@Override
    public void nodeCreated(String path) {
      if (path.equals(node)) {
        LOG.debug("nodeCreated(" + path + ")");
        lock.release();
      }
    }
Unit tests that uses ZooKeeper but does not use the master-side methods but rather acts
directly on ZK.
hbase-zookeeper/src/test/java/org/apache/hadoop/hbase/zookeeper/TestMasterAddressTracker.java