@Override
        public Result search(Query query, Execution exec) {
            Result ret = exec.search(query);
            if (passnum > failOnPassN) {
                continuedOnFail = true;
                return ret;
            }
            if (passnum == failOnPassN) {
                ret.hits().addError(ErrorMessage.createTimeout("timeout"));
            }
            passnum++;
            return ret;
        }
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