Setup solution

ModernKeePassLib.Test/Cryptography/HmacOtpTests.cs

@@ -0,0 +1,31 @@
+using System.Text;
+using ModernKeePassLib.Cryptography;
+using Xunit;
+
+namespace ModernKeePassLib.Test.Cryptography
+{
+    public class HmacOtpTests
+    {
+        // Using the test case from Appendix D of RFC 4226
+
+        const string secret = "12345678901234567890";
+
+        static readonly string[] expectedHOTP = new string[]
+        {
+            "755224", "287082", "359152", "969429", "338314",
+            "254676", "287922", "162583", "399871", "520489"
+        };
+
+        [Fact]
+        public void TestGenerate()
+        {
+            var secretBytes = Encoding.UTF8.GetBytes(secret);
+
+            for (ulong i = 0; i < 10; i++)
+            {
+                var hotp = HmacOtp.Generate(secretBytes, i, 6, false, -1);
+                Assert.Equal(hotp, expectedHOTP[i]);
+            }
+        }
+    }
+}