest of all cases in a test bucket but sometimes due to constraints of time, use of multiple development and test platforms, product scenarios, geographically distributed teams and other unforeseen reasons, conducting time consuming retest of all test cases is not impossible.
In situations where few if not all of the hindrances are mitigated, you have to prioritize test cases based on criticality and frequency. Test cases can also be categorized on the basis of usability for retest as:
* Reusable Test Cases, that can be used in succeeding regression cycles
* Obsolete Test Cases, the use of which can be dropped in order to avoid redundancy of unwanted test cases.
The ultimate alternative to a detailed regression testing is impact analysis where only those portions of the software are tested that have the highest probability of being affected by a change.