/// <summary>
/// Calculates the check digit.
/// </summary>
/// <param name="creditCardNumber">The credit card number.</param>
/// <returns></returns>
public static string CalculateCheckDigit(this string creditCardNumber)
{
return(creditCardNumberCheck.CalculateCheckDigit(creditCardNumber, CreditCardNetwork.Automatic));
}
public void Should_Calculate_A_Digit_With_Visa()
{
ICreditCardNumberCheck sut = SuT;
Assert.AreEqual("6", sut.CalculateCheckDigit("4992739871", CreditCardNetwork.Visa));
}
