Using Spring MVC Test to unit test multipart POST request

Since MockMvcRequestBuilders#fileUpload is deprecated, you'll want to use MockMvcRequestBuilders#multipart(String, Object...) which returns a MockMultipartHttpServletRequestBuilder. Then chain a bunch of file(MockMultipartFile) calls.

Here's a working example. Given a @Controller

@Controllerpublic class NewController {    @RequestMapping(value = "/upload", method = RequestMethod.POST)    @ResponseBody    public String saveAuto(            @RequestPart(value = "json") JsonPojo pojo,            @RequestParam(value = "some-random") String random,            @RequestParam(value = "data", required = false) List<MultipartFile> files) {        System.out.println(random);        System.out.println(pojo.getJson());        for (MultipartFile file : files) {            System.out.println(file.getOriginalFilename());        }        return "success";    }    static class JsonPojo {        private String json;        public String getJson() {            return json;        }        public void setJson(String json) {            this.json = json;        }    }}

and a unit test

@WebAppConfiguration@ContextConfiguration(classes = WebConfig.class)@RunWith(SpringJUnit4ClassRunner.class)public class Example {    @Autowired    private WebApplicationContext webApplicationContext;    @Test    public void test() throws Exception {        MockMultipartFile firstFile = new MockMultipartFile("data", "filename.txt", "text/plain", "some xml".getBytes());        MockMultipartFile secondFile = new MockMultipartFile("data", "other-file-name.data", "text/plain", "some other type".getBytes());        MockMultipartFile jsonFile = new MockMultipartFile("json", "", "application/json", "{\"json\": \"someValue\"}".getBytes());        MockMvc mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();        mockMvc.perform(MockMvcRequestBuilders.multipart("/upload")                        .file(firstFile)                        .file(secondFile)                        .file(jsonFile)                        .param("some-random", "4"))                    .andExpect(status().is(200))                    .andExpect(content().string("success"));    }}

And the @Configuration class

@Configuration@ComponentScan({ "test.controllers" })@EnableWebMvcpublic class WebConfig extends WebMvcConfigurationSupport {    @Bean    public MultipartResolver multipartResolver() {        CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();        return multipartResolver;    }}

The test should pass and give you output of

4 // from paramsomeValue // from json filefilename.txt // from first fileother-file-name.data // from second file

The thing to note is that you are sending the JSON just like any other multipart file, except with a different content type.

The method MockMvcRequestBuilders.fileUpload is deprecated use MockMvcRequestBuilders.multipart instead.

This is an example:

import static org.hamcrest.CoreMatchers.containsString;import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;import org.junit.Before;import org.junit.Test;import org.junit.runner.RunWith;import org.mockito.Mockito;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;import org.springframework.boot.test.mock.mockito.MockBean;import org.springframework.mock.web.MockMultipartFile;import org.springframework.test.context.junit4.SpringRunner;import org.springframework.test.web.servlet.MockMvc;import org.springframework.test.web.servlet.ResultActions;import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;import org.springframework.test.web.servlet.result.MockMvcResultHandlers;import org.springframework.test.web.servlet.setup.MockMvcBuilders;import org.springframework.web.context.WebApplicationContext;import org.springframework.web.multipart.MultipartFile;/** * Unit test New Controller. * */@RunWith(SpringRunner.class)@WebMvcTest(NewController.class)public class NewControllerTest {    private MockMvc mockMvc;    @Autowired    WebApplicationContext wContext;    @MockBean    private NewController newController;    @Before    public void setup() {        this.mockMvc = MockMvcBuilders.webAppContextSetup(wContext)                   .alwaysDo(MockMvcResultHandlers.print())                   .build();    }   @Test    public void test() throws Exception {       // Mock Request        MockMultipartFile jsonFile = new MockMultipartFile("test.json", "", "application/json", "{\"key1\": \"value1\"}".getBytes());        // Mock Response        NewControllerResponseDto response = new NewControllerDto();        Mockito.when(newController.postV1(Mockito.any(Integer.class), Mockito.any(MultipartFile.class))).thenReturn(response);        mockMvc.perform(MockMvcRequestBuilders.multipart("/fileUpload")                .file("file", jsonFile.getBytes())                .characterEncoding("UTF-8"))        .andExpect(status().isOk());    }}

Have a look at this example taken from the spring MVC showcase, this is the link to the source code:

@RunWith(SpringJUnit4ClassRunner.class)public class FileUploadControllerTests extends AbstractContextControllerTests {    @Test    public void readString() throws Exception {        MockMultipartFile file = new MockMultipartFile("file", "orig", null, "bar".getBytes());        webAppContextSetup(this.wac).build()            .perform(fileUpload("/fileupload").file(file))            .andExpect(model().attribute("message", "File 'orig' uploaded successfully"));    }}