ot = OptionalThing.empty();
            } else {
                final SortBuilder[] sortBuilders = split(sorts, ",").get(stream -> stream.filter(StringUtil::isNotBlank).map(s -> {
                    final String[] values = s.split(":");
                    if (values.length > 1) {
                        return SortBuilders.fieldSort(values[0]).order("desc".equalsIgnoreCase(values[0]) ? SortOrder.DESC : SortOrder.ASC);

        queryHelper.addDefaultSort("timestamp", "DESC");

        QueryContext context = buildQuery("test");
        assertEquals(1, context.sortBuilders().size());
        assertTrue(context.sortBuilders().get(0).toString().contains("timestamp"));
        assertTrue(context.sortBuilders().get(0).toString().contains("desc"));
    }

    @Test
    public void test_addDefaultSort_multipleFields() {