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); }