@Override
        public Result search(com.yahoo.search.Query query, Execution execution) {
            AndItem a = new AndItem();
            a.addItem(query.getModel().getQueryTree().getRoot());
            WordItem item = new WordItem("b");
            item.setFromQuery(true);
            a.addItem(item);

            query.getModel().getQueryTree().setRoot(a);

            return execution.search(query);
        }
Simulates the return when grouping is used for aggregation purposes and there is a plain hit list in addition:
The returned result contains both regular hits at the top level (from non-grouping)
and groups contained aggregation information.
container-search/src/test/java/com/yahoo/prelude/searcher/test/FieldCollapsingSearcherTestCase.java