public void SellArticle_Success() { DatabaseDriver databaseDriver = new DatabaseDriver(); Logger logger = new Logger(); ShopService shopService = new ShopService(databaseDriver, logger, new List <ISupplier>()); shopService.SellArticle(new FirstSupplier(new Article(1, "Test", 1)), 1, 9); Assert.AreEqual(9, databaseDriver.GetArticleByID(1).BuyerUserID); }