public static List<URI> getNamespaceEditsDirs(Configuration conf)
      throws IOException {
    return getNamespaceEditsDirs(conf, true);
  }
@Test
  public void testUniqueEditDirs() throws IOException {
    Configuration config = new Configuration();

    config.set(DFS_NAMENODE_EDITS_DIR_KEY, "file://edits/dir, "
        + "file://edits/dir1,file://edits/dir1"); // overlapping internally

    // getNamespaceEditsDirs removes duplicates
    Collection<URI> editsDirs = FSNamesystem.getNamespaceEditsDirs(config);
    assertEquals(2, editsDirs.size());
  }