Enable netfx testing. (#588)

* Enable netfx testing.

* Skip impacted tests and re-enable netfx testing.

* Remove redundant comment.

* Remove unnecessary project configuration.

* Simplify test server copying.

src/ModelContextProtocol.Core/Client/StdioClientSessionTransport.cs

@@ -13,7 +13,7 @@ internal sealed class StdioClientSessionTransport : StreamClientSessionTransport
     private int _cleanedUp = 0;
 
     public StdioClientSessionTransport(StdioClientTransportOptions options, Process process, string endpointName, Queue<string> stderrRollingLog, ILoggerFactory? loggerFactory)
-        : base(process.StandardInput, process.StandardOutput, endpointName, loggerFactory)
+        : base(process.StandardInput.BaseStream, process.StandardOutput.BaseStream, encoding: null, endpointName, loggerFactory)
     {
         _process = process;
         _options = options;

src/ModelContextProtocol.Core/Client/StdioClientTransport.cs

@@ -69,8 +69,6 @@ public sealed partial class StdioClientTransport : IClientTransport
         {
             LogTransportConnecting(logger, endpointName);
 
-            UTF8Encoding noBomUTF8 = new(encoderShouldEmitUTF8Identifier: false);
-
             ProcessStartInfo startInfo = new()
             {
                 FileName = command,
@@ -80,10 +78,10 @@ public sealed partial class StdioClientTransport : IClientTransport
                 UseShellExecute = false,
                 CreateNoWindow = true,
                 WorkingDirectory = _options.WorkingDirectory ?? Environment.CurrentDirectory,
-                StandardOutputEncoding = noBomUTF8,
-                StandardErrorEncoding = noBomUTF8,
+                StandardOutputEncoding = StreamClientSessionTransport.NoBomUtf8Encoding,
+                StandardErrorEncoding = StreamClientSessionTransport.NoBomUtf8Encoding,
 #if NET
-                StandardInputEncoding = noBomUTF8,
+                StandardInputEncoding = StreamClientSessionTransport.NoBomUtf8Encoding,
 #endif
             };
 
@@ -164,7 +162,7 @@ public sealed partial class StdioClientTransport : IClientTransport
             Encoding originalInputEncoding = Console.InputEncoding;
             try
             {
-                Console.InputEncoding = noBomUTF8;
+                Console.InputEncoding = StreamClientSessionTransport.NoBomUtf8Encoding;
                 processStarted = process.Start();
             }
             finally

src/ModelContextProtocol.Core/Client/StreamClientSessionTransport.cs

@@ -1,5 +1,6 @@
 using Microsoft.Extensions.Logging;
 using ModelContextProtocol.Protocol;
+using System.Text;
 using System.Text.Json;
 
 namespace ModelContextProtocol.Client;
@@ -7,6 +8,8 @@ namespace ModelContextProtocol.Client;
 /// <summary>Provides the client side of a stream-based session transport.</summary>
 internal class StreamClientSessionTransport : TransportBase
 {
+    internal static UTF8Encoding NoBomUtf8Encoding { get; } = new(encoderShouldEmitUTF8Identifier: false);
+
     private readonly TextReader _serverOutput;
     private readonly TextWriter _serverInput;
     private readonly SemaphoreSlim _sendLock = new(1, 1);
@@ -54,6 +57,43 @@ internal class StreamClientSessionTransport : TransportBase
         readTask.Start();
     }
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="StreamClientSessionTransport"/> class.
+    /// </summary>
+    /// <param name="serverInput">
+    /// The server's input stream. Messages written to this stream will be sent to the server.
+    /// </param>
+    /// <param name="serverOutput">
+    /// The server's output stream. Messages read from this stream will be received from the server.
+    /// </param>
+    /// <param name="encoding">
+    /// The encoding used for reading and writing messages from the input and output streams. Defaults to UTF-8 without BOM if null.
+    /// </param>
+    /// <param name="endpointName">
+    /// A name that identifies this transport endpoint in logs.
+    /// </param>
+    /// <param name="loggerFactory">
+    /// Optional factory for creating loggers. If null, a NullLogger will be used.
+    /// </param>
+    /// <remarks>
+    /// This constructor starts a background task to read messages from the server output stream.
+    /// The transport will be marked as connected once initialized.
+    /// </remarks>
+    public StreamClientSessionTransport(Stream serverInput, Stream serverOutput, Encoding? encoding, string endpointName, ILoggerFactory? loggerFactory)
+        : this(
+            new StreamWriter(serverInput, encoding ?? NoBomUtf8Encoding),
+#if NET
+            new StreamReader(serverOutput, encoding ?? NoBomUtf8Encoding),
+#else
+            new CancellableStreamReader(serverOutput, encoding ?? NoBomUtf8Encoding),
+#endif
+            endpointName,
+            loggerFactory)
+    {
+        Throw.IfNull(serverInput);
+        Throw.IfNull(serverOutput);
+    }
+
     /// <inheritdoc/>
     public override async Task SendMessageAsync(JsonRpcMessage message, CancellationToken cancellationToken = default)
     {

src/ModelContextProtocol.Core/Client/StreamClientTransport.cs

@@ -47,8 +47,9 @@ public sealed class StreamClientTransport : IClientTransport
     public Task<ITransport> ConnectAsync(CancellationToken cancellationToken = default)
     {
         return Task.FromResult<ITransport>(new StreamClientSessionTransport(
-            new StreamWriter(_serverInput),
-            new StreamReader(_serverOutput),
+            _serverInput,
+            _serverOutput,
+            encoding: null,
             "Client (stream)",
             _loggerFactory));
     }