public static NamenodeRole convert(NamenodeRoleProto role) {
    switch (role) {
    case NAMENODE:
      return NamenodeRole.NAMENODE;
    case BACKUP:
      return NamenodeRole.BACKUP;
    case CHECKPOINT:
      return NamenodeRole.CHECKPOINT;
    }
    return null;
  }
@Test
  public void testFSServerDefaultsHelper() {
    HdfsProtos.FsServerDefaultsProto.Builder b =
        HdfsProtos.FsServerDefaultsProto
        .newBuilder();
    b.setBlockSize(DFSConfigKeys.DFS_BLOCK_SIZE_DEFAULT);
    b.setBytesPerChecksum(DFSConfigKeys.DFS_BYTES_PER_CHECKSUM_DEFAULT);
    b.setWritePacketSize(
        HdfsClientConfigKeys.DFS_CLIENT_WRITE_PACKET_SIZE_DEFAULT);
    b.setReplication(DFSConfigKeys.DFS_REPLICATION_DEFAULT);
    b.setFileBufferSize(DFSConfigKeys.IO_FILE_BUFFER_SIZE_DEFAULT);
    b.setEncryptDataTransfer(DFSConfigKeys.DFS_ENCRYPT_DATA_TRANSFER_DEFAULT);
    b.setTrashInterval(DFSConfigKeys.FS_TRASH_INTERVAL_DEFAULT);
    b.setChecksumType(HdfsProtos.ChecksumTypeProto.forNumber(
        DataChecksum.Type.valueOf(DFSConfigKeys.DFS_CHECKSUM_TYPE_DEFAULT).id));
    HdfsProtos.FsServerDefaultsProto proto = b.build();

    assertFalse("KeyProvider uri is not supported",
        proto.hasKeyProviderUri());
    FsServerDefaults fsServerDefaults = PBHelperClient.convert(proto);
    Assert.assertNotNull("FsServerDefaults is null", fsServerDefaults);
    Assert.assertNull("KeyProviderUri should be null",
        fsServerDefaults.getKeyProviderUri());
  }