How to write a JUnit test case to test custom workitemhandler implementation in jBPM 6 ?

Issue

• There is a custom woritemhanlder implementation which is developed in jBPM 6 . Users would need to write JUnit test cases to test it's functionality (e.g. complete a task) separately. Is there any sample JUnit test case to the requirements on this woritemhanlder as listed below?

public class SimpleWoritemHandler extends
        AbstractLogOrThrowWorkItemHandler {

        public void executeWorkItem(WorkItem workItem, WorkItemManager manager) {

        Map<String, Object> params = workItem.getParameters();
        Map<String, Object> results = new HashMap<String, Object>();
        ...
        }

@Override
    public void abortWorkItem(WorkItem workItem, WorkItemManager manager) {

    }
...

}

Requirements.

(1) Excecute and test the executeWorkItem(...) method from a JUnit test case.
(2) Pass dummy WorkItem and WorkItemManager parameters from the JUnit test case.

• Also, how to write a JUnit test case which would be able to test the sample workitemhandler implementation which is declared inside kmodule.xml file instead of registering it through jBPM 6 API (i.e. registerWorkItemHandler(String, WorkItemHandler)) ?