code: @Deployment public void testChangeCategoryInDelegateTask(){
    Map<String,Object> variables=new HashMap<String,Object>();
    variables.put("approvers",Collections.singletonList("kermit"));
    ProcessInstance processInstance=runtimeService.startProcessInstanceByKey("delegateTaskTest",variables);
    List<Task> tasks=taskService.createTaskQuery().processInstanceId(processInstance.getId()).list();
    for (  Task task : tasks) {
      assertEquals("approval",task.getCategory());
      Map<String,Object> taskVariables=new HashMap<String,Object>();
      taskVariables.put("outcome","approve");
      taskService.complete(task.getId(),taskVariables,true);
    }
    assertEquals(0,taskService.createTaskQuery().processInstanceId(processInstance.getId()).count());
    for (  HistoricTaskInstance historicTaskInstance : historyService.createHistoricTaskInstanceQuery().list()) {
      assertEquals("approved",historicTaskInstance.getCategory());
    }
  }
  