@Override
        public void fill(Result result, String summaryClass, Execution exec) {
            for (Iterator<Hit> it = result.hits().deepIterator(); it.hasNext();) {
                Hit hit = it.next();
                Query query = hit.getQuery();
                List<Hit> lst = hitsByQuery.computeIfAbsent(query, k -> new LinkedList<>());
                lst.add(hit);
            }
        }
Tests the internal rewriting of rank properties which happens in the query.prepare() call
(triggered by the exc.search call in the below).
container-search/src/test/java/com/yahoo/search/grouping/vespa/GroupingExecutorTestCase.java