public void Validate_TransactionReferenceHasNonAlphanumericCharacter_ThrowsException() { PaymentRequest request = new PaymentRequest() { Amount = 15.95m, CurrencyCode = CurrencyCode.Euro, ReturnUrl = new Uri("https://www.github.com"), TransactionReference = "&" }; ExceptionAssert.ThrowsAlphanumericValidationException(nameof(request.TransactionReference), () => { PaymentRequestValidator.Validate(request); }); }