How can we reduce regression bugs?

It’s a well known fact that fixing a small bug or adding an enhancement can introduce regression bugs in the application. Most of us would have encountered this situation many a times. This means that there will be multiple QA cycles for a small fix which results in the cost going up. This cost cannot be eliminated completely but what a tester can do to reduce such cost can be seen in the following :

• Testers can stress that unit testing should always take place no matter how small the fix is.
• Testers can help the development team to enhance their unit test cases to cover more features.
• Testers can stress that peer code reviews are done. Reviews can help catch a lot of errors/bugs.
• Developers should be involved in the test case review between QA and Business so that if they have any understanding gaps, they are filled up.

QA is not just testing the application. It also involves verification of the process and help in setting up the same. A well driven unit testing and review process can reduce a lot of bugs and ,therefore, the cost of the project.