public void TestingSha1()
        {
            string secret = "SomeKey";
            byte[] key = Encoding.UTF8.GetBytes(secret);
            long interval = 66778;
            int returnDigits = 6;

            var hmacSha = new HashSha1();
            OneTimePassword generator = new OneTimePassword(key, hmacSha, returnDigits);
            String otp = generator.Generate("12345", interval);

            Assert.IsNotNull(otp);
            Assert.AreEqual(6, otp.Length);
            Assert.AreEqual("337162", otp);
        }
        public void TestingUserIdWithoutInterval()
        {
            string secret = "SomeKey";
            byte[] key = Encoding.UTF8.GetBytes(secret);

            var hmacSha1 = new HashSha1();
            OneTimePassword generator = new OneTimePassword(key, hmacSha1);
            String otp = generator.Generate("user", 0);

            Assert.AreEqual(OneTimePassword.MAXIMUM_DIGITS, otp.Length);
            Assert.AreEqual("31249860", otp);
        }