public  void doTest(String jspName) throws Exception 
{
        // test keep
        WebRequest request = new GetMethodWebRequest(jspName);
        // test remove
        ParamEncoder encoder = new ParamEncoder("table");
        String mediaParameter = encoder.encodeParameterName(TableTagParameters.PARAMETER_EXPORTTYPE);
        request.setParameter(mediaParameter, Integer.toString(MediaTypeEnum.XML.getCode()));
        WebResponse response = runner.getResponse(request);
        String encoding = response.getCharacterSet();
        assertEquals("Encoding is not utf-8 as expected", "utf-8", encoding);
}

Test response encoding.

 public String getJspName() 
{
        return "utf8.jsp";
}