Are you a puppet module author? Do other people use your puppet code? Do you want to know what your change broke? Would future-you still know what you expected here?
Using automated tests can help you with this. There are tools to help you answer all this for puppet modules, but only few use them. Join this talk to get an introduction to the rspec-puppet and beaker-rspec test frameworks, learn how to run automated tests on your puppet modules, and learn how to write good tests.