Fix port numbers used by SSE server tests

Author: stephentoub

tests/ModelContextProtocol.TestSseServer/Program.cs

@@ -377,10 +377,12 @@ public static async Task MainAsync(string[] args, ILoggerProvider? loggerProvide
     {
         Console.WriteLine("Starting server...");
 
+        int port = args.Length > 0 &&  uint.TryParse(args[0], out var parsedPort) ? (int)parsedPort : 3001;
+
         var builder = WebApplication.CreateSlimBuilder(args);
         builder.WebHost.ConfigureKestrel(options =>
         {
-            options.ListenLocalhost(3001);
+            options.ListenLocalhost(port);
         });
 
         ConfigureSerilog(builder.Logging);

tests/ModelContextProtocol.Tests/SseServerIntegrationTestFixture.cs

@@ -17,16 +17,19 @@ public class SseServerIntegrationTestFixture : IAsyncDisposable
 
     public SseServerIntegrationTestFixture()
     {
+        // Ensure that test suites running against different TFMs and possibly concurrently use different port numbers.
+        int port = 3001 + Environment.Version.Major;
+
         DefaultConfig = new McpServerConfig
         {
             Id = "test_server",
             Name = "TestServer",
             TransportType = TransportTypes.Sse,
             TransportOptions = [],
-            Location = "http://localhost:3001/sse"
+            Location = $"http://localhost:{port}/sse"
         };
 
-        _serverTask = Program.MainAsync([], new XunitLoggerProvider(_delegatingTestOutputHelper), _stopCts.Token);
+        _serverTask = Program.MainAsync([port.ToString()], new XunitLoggerProvider(_delegatingTestOutputHelper), _stopCts.Token);
     }
 
     public static McpClientOptions CreateDefaultClientOptions() => new()