Ability to set custom protocol version (#117)

tests/Unit/Server/Handler/Request/InitializeHandlerTest.php

@@ -0,0 +1,76 @@
+<?php
+
+/*
+ * This file is part of the official PHP MCP SDK.
+ *
+ * A collaboration between Symfony and the PHP Foundation.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Mcp\Tests\Unit\Server\Handler\Request;
+
+use Mcp\Schema\Enum\ProtocolVersion;
+use Mcp\Schema\Implementation;
+use Mcp\Schema\JsonRpc\MessageInterface;
+use Mcp\Schema\Request\InitializeRequest;
+use Mcp\Schema\Result\InitializeResult;
+use Mcp\Schema\ServerCapabilities;
+use Mcp\Server\Configuration;
+use Mcp\Server\Handler\Request\InitializeHandler;
+use Mcp\Server\Session\SessionInterface;
+use PHPUnit\Framework\Attributes\TestDox;
+use PHPUnit\Framework\TestCase;
+
+class InitializeHandlerTest extends TestCase
+{
+    #[TestDox('uses configuration protocol version when provided')]
+    public function testHandleUsesConfigurationProtocolVersion(): void
+    {
+        $customProtocolVersion = ProtocolVersion::V2024_11_05;
+
+        $configuration = new Configuration(
+            serverInfo: new Implementation('server', '1.2.3'),
+            capabilities: new ServerCapabilities(),
+            protocolVersion: $customProtocolVersion,
+        );
+
+        $handler = new InitializeHandler($configuration);
+
+        $session = $this->createMock(SessionInterface::class);
+        $session->expects($this->once())
+            ->method('set')
+            ->with('client_info', [
+                'name' => 'client-app',
+                'version' => '1.0.0',
+            ]);
+
+        $request = InitializeRequest::fromArray([
+            'jsonrpc' => MessageInterface::JSONRPC_VERSION,
+            'id' => 'request-1',
+            'method' => InitializeRequest::getMethod(),
+            'params' => [
+                'protocolVersion' => ProtocolVersion::V2024_11_05->value,
+                'capabilities' => [],
+                'clientInfo' => [
+                    'name' => 'client-app',
+                    'version' => '1.0.0',
+                ],
+            ],
+        ]);
+
+        $response = $handler->handle($request, $session);
+
+        $this->assertInstanceOf(InitializeResult::class, $response->result);
+
+        /** @var InitializeResult $result */
+        $result = $response->result;
+
+        $this->assertSame($customProtocolVersion, $result->protocolVersion);
+        $this->assertSame(
+            $customProtocolVersion->value,
+            $result->jsonSerialize()['protocolVersion']
+        );
+    }
+}