scripts: add conformance test runner (#694)

Add a script to run the official MCP conformance tests against the SDK's
conformance server. The script supports saving results to a custom
directory (--result_dir) and running against a local checkout of the
conformance repo (--conformance_repo).

Document the script in CONTRIBUTING.md.

For #650

scripts/conformance.sh

@@ -0,0 +1,111 @@
+#!/bin/bash
+# Copyright 2025 The Go MCP SDK Authors. All rights reserved.
+# Use of this source code is governed by an MIT-style
+# license that can be found in the LICENSE file.
+
+# Run MCP conformance tests against the Go SDK conformance server.
+
+set -e
+
+PORT="${PORT:-3000}"
+SERVER_PID=""
+RESULT_DIR=""
+WORKDIR=""
+CONFORMANCE_REPO=""
+
+usage() {
+    echo "Usage: $0 [options]"
+    echo ""
+    echo "Run MCP conformance tests against the Go SDK conformance server."
+    echo ""
+    echo "Options:"
+    echo "  --result_dir <dir>       Save results to the specified directory"
+    echo "  --conformance_repo <dir> Run conformance tests from a local checkout"
+    echo "                           instead of using the latest npm release"
+    echo "  --help                   Show this help message"
+}
+
+# Parse arguments.
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        --result_dir)
+            RESULT_DIR="$2"
+            shift 2
+            ;;
+        --conformance_repo)
+            CONFORMANCE_REPO="$2"
+            shift 2
+            ;;
+        --help)
+            usage
+            exit 0
+            ;;
+        *)
+            echo "Unknown option: $1"
+            usage
+            exit 1
+            ;;
+    esac
+done
+
+cleanup() {
+    if [ -n "$SERVER_PID" ]; then
+        kill "$SERVER_PID" 2>/dev/null || true
+    fi
+    # Clean up the work directory unless --result_dir was specified.
+    if [ -z "$RESULT_DIR" ] && [ -n "$WORKDIR" ]; then
+        rm -rf "$WORKDIR"
+    fi
+}
+trap cleanup EXIT
+
+# Set up the work directory.
+if [ -n "$RESULT_DIR" ]; then
+    mkdir -p "$RESULT_DIR"
+    WORKDIR="$RESULT_DIR"
+else
+    WORKDIR=$(mktemp -d)
+fi
+
+# Build the conformance server.
+go build -o "$WORKDIR/conformance-server" ./examples/server/conformance
+
+# Start the server in the background
+echo "Starting conformance server on port $PORT..."
+"$WORKDIR/conformance-server" -http=":$PORT" &
+SERVER_PID=$!
+
+echo "Server pid is $SERVER_PID"
+
+# Wait for server to be ready
+echo "Waiting for server to be ready..."
+for i in {1..30}; do
+    if curl -s "http://localhost:$PORT" > /dev/null 2>&1; then
+        echo "Server is ready."
+        break
+    fi
+    if [ "$i" -eq 30 ]; then
+        echo "Server failed to start within 15 seconds."
+        exit 1
+    fi
+    sleep 0.5
+done
+
+# Run conformance tests from the work directory to avoid writing results to the repo.
+echo "Running conformance tests..."
+if [ -n "$CONFORMANCE_REPO" ]; then
+    # Run from local checkout using npm run start.
+    (cd "$WORKDIR" && \
+        npm --prefix "$CONFORMANCE_REPO" run start -- \
+            server --url "http://localhost:$PORT")
+else
+    (cd "$WORKDIR" && \
+        npx @modelcontextprotocol/conformance@latest server --url "http://localhost:$PORT")
+fi
+
+echo ""
+if [ -n "$RESULT_DIR" ]; then
+    echo "See $RESULT_DIR for details."
+else
+    echo "Run with --result_dir to save results."
+fi