@Test
  public void isShutdownTest() {
    PrioritySchedulerDefaultPriorityWrapper psw =
        new PrioritySchedulerDefaultPriorityWrapper(scheduler, TaskPriority.Low);
    assertEquals(scheduler.isShutdown(), psw.isShutdown());

    TestPriorityScheduler tps = new TestPriorityScheduler();
    psw = new PrioritySchedulerDefaultPriorityWrapper(tps, TaskPriority.Low);
    psw.isShutdown();

    assertTrue(tps.isShutdownCalled);
  }
 @AfterClass
 public static void cleanupClass() {
   scheduler.shutdown();
   scheduler = null;
 }