public void CannotGiveChange_2()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.TwoPence(3),
Change.FivePence(1),
Change.TwentyPence(3),
Change.FiftyPence(1)
);
int totalValueMachineBeforeVend = machine.Balance.TotalValue();
// The change here is 66p and we've got the right coins, 3 x 20p and 3 x 2p
// However, the greedy approach will fail here as it will take the 50p but not be able to make up the 16p
VendingResult result = machine.Vend(34, Change.OnePound(1));
Assert.IsNotNull(result);
Assert.IsTrue(result.Failed);
// We should have 6p change...
Assert.AreEqual(result.Change.TotalValue(), 0);
// ...and the machine should have 14p more than before then vend
Assert.AreEqual(machine.Balance.TotalValue(), totalValueMachineBeforeVend);
}
public void RemoveChangeItem()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.TenPence(5),
Change.TwentyPence(1)
);
int preBalance = machine.Balance.TotalValue();
// Take out 20p and make sure the balance is right
machine.Remove(Change.TenPence(2));
Assert.AreEqual(machine.Balance.TotalValue(), preBalance - 20);
}
public void Add()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.TenPence(5),
Change.TwentyPence(1),
Change.OnePence(3),
Change.FiftyPence(1),
Change.TwoPence(3)
);
// The balance order should be from high to low
CompareBalanceOrder(machine.Balance, 50, 20, 10, 2, 1);
}
public void RemoveAllChangeItem()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.TenPence(5),
Change.TwentyPence(1)
);
int preBalance = machine.Balance.TotalValue();
// Take out 20p and make sure the balance is right
machine.Remove(Change.TenPence(5));
Assert.AreEqual(machine.Balance.TotalValue(), preBalance - 50);
// There shouldn't be any 10p items in the machine
Assert.IsFalse(machine.Balance.Any(c => c.Denomination == 10));
}
public void CanGiveChange()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.OnePence(100),
Change.FivePence(50),
Change.TenPence(50)
);
int totalValueMachineBeforeVend = machine.Balance.TotalValue();
VendingResult result = machine.Vend(25, Change.TwentyPence(2));
Assert.IsNotNull(result);
Assert.IsTrue(result.Success);
Assert.IsNotNull(result.Change);
// We should have 15p in change...
Assert.AreEqual(result.Change.TotalValue(), 15);
// ...and the machine should have 25p more than before then vend
Assert.AreEqual(machine.Balance.TotalValue(), 25 + totalValueMachineBeforeVend);
}
public void CannotGiveChange()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.TwoPence(3),
Change.FivePence(1)
);
int totalValueMachineBeforeVend = machine.Balance.TotalValue();
// The change here is 6p.
// We've got the right coins, 3 x 2p, but the gready algorithm
// will take the 5p and then not be able to find a 1p
VendingResult result = machine.Vend(14, Change.TenPence(2));
Assert.IsNotNull(result);
Assert.IsTrue(result.Failed);
// We shouldn't have any change...
Assert.AreEqual(result.Change.TotalValue(), 0);
// ...and the machine should have the same balance as before the vend
Assert.AreEqual(machine.Balance.TotalValue(), totalValueMachineBeforeVend);
}
public void ExactAmountTendered()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.OnePence(100),
Change.FivePence(50),
Change.TenPence(50)
);
int totalValueMachineBeforeVend = machine.Balance.TotalValue();
VendingResult result = machine.Vend(60, Change.FiftyPence(1), Change.TenPence(1));
Assert.IsNotNull(result);
Assert.IsTrue(result.Success);
Assert.IsNotNull(result.Change);
// We should have no change...
Assert.AreEqual(result.Change.TotalValue(), 0);
// ...and the machine should have 60p more than before then vend
Assert.AreEqual(machine.Balance.TotalValue(), 60 + totalValueMachineBeforeVend);
}
public void RemoveChangeItem_DoesNotExist()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.TenPence(5),
Change.TwentyPence(1)
);
// Take out 5p. This isn't in the machine, so should fail
machine.Remove(Change.FivePence(1));
}
public void RemoveChangeItem_TooManySpecified()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.TenPence(5),
Change.TwentyPence(1)
);
// Take out 6 x 10p. That's more than is in the machine, so should fail
machine.Remove(Change.TenPence(6));
}
public void RemoveChangeItem_Rollback()
{
VendingMachine machine = new GreedyVendingMachine();
machine.Add
(
Change.TenPence(5),
Change.TwentyPence(3),
Change.FiftyPence(1)
);
int preBalance = machine.Balance.TotalValue();
Change[] changeToRemove =
{
Change.FiftyPence(1),
Change.TwentyPence(4)
};
bool caughtException = false;
try
{
machine.Remove(changeToRemove);
}
catch(ArgumentException)
{
caughtException = true;
}
Assert.IsTrue(caughtException);
// The balance should be the same
Assert.AreEqual(preBalance, machine.Balance.TotalValue());
// And the coins should be the same
Assert.AreEqual(3, machine.Balance.Count());
Assert.IsTrue(machine.Balance.FirstOrDefault(c => c.Denomination == 10 && c.Quantity == 5) != null);
Assert.IsTrue(machine.Balance.FirstOrDefault(c => c.Denomination == 20 && c.Quantity == 3) != null);
Assert.IsTrue(machine.Balance.FirstOrDefault(c => c.Denomination == 50 && c.Quantity == 1) != null);
}