public void TestBuyItem() { _repo.BuyItem(new PurchaseHistory() { Id = "TID09", ItemId = "I002", BuyerId = "B001", SellerId = "S001", NumberOfItems = "1", DateTime = DateTime.Now, Remarks = "Nothing", TransactionType = "Debit" }); var result = _repo.GetPurchaseHistory("TID09"); Assert.IsNotNull(result); }