@Test
  public void testLogDirectoryShouldBeDeletedAfterSuccessfulSplit() throws IOException {
    generateWALs(-1);
    useDifferentDFSClient();
    WALSplitter.split(HBASELOGDIR, WALDIR, OLDLOGDIR, fs, conf, wals);
    FileStatus[] statuses = null;
    try {
      statuses = fs.listStatus(WALDIR);
      if (statuses != null) {
        fail("Files left in log dir: " + Joiner.on(",").join(FileUtil.stat2Paths(statuses)));
      }
    } catch (FileNotFoundException e) {
      // hadoop 0.21 throws FNFE whereas hadoop 0.20 returns null
    }
  }
@return set of wal names present prior to split attempt.
@throws IOException if the split process fails
hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALSplit.java