public void TestChecksum_IncorrectChecksum_Fails()
        {
            string accountNumber = "057508000";
            var sut = new ChecksumCalculator();

            bool result = sut.TestChecksum(accountNumber);

            Assert.IsFalse(result);
        }
        public void TestChecksum_CorrectChecksum_Ok()
        {
            string accountNumber = "123456789";
            var sut = new ChecksumCalculator();

            bool result = sut.TestChecksum(accountNumber);

            Assert.IsTrue(result);
        }