code: @Deployment(resources={"org/activiti/engine/test/api/oneTaskProcess.bpmn20.xml"}) public void testDeleteTaskPartOfProcess(){
    runtimeService.startProcessInstanceByKey("oneTaskProcess");
    Task task=taskService.createTaskQuery().singleResult();
    assertNotNull(task);
    try {
      taskService.deleteTask(task.getId());
    }
   catch (  ActivitiException ae) {
      assertEquals("The task cannot be deleted because is part of a running process",ae.getMessage());
    }
    try {
      taskService.deleteTask(task.getId(),true);
    }
   catch (  ActivitiException ae) {
      assertEquals("The task cannot be deleted because is part of a running process",ae.getMessage());
    }
    try {
      taskService.deleteTask(task.getId(),"test");
    }
   catch (  ActivitiException ae) {
      assertEquals("The task cannot be deleted because is part of a running process",ae.getMessage());
    }
    try {
      taskService.deleteTasks(Collections.singletonList(task.getId()));
    }
   catch (  ActivitiException ae) {
      assertEquals("The task cannot be deleted because is part of a running process",ae.getMessage());
    }
    try {
      taskService.deleteTasks(Collections.singletonList(task.getId()),true);
    }
   catch (  ActivitiException ae) {
      assertEquals("The task cannot be deleted because is part of a running process",ae.getMessage());
    }
    try {
      taskService.deleteTasks(Collections.singletonList(task.getId()),"test");
    }
   catch (  ActivitiException ae) {
      assertEquals("The task cannot be deleted because is part of a running process",ae.getMessage());
    }
  }
  