I want to ask for your prefered way to test Java EE code?
I found only three project, that are trying to help to code unit tests in Java EE environment:
As you are interested in unit testing, I recommend JUnit. You can unit test the methods in the core classes. If you have difficulty in writing unit test cases using JUnit, then probably the design is not modular and it is highly coupled. First focus on your core functionality and test it using JUnit.