@Override
    public List<AmbryReplica> getReplicaIdsForPartition(AmbryPartition partition) {
      return new ArrayList<>(partitionToReplicas.get(partition));
    }
A helper class that mocks the {@link ClusterManagerQueryHelper} and stores partition to replicas mapping internally
as told.
ambry-clustermap/src/test/java/com/github/ambry/clustermap/DynamicClusterManagerComponentsTest.java