public void Given_ValidCard_It_Should_TopUp_Balance()
{
Card card = CreateValidCard();
Assert.That(card.GetBalance() == 0);
Assert.That(card.TopupBy(100, validPin).GetBalance(), Is.EqualTo(100));
}
public void Given_CardHasEnoughBalance_ItShouldBeUsedByManyPlaces_AtSameTime()
{
Card card = CreateValidCard();
card.TopupBy(1000, validPin);
Parallel.Invoke(() => card.WithdrawBy(100, validPin),
() => card.WithdrawBy(100, validPin),
() => card.WithdrawBy(100, validPin),
() => card.WithdrawBy(100, validPin),
() => card.WithdrawBy(100, validPin),
() => card.WithdrawBy(100, validPin));
Assert.That(card.GetBalance(), Is.EqualTo(400));
}
