private void writeTest(FileSystem fs) throws IOException {
    Path writeDir = getWriteDir(config);
    fs.delete(getDataDir(config), true);
    fs.delete(writeDir, true);

    runIOTest(WriteMapper.class, writeDir);
  }
 private void randomReadTest(FileSystem fs) throws IOException {
   Path readDir = getRandomReadDir(config);
   fs.delete(readDir, true);
   runIOTest(RandomReadMapper.class, readDir);
 }
 private void appendTest(FileSystem fs) throws IOException {
   Path appendDir = getAppendDir(config);
   fs.delete(appendDir, true);
   runIOTest(AppendMapper.class, appendDir);
 }