public void CheckForValidationErrors_ValidCreditCards()
{
List <string> errorsListCheapPayment = paymentValidator.CheckForValidationErrors(validCreaditCardCheap);
List <string> errorsListExpensivePayment = paymentValidator.CheckForValidationErrors(validCreaditCardExpensive);
List <string> errorsListPremiumPayment = paymentValidator.CheckForValidationErrors(validCreaditCardPremium);
List <string> expectedErorsList = new List <string>();
Assert.AreEqual(errorsListCheapPayment, expectedErorsList);
Assert.AreEqual(errorsListExpensivePayment, expectedErorsList);
Assert.AreEqual(errorsListPremiumPayment, expectedErorsList);
}