@VisibleForTesting
  @Override
  public BlockType getBlockType() {
    return HeaderFormat.getBlockType(header);
  }
@Test
  public void testGetBlockType() {
    replication = 3;
    preferredBlockSize = 128*1024*1024;
    INodeFile inf = createINodeFile(replication, preferredBlockSize);
    assertEquals(inf.getBlockType(), CONTIGUOUS);
    INodeFile striped = createStripedINodeFile(preferredBlockSize);
    assertEquals(striped.getBlockType(), STRIPED);
  }