public void PurchaseServiceCanAffordProductWorksCorrectlyWhenInsufficientFundsAreIn()
{
//These could be mocked out, but since they are simple in memory
//instaces there is no point.
ISessionService sessionService = new InMemorySessionService();
IItemRepository itemRepository = new ItemRepository();
IPurchaseService purchaseService = new PurchaseService(itemRepository, sessionService);
Guid sessionId = Guid.NewGuid();
double tallyValue = 0.5;
sessionService.StoreCurrentTally(sessionId, tallyValue);
//If sufficient money is in a session, the item price minus the session tally is returned.
double checkResult = tallyValue - itemRepository.GetItem(0).Price;
double result = purchaseService.CanAffordProduct(sessionId, 0);
Assert.True(result < 0);
Assert.True(checkResult == result);
//Make sure the session hasn't been modified
Assert.True(sessionService.GetStoredTally(sessionId) == tallyValue);
}
