public void SetupClient(string content, HttpStatusCode code) { List <FieldInfo> fields = _testedService.GetType().GetFields(BindingFlags.Instance | BindingFlags.NonPublic).ToList(); FieldInfo client = fields.Find(x => x.Name == "_client"); HttpResponseMessage msg = new HttpResponseMessage() { Content = new StringContent(content), StatusCode = code }; FakeHandler h = new FakeHandler(msg); HttpClient c = new HttpClient(h); client.SetValue(_testedService, c); }