public <T> HttpResponse<T> httpRequest(String url, String method, HttpHeaders headers, Object requestBodyData,
                                                  TypeReference<T> responseFormat) {
        return httpRequest(url, method, headers, requestBodyData, responseFormat, null, null);
    }
@Test
    public void testNullMethod() {
        RestClient client = spy(new RestClient(null));
        assertThrows(NullPointerException.class, () -> client.httpRequest(
                MOCK_URL,
                null,
                null,
                TEST_DTO,
                TEST_TYPE,
                MOCK_SECRET_KEY,
                TEST_SIGNATURE_ALGORITHM
        ));
    }