Extend MqttPacketReader constructor to allow more unit tests.

Source/MQTTnet.AspnetCore/ReaderExtensions.cs

@@ -32,7 +32,8 @@ namespace MQTTnet.AspNetCore
             }
 
             var bodySlice = copy.Slice(0, bodyLength);
-            packet = serializer.Deserialize(new ReceivedMqttPacket(fixedheader, new MqttPacketBodyReader(bodySlice.GetArray(), 0)));
+            var buffer = bodySlice.GetArray();
+            packet = serializer.Deserialize(new ReceivedMqttPacket(fixedheader, new MqttPacketBodyReader(buffer, 0, buffer.Length)));
             consumed = bodySlice.End;
             observed = bodySlice.End;
             return true;

Source/MQTTnet/Adapter/MqttChannelAdapter.cs

@@ -201,7 +201,7 @@ namespace MQTTnet.Adapter
                     bodyOffset += readBytes;
                 } while (bodyOffset < body.Length);
 
-                return new ReceivedMqttPacket(fixedHeader.Flags, new MqttPacketBodyReader(body, 0));
+                return new ReceivedMqttPacket(fixedHeader.Flags, new MqttPacketBodyReader(body, 0, body.Length));
             }
             finally
             {

Source/MQTTnet/Internal/TestMqttChannel.cs

@@ -14,11 +14,7 @@ namespace MQTTnet.Internal
             _stream = stream;
         }
 
-        public void Dispose()
-        {
-        }
-
-        public string Endpoint { get; }
+        public string Endpoint { get; } = "<Test channel>";
 
         public Task ConnectAsync(CancellationToken cancellationToken)
         {
@@ -39,5 +35,9 @@ namespace MQTTnet.Internal
         {
             return _stream.WriteAsync(buffer, offset, count, cancellationToken);
         }
+
+        public void Dispose()
+        {
+        }
     }
 }

Source/MQTTnet/Serializer/MqttPacketBodyReader.cs

@@ -6,17 +6,20 @@ namespace MQTTnet.Serializer
     public class MqttPacketBodyReader
     {
         private readonly byte[] _buffer;
-        private int _offset;
+        private readonly int _length;
 
-        public MqttPacketBodyReader(byte[] buffer, int offset)
+        private int _offset;
+        
+        public MqttPacketBodyReader(byte[] buffer, int offset, int length)
         {
             _buffer = buffer;
             _offset = offset;
+            _length = length;
         }
 
-        public int Length => _buffer.Length - _offset;
+        public int Length => _length - _offset;
 
-        public bool EndOfStream => _offset == _buffer.Length;
+        public bool EndOfStream => _offset == _length;
 
         public byte ReadByte()
         {
@@ -26,7 +29,7 @@ namespace MQTTnet.Serializer
 
         public ArraySegment<byte> ReadRemainingData()
         {
-            return new ArraySegment<byte>(_buffer, _offset, _buffer.Length - _offset);
+            return new ArraySegment<byte>(_buffer, _offset, _length - _offset);
         }
 
         public ushort ReadUInt16()
@@ -53,9 +56,9 @@ namespace MQTTnet.Serializer
 
         private void ValidateReceiveBuffer(ushort length)
         {
-            if (_buffer.Length < _offset + length)
+            if (_length < _offset + length)
             {
-                throw new ArgumentOutOfRangeException(nameof(_buffer), $"expected at least {_offset + length} bytes but there are only {_buffer.Length} bytes");
+                throw new ArgumentOutOfRangeException(nameof(_buffer), $"expected at least {_offset + length} bytes but there are only {_length} bytes");
             }
         }
 

Source/MQTTnet/Serializer/MqttPacketReader.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Threading;
+using System.Threading;
 using System.Threading.Tasks;
 using MQTTnet.Channel;
 using MQTTnet.Exceptions;