TestController.php

<?php

declare (strict_types=1);
namespace Drupal\package_manager_test_release_history;

use Drupal\Core\Controller\ControllerBase;
use Symfony\Component\HttpFoundation\BinaryFileResponse;
use Symfony\Component\HttpFoundation\Response;
class TestController extends ControllerBase {
    
    /**
     * Page callback: Prints mock XML for the Update Manager module.
     *
     * @todo This is a wholesale copy of
     *   \Drupal\update_test\Controller\UpdateTestController::updateTest() for
     *   testing package_manager. This was done in order to use a different
     *   directory of mock XML files. Remove this module in
     *   https://drupal.org/i/3274826.
     */
    public function metadata($project_name = 'drupal', $version = NULL) : Response {
        $xml_map = $this->config('update_test.settings')
            ->get('xml_map');
        if (isset($xml_map[$project_name])) {
            $file = $xml_map[$project_name];
        }
        elseif (isset($xml_map['#all'])) {
            $file = $xml_map['#all'];
        }
        else {
            // The test didn't specify, for example, the webroot has other modules and
            // themes installed but they're disabled by the version of the site
            // running the test. So, we default to a file we know won't exist, so at
            // least we'll get an empty xml response instead of a bunch of Drupal page
            // output.
            $file = '#broken#';
        }
        $headers = [
            'Content-Type' => 'text/xml; charset=utf-8',
        ];
        if (!is_file($file)) {
            // Return an empty response.
            return new Response('', 200, $headers);
        }
        return new BinaryFileResponse($file, 200, $headers);
    }

}