public void GivenAddNewItem_WhenItemExiting_ThenReturnfalse() { var articleGuid = Guid.NewGuid(); var basket = new Basket(); var bi = new BasketItem() { Article = new Article() { IdArticle = articleGuid } }; basket.BasketItems = new List <BasketItem>(); basket.BasketItems.Add(bi); _basketRepository.Setup(x => x.Find(articleGuid)).Returns(basket); var res = _basketService.AddItemsToBasket(articleGuid, bi); Assert.IsFalse(res); }