unit testing ejb 2.x

I was asked to work on a product which is developed in ejb2.x. The code base is very larger and the code is more generic (same interface for more than 5 implementations). To understand the flow and what do the methods in the classes do,开发者_JS百科 I want to unit test the code base. How can I do this? Any help would be appreciated.

Thanks, Anjali.

I thinks it's a late answer, but I do my unit tests with a web project using Cactus and jUnit. I use some mocks: EasyMOck, PowerMock e MockEjb when necessary.