public void ReturnsTheDigit_If_InputOnlyHasTwoSameDigits()
        {
            var inverter = new CaptchaInverter2("22");

            var sum = inverter.GetSum();

            sum.Should().Be(4);
        }
        public void ReturnsExpected(string input, int expected)
        {
            var inverter = new CaptchaInverter2(input);

            var sum = inverter.GetSum();

            sum.Should().Be(expected);
        }
        public void ReturnsZero_If_InputOnlyHasTwoDifferentDigits()
        {
            var inverter = new CaptchaInverter2("12");

            var sum = inverter.GetSum();

            sum.Should().Be(0);
        }