@Test
public void testExtraConfig() {

  String key = "test.extra.config";
  String oldValue = "old value";
  String newValue = "new value";
  Configuration conf = new Configuration();
  conf.set(TEST_PREFIX + key, oldValue);
  LinkedList<ConfigurationPair> extraConfig =
      new LinkedList<ConfigurationPair>();
  extraConfig.add(new ConfigurationPair(TEST_PREFIX + key, newValue));
  HTraceConfiguration wrapped = TraceUtils.wrapHadoopConf(TEST_PREFIX, conf, extraConfig);
  assertEquals(newValue, wrapped.get(key));
}