Spring MVC 4.2 : How to Unit Test Controller with #RequestPart Params - unit-testing

Question

I have a requestMapping of the form:
#RequestMapping(
value = "/submitCase",
consumes = MediaType.MULTIPART_FORM_DATA_VALUE,
produces = MediaType.APPLICATION_JSON_UTF8_VALUE,
method = RequestMethod.POST
)
public Object submitCase(
#RequestPart(name = "attachment[0]", required = false) MultipartFile attachment1,
#RequestPart(name = "attachment[1]", required = false) MultipartFile attachment2,
#RequestPart(name = "attachment[2]", required = false) MultipartFile attachment3,
#RequestPart(name = "attachment[3]", required = false) MultipartFile attachment4,
#RequestPart(name = "attachment[4]", required = false) MultipartFile attachment5,
#RequestPart(name = "caseDetails") CaseDetails caseDetails) {}
Now I want to write a test for this with MockMvcBuilders. However I am unable to do so.
The challenge here is that the request handler consumes multipart/form-data, which consists of 4 Multipart Files, and 1 Json data.
Any ideas on how to solve this? Please bear in mind i am constrained to use Spring 4.3.
Please let me know if you require any more information.

Answer 1

Have a look at the great example here: https://stackoverflow.com/a/21805186/3976662
Note, that MockMvcRequestBuilders.html#multipart used in the example is not available in Spring 4.3.0, yet. Use MockMvcRequestBuilders.html#fileUpload instead (deprecated in Spring 5).
CaseDetails.java:
public class CaseDetails {
private String exampleAttr;
public String getExampleAttr() {
return exampleAttr;
}
public void setExampleAttr(String exampleAttr) {
this.exampleAttr = exampleAttr;
}
}
UploadController.java:
#Controller
public class UploadController {
#RequestMapping(
value = "/submitCase",
consumes = MediaType.MULTIPART_FORM_DATA_VALUE,
produces = MediaType.APPLICATION_JSON_UTF8_VALUE,
method = RequestMethod.POST
)
#ResponseBody
public Object submitCase(
#RequestPart(name = "attachment[0]", required = false) MultipartFile attachment1,
#RequestPart(name = "attachment[1]", required = false) MultipartFile attachment2,
#RequestPart(name = "attachment[2]", required = false) MultipartFile attachment3,
#RequestPart(name = "attachment[3]", required = false) MultipartFile attachment4,
#RequestPart(name = "attachment[4]", required = false) MultipartFile attachment5,
#RequestPart(name = "caseDetails") CaseDetails caseDetails) {
Map<String,String> result = new HashMap<>();
result.put("success", "true");
return result;
}
}
UploadControllerTest.java:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = UploadControllerTest.TestConfig.class)
public class UploadControllerTest {
#Autowired
private UploadController uploadController;
#Test
public void testSubmitCase() throws Exception {
MockMultipartFile file1 = new MockMultipartFile("attachment[0]", "filename-1.txt", "text/plain", "1".getBytes());
MockMultipartFile file2 = new MockMultipartFile("attachment[1]", "filename-2.txt", "text/plain", "2".getBytes());
MockMultipartFile file3 = new MockMultipartFile("attachment[2]", "filename-3.txt", "text/plain", "3".getBytes());
MockMultipartFile file4 = new MockMultipartFile("attachment[3]", "filename-4.txt", "text/plain", "4".getBytes());
MockMultipartFile file5 = new MockMultipartFile("attachment[4]", "filename-5.txt", "text/plain", "5".getBytes());
MockMultipartFile caseDetailsJson = new MockMultipartFile("caseDetails", "", "application/json","{\"exampleAttr\": \"someValue\"}".getBytes());
MockMvc mockMvc = MockMvcBuilders.standaloneSetup(uploadController).build();
mockMvc.perform(MockMvcRequestBuilders.fileUpload("/submitCase")
.file(file1)
.file(file2)
.file(file3)
.file(file4)
.file(file5)
.file(caseDetailsJson))
.andDo(MockMvcResultHandlers.print())
.andExpect(MockMvcResultMatchers.content().string("{\"success\":\"true\"}"))
.andReturn();
}
#Configuration
static class TestConfig {
#Bean
public UploadController uploadController() {
return new UploadController();
}
}
}
Please note, in UploadControllerTest the JSON data must be wrapped in a MockMultipartFile - equivalent to the uploaded files. Make sure, that jackson-core and jackson-databind are available on the classpath.