public Searcher searcher() {
        return new Searcher();
    }
@Test
    void require_that_multi_term_queries_are_supported() {
        ConjunctionIndexBuilder builder = new ConjunctionIndexBuilder();
        IndexableFeatureConjunction c1 = indexableConj(
                conj(
                        feature("a").inSet("1"),
                        feature("b").inSet("3")));
        builder.indexConjunction(c1);
        ConjunctionIndex index = builder.build();
        ConjunctionIndex.Searcher searcher = index.searcher();

        PredicateQuery query = new PredicateQuery();
        query.addFeature("a", "1");
        query.addFeature("a", "2");
        assertTrue(searcher.search(query).isEmpty());
        query.addFeature("b", "3");
        assertHitsEquals(searcher.search(query), c1);
    }