code = "";
        value = FessFunctions.formatCode("L", "prettyprint", "text/plain", code);
        assertEquals("<pre class=\"prettyprint\"></pre>", value);

        code = "aaa";
        value = FessFunctions.formatCode("L", "prettyprint", "text/plain", code);
        assertEquals("<pre class=\"prettyprint\">aaa</pre>", value);

        code = "aaa\nbbb";
        value = FessFunctions.formatCode("L", "prettyprint", "text/plain", code);

     * @param mimetype the MIME type of the content (currently unused)
     * @param input the code content to format
     * @return HTML formatted code with line numbers and styling
     */
    public static String formatCode(final String prefix, final String style, final String mimetype, final String input) {
        if (input == null) {
            return StringUtil.EMPTY;
        }