How to extract value from JSON response when using Spring MockMVC

Question

I have an endpoint that accepts a POST request. I want to get the ID of the newly created entity from the JSON response.

Below is a segment of my code where I'm attempting to do that.

mockMvc.perform(post("/api/tracker/jobs/work")
        .contentType(TestUtil.APPLICATION_JSON_UTF8)
        .content(TestUtil.convertObjectToJsonBytes(workRequest)))
        .andExpect(status().isCreated());

If I get that ID I'll query the database for the newly created entity and do some assertions like below:

Work work = work service.findWorkById(id);

assertThat(work.getJobItem().getJobItemName()).isEqualTo(workRequest.getJobItem().getJobItemName());
assertThat(work.getJobItem().getQuantities()).hasSize(workRequest.getQuantities().size());
assertThat(work.getJobItem().getQuantityPools()).hasSize(workRequest.getQuantities().size());

Answer 1

I have managed to solve my problem using Spring MockMVC result handler. I created a testing utility to convert the JSON string back to an object and so allowing me to get the ID.

Conversion Utility:

 public static <T>  Object convertJSONStringToObject(String json, Class<T> objectClass) throws IOException {
    ObjectMapper mapper = new ObjectMapper();
    mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

    JavaTimeModule module = new JavaTimeModule();
    mapper.registerModule(module);
    return mapper.readValue(json, objectClass);
}

Unit Test:

 @Test
@Transactional
public void createNewWorkWorkWhenCreatedJobItemAndQuantitiesPoolShouldBeCreated() throws Exception {

    mockMvc.perform(post("/api/tracker/jobs/work")
        .contentType(TestUtil.APPLICATION_JSON_UTF8)
        .content(TestUtil.convertObjectToJsonBytes(workRequest)))
        .andExpect(status().isCreated())
        .andDo(mvcResult -> {
            String json = mvcResult.getResponse().getContentAsString();
            workRequestResponse = (WorkRequestResponse) TestUtil.convertJSONStringToObject(json, WorkRequestResponse.class);
        });

    Work work = workService.findWorkById(workRequestResponse.getWorkId());

    assertThat(work.getJobItem().getJobItemName()).isEqualTo(workRequest.getJobItem().getJobItemName());
    assertThat(work.getJobItem().getQuantities()).hasSize(workRequest.getQuantities().size());
    assertThat(work.getJobItem().getQuantityPools()).hasSize(workRequest.getQuantities().size());
}