public async Task VideoGetByIdCorrectly() { var videoList = new List <Video>(); var videoRepo = new Mock <IDeletableEntityRepository <Video> >(); videoRepo.Setup(x => x.All()).Returns(videoList.AsQueryable()); videoRepo.Setup(x => x.AddAsync(It.IsAny <Video>())) .Callback((Video x) => videoList.Add(x)); await videoRepo.Object.AddAsync(this.test); var videoService = new VideosService(videoRepo.Object); var videoResult = videoService.GetById(this.test.Id); Assert.Equal(test, videoResult); }