406 error while mocking File Download REST API using MockMVC

Question

I am implementing a REST API using Spring framework, which returns

return new ResponseEntity<>(new InputStreamResource(myInputStream),
                responseHeaders, HttpStatus.OK);

REST API is declared as:

@RequestMapping(value = "/download", method = RequestMethod.GET, 
produces = { MediaType.APPLICATION_OCTET_STREAM_VALUE })

While writing unit test for this API, I am using MockMVC like below:

final MappingJackson2HttpMessageConverter messageConverter = 
new MappingJackson2HttpMessageConverter();
messageConverter.setObjectMapper(new ObjectMapper());
messageConverter.getObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);

this.mockMvc = 
MockMvcBuilders.standaloneSetup(myController)
.setMessageConverters(messageConverter)
.apply(new RestDocumentationConfigurer()
.withScheme("https").withHost("localhost")
.withPort(443)).build();

And my Test case looks like this:

mockMvc.perform(
org.springframework.test.web.servlet.request.MockMvcRequestBuilders
.get(restUri))
.andExpect(
org.springframework.test.web.servlet.result.MockMvcResultMatchers
.status().isOk())
.andDo(document("myApi")).andReturn();   

But I am getting status as error 406.

java.lang.AssertionError: Status expected:<200> but was:<406>
at org.springframework.test.util.AssertionErrors.fail

What I am missing here? Any help would be much appreciated.

Answer 1

You inject instance of MappingJackson2HttpMessageConverter to MockMvcBuilders which can't deal with converting classes inheriting from Resource . All you need to do is add ResourceHttpMessageConverter to your test specification:

MockMvcBuilders.standaloneSetup(myController)
.setMessageConverters(messageConverter, new ResourceHttpMessageConverter())

Answer 2

Status code 406 means "Not Acceptable", which indicates that the server is missing a header specifying an accepted content type. You'll need to include that in your mockMvc call.