public void Concert_BuyTickets_TicketsBuySuccessfull()
{
Concert concert = CreateConcert(3);
concert.BuyTickets(2, 3);
Assert.True(concert.BoughtTickets.Quantity == 2);
}
public void Concert_BuyTickets_MaximumNumnberOfTicketsReached()
{
Concert concert = CreateConcert(3);
Assert.Throws <MaximumNumberOfTicketsReached>(() => concert.BuyTickets(4, 3));
}