Describe: isValid()
Test: “it should return valid if the card number is 0.” Code: isValid("0"); Expected Output: “Your card number is valid.”
Test: "It should return invalid if the card number is 1." Code: isValid("1"); Expected Output: "Your card number is invalid."
Describe: sumCardDigits()
Test: "It should return 0 if the card number is 0, and 1 if the card number is 1" Code: sumCardDigits("0"); sumCardDigits("1"); Expected Output: 0 1
Test: "It should return 2 if the card number is 11" Code: sumCardDigits("11"); Expected Output: 2
Describe: sumAlternatingCardDigits()
Test: "It should return 0 if the card number is 0." Code: sumAlternatingCardDigits(0); Expected Output: 0
Test: "It should return 21 if the card number is 11." Code: sumAlternatingCardDigits(11); Expected Output: 21
Test: "It should return 50 if the card number is 70." Code: sumAlternatingCardDigits(70); Expected Output: 50