I have to agree. Unit tests are some of the most helpful things I’ve used whilst refactoring the Libreoffice vcl module. In fact, I’m now at the stage where if I only move a class into a new header I’m writing a test that covers that class.

An example I’m currently working on is:

https://gerrit.libreoffice.org/c/core/+/121403/5/vcl/qa/cppu...