public async Task NonExistentScalarField_Get_404()
        {
            HttpResponseMessage response = await HttpClient.GetAsync("/artists/123/ohdear");

            ResponseAssert.Status(response, HttpStatusCode.NotFound);

            string json = await response.Content.ReadAsStringAsync();

            dynamic obj = JsonConvert.DeserializeObject(json);

            Assert.NotNull(obj);
            Assert.Equal("field_not_found", (string)obj.error);
        }
        public async Task NonExistentItemID_Get_404()
        {
            HttpResponseMessage response = await HttpClient.GetAsync("/artists/321");

            ResponseAssert.Status(response, HttpStatusCode.NotFound);

            string json = await response.Content.ReadAsStringAsync();

            dynamic obj = JsonConvert.DeserializeObject(json);

            Assert.NotNull(obj);
            Assert.Equal("item_with_identifier_not_found", (string)obj.error);
        }