"JbpmJUnitTestCase" is calling 'abortWorkItem' when task completes and thus it causes the 'task parameter' to 'process variable' mapping to fail

Issue

• We have a JUnit test class which extends JbpmJUnitTestCase where we are creating a TaskService like the following way:

  TaskService taskService = getTaskService(ksession); 

Everything goes well with claiming and starting the task like this:

  taskService.claim(task.getId(), "xxx",  groupIds);
  taskService.start(task.getId(), "xxx");

But after that we have observed that the task parameter to process variable mapping seems to be failing which results in a java.lang.NullPointerException, something like the one given below.

java.lang.NullPointerException
    at org.drools.bpmn2.Process_org_drools_bpmn2_Hello_World_2.action2(Process_org_drools_bpmn2_Hello_World_2.java:26)
    at org.drools.bpmn2.Process_org_drools_bpmn2_Hello_World_2Action2Invoker.execute(Process_org_drools_bpmn2_Hello_World_2Action2Invoker.java:16)
    at org.jbpm.workflow.instance.impl.ExtendedNodeInstanceImpl.executeAction(ExtendedNodeInstanceImpl.java:68)
    at org.jbpm.workflow.instance.impl.ExtendedNodeInstanceImpl.triggerEvent(ExtendedNodeInstanceImpl.java:58)
    at org.jbpm.workflow.instance.impl.ExtendedNodeInstanceImpl.triggerCompleted(ExtendedNodeInstanceImpl.java:46)
    at org.jbpm.workflow.instance.node.StateBasedNodeInstance.triggerCompleted(StateBasedNodeInstance.java:162)
    at org.jbpm.workflow.instance.node.StateBasedNodeInstance.triggerCompleted(StateBasedNodeInstance.java:143)
    at org.jbpm.workflow.instance.node.WorkItemNodeInstance.triggerCompleted(WorkItemNodeInstance.java:239)
    at org.jbpm.workflow.instance.node.HumanTaskNodeInstance.triggerCompleted(HumanTaskNodeInstance.java:90)
    at org.jbpm.workflow.instance.node.WorkItemNodeInstance.workItemAborted(WorkItemNodeInstance.java:293)
    at org.jbpm.workflow.instance.node.WorkItemNodeInstance.signalEvent(WorkItemNodeInstance.java:279)
    at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.signalEvent(WorkflowProcessInstanceImpl.java:338)
    at org.drools.persistence.jpa.processinstance.JPAWorkItemManager.abortWorkItem(JPAWorkItemManager.java:154)
    at org.drools.command.runtime.process.AbortWorkItemCommand.execute(AbortWorkItemCommand.java:56)
    at org.drools.command.runtime.process.AbortWorkItemCommand.execute(AbortWorkItemCommand.java:29)
    at org.drools.command.impl.DefaultCommandService.execute(DefaultCommandService.java:36)
    at org.drools.persistence.SingleSessionCommandService.execute(SingleSessionCommandService.java:355)
    at org.drools.command.impl.CommandBasedStatefulKnowledgeSession$1.abortWorkItem(CommandBasedStatefulKnowledgeSession.java:156)
    at org.jbpm.process.workitem.wsht.SyncWSHumanTaskHandler$TaskCompletedHandler.handleCompletedTask(SyncWSHumanTaskHandler.java:378)
    at org.jbpm.process.workitem.wsht.SyncWSHumanTaskHandler$TaskCompletedHandler.execute(SyncWSHumanTaskHandler.java:319)
    at org.jbpm.task.service.local.LocalTaskService$SimpleEventTransport.trigger(LocalTaskService.java:287)
    at org.jbpm.task.event.MessagingTaskEventListener.taskCompleted(MessagingTaskEventListener.java:73)
    at org.jbpm.task.event.TaskEventSupport.fireTaskCompleted(TaskEventSupport.java:47)
    at org.jbpm.task.service.TaskServiceSession.postTaskCompleteOperation(TaskServiceSession.java:502)
    at org.jbpm.task.service.TaskServiceSession.taskOperation(TaskServiceSession.java:469)
    at org.jbpm.task.service.local.LocalTaskService.complete(LocalTaskService.java:76)
    at com.sample.TestingProcess_BUG.testProcess(TestingProcess_BUG.java:113)
        ...

Can you please guide us how to solve this issue?