java spring boot test POST REST with object in content

Question

I'm tryin to unit test a post rest service, this service takes an object (not a json) as content. The result is that I can't test it, the MockMvc object expects some json content.

Part of the controller, where Dsd is an internal class of the application :

@PostMapping(path="dsd")
@ApiOperation(value = "Sends Dsd  data",response = Dsd.class)
public Dsd requestPostDsd (
        @ApiParam("DSD data")
        @Valid @RequestBody Dsd dsd,
        HttpServletResponse response
) throws IOException, ParseException {
    if (dsd.getId() != null) {
        // do something
    } else {
        response.sendError(HttpStatus.BAD_REQUEST.value(), "the id doesn't exist");
    }
    return dsd;
}

In the unit testing code, I create a MockMvc object but the perform().content method expects a string json content, I can't pass my Dsd object instead.

How can test this POST api ?

Edit : part of the test code :

 @Test
public void postDsdTest() throws Exception {

    Dsd dsd = new Dsd();

    this.mvc.perform(post("/services/latest/validation/dsd")
            .header("Origin", HTTP_HEADER_ORIGIN)
            .header("Accept", "application/json")
            .content(dsd)
            .contentType(MediaType.APPLICATION_JSON))
            .andExpect(header().string("Access-Control-Allow-Origin", HTTP_HEADER_ORIGIN))
            .andExpect(status().isOk())
            .andDo(MockMvcResultHandlers.print());

}

Answer 1

You could try to write a TestUtil class that serializes your object into a JSON string: https://www.petrikainulainen.net/programming/spring-framework/unit-testing-of-spring-mvc-controllers-rest-api/

With Jackson you can serialize objects to JSON:

ObjectMapper mapper = new ObjectMapper();
mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
return mapper.writeValueAsBytes(object);