public void IncreaseBuyerStockQty_DecreaseBuyerBalance() { var tradableType = new TradableType { Price = 1000, Type = "TestType1" }; var buyerStock = new Stock { Quantity = 100, TradableType = tradableType }; var stockForBuy = new Stock { Quantity = 10, TradableType = tradableType }; var trader = new Trader { Balance = 100000, Assets = new List <Stock> { new Stock(), buyerStock } }; BusinessService.Acquire(trader, stockForBuy); Assert.AreEqual(buyerStock.Quantity, 110); Assert.AreEqual(trader.Balance, 90000); }