public PartitionId createNewPartition(List<MockDataNodeId> dataNodes) {
    int mountPathSize;
    if (cloudDatacenterName == null) {
      mountPathSize = this.dataNodes.get(0).getMountPaths().size();
    } else {
      // the get(0) is cloud DC which doesn't have mount path. So we use get(1) DC.
      mountPathSize = this.dataNodes.get(1).getMountPaths().size();
    }

    int mountPathIndexToUse = (new Random()).nextInt(mountPathSize);
    return createNewPartition(dataNodes, mountPathIndexToUse);
  }
Create a new partition and add it to mock clustermap.
@param dataNodes the replicas of new partition should be placed on the given data nodes only.
@return new {@link PartitionId}
ambry-test-utils/src/main/java/com/github/ambry/clustermap/MockClusterMap.java