private static Task<MapredWork> getMapredWork() {
    return TaskFactory.get(MapredWork.class);
  }
This test tests that Utilities.get*Tasks do not repeat themselves in the process
of extracting tasks from a given set of root tasks when given DAGs that can have
multiple paths, such as the case with Diamond-shaped DAGs common to replication.
ql/src/test/org/apache/hadoop/hive/ql/exec/TestUtilities.java