Minor Description
Right now MockHttpServletRequest keeps a Map<String, UploadedFile> uploadedFiles to simulate the uploads, but that only covers multiple FileUploadFields in the Page(each holding a single upload file).
When doing MockHttpServletRequest.addFile(...), it does not add the file to a list, but rather replaces the last one:
uploadedFiles.put(fieldName, uf);
However with the HTML5 type of input type multiple="multiple", FileUploadField.getFileUploads() returns list of uploaded files, so I guess that MockHttpServletRequest should honor this and keep the files into Map<String, List<UploadedFile>>.