@Test
  public void scheduleAtFixedRateTest() {
    TestPriorityScheduler testScheduler = new TestPriorityScheduler();
    PrioritySchedulerDefaultPriorityWrapper psw =
        new PrioritySchedulerDefaultPriorityWrapper(testScheduler, TaskPriority.Low);
    psw.scheduleAtFixedRate(DoNothingRunnable.instance(), 10, 10);
    assertTrue(testScheduler.scheduleAtFixedRateCalled);

    // reset and try with priority
    testScheduler.scheduleAtFixedRateCalled = false;
    psw.scheduleAtFixedRate(DoNothingRunnable.instance(), 10, 10, TaskPriority.High);
    assertTrue(testScheduler.scheduleAtFixedRateCalled);
  }