This project should serve as a basis to try and explore unit testing, and improving quality assurance on your own projects.
If you would like to know more about unit testing, I can highly recommend the following books, both written by Chris Hartjes who's better known as @grmpyprogrammer:
- The Grumpy Programmer's Guide To Building Testable PHP Applications
- The Grumpy Programmer's PHPUnit Cookbook
These unit tests also make use of joindin, a community driven project that provides a feedback mechanism for conference speakers and organisers.