@Override
  public long getPreferredBlockSize() {
    return HeaderFormat.getPreferredBlockSize(header);
  }
@Test
  public void testPreferredBlockSizeUpperBound () {
    replication = 3;
    preferredBlockSize = BLKSIZE_MAXVALUE;
    INodeFile inf = createINodeFile(replication, preferredBlockSize);
    assertEquals("True has to be returned in this case", BLKSIZE_MAXVALUE,
                 inf.getPreferredBlockSize());
  }