[Theory] public static void Invariants (Customer customer) {
Assume.That(customer != null);
// ReSharper disable once PossibleNullReferenceException
customer.AssertInvariants();
Assert.That(customer.StringsAreNormalized);
Assert.NotNull(customer.name);
Assert.NotNull(customer.username);
Assert.NotNull(customer.password);
}
public Receipt ConductSaleOrThrow (Customer customer, Item clientDescriptionOfItem) {
var actualItem = ItemMatching(clientDescriptionOfItem);
if (actualItem == null) Global.ThrowComplaint("Item not carried.", true);
if (!customer.CanAfford(actualItem)) Global.ThrowComplaint("Insufficient money.", true);
return ConductSale(customer, actualItem);
}
///<summary>Precondition: sale is valid.</summary>
public Receipt ConductSale (Customer customer, Item item) {
customer.MoneyInWallet -= item.Price;
MoneyInRegister += item.Price;
inventory.Remove(item);
return new Receipt(customer, item);
}
