This is actually a good idea that I overlooked. Thank you. I mean, I already modularize my code fairly well, I just never had thought about only testing components that have changed. I think such a build system might be complex to make. I'm using CMake primarily for my unit testing system. I wonder if CMake alone is enough for this. Usually the CI testing is done on the client machine in my case, but maybe the server could do it as a post-commit? These are all details that get a bit off-topic, but hopefully I can figure something out.

The important thing is that I don't have to make any changes to the way I am using boost (mostly), and I can focus on doing a bit more than naive testing approach of testing everything regardless of if it changed.