@Override
  public boolean checkGaugeExists(String name, BaseSource source) {
    getMetrics(source);
    String cName = canonicalizeMetricName(name);
    return gauges.get(cName) != null;
  }
A helper class that will allow tests to get into hadoop2's metrics2 values.
hbase-hadoop-compat/src/test/java/org/apache/hadoop/hbase/test/MetricsAssertHelperImpl.java