public void InverseCaptchaPartTwo_OneDigitRepeatedFourTimes()
        {
            // act
            var result = InverseCaptcha.CalculateInverseCaptchaPartTwo("12131415");

            // assert
            Assert.AreEqual(4, result);
        }
        public void InverseCaptchaPartTwo_TrioOfRepeatingDigits()
        {
            // act
            var result = InverseCaptcha.CalculateInverseCaptchaPartTwo("123123");

            // assert
            Assert.AreEqual(12, result);
        }
        public void InverseCaptchaPartTwo_NoRepeatingDigits()
        {
            // act
            var result = InverseCaptcha.CalculateInverseCaptchaPartTwo("1221");

            // assert
            Assert.AreEqual(0, result);
        }
        public void InverseCaptchaPartTwo_SingleRepeatingSet()
        {
            // act
            var result = InverseCaptcha.CalculateInverseCaptchaPartTwo("123425");

            // assert
            Assert.AreEqual(4, result);
        }
        public void InverseCaptchaPartTwo_PairsOfRepeatingDigits()
        {
            // act
            var result = InverseCaptcha.CalculateInverseCaptchaPartTwo("1212");

            // assert
            Assert.AreEqual(6, result);
        }