Regression with an automated test suite is a frequently used/abused phrase. People need to first understand what “regression” actually means.
Regression testing in a nutshell relates to the activity, by which we check a new application/product, for all the previous functionality; while keeping the newly added features unused. Basically, we validate that the new code has no effect on the older functionality. Regression is not used/should not be used to check for a functionality which has changed. As a change in functionality means that it is a new feature and needs to be verified first before it is validated.