code: @Deployment public void testRelativeDueDateStringExtension() throws Exception {
    Clock clock=processEngineConfiguration.getClock();
    clock.setCurrentCalendar(new GregorianCalendar(2015,0,1));
    Map<String,Object> variables=new HashMap<String,Object>();
    variables.put("dateVariable","P2DT5H40M");
    ProcessInstance processInstance=runtimeService.startProcessInstanceByKey("dueDateExtension",variables);
    Task task=taskService.createTaskQuery().processInstanceId(processInstance.getId()).singleResult();
    assertNotNull(task.getDueDate());
    Period period=new Period(task.getCreateTime().getTime(),task.getDueDate().getTime());
    assertEquals(2,period.getDays());
    assertEquals(5,period.getHours());
    assertEquals(40,period.getMinutes());
    clock.reset();
  }
  