### Question:
HelixClusterManager implements ClusterMap { @Override public byte getLocalDatacenterId() { return localDatacenterId; } HelixClusterManager(ClusterMapConfig clusterMapConfig, String instanceName, HelixFactory helixFactory,
      MetricRegistry metricRegistry); @Override boolean hasDatacenter(String datacenterName); @Override byte getLocalDatacenterId(); @Override String getDatacenterName(byte id); @Override AmbryDataNode getDataNodeId(String hostname, int port); @Override List<AmbryReplica> getReplicaIds(DataNodeId dataNodeId); @Override List<AmbryDataNode> getDataNodeIds(); @Override MetricRegistry getMetricRegistry(); @Override void onReplicaEvent(ReplicaId replicaId, ReplicaEventType event); @Override JSONObject getSnapshot(); @Override PartitionId getPartitionIdFromStream(InputStream stream); @Override List<PartitionId> getWritablePartitionIds(String partitionClass); @Override PartitionId getRandomWritablePartition(String partitionClass, List<PartitionId> partitionsToExclude); @Override List<PartitionId> getAllPartitionIds(String partitionClass); @Override ReplicaId getBootstrapReplica(String partitionIdStr, DataNodeId dataNodeId); @Override void registerClusterMapListener(ClusterMapChangeListener clusterMapChangeListener); @Override void close();  }### Answer:
@Test public void basicInterfaceTest() throws Exception { assumeTrue(!overrideEnabled); assertEquals("Incorrect local datacenter ID", 0, clusterManager.getLocalDatacenterId()); testPartitionReplicaConsistency(); testInvalidPartitionId(); testDatacenterDatanodeReplicas(); assertStateEquivalency(helixCluster.getDownInstances(), helixCluster.getUpInstances()); }