public void GetCountOfPhotosCommentsShouldWorkCorrectly() { var comments = new List <Comment>(); var photos = new List <Photo>(); var mockCommentRepo = new Mock <IDeletableEntityRepository <Comment> >(); mockCommentRepo.Setup(x => x.All()).Returns(comments.AsQueryable()); mockCommentRepo.Setup(x => x.AddAsync(It.IsAny <Comment>())).Callback((Comment comm) => comments.Add(comm)); var mockPhoto = new Mock <IDeletableEntityRepository <Photo> >(); mockPhoto.Setup(x => x.All()).Returns(photos.AsQueryable()); mockPhoto.Setup(x => x.AddAsync(It.IsAny <Photo>())).Callback((Photo ph) => photos.Add(ph)); var service = new AdminsService(null, mockCommentRepo.Object, mockPhoto.Object, null, null); var photo = new Photo { Id = "1", ImagePath = "/images/photos", }; var comment = new Comment { Id = "1", ImagePath = "/images/photos", PhotoId = "1", UserId = "1", SentById = "1", }; var secondComment = new Comment { Id = "2", ImagePath = "/images/photos", PhotoId = "1", UserId = "1", SentById = "1", }; photos.Add(photo); comments.Add(comment); comments.Add(secondComment); var result = service.GetCountOfPhotosComments(); var expectedResult = 2; Assert.Equal(expectedResult, result); }