request.addField("field1");
        request.addLanguage("ja");
        request.addExcludeWord("exclude");
        request.setQueryFreqThreshold(5);

        assertNotNull(request.buildQuery());
    }

    @Test
    public void test_buildRescore() throws Exception {
        PopularWordsRequest request = new PopularWordsRequest();
        request.setSeed("test-seed");

    public void test_fieldQueryBuilder_interface() {
        QueryCommand.FieldQueryBuilder builder = (field, text, boost) -> QueryBuilders.termQuery(field, text).boost(boost);

        QueryBuilder result = builder.buildQuery("title", "test", 2.0f);
        assertNotNull(result);
    }

    /**
     * Test DefaultQueryBuilderFunction functional interface.
     */
    @Test