public void CreateInstance_CallsSendOnBuilder() { //arrange var uut = new UserProxy(_fakeFactory); _fakeFactory.Post("api/User", _userFake).Returns(_fakeBuilder); _fakeBuilder.SendAsync().Returns(new HttpResponseMessage() { StatusCode = HttpStatusCode.BadRequest }); //act var result = uut.CreateInstanceAsync(_userFake).Result; //assert _fakeBuilder.Received(1).SendAsync(); }