@SuppressWarnings("unchecked")
  private void populateMapPlan1(Table src) throws Exception {

    Operator<FileSinkDesc> op2 = OperatorFactory.get(ctx, new FileSinkDesc(new Path(TMPDIR + File.separator
        + "mapplan1.out"), Utilities.defaultTd, true));
    Operator<FilterDesc> op1 = OperatorFactory.get(getTestFilterDesc("key"), op2);

    addMapWork(mr, src, "a", op1);
  }
Mimics the actual query compiler in generating end to end plans and testing
them out.
ql/src/test/org/apache/hadoop/hive/ql/exec/TestExecDriver.java