Need help to find unit test strategy

Hi everyone !

I'm a Cactus beginner, and I need for my company to find unit test strategy 
for developpers to write unit tests. Could anyone give me the way you work ?
What to test ? How to test methods ?

Do you use mok ejb ? We're using EJB 3, so is it necessary ? I can't find 
any informations on the web about mock objects and Ejb 3...

Do you test POJOs ? Do each developper need to have a Web project in their 
workspace for testing with Cactus?

I'm a little lost, and need to write a white paper for developpers here ... 
!

Thanks for your experience :)

Sincerely,