### Question:
ZkRoutingDataWriter implements MetadataStoreRoutingDataWriter { @Override public synchronized boolean addMetadataStoreRealm(String realm) { if (_leaderElection.isLeader()) { if (_zkClient.isClosed()) { throw new IllegalStateException("ZkClient is closed!"); } return createZkRealm(realm); } String urlSuffix = constructUrlSuffix(MetadataStoreRoutingConstants.MSDS_GET_ALL_REALMS_ENDPOINT, realm); return buildAndSendRequestToLeader(urlSuffix, HttpConstants.RestVerbs.PUT, Response.Status.CREATED.getStatusCode()); } ZkRoutingDataWriter(String namespace, String zkAddress); static String buildEndpointFromLeaderElectionNode(ZNRecord znRecord); @Override synchronized boolean addMetadataStoreRealm(String realm); @Override synchronized boolean deleteMetadataStoreRealm(String realm); @Override synchronized boolean addShardingKey(String realm, String shardingKey); @Override synchronized boolean deleteShardingKey(String realm, String shardingKey); @Override synchronized boolean setRoutingData(Map<String, List<String>> routingData); @Override synchronized void close();  }### Answer:
@Test public void testAddMetadataStoreRealm() { _zkRoutingDataWriter.addMetadataStoreRealm(DUMMY_REALM); ZNRecord znRecord = _gZkClientTestNS .readData(MetadataStoreRoutingConstants.ROUTING_DATA_PATH + "/" + DUMMY_REALM); Assert.assertNotNull(znRecord); }