unit tests for PeerWirePacket, plus a small refactor

bzTorrent.Tests/Data/PeerWirePacketTests.cs

@@ -0,0 +1,106 @@
+using FluentAssertions;
+using System;
+using System.Diagnostics;
+using bzTorrent.Helpers;
+using Xunit;
+using bzTorrent.Data;
+
+namespace bzTorrent.Tests.Data
+{
+    public class PeerWirePacketTests
+    {
+        [Fact]
+        public void KeepAlivePacketHasZeroCommandLength()
+        {
+            var pwp = new PeerWirePacket();
+            pwp.Parse(new byte[] { 0, 0, 0, 0, 0, 0, 0, 1 }).Should().BeTrue();
+
+            pwp.Command.Should().Be(PeerClientCommands.KeepAlive);
+            pwp.CommandLength.Should().Be(0);
+            pwp.PacketByteLength.Should().Be(4);
+        }
+
+        [Fact]
+        public void HavePacketHas5ByteCommandLength()
+        {
+            var pwp = new PeerWirePacket();
+            pwp.Parse(new byte[] { 0, 0, 0, 5, 4, 0, 0, 0, 1 }).Should().BeTrue();
+
+            pwp.Command.Should().Be(PeerClientCommands.Have);
+            pwp.CommandLength.Should().Be(5);
+            pwp.PacketByteLength.Should().Be(9);
+        }
+
+        [Fact]
+        public void ParseShouldReturnFalseIfNotEnoughData()
+        {
+            var pwp = new PeerWirePacket();
+            pwp.Parse(new byte[] { 0, 0, 0, 5, 4, 0, 0 }).Should().BeFalse();
+        }
+
+        [Fact]
+        public void OutputShouldEqualValidInput()
+        {
+            var inputOutput = new byte[] { 0, 0, 0, 5, 4, 0, 0, 0, 1 };
+            var pwp = new PeerWirePacket();
+            pwp.Parse(inputOutput).Should().BeTrue();
+
+            pwp.GetBytes().Should().BeEquivalentTo(inputOutput);
+        }
+
+        [Fact]
+        public void CommandPacketShouldBe5Bytes()
+        {
+            var pwp = new PeerWirePacket();
+            pwp.Parse(new byte[] { 0, 0, 0, 1, 1 }).Should().BeTrue();
+
+            pwp.CommandLength.Should().Be(1);
+            pwp.PacketByteLength.Should().Be(5);
+        }
+
+        [Fact]
+        public void Command0IsChoke()
+        {
+            var pwp = new PeerWirePacket();
+            pwp.Parse(new byte[] { 0, 0, 0, 1, 0 }).Should().BeTrue();
+
+            pwp.Command.Should().Be(PeerClientCommands.Choke);
+        }
+
+        [Fact]
+        public void Command1IsUnchoke()
+        {
+            var pwp = new PeerWirePacket();
+            pwp.Parse(new byte[] { 0, 0, 0, 1, 1 }).Should().BeTrue();
+
+            pwp.Command.Should().Be(PeerClientCommands.Unchoke);
+        }
+
+        [Fact]
+        public void Command2IsUnchoke()
+        {
+            var pwp = new PeerWirePacket();
+            pwp.Parse(new byte[] { 0, 0, 0, 1, 2 }).Should().BeTrue();
+
+            pwp.Command.Should().Be(PeerClientCommands.Interested);
+        }
+
+        [Fact]
+        public void Command3IsUnchoke()
+        {
+            var pwp = new PeerWirePacket();
+            pwp.Parse(new byte[] { 0, 0, 0, 1, 3 }).Should().BeTrue();
+
+            pwp.Command.Should().Be(PeerClientCommands.NotInterested);
+        }
+
+        [Fact]
+        public void Command4IsHave()
+        {
+            var pwp = new PeerWirePacket();
+            pwp.Parse(new byte[] { 0, 0, 0, 5, 4, 0, 0, 0, 1 }).Should().BeTrue();
+
+            pwp.Command.Should().Be(PeerClientCommands.Have);
+        }
+    }
+}

bzTorrent/Data/PeerWirePacket.cs

@@ -43,26 +43,21 @@ public class PeerWirePacket
 		public bool Parse(byte[] currentPacketBuffer)
 		{
 			var commandLength = UnpackHelper.UInt32(currentPacketBuffer, 0, UnpackHelper.Endianness.Big);
-			if (commandLength == 0)
+			CommandLength = commandLength;
+
+			if (CommandLength == 0)
 			{
 				//keep-alive message
 				Command = PeerClientCommands.KeepAlive;
 				return true;
 			}
 
-			if (commandLength > (currentPacketBuffer.Length - 4))
+			if (CommandLength > (currentPacketBuffer.Length - 4))
 			{
 				//need more data first
 				return false;
 			}
 
-			CommandLength = commandLength;
-
-			if(CommandLength == 0)
-			{
-				Command = PeerClientCommands.KeepAlive;
-			}
-
 			if (CommandLength > 0)
 			{
 				Command = (PeerClientCommands)currentPacketBuffer[4];
@@ -71,8 +66,7 @@ public bool Parse(byte[] currentPacketBuffer)
 			if(CommandLength > 1)
 			{
 				Payload = currentPacketBuffer.GetBytes(5, (int)CommandLength - 1);
-			}
-
+			}		
 
 			return true;
 		}