public void testGroupProjector() throws ExecutionException, InterruptedException {
// in(0) in(1) in(0), in(2)
// select race, avg(age), count(race), gender ... group by race, gender
GroupProjection projection = new GroupProjection();
projection.keys(Arrays.<DataTypeSymbol>asList(new InputColumn(0, DataTypes.STRING), new InputColumn(2, DataTypes.STRING)));
projection.values(Arrays.asList(
new Aggregation(avgInfo, Arrays.<Symbol>asList(new InputColumn(1)), Aggregation.Step.ITER, Aggregation.Step.FINAL),
new Aggregation(countInfo, Arrays.<Symbol>asList(new InputColumn(0)), Aggregation.Step.ITER, Aggregation.Step.FINAL)
));
Projector projector = visitor.process(projection);