@Test
  public void testIsSameHdfs() throws IOException {
    String hadoopVersion = org.apache.hadoop.util.VersionInfo.getVersion();
    LOG.info("hadoop version is: " + hadoopVersion);
    boolean isHadoop3_0_0 = hadoopVersion.startsWith("3.0.0");
    if (isHadoop3_0_0) {
      // Hadoop 3.0.0 alpha1+ ~ 3.0.0 GA changed default nn port to 9820.
      // See HDFS-9427
      testIsSameHdfs(9820);
    } else {
      // pre hadoop 3.0.0 defaults to port 8020
      // Hadoop 3.0.1 changed it back to port 8020. See HDFS-12990
      testIsSameHdfs(8020);
    }
  }
Ugly test that ensures we can get at the hedged read counters in dfsclient. Does a bit of
preading with hedged reads enabled using code taken from hdfs TestPread.
hbase-server/src/test/java/org/apache/hadoop/hbase/util/TestFSUtils.java