Run stateful and stateless conformance endpoints in a single server process (#1672)

tests/ModelContextProtocol.AspNetCore.Tests/ConformanceServerFixture.cs

@@ -0,0 +1,104 @@
+using System.Diagnostics;
+using ModelContextProtocol.Tests.Utils;
+
+namespace ModelContextProtocol.ConformanceTests;
+
+/// <summary>
+/// Shared fixture that starts a single ConformanceServer exposing both the legacy stateful MCP
+/// lifecycle (at <see cref="ServerUrl"/>, "/") and the SEP-2575 stateless lifecycle (at
+/// <see cref="StatelessServerUrl"/>, "/stateless") on one port. A single long-lived server avoids
+/// the TCP TIME_WAIT conflicts that per-test restarts on a fixed port cause on Windows, and
+/// centralizes the port-binding logic that the stateful and stateless conformance tests previously
+/// duplicated. Shared by <see cref="ServerConformanceTests"/> and <see cref="CachingConformanceTests"/>
+/// via <see cref="ConformanceServerCollection"/>.
+/// </summary>
+public sealed class ConformanceServerFixture : IAsyncLifetime
+{
+    // Use different ports for each target framework to allow parallel execution across the
+    // multi-targeted test processes. net10.0 -> 3001, net9.0 -> 3002, net8.0 -> 3003.
+    private static int GetPortForTargetFramework()
+    {
+        var testBinaryDir = AppContext.BaseDirectory;
+        var targetFramework = Path.GetFileName(testBinaryDir.TrimEnd(Path.DirectorySeparatorChar));
+
+        return targetFramework switch
+        {
+            "net10.0" => 3001,
+            "net9.0" => 3002,
+            "net8.0" => 3003,
+            _ => 3001 // Default fallback
+        };
+    }
+
+    private Task? _serverTask;
+    private CancellationTokenSource? _serverCts;
+
+    /// <summary>Base URL of the stateful MCP endpoint (mapped at "/").</summary>
+    public string ServerUrl { get; } = $"http://localhost:{GetPortForTargetFramework()}";
+
+    /// <summary>
+    /// URL of the stateless MCP endpoint (mapped at "/stateless"), used by the 2026-07-28
+    /// scenarios (caching, MRTR, SEP-2243) that negotiate the stateless lifecycle.
+    /// </summary>
+    public string StatelessServerUrl => $"{ServerUrl}/stateless";
+
+    public async ValueTask InitializeAsync()
+    {
+        _serverCts = new CancellationTokenSource();
+        _serverTask = Task.Run(() => ConformanceServer.Program.MainAsync(
+            ["--urls", ServerUrl], cancellationToken: _serverCts.Token));
+
+        // Wait for server to be ready (retry for up to 30 seconds)
+        var timeout = TimeSpan.FromSeconds(30);
+        var stopwatch = Stopwatch.StartNew();
+        using var httpClient = new HttpClient { Timeout = TestConstants.HttpClientPollingTimeout };
+
+        while (stopwatch.Elapsed < timeout)
+        {
+            try
+            {
+                await httpClient.GetAsync($"{ServerUrl}/health");
+                return;
+            }
+            catch (HttpRequestException)
+            {
+                // Connection refused means server not ready yet
+            }
+            catch (TaskCanceledException)
+            {
+                // Timeout means server might be processing, give it more time
+            }
+
+            await Task.Delay(500);
+        }
+
+        throw new InvalidOperationException("ConformanceServer failed to start within the timeout period");
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_serverCts != null)
+        {
+            _serverCts.Cancel();
+            if (_serverTask != null)
+            {
+                try
+                {
+                    await _serverTask.WaitAsync(TestConstants.DefaultTimeout);
+                }
+                catch
+                {
+                    // Ignore exceptions during shutdown
+                }
+            }
+            _serverCts.Dispose();
+        }
+    }
+}
+
+/// <summary>
+/// xUnit collection that shares one <see cref="ConformanceServerFixture"/> across the conformance
+/// test classes so they run against a single server instance (and a single bound port).
+/// </summary>
+[CollectionDefinition(nameof(ConformanceServerCollection))]
+public sealed class ConformanceServerCollection : ICollectionFixture<ConformanceServerFixture>;