@BeforeClass
  public static void provisionCluster() throws Exception {
    conf = util.getConfiguration();
    conf.set("hbase.coprocessor.master.classes", OperationAttributesTestController.class.getName());
    conf.set("hbase.coprocessor.region.classes", OperationAttributesTestController.class.getName());
    util.startMiniCluster();
  }
Force use of combiner in doMROnTableTest. Boolean. Default is true.
hbase-mapreduce/src/test/java/org/apache/hadoop/hbase/mapreduce/TestImportTSVWithOperationAttributes.java