What is Regression testing?
Regression testing is re-running existing tests after a code change, update or integration to confirm that features which worked before still work. It targets unintended side effects rather than new functionality, and is most practical when the bulk of the test suite is automated.
Why it matters for your business
Every release carries a risk of breaking something that already worked. Regression testing keeps frequent releases safe and avoids costly fixes after customers find the problem.
Before applying a quarterly ERP update, a finance team's test suite re-checks invoicing, payments and reports, revealing a broken report filter that is fixed before rollout.