Expert Python Programming - Third Edition

Preventing software regression

We all face software regression issues in our developer lives. Software regression is a new bug introduced by a change. It manifests when features or functionalities that were known to be working in the previous versions of the software get broken and stop working at some point of project development.

The main reason for regressions is high complexity of the software. At some point, it is impossible to guess what a single change in the code base might lead to. Changing some code might break some other features, and sometimes lead to vicious side effects, such as silently corrupting data. And high complexity is not only a problem of huge code bases. There is, of course, obvious correlation between the amount ...