public void MaskedPAN(string pan)
{
//arrange
//act
string maskedPAN = CreditCardService.MaskPAN(pan);
_output.WriteLine($"{pan} ==> {maskedPAN}");
//assert
switch (pan.Length)
{
case int n when n <= 4:
Assert.Equal(pan, maskedPAN);
break;
case int n when n <= 8:
Assert.Equal(4, maskedPAN.Count(c => c == '*'));
Assert.Equal("****", maskedPAN.Substring(0, 4));
break;
case int n when n > 8:
Assert.Equal(pan.Length - 8, maskedPAN.Count(c => c == '*'));
Assert.NotEqual("****", maskedPAN.Substring(0, 4));
Assert.Equal(pan.Substring(pan.Length - 4), maskedPAN.Substring(maskedPAN.Length - 4));
break;
default:
break;
}
}