public  void doTest(String jspName) throws Exception 
{
        WebRequest request = new GetMethodWebRequest(jspName);
        WebResponse response = runner.getResponse(request);
        assertEquals("Wrong encoding", "UTF8", response.getCharacterSet());
        ParamEncoder encoder = new ParamEncoder("table");
        String mediaParameter = encoder.encodeParameterName(TableTagParameters.PARAMETER_EXPORTTYPE);
        request = new GetMethodWebRequest(jspName);
        request.setParameter(mediaParameter, Integer.toString(MediaTypeEnum.CSV.getCode()));
        response = runner.getResponse(request);
        checkContent(response);
        // enabled filter
        request.setParameter(TableTagParameters.PARAMETER_EXPORTING, "1");
        response = runner.getResponse(request);
        checkContent(response);
}

Encoding should be utf8.

 public String getJspName() 
{
        return "DISPL-107.jsp";
}