public void Calculate_The_Correct_Result()
{
var sut = new LuhnChecksumCalculator();
sut.Calculate("7992739871").Should().Be(3);
sut.Calculate("123456789").Should().Be(7);
}
private CreditCard(string cardNumber, bool bypassChecks)
{
var trimmed = cardNumber?.Replace(" ", "");
if (!bypassChecks && !string.IsNullOrEmpty(cardNumber))
{
if (trimmed.Length < 8)
{
throw new ArgumentOutOfRangeException(nameof(cardNumber), Resources.CreditCard_MoreThan8Characters);
}
if (trimmed.Length > 19)
{
throw new ArgumentOutOfRangeException(nameof(cardNumber), Resources.CreditCard_LessThan20Characters);
}
if (trimmed.Any(chr => !char.IsDigit(chr)))
{
throw new ArgumentOutOfRangeException(nameof(cardNumber), Resources.CreditCard_OnlyDigits);
}
var algorithm = new LuhnChecksumCalculator();
if (!algorithm.Validate(trimmed))
{
throw new ArgumentOutOfRangeException(nameof(cardNumber), Resources.CreditCard_InvalidChecksum);
}
}
_value = trimmed;
}
/// <summary>
/// Try to parse the text to a credit card. Returns true when the parsing succeeds, false otherwise
/// </summary>
/// <param name="text">the text to parse</param>
/// <param name="result">the resulting credit card</param>
public static bool TryParse(string text, out CreditCard result)
{
var trimmed = text?.Replace(" ", "");
if (string.IsNullOrEmpty(text))
{
result = new CreditCard();
return(true);
}
if (!trimmed.All(char.IsDigit))
{
result = new CreditCard();
return(false);
}
if (trimmed.Length < 8)
{
result = new CreditCard();
return(false);
}
if (trimmed.Length > 19)
{
result = new CreditCard();
return(false);
}
var algorithm = new LuhnChecksumCalculator();
if (!algorithm.Validate(text))
{
result = new CreditCard();
return(false);
}
result = new CreditCard(text);
return(true);
}
public void When_Subject_Is_Null_Throw_ArgumentNullException()
{
var sut = new LuhnChecksumCalculator();
Action action = () => sut.Calculate(null);
action.Should().Throw <ArgumentNullException>();
}