def test_refund(self):
machine = VendingMachine()
machine.treat_coin(Coin(500))
machine.treat_coin(Coin(100))
machine.treat_coin(Coin(50))
assert [Coin(500).amount,
Coin(100).amount,
Coin(50).amount] == [coin.amount for coin in machine.refund()]
assert [] == [coin.amount for coin in machine.contained]
def test_coin_total(self):
machine = VendingMachine()
machine.treat_coin(Coin(500))
machine.treat_coin(Coin(100))
machine.treat_coin(Coin(50))
assert 500 + 100 + 50 == machine.coin_total()
def test_treat_coin(self):
machine = VendingMachine()
machine.treat_coin(Coin(50))
assert machine.contained[0].amount == Coin(50).amount
assert machine.treat_coin(Coin(20)).amount == 20