Test a Spring multipart/form-data controller with uploading of some files

Question

I am trying to test this controller:

@RequestMapping(value="/u",consumes="multipart/form-data", method = RequestMethod.POST)
public @ResponseBody String register(
    @RequestParam String u,
    @RequestParam CommonsMultipartFile filea,
    @RequestParam CommonsMultipartFile fileb,
    @RequestParam CommonsMultipartFile filec,
    @RequestParam CommonsMultipartFile filed) {

    return "hi";
}

Whit this mock of a request:

mockMvc.perform(
    MockMvcRequestBuilders.fileUpload("/u")
        .file("filea","id.jpg".getBytes())
        .file("fileb","pc.jpg".getBytes())
        .file("filec","cl.jpg".getBytes())
        .file("filed","fo.jpg".getBytes())
        .param("u", u))
        .andExpect(MockMvcResultMatchers.status().isOk())
        .andDo(MockMvcResultHandlers.print());

Although, I guess I am writing the MockMvcRequest wrongly because the test fails (the status returned is 500).

Thanks in advance.

Answer 1

The issue is a very small one - just change your CommonsMultipartFile to MultipartFile and your test should run through cleanly.

The reason for this issue is the mock file upload parameter that is created is a MockMultipartFile which cannot be cast to the more specific CommonsMultipartFile type.

Answer 2

The simple way how to test multipart upload is use StandardServletMultipartResolver. and for test use this code:

    final MockPart profilePicture = new MockPart("profilePicture", "stview.jpg", "image/gif", "dsdsdsd".getBytes());
    final MockPart userData = new MockPart("userData", "userData", "application/json", "{\"name\":\"test aida\"}".getBytes());

    this.mockMvc.perform(
            fileUpload("/endUsers/" + usr.getId().toString()).with(new RequestPostProcessor() {

                @Override
                public MockHttpServletRequest postProcessRequest(MockHttpServletRequest request) {
                    request.addPart(profilePicture);
                    request.addPart(userData);
                    return request;
                }
            }) 

MockPart class

public class MockPart extends MockMultipartFile implements Part {

private Map<String, String> headers;

public MockPart(String name, byte[] content) {
    super(name, content);
    init();
}

public MockPart(String name, InputStream contentStream) throws IOException {
    super(name, contentStream);
    init();
}

public MockPart(String name, String originalFilename, String contentType, byte[] content) {
    super(name, originalFilename, contentType, content);
    init();
}

public MockPart(String name, String originalFilename, String contentType, InputStream contentStream) throws IOException {
    super(name, originalFilename, contentType, contentStream);
    init();
}

public void init() {
    this.headers = new HashMap<String, String>();
    if (getOriginalFilename() != null) {
        this.headers.put("Content-Disposition".toLowerCase(), "form-data; name=\"" + getName() + "\"; filename=\"" + getOriginalFilename() + "\"");
    } else {
        this.headers.put("Content-Disposition".toLowerCase(), "form-data; name=\"" + getName() + "\"");
    }
    if (getContentType() != null) {
        this.headers.put("Content-Type".toLowerCase(), getContentType());
    }
}

@Override
public void write(String fileName) throws IOException {
}

@Override
public void delete() throws IOException {
}

@Override
public String getHeader(String name) {
    return this.headers.get(name.toLowerCase());
}

@Override
public Collection<String> getHeaders(String name) {
    List<String> res = new ArrayList<String>();
    if (getHeader(name) != null) {
        res.add(getHeader(name));
    }
    return res;
}

@Override
public Collection<String> getHeaderNames() {
    return this.headers.keySet();
}

}