Rewrite packet writing code for HdHomerun

tests/Jellyfin.Server.Implementations.Tests/LiveTv/HdHomerunManagerTests.cs

@@ -0,0 +1,39 @@
+using System;
+using Emby.Server.Implementations.LiveTv.TunerHosts.HdHomerun;
+using Xunit;
+
+namespace Jellyfin.Server.Implementations.Tests.LiveTv
+{
+    public class HdHomerunManagerTests
+    {
+        [Fact]
+        public void WriteNullTerminatedString_Empty_Success()
+        {
+            ReadOnlySpan<byte> expected = stackalloc byte[]
+            {
+                1, 0
+            };
+
+            Span<byte> buffer = stackalloc byte[128];
+            int len = HdHomerunManager.WriteNullTerminatedString(buffer, string.Empty);
+
+            Assert.Equal(expected.Length, len);
+            Assert.True(expected.SequenceEqual(buffer.Slice(0, len)));
+        }
+
+        [Fact]
+        public void WriteNullTerminatedString_Valid_Success()
+        {
+            ReadOnlySpan<byte> expected = stackalloc byte[]
+            {
+                10, (byte)'T', (byte)'h', (byte)'e', (byte)' ', (byte)'q', (byte)'u', (byte)'i', (byte)'c', (byte)'k', 0
+            };
+
+            Span<byte> buffer = stackalloc byte[128];
+            int len = HdHomerunManager.WriteNullTerminatedString(buffer, "The quick");
+
+            Assert.Equal(expected.Length, len);
+            Assert.True(expected.SequenceEqual(buffer.Slice(0, len)));
+        }
+    }
+}