Avoid docker port conflicts from test suites running concurrently

Author: stephentoub

tests/ModelContextProtocol.Tests/SseIntegrationTests.cs

@@ -8,6 +8,20 @@ namespace ModelContextProtocol.Tests;
 
 public class SseIntegrationTests(ITestOutputHelper outputHelper) : LoggedTest(outputHelper)
 {
+    /// <summary>Port number to be grabbed by the next test.</summary>
+    private static int s_nextPort = 3000;
+
+    // If the tests run concurrently against different versions of the runtime, tests can conflict with
+    // each other in the ports set up for interacting with containers. Ensure that such suites running
+    // against different TFMs use different port numbers.
+    private static readonly int s_portOffset = 1000 * (Environment.Version.Major switch
+    {
+        int v when v >= 8 => Environment.Version.Major - 7,
+        _ => 0,
+    });
+
+    private static int CreatePortNumber() => Interlocked.Increment(ref s_nextPort) + s_portOffset;
+
     [Fact]
     public async Task ConnectAndReceiveMessage_InMemoryServer()
     {
@@ -52,7 +66,7 @@ public async Task ConnectAndReceiveMessage_EverythingServerWithSse()
     {
         Assert.SkipWhen(!EverythingSseServerFixture.IsDockerAvailable, "docker is not available");
 
-        int port = 3001;
+        int port = CreatePortNumber();
 
         await using var fixture = new EverythingSseServerFixture(port);
         await fixture.StartAsync();
@@ -89,7 +103,7 @@ public async Task Sampling_Sse_EverythingServer()
     {
         Assert.SkipWhen(!EverythingSseServerFixture.IsDockerAvailable, "docker is not available");
 
-        int port = 3002;
+        int port = CreatePortNumber();
 
         await using var fixture = new EverythingSseServerFixture(port);
         await fixture.StartAsync();
@@ -161,7 +175,6 @@ public async Task ConnectAndReceiveMessage_InMemoryServer_WithFullEndpointEventU
         server.UseFullUrlForEndpointEvent = true;
         await server.StartAsync();
 
-
         var defaultOptions = new McpClientOptions
         {
             ClientInfo = new() { Name = "IntegrationTestClient", Version = "1.0.0" }