added unit tests for core methods of Asn1Utils class.

Author: Crypt32

tests/Asn1Parser.Tests/Asn1UtilsTests.cs

@@ -0,0 +1,72 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using SysadminsLV.Asn1Parser;
+
+namespace Asn1Parser.Tests;
+
+[TestClass]
+public class Asn1UtilsTests {
+    [TestMethod]
+    public void TestGetLengthBytes() {
+        ReadOnlyMemory<Byte> lenBytes = Asn1Utils.GetLengthBytesAsMemory(0);
+        Assert.AreEqual(1, lenBytes.Length);
+        Assert.IsTrue(lenBytes.Span.SequenceEqual(new Byte[] { 0 }));
+
+        lenBytes = Asn1Utils.GetLengthBytesAsMemory(127);
+        Assert.AreEqual(1, lenBytes.Length);
+        Assert.IsTrue(lenBytes.Span.SequenceEqual(new Byte[] { 127 }));
+
+        lenBytes = Asn1Utils.GetLengthBytesAsMemory(128);
+        Assert.AreEqual(2, lenBytes.Length);
+        Assert.IsTrue(lenBytes.Span.SequenceEqual(new Byte[] { 129, 128 }));
+
+        lenBytes = Asn1Utils.GetLengthBytesAsMemory(255);
+        Assert.AreEqual(2, lenBytes.Length);
+        Assert.IsTrue(lenBytes.Span.SequenceEqual(new Byte[] { 129, 255 }));
+
+        lenBytes = Asn1Utils.GetLengthBytesAsMemory(256);
+        Assert.AreEqual(3, lenBytes.Length);
+        Assert.IsTrue(lenBytes.Span.SequenceEqual(new Byte[] { 130, 1, 0 }));
+
+        lenBytes = Asn1Utils.GetLengthBytesAsMemory(100000);
+        Assert.AreEqual(4, lenBytes.Length);
+        Assert.IsTrue(lenBytes.Span.SequenceEqual(new Byte[] { 131, 1, 134, 160 }));
+    }
+
+    [TestMethod]
+    public void TestCalculatePayloadLength() {
+        Int64 length = Asn1Utils.CalculatePayloadLength([0]);
+        Assert.AreEqual(0, length);
+
+        length = Asn1Utils.CalculatePayloadLength([127]);
+        Assert.AreEqual(127, length);
+
+        length = Asn1Utils.CalculatePayloadLength([129, 128]);
+        Assert.AreEqual(128, length);
+
+        length = Asn1Utils.CalculatePayloadLength([129, 255]);
+        Assert.AreEqual(255, length);
+
+        length = Asn1Utils.CalculatePayloadLength([130, 1, 0]);
+        Assert.AreEqual(256, length);
+
+        length = Asn1Utils.CalculatePayloadLength([131, 1, 134, 160]);
+        Assert.AreEqual(100000, length);
+    }
+
+    [TestMethod]
+    public void TestEncode() {
+        Byte[] array = new Byte[130];
+        for (Int32 i = 0; i < array.Length; i++) {
+            array[i] = (Byte)i;
+        }
+
+        ReadOnlyMemory<Byte> encoded = Asn1Utils.Encode(array.AsSpan(), Asn1Type.OCTET_STRING);
+        var list = new List<Byte>([4, 129, 130]);
+        list.AddRange(array);
+        
+        Assert.AreEqual(list.Count, encoded.Length);
+        Assert.IsTrue(encoded.Span.SequenceEqual(list.ToArray()));
+    }
+}