public void CreateAd_Should_Successfully_Add_To_Repository()
        {
            var ads = new List<Ad>();

            var fakeUser = this.mocks.UserRepositoryMock.Object.All().FirstOrDefault();
            if (fakeUser == null)
            {
                Assert.Fail("Cannot perform test - no user available.");
            }

            this.mocks.AdRepositoryMock
                .Setup(r => r.Add(It.IsAny<Ad>()))
                .Callback((Ad ad) =>
                    {
                        ad.Owner = fakeUser;
                        ads.Add(ad);
                    });

            var mockContext = new Mock<IOnlineShopData>();
            mockContext.Setup(c => c.Ads)
                .Returns(this.mocks.AdRepositoryMock.Object);
            mockContext.Setup(c => c.AdTypes)
                .Returns(this.mocks.AdTypeRepositoryMock.Object);
            mockContext.Setup(c => c.Users)
                .Returns(this.mocks.UserRepositoryMock.Object);
            mockContext.Setup(c => c.Categories)
                .Returns(this.mocks.CategoryRepositoryMock.Object);

            var mockIdProvider = new Mock<IUserIdProvider>();
            mockIdProvider.Setup(ip => ip.GetUserId())
                .Returns(fakeUser.Id);

            var adsController = new AdsController(mockContext.Object, mockIdProvider.Object);
            this.SetupController(adsController);

            var randomName = Guid.NewGuid().ToString();
            var newAd = new AdBindingModel
                {
                    Name = randomName, 
                    Price = 555, 
                    TypeId = 1, 
                    Description = "No description", 
                    Categories = new[] { 1 }
                };

            var response = adsController.CreateAd(newAd).ExecuteAsync(CancellationToken.None).Result;
            Assert.AreEqual(HttpStatusCode.OK, response.StatusCode);

            mockContext.Verify(c => c.SaveChanges(), Times.Once);

            Assert.AreEqual(1, ads.Count);
            Assert.AreEqual(randomName, ads[0].Name);
        }