Use package-lock.json to pin conformance test dependencies (#1247)

tests/Common/Utils/NodeHelpers.cs

@@ -8,20 +8,88 @@ namespace ModelContextProtocol.Tests.Utils;
 /// </summary>
 public static class NodeHelpers
 {
+    private static readonly object _npmInstallLock = new();
+    private static bool _npmInstallCompleted;
+
     /// <summary>
-    /// Creates a ProcessStartInfo configured to run npx with the specified arguments.
+    /// Finds the repository root by searching for package-lock.json in ancestor directories.
     /// </summary>
-    /// <param name="arguments">The arguments to pass to npx.</param>
-    /// <returns>A configured ProcessStartInfo for running npx.</returns>
-    public static ProcessStartInfo NpxStartInfo(string arguments)
+    private static string FindRepoRoot()
     {
+        var dir = AppContext.BaseDirectory;
+        while (dir is not null)
+        {
+            if (File.Exists(Path.Combine(dir, "package-lock.json")))
+            {
+                return dir;
+            }
+            dir = Path.GetDirectoryName(dir);
+        }
+
+        throw new InvalidOperationException("Could not find repository root (no package-lock.json found in ancestor directories).");
+    }
+
+    /// <summary>
+    /// Ensures npm dependencies are installed by running 'npm ci' from the repo root.
+    /// This is safe to call multiple times; it only runs once per test process.
+    /// </summary>
+    public static void EnsureNpmDependenciesInstalled()
+    {
+        if (_npmInstallCompleted)
+        {
+            return;
+        }
+
+        lock (_npmInstallLock)
+        {
+            if (_npmInstallCompleted)
+            {
+                return;
+            }
+
+            var repoRoot = FindRepoRoot();
+            var nodeModulesPath = Path.Combine(repoRoot, "node_modules");
+
+            // Use 'npm ci' if node_modules doesn't exist, otherwise assume it's up to date.
+            if (!Directory.Exists(nodeModulesPath))
+            {
+                var startInfo = NpmStartInfo("ci", repoRoot);
+                using var process = Process.Start(startInfo)
+                    ?? throw new InvalidOperationException("Failed to start 'npm ci'.");
+                process.WaitForExit(120_000);
+
+                if (process.ExitCode != 0)
+                {
+                    var error = process.StandardError.ReadToEnd();
+                    throw new InvalidOperationException($"'npm ci' failed with exit code {process.ExitCode}: {error}");
+                }
+            }
+
+            _npmInstallCompleted = true;
+        }
+    }
+
+    /// <summary>
+    /// Creates a ProcessStartInfo configured to run a binary from node_modules/.bin/conformance.
+    /// Calls <see cref="EnsureNpmDependenciesInstalled"/> first.
+    /// </summary>
+    /// <param name="binaryName">The name of the binary in node_modules/.bin (e.g. "conformance").</param>
+    /// <param name="arguments">The arguments to pass to the binary.</param>
+    /// <returns>A configured ProcessStartInfo for running the binary.</returns>
+    public static ProcessStartInfo ConformanceTestStartInfo(string arguments)
+    {
+        EnsureNpmDependenciesInstalled();
+
+        var repoRoot = FindRepoRoot();
+        var binPath = Path.Combine(repoRoot, "node_modules", ".bin", "conformance");
+
         if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
         {
-            // On Windows, npx is a PowerShell script, so we need to use cmd.exe to invoke it
+            // On Windows, node_modules/.bin contains .cmd shims that can be executed directly
             return new ProcessStartInfo
             {
-                FileName = "cmd.exe",
-                Arguments = $"/c npx {arguments}",
+                FileName = $"{binPath}.cmd",
+                Arguments = arguments,
                 RedirectStandardOutput = true,
                 RedirectStandardError = true,
                 UseShellExecute = false,
@@ -30,10 +98,9 @@ public static class NodeHelpers
         }
         else
         {
-            // On Unix-like systems, npx is typically a shell script that can be executed directly
             return new ProcessStartInfo
             {
-                FileName = "npx",
+                FileName = binPath,
                 Arguments = arguments,
                 RedirectStandardOutput = true,
                 RedirectStandardError = true,
@@ -44,16 +111,22 @@ public static class NodeHelpers
     }
 
     /// <summary>
-    /// Checks if Node.js and npx are installed and available on the system.
+    /// Checks if Node.js is installed and available on the system.
     /// </summary>
-    /// <returns>True if npx is available, false otherwise.</returns>
-    public static bool IsNpxInstalled()
+    public static bool IsNodeInstalled()
     {
         try
         {
-            var startInfo = NpxStartInfo("--version");
+            using var process = Process.Start(new ProcessStartInfo
+            {
+                FileName = "node",
+                Arguments = "--version",
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false,
+                CreateNoWindow = true
+            });
 
-            using var process = Process.Start(startInfo);
             if (process == null)
             {
                 return false;
@@ -67,4 +140,34 @@ public static class NodeHelpers
             return false;
         }
     }
+
+    private static ProcessStartInfo NpmStartInfo(string arguments, string workingDirectory)
+    {
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        {
+            return new ProcessStartInfo
+            {
+                FileName = "cmd.exe",
+                Arguments = $"/c npm {arguments}",
+                WorkingDirectory = workingDirectory,
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false,
+                CreateNoWindow = true
+            };
+        }
+        else
+        {
+            return new ProcessStartInfo
+            {
+                FileName = "npm",
+                Arguments = arguments,
+                WorkingDirectory = workingDirectory,
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false,
+                CreateNoWindow = true
+            };
+        }
+    }
 }