### Question:
ZookeeperLockChecker implements TabletServerLockChecker { @Override public void invalidateCache(String tserver) { zc.clear(root + "/" + tserver); } ZookeeperLockChecker(ClientContext context); @Override boolean isLockHeld(String tserver, String session); @Override void invalidateCache(String tserver);  }### Answer:
@Test public void testInvalidateCache() { zc.clear(context.getZooKeeperRoot() + Constants.ZTSERVERS + "/server"); replay(zc); zklc.invalidateCache("server"); verify(zc); }