public Path getDataTestDirOnTestFS(final String subdirName) throws IOException {
    return new Path(getDataTestDirOnTestFS(), subdirName);
  }
Returns a Path in the test filesystem, obtained from {@link #getTestFileSystem()} to write
temporary test data. Call this method after setting up the mini dfs cluster if the test relies
on it.
@param subdirName name of the subdir to create under the base test dir
@return a unique path in the test filesystem
hbase-diagnostics/src/main/java/org/apache/hadoop/hbase/util/WALPerformanceEvaluationUtil.java