public void ConvertListOfBalancesToGivenCurrency() { var balance1 = new CustomerBalance { Currency = (int)Currency.GBP, Balance = 1000 }; var balance2 = new CustomerBalance { Currency = (int)Currency.USD, Balance = 1000 }; var balances = new List <CustomerBalance> { balance1, balance2 }; var curr = new CurrencyConverter(); var res = curr.ConvertListOfBalancesToGivenCurrency(balances, Currency.PLN); output.WriteLine($"I got {res} PLN from those monies"); }