spring boot multipartFile with application/octet-stream throws exception

I wanted to build a simple Rest api using Spring boot which accepts any given file and then performs some operations on it . I went through the spring examples on multipartFile https://spring.io/guides/gs/uploading-files/ and I decided to follow the same approach. The files that will be uploaded through my rest api will have some specific extension. So,i gave the content-type as application/octet-stream . When I try to run my unit test cases for the same, I always get the exception of

nested exception is org.springframework.web.multipart.MultipartException: The current request is not a multipart request

This exception does not appear if the content type is text/plain or if there is no 'consumes' parameter in the requestMapping.

My controller code looks as follows :

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RequestPart;
import org.springframework.web.multipart.MultipartFile;

@Controller
@RequestMapping("/v1/sample")
public class SampleController {

    private static Logger log = LoggerFactory.getLogger(SampleController.class);

    @RequestMapping(path = "/{id}/upload",
                    consumes = {MediaType.APPLICATION_OCTET_STREAM_VALUE},
                    method = RequestMethod.POST)
    public ResponseEntity<String> uploadfile(@PathVariable String id,
            @RequestParam("file") MultipartFile upgradeFile) {
        log.info("Obtained a upload request for the id {}",id );
        return new ResponseEntity<String>("file upload has been accepted.",
                HttpStatus.ACCEPTED);
    }

}

And my unit test snippet is as follows :

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.fileUpload;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import static org.springframework.test.web.servlet.setup.MockMvcBuilders.webAppContextSetup;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.http.MediaType;
import org.springframework.mock.web.MockMultipartFile;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

import com.stellapps.devicemanager.fota.Application;

@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@SpringApplicationConfiguration(classes = Application.class)
@EnableWebMvc
public class ControllerTest {

    @Autowired
    private WebApplicationContext webApplicationContext;

    private MockMvc mockMvc;

    @Before
    public void mockMvcBuilder() {
        this.mockMvc = webAppContextSetup(webApplicationContext).build();
    }

    @Test
        public void test_ValidPayload() {
            String uri = "/v1/sample/1234/upload";
            Path path = Paths.get("src/test/resources/someFile");
            try {
                byte[] bytes = Files.readAllBytes(path);
                 MockMultipartFile multipartFile =
                            new MockMultipartFile("file", "someFile.diff", "application/octet-stream", bytes);
                 mockMvc.perform(fileUpload(uri).file(multipartFile).contentType(MediaType.APPLICATION_OCTET_STREAM_VALUE))
                    .andExpect(status().isAccepted());
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
}

If I use text/plain as the content-type and i give a normal text file, it goes through fine. If I add the content-type as application/octet-stream it throws the following exception

    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.springframework.web.multipart.MultipartException: The current request is not a multipart request
    at org.springframework.web.servlet.mvc.method.annotation.RequestPartMethodArgumentResolver.assertIsMultipartRequest(RequestPartMethodArgumentResolver.java:204)
    at org.springframework.web.servlet.mvc.method.annotation.RequestPartMethodArgumentResolver.resolveArgument(RequestPartMethodArgumentResolver.java:129)
    at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:99)
    at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:161)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:128)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:817)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:731)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:968)

How Do I make my request accept application/octet-stream and what changes should I make to the test case to ensure it succeeds.

UPDATE:

Removing the consumes header and by not specifying the content-type in MockPartFile is one of the way to upload a file. I suppose by default the controller takes it as application/octet-stream

UPDATE:

Thank you for the response. I was using an earlier version of spring (1.3.1) and after going through the answer, I updated my spring version and the test case to match it and It started working.