public PartitionId getPartitionIdFromStream(InputStream inputStream) throws IOException {
      if (this.throwException) {
        throw new IOException();
      } else {
        byte[] bytes = new byte[10];
        inputStream.read(bytes);
        ByteBuffer bb = ByteBuffer.wrap(bytes);
        bb.getShort();
        long num = bb.getLong();
        return new MockPartitionId(num, (String) null);
      }
    }
Mock clusterMap used when one wants the inputStream input for getPartitionIdFromStream
to be read and have constructed a MockPartitionId from the input
ambry-replication/src/test/java/com/github/ambry/replication/BlobIdTransformerTest.java