The overall functionality and stability of the existing features are taken care of by this testing method. Whenever there are changes being made to the code, there may be chances of malfunctions, defects and dependencies. Regression testing is applied in order to mitigate these risks. Read more https://www.reddit.com/user/serenagray2451/comments/szh1ka/what_is_smoke_sanity_and_regression_testing_how/