facesContext.getExternalContext().getApplicationMap().put(MyfacesConfig.class.getName(), config);
request.addHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"); //Firefox
request.addHeader("Faces-Request", "partial/ajax");
HtmlRenderKitImpl renderKit = new HtmlRenderKitImpl();
StringWriter writer = new StringWriter();
HtmlResponseWriterImpl responseWriter = (HtmlResponseWriterImpl) renderKit.createResponseWriter(writer, null, null);
Assert.assertEquals(ContentTypeUtils.HTML_CONTENT_TYPE, responseWriter.getContentType());
Assert.assertEquals(ContentTypeUtils.HTML_CONTENT_TYPE, responseWriter.getWriterContentTypeMode());
}