queryHelper.setSortPrefix("customSort:");
        assertEquals("customSort:", queryHelper.getSortPrefix());
    }

    @Test
    public void test_getAdditionalQuery() {
        assertNull(queryHelper.getAdditionalQuery());
    }

    @Test
    public void test_setAdditionalQuery() {
        queryHelper.setAdditionalQuery("additional query");
        assertEquals("additional query", queryHelper.getAdditionalQuery());