source: class AbstractScheduledEventExecutorTest {
  
      private static final Runnable TEST_RUNNABLE;
      private static final Callable<?> TEST_CALLABLE;
  
      @Test(expected = IllegalArgumentException.class)
      public void testScheduleAtFixedRateRunnableNegative() {
  
target:         TestScheduledEventExecutor executor = new TestScheduledEventExecutor();
          executor.scheduleAtFixedRate(TEST_RUNNABLE, 0, -1, TimeUnit.DAYS);
      }
  
  }