problem with Fork/Join

Hi,I have get a problem in using the JBPM framework, the version of JBPM framework is 4.2 . You can copy my junit test files into your project and run the AsyncForkTest class as a junit test application, the test result won't be passed.So what just happen?
ps.I have another question,Is it a necessary to use a Fork and Join tag at the same time in the xxx.jpdl.xml? Cause in my junit test , I only use the Fork tag.
Thanks.