Add initial Activity / Metric support (#183)

tests/ModelContextProtocol.Tests/DiagnosticTests.cs

@@ -0,0 +1,79 @@
+using ModelContextProtocol.Client;
+using ModelContextProtocol.Protocol.Transport;
+using ModelContextProtocol.Protocol.Types;
+using ModelContextProtocol.Server;
+using OpenTelemetry.Trace;
+using System.Diagnostics;
+using System.IO.Pipelines;
+
+namespace ModelContextProtocol.Tests;
+
+[Collection(nameof(DisableParallelization))]
+public class DiagnosticTests
+{
+    [Fact]
+    public async Task Session_TracksActivities()
+    {
+        var activities = new List<Activity>();
+
+        using (var tracerProvider = OpenTelemetry.Sdk.CreateTracerProviderBuilder()
+            .AddSource("ModelContextProtocol")
+            .AddInMemoryExporter(activities)
+            .Build())
+        {
+            await RunConnected(async (client, server) =>
+            {
+                var tools = await client.ListToolsAsync(TestContext.Current.CancellationToken);
+                Assert.NotNull(tools);
+                Assert.NotEmpty(tools);
+
+                var tool = tools.First(t => t.Name == "DoubleValue");
+                await tool.InvokeAsync(new Dictionary<string, object?>() { ["amount"] = 42 }, TestContext.Current.CancellationToken);
+            });
+        }
+
+        Assert.NotEmpty(activities);
+
+        Activity toolCallActivity = activities.First(a =>
+            a.Tags.Any(t => t.Key == "rpc.method" && t.Value == "tools/call"));
+        Assert.Equal("DoubleValue", toolCallActivity.Tags.First(t => t.Key == "mcp.request.params.name").Value);
+    }
+
+    private static async Task RunConnected(Func<IMcpClient, IMcpServer, Task> action)
+    {
+        Pipe clientToServerPipe = new(), serverToClientPipe = new();
+        StreamServerTransport serverTransport = new(clientToServerPipe.Reader.AsStream(), serverToClientPipe.Writer.AsStream());
+        StreamClientTransport clientTransport = new(clientToServerPipe.Writer.AsStream(), serverToClientPipe.Reader.AsStream());
+
+        Task serverTask;
+
+        await using (IMcpServer server = McpServerFactory.Create(serverTransport, new()
+            {
+                ServerInfo = new Implementation { Name = "TestServer", Version = "1.0.0" },
+                Capabilities = new()
+                {
+                    Tools = new()
+                    {
+                        ToolCollection = [McpServerTool.Create((int amount) => amount * 2, new() { Name = "DoubleValue", Description = "Doubles the value." })],
+                    }
+                }
+            }))
+        {
+            serverTask = server.RunAsync(TestContext.Current.CancellationToken);
+
+            await using (IMcpClient client = await McpClientFactory.CreateAsync(new()
+                {
+                    Id = "TestServer",
+                    Name = "TestServer",
+                    TransportType = TransportTypes.StdIo,
+                },
+                createTransportFunc: (_, __) => clientTransport,
+                cancellationToken: TestContext.Current.CancellationToken))
+            {
+                await action(client, server);
+            }
+        }
+
+        await serverTask;
+    }
+}