tried to fix unit tests

Author: kerryjiang

src/SuperSocket.MySQL/MySQLConnection.cs

@@ -24,7 +24,7 @@ public class MySQLConnection : EasyClient<MySQLPacket>
         public bool IsAuthenticated { get; private set; }
 
         public MySQLConnection(string host, int port, string userName, string password)
-            : base(new MySQLPacketFilter(MySQLPacketDecoder.Singleton))
+            : base(new MySQLPacketFilter(MySQLPacketDecoder.ClientInstance))
         {
             _host = host ?? throw new ArgumentNullException(nameof(host));
             _port = port > 0 ? port : DefaultPort;
@@ -40,9 +40,12 @@ public async Task ConnectAsync(CancellationToken cancellationToken = default)
             if (_port <= 0)
                 throw new ArgumentOutOfRangeException(nameof(_port), "Port must be a positive integer.");
 
-            var endPoint = new DnsEndPoint(_host, _port);
+            var endPoint = new DnsEndPoint(_host, _port, AddressFamily.InterNetwork);
 
-            await ConnectAsync(endPoint, cancellationToken).ConfigureAwait(false);
+            var connected = await ConnectAsync(endPoint, cancellationToken).ConfigureAwait(false);
+
+            if (!connected)
+                throw new InvalidOperationException($"Failed to connect to MySQL server at {_host}:{_port}");
 
             // Wait for server's handshake packet
             var packet = await ReceiveAsync().ConfigureAwait(false);
@@ -52,7 +55,7 @@ public async Task ConnectAsync(CancellationToken cancellationToken = default)
             // Prepare handshake response
             var handshakeResponse = new HandshakeResponsePacket
             {
-                CapabilityFlags = (uint)(ClientCapabilities.CLIENT_PROTOCOL_41 | 
+                CapabilityFlags = (uint)(ClientCapabilities.CLIENT_PROTOCOL_41 |
                                        ClientCapabilities.CLIENT_SECURE_CONNECTION |
                                        ClientCapabilities.CLIENT_PLUGIN_AUTH |
                                        ClientCapabilities.CLIENT_CONNECT_WITH_DB),
@@ -71,7 +74,7 @@ public async Task ConnectAsync(CancellationToken cancellationToken = default)
 
             // Wait for authentication result (OK packet or Error packet)
             var authResult = await ReceiveAsync().ConfigureAwait(false);
-            
+
             switch (authResult)
             {
                 case OKPacket okPacket:
@@ -80,8 +83,8 @@ public async Task ConnectAsync(CancellationToken cancellationToken = default)
                     break;
                 case ErrorPacket errorPacket:
                     // Authentication failed
-                    var errorMsg = !string.IsNullOrEmpty(errorPacket.ErrorMessage) 
-                        ? errorPacket.ErrorMessage 
+                    var errorMsg = !string.IsNullOrEmpty(errorPacket.ErrorMessage)
+                        ? errorPacket.ErrorMessage
                         : "Authentication failed";
                     throw new InvalidOperationException($"MySQL authentication failed: {errorMsg} (Error {errorPacket.ErrorCode})");
                 default:
@@ -166,5 +169,9 @@ public async Task DisconnectAsync()
                 IsAuthenticated = false;
             }
         }
+
+        protected override void OnError(string message, Exception exception)
+        {
+        }
     }
 }

src/SuperSocket.MySQL/MySQLPacketDecoder.cs

@@ -1,15 +1,16 @@
 using System;
 using System.Buffers;
+using System.IO;
 using SuperSocket.ProtoBase;
 
 namespace SuperSocket.MySQL
 {
     internal class MySQLPacketDecoder : IPackageDecoder<MySQLPacket>
     {
-        public static MySQLPacketDecoder Singleton { get; }
+        public static MySQLPacketDecoder ClientInstance { get; }
         static MySQLPacketDecoder()
         {
-            Singleton = new MySQLPacketDecoder(MySQLPacketFactory.Singleton);
+            ClientInstance = new MySQLPacketDecoder(MySQLPacketFactory.ClientInstance);
         }
 
         private readonly IMySQLPacketFactory _packetFactory;
@@ -21,9 +22,28 @@ private MySQLPacketDecoder(IMySQLPacketFactory packetFactory)
 
         public MySQLPacket Decode(ref ReadOnlySequence<byte> buffer, object context)
         {
-            var package = _packetFactory.Create(0);
+            if (buffer.Length == 0)
+                return null;
+
             var reader = new SequenceReader<byte>(buffer);
+            
+            // Read the first byte to determine packet type
+            if (!reader.TryRead(out byte packetType))
+                return null;
+
+            var filter = context as MySQLPacketFilter;
+
+            // Reset reader to beginning
+            reader = new SequenceReader<byte>(buffer);
+
+            var package = _packetFactory.Create(
+                    (filter.ReceivedHandshake == true
+                        ? packetType
+                        : -1)); // Use -1 for HandshakePacket if not received yet
+
             package.Decode(ref reader, context);
+
+            filter.ReceivedHandshake = true;
             return package;
         }
     }

src/SuperSocket.MySQL/MySQLPacketFactory.cs

@@ -8,13 +8,12 @@ namespace SuperSocket.MySQL
 {
     internal class MySQLPacketFactory : IMySQLPacketFactory
     {
-        public static MySQLPacketFactory Singleton { get; }
+        public static MySQLPacketFactory ClientInstance { get; }
 
         static MySQLPacketFactory()
         {
-            Singleton = new MySQLPacketFactory()
-                .RegisterPacketType<HandshakePacket>(0x0A)
-                .RegisterPacketType<HandshakeResponsePacket>(0x00)
+            ClientInstance = new MySQLPacketFactory()
+                .RegisterPacketType<HandshakePacket>(-1)
                 .RegisterPacketType<OKPacket>(0x00)
                 .RegisterPacketType<ErrorPacket>(0xFF);
         }

src/SuperSocket.MySQL/MySQLPacketFilter.cs

@@ -8,10 +8,13 @@ internal class MySQLPacketFilter : FixedHeaderPipelineFilter<MySQLPacket>
     {
         private const int headerSize = 4; // MySQL package header size is 4 bytes
 
+        internal bool ReceivedHandshake { get; set; }
+
         public MySQLPacketFilter(IPackageDecoder<MySQLPacket> decoder)
             : base(headerSize)
         {
             this.Decoder = decoder ?? throw new ArgumentNullException(nameof(decoder));
+            this.Context = this;
         }
 
         protected override int GetBodyLengthFromHeader(ref ReadOnlySequence<byte> buffer)