### Question:
ThrottleUtil { public static int esClusterInc(String host) { String key = THROTTLE_KEY_ESCLUSTER + host; AtomicInteger counter = getCounter(key); return counter.incrementAndGet(); }  static int esClusterInc(String host); static int esClusterDesc(String host);  }### Answer:
@Test public void testEsClusterInc () { ThrottleUtil.esClusterInc("test_cluster"); ThrottleUtil.esClusterInc("test_cluster"); AtomicInteger c = ThrottleUtil.getCounter("cluster:test_cluster"); assertEquals(2, c.get()); }