private static void appendCoprocessor(Configuration conf, String property, String value) {
    if (conf.get(property) == null) {
      conf.set(property, VisibilityController.class.getName());
    } else {
      conf.set(property, conf.get(property) + "," + VisibilityController.class.getName());
    }
  }
Utility methods for testing visibility labels.
hbase-server/src/test/java/org/apache/hadoop/hbase/security/visibility/VisibilityTestUtil.java