@Test public void multipartFileResource() throws IOException { String name = "file"; String disposition = "form-data; name=\"" + name + "\"; filename=\"myFile.txt\""; StandardMultipartHttpServletRequest request = requestWithPart(name, disposition, "myBody"); MultipartFile multipartFile = request.getFile(name); assertNotNull(multipartFile); MultiValueMap<String, Object> map = new LinkedMultiValueMap<>(); map.add(name, multipartFile.getResource()); MockHttpOutputMessage output = new MockHttpOutputMessage(); new FormHttpMessageConverter().write(map, null, output); assertThat(output.getBodyAsString(StandardCharsets.UTF_8), containsString( "Content-Disposition: form-data; name=\"file\"; filename=\"myFile.txt\"\r\n" + "Content-Type: text/plain\r\n" + "Content-Length: 6\r\n" + "\r\n" + "myBody\r\n")); }