Hi, in jBPM5 you have the concept of work item. Using that you can provide different implementations of your services that can run in different environments. Creating a workitemHandler that mock your services and another one that do the real thing, will help you to test your business processes without changeing them when you need to test them.
I was creating a simple project to be able to easily test processes, but I think that kris will probably do something similar and include it in the master repository for the next version. Take a look at:
https://github.com/Salaboy/JBPM5-Test-Framework
Greetings.