this.sortPrefix = sortPrefix;
    }

    /**
     * Gets the additional query string that is appended to all search queries.
     *
     * @return the additionalQuery
     */
    public String getAdditionalQuery() {
        return additionalQuery;
    }

    /**
     * Sets the additional query string that is appended to all search queries.
     *
     * @param additionalQuery the additionalQuery to set

    }

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

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

    public void test_setHighlightPrefix() {
        queryHelper.setHighlightPrefix("highlight_");