How to make work multiple scripts in a folder for an addon?

As I see it you have three main options when it comes to registering all your classes.

  1. After you did from . import TestModule in __init__.py you can call TestModule.register() and TestModule.unregister() in the register/unregister function in __init__.py
  2. You can import all the classes into __init__.py, put them into one classes tuple and then register them the way you are doing it already. from . TestModule import EmptyClass, TestClass can be used to import these classes.
  3. Use my auto_load.py that can do all the class registration for you. However it would be good if you could get this working without it just for the purpose of learning how it works. You can find it here. Make sure to also read the limitations of that script.