Several years ago I started managing my dotfiles based on Zach Holman’s dotfiles repo. His setup is quite nice and I found it relatively easy to adapt to my own purposes. My workflow generally consisted of making a bunch of local changes until I was happy and then pushing to my own GitHub fork.
The big problem I eventually found is that I wasn’t fully capturing the correct steps to reproduce my environment. Every time that I tried to install my dotfiles on a new machine, I would be met with several errors that I would eventually resolve. The fix would not always result in something which was reproducible on another machine. I wanted a solution that would let me automatically test that my dotfiles would cleanly install every time I pushed to GitHub, so I turned to Docker.
Traditional CI services would have been a bit of a pain to use with all the packages that needed to be installed. Docker Hub made things nice and easy. My Dockerfile simply installs the necessary OS packages, adds a new user and then tries to run my install script. I currently don’t have any other testing other than to ensure that the script exits without error, but this has already saved me a lot of trouble.
Update: I have since switched to using Travis CI as I do with my other projects. It turns out this is easier than I expected. I still haven’t explicitly added any tests but even being able to confirm that the installation steps succeed is useful to ensure nothing breaks.