fix tests

Author: dotmarn

src/Server/Transport/StreamableHttpTransport.php

@@ -124,7 +124,7 @@ protected function createJsonResponse(): ResponseInterface
         }
 
         $messages = array_column($outgoingMessages, 'message');
-        $responseBody = 1 === \count($messages) ? $messages[0] : '[' . implode(',', $messages) . ']';
+        $responseBody = 1 === \count($messages) ? $messages[0] : '['.implode(',', $messages).']';
 
         $response = $this->responseFactory->createResponse(200)
             ->withHeader('Content-Type', 'application/json')
@@ -242,7 +242,7 @@ protected function createErrorResponse(Error $jsonRpcError, int $statusCode): Re
             ->withHeader('Content-Type', 'application/json')
             ->withBody($this->streamFactory->createStream($payload));
 
-        if (405 === $statusCode) {
+        if ($statusCode === 405) {
             $response = $response->withHeader('Allow', 'POST, DELETE, OPTIONS');
         }