[FIXED] How can I create a header response for unit tests?

Issue

I have some method that sends a request and receive a response. I get the response in header, it's a String.

My method:

@Override
    public String myMethod(SomeClass someItem) {
        try {

            HttpRequest request = HttpRequest.newBuilder()
                    .POST(HttpRequest.BodyPublishers.ofString(myBodyString))
                    .uri(getUri())
                    .header(OAUTH, getToken())
                    .headers(KEY_HEADER, valueHeader)
                    .headers(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON)
                    .build();

            var response = httpClient.send(request, HttpBodyHandlers.ofCodec());

            if (response.statusCode() == HttpStatus.OK.value()) {
                return response.headers().allValues(LOCATION).get(0);
            } else {
                log.warn(ERROR_LOG + response.statusCode());
                return null;
            }
        } catch (Exception e) {
            log.error(ERROR_LOG + e.getCause());
            return null;
        }
    }

I'm trying do assert this response in my test, but without success. My test:

@ExtendWith(MockitoExtension.class)
class ClassToTest {

    private final static String URL = "https://myUrl/";
    private final static String ACCESS_TOKEN = "access_token";

    private final Clock clock = Clock.fixed(Instant.now(), ZoneId.of("UTC"));

    private ClassToTest service;

    @Mock
    private HttpClient httpClient;

    @Mock
    private OAuth oAuthClient;

    @Mock
    private HttpResponse httpResponse;

    @BeforeEach
    void setUp() {
        service = new ClassToTest(httpClient, oAuthClient);
        when(config.getValue(SERVICE_URL)).thenReturn(AVISO_URL);
        when(oAuthClient.getToken()()).thenReturn(ACCESS_TOKEN);
    }

    @Test
    void myMethod_toTest_success() throws IOException, InterruptedException {
        when(httpClient.send(any(HttpRequest.class), any(HttpResponse.BodyHandler.class))).thenReturn(httpResponse);
        when(httpResponse.statusCode()).thenReturn(HttpStatus.OK.value());

        var result = service.myMethod(myItem);
        assertEquals("UUID", result);
    }
...
}

I'm not able to create a expected item to assert my result. I'm getting null on my result

Solution

Instead of mocking HttpRespone object calls i will recommend to create. HttpResponse object with corresponding values

   HttpResponse<String> httpResponse = new HttpResponse<String>() {
        @Override
        public int statusCode() {
            return 200;
        }

        @Override
        public HttpRequest request() {
            return null;
        }

        @Override
        public Optional<HttpResponse<String>> previousResponse() {
            return Optional.empty();
        }

        @Override
        public HttpHeaders headers() {
            return HttpHeaders.of(Map.of("", List.of()), (v1,v2)->true);
        }

        @Override
        public String body() {
            return null;
        }

        @Override
        public Optional<SSLSession> sslSession() {
            return Optional.empty();
        }

        @Override
        public URI uri() {
            return null;
        }

        @Override
        public HttpClient.Version version() {
            return null;
        }
    };

Answered By - Deadpool
Answer Checked By - Marilyn (JavaFixing Volunteer)