phpbb_functional_test_case::assert_response_xml PHP Method

    public static function assert_response_xml($status_code = 200)
    {
        if ($status_code !== false) {
            self::assert_response_status_code($status_code);
        }
        // Any output before the xml opening means there was an error
        $content = self::$client->getResponse()->getContent();
        self::assertNotContains('[phpBB Debug]', $content);
        self::assertStringStartsWith('<?xml', trim($content), 'Output found before XML specification.');
    }