Gate SEP-2243 conformance tests on harness version >= 0.1.16

The http-standard-headers, http-custom-headers, and http-invalid-tool-headers
client scenarios and http-header-validation, http-custom-header-server-validation
server scenarios require conformance package >= 0.1.16 which is not yet
published to npm.

Add NodeHelpers.GetConformanceVersion() that runs 'conformance --version'
and NodeHelpers.IsConformanceVersionAtLeast() for runtime version checks.
Tests auto-skip when the harness is too old and auto-run once the package
is updated. Works with both npm-published and local file: references.

Author: tarekgh

tests/Common/Utils/NodeHelpers.cs

@@ -133,6 +133,82 @@ public static ProcessStartInfo ConformanceTestStartInfo(string arguments)
         return startInfo;
     }
 
+    /// <summary>
+    /// Gets the installed conformance package version by running 'conformance --version'.
+    /// Returns null if the version cannot be determined.
+    /// </summary>
+    public static Version? GetConformanceVersion()
+    {
+        if (!IsNodeInstalled())
+        {
+            return null;
+        }
+
+        try
+        {
+            EnsureNpmDependenciesInstalled();
+            var repoRoot = FindRepoRoot();
+            var binPath = Path.Combine(repoRoot, "node_modules", ".bin", "conformance");
+
+            ProcessStartInfo startInfo;
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                startInfo = new ProcessStartInfo
+                {
+                    FileName = $"{binPath}.cmd",
+                    Arguments = "--version",
+                    RedirectStandardOutput = true,
+                    RedirectStandardError = true,
+                    UseShellExecute = false,
+                    CreateNoWindow = true
+                };
+            }
+            else
+            {
+                startInfo = new ProcessStartInfo
+                {
+                    FileName = binPath,
+                    Arguments = "--version",
+                    RedirectStandardOutput = true,
+                    RedirectStandardError = true,
+                    UseShellExecute = false,
+                    CreateNoWindow = true
+                };
+            }
+
+            using var process = Process.Start(startInfo);
+            if (process == null)
+            {
+                return null;
+            }
+
+            var output = process.StandardOutput.ReadToEnd().Trim();
+            process.WaitForExit(10_000);
+
+            if (process.ExitCode == 0 && Version.TryParse(output, out var version))
+            {
+                return version;
+            }
+
+            return null;
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    /// <summary>
+    /// Checks if the installed conformance package version is at least the specified minimum.
+    /// </summary>
+    public static bool IsConformanceVersionAtLeast(string minimumVersion)
+    {
+        var installed = GetConformanceVersion();
+        return installed != null
+            && Version.TryParse(minimumVersion, out var min)
+            && installed >= min;
+    }
+
     /// <summary>
     /// Checks if Node.js is installed and available on the system.
     /// </summary>

tests/ModelContextProtocol.AspNetCore.Tests/ClientConformanceTests.cs

@@ -17,6 +17,9 @@ public class ClientConformanceTests
     // Public static property required for SkipUnless attribute
     public static bool IsNodeInstalled => NodeHelpers.IsNodeInstalled();
 
+    // SEP-2243 scenarios require conformance package >= 0.1.16
+    public static bool HasSep2243Scenarios => NodeHelpers.IsConformanceVersionAtLeast("0.1.16");
+
     public ClientConformanceTests(ITestOutputHelper output)
     {
         _output = output;
@@ -51,12 +54,22 @@ public ClientConformanceTests(ITestOutputHelper output)
     // [InlineData("auth/client-credentials-jwt")]
     // [InlineData("auth/client-credentials-basic")]
 
-    // HTTP Standardization (SEP-2243)
+    public async Task RunConformanceTest(string scenario)
+    {
+        // Run the conformance test suite
+        var result = await RunClientConformanceScenario(scenario);
+
+        // Report the results
+        Assert.True(result.Success,
+            $"Conformance test failed.\n\nStdout:\n{result.Output}\n\nStderr:\n{result.Error}");
+    }
+
+    // HTTP Standardization (SEP-2243) — requires conformance package >= 0.1.16
+    [Theory(Skip = "Conformance package >= 0.1.16 not available.", SkipUnless = nameof(HasSep2243Scenarios))]
     [InlineData("http-standard-headers")]
     [InlineData("http-custom-headers")]
     [InlineData("http-invalid-tool-headers")]
-
-    public async Task RunConformanceTest(string scenario)
+    public async Task RunConformanceTest_Sep2243(string scenario)
     {
         // Run the conformance test suite
         var result = await RunClientConformanceScenario(scenario);

tests/ModelContextProtocol.AspNetCore.Tests/ServerConformanceTests.cs

@@ -131,6 +131,7 @@ public async Task RunPendingConformanceTest_ServerSsePolling()
     public async Task RunConformanceTest_HttpHeaderValidation()
     {
         Assert.SkipWhen(!NodeHelpers.IsNodeInstalled(), "Node.js is not installed. Skipping conformance tests.");
+        Assert.SkipWhen(!NodeHelpers.IsConformanceVersionAtLeast("0.1.16"), "Conformance package >= 0.1.16 not available.");
 
         var result = await RunConformanceTestsAsync($"server --url {fixture.ServerUrl} --scenario http-header-validation");
 
@@ -142,6 +143,7 @@ public async Task RunConformanceTest_HttpHeaderValidation()
     public async Task RunConformanceTest_HttpCustomHeaderServerValidation()
     {
         Assert.SkipWhen(!NodeHelpers.IsNodeInstalled(), "Node.js is not installed. Skipping conformance tests.");
+        Assert.SkipWhen(!NodeHelpers.IsConformanceVersionAtLeast("0.1.16"), "Conformance package >= 0.1.16 not available.");
 
         var result = await RunConformanceTestsAsync($"server --url {fixture.ServerUrl} --scenario http-custom-header-server-validation");