String mediaParameter = encoder.encodeParameterName(TableTagParameters.PARAMETER_EXPORTTYPE);
WebRequest request = new GetMethodWebRequest(getJspUrl(getJspName()));
// this will force media type initialization
MediaTypeEnum.registerMediaType("wpdf");
ExportViewFactory factory = ExportViewFactory.getInstance();
factory.registerExportView("wpdf", "org.displaytag.export.DefaultPdfExportView");
MediaTypeEnum pdfMedia = MediaTypeEnum.fromName("wpdf");
Assert.assertNotNull("Pdf export view not correctly registered.", pdfMedia);
request.setParameter(mediaParameter, Integer.toString(pdfMedia.getCode()));
WebResponse response = runner.getResponse(request);