Improve code coverage (#40)

* Add tests for tool generation

* Add couple of MCPServer tests

* Fix merge issues

* More tests for McpServer

* Some more tests

* Fix merge issues

tests/mcpdotnet.Tests/Utils/MockHttpHandler.cs

@@ -0,0 +1,22 @@
+namespace McpDotNet.Tests.Utils;
+
+public class MockHttpHandler : HttpMessageHandler
+{
+    public Func<HttpRequestMessage, Task<HttpResponseMessage>>? RequestHandler { get; set; }
+
+    protected async override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+    {
+        if (RequestHandler == null)
+            throw new InvalidOperationException($"No {nameof(RequestHandler)} was set! Please set handler first and make request afterwards.");
+
+        if (cancellationToken.IsCancellationRequested)
+            throw new OperationCanceledException(cancellationToken);
+
+        var result = await RequestHandler.Invoke(request);
+
+        if (cancellationToken.IsCancellationRequested)
+            throw new OperationCanceledException(cancellationToken);
+
+        return result;
+    }
+}

tests/mcpdotnet.Tests/Utils/TestServerTransport.cs

@@ -0,0 +1,91 @@
+using System.Threading.Channels;
+using McpDotNet.Protocol.Messages;
+using McpDotNet.Protocol.Transport;
+
+namespace McpDotNet.Tests.Utils;
+
+public class TestServerTransport : IServerTransport
+{
+    private readonly Channel<IJsonRpcMessage> _messageChannel;
+    private bool _isStarted;
+
+    public bool IsConnected => _isStarted;
+
+    public ChannelReader<IJsonRpcMessage> MessageReader => _messageChannel;
+
+    public List<IJsonRpcMessage> SentMessages { get; } = [];
+
+    public Action<IJsonRpcMessage>? OnMessageSent { get; set; }
+
+    public TestServerTransport()
+    {
+        _messageChannel = Channel.CreateUnbounded<IJsonRpcMessage>(new UnboundedChannelOptions
+        {
+            SingleReader = true,
+            SingleWriter = true,
+        });
+    }
+
+    public ValueTask DisposeAsync() => ValueTask.CompletedTask;
+
+    public async Task SendMessageAsync(IJsonRpcMessage message, CancellationToken cancellationToken = default)
+    {
+        SentMessages.Add(message);
+        if (message is JsonRpcRequest request)
+        {
+            if (request.Method == "roots/list")
+                await ListRoots(request, cancellationToken);
+            else if (request.Method == "sampling/createMessage")
+                await Sampling(request, cancellationToken);
+            else
+                await WriteMessageAsync(request, cancellationToken);
+        }
+        else if (message is JsonRpcNotification notification)
+        {
+            await WriteMessageAsync(notification, cancellationToken);
+        }
+
+        OnMessageSent?.Invoke(message);
+    }
+
+    public Task StartListeningAsync(CancellationToken cancellationToken = default)
+    {
+        _isStarted = true;
+        return Task.CompletedTask;
+    }
+
+    private async Task ListRoots(JsonRpcRequest request, CancellationToken cancellationToken)
+    {
+        await WriteMessageAsync(new JsonRpcResponse
+        {
+            Id = request.Id,
+            Result = new McpDotNet.Protocol.Types.ListRootsResult
+            {
+                Roots = []
+            }
+        }, cancellationToken);
+    }
+
+    private async Task Sampling(JsonRpcRequest request, CancellationToken cancellationToken)
+    {
+        await WriteMessageAsync(new JsonRpcResponse
+        {
+            Id = request.Id,
+            Result = new Protocol.Types.CreateMessageResult { Content = new(), Model = "model", Role = "role" }
+        }, cancellationToken);
+    }
+
+    private async Task Error(JsonRpcRequest request, CancellationToken cancellationToken)
+    {
+        await WriteMessageAsync(new JsonRpcError
+        {
+            Id = request.Id,
+            Error = new JsonRpcErrorDetail() { Code = -32601, Message = $"Method '{request.Method}' not supported" }
+        }, cancellationToken);
+    }
+
+    protected async Task WriteMessageAsync(IJsonRpcMessage message, CancellationToken cancellationToken = default)
+    {
+        await _messageChannel.Writer.WriteAsync(message, cancellationToken);
+    }
+}