diff --git a/phpBB/includes/functions_install.php b/phpBB/includes/functions_install.php
index 1b63414cec..4ed44da0b1 100644
--- a/phpBB/includes/functions_install.php
+++ b/phpBB/includes/functions_install.php
@@ -472,6 +472,7 @@ function phpbb_create_config_file_data($data, $dbms, $debug = false, $debug_cont
 	if ($debug_test)
 	{
 		$config_data .= "@define('DEBUG_TEST', true);\n";
+		$config_data .= "@define('DEBUG', true);\n"; // Mandatory for the functional tests, will be removed by PHPBB3-12623
 	}
 
 	return $config_data;
diff --git a/phpBB/install/index.php b/phpBB/install/index.php
index 3dd73adc60..00a35b4690 100644
--- a/phpBB/install/index.php
+++ b/phpBB/install/index.php
@@ -16,6 +16,7 @@
 */
 define('IN_PHPBB', true);
 define('IN_INSTALL', true);
+define('ENVIRONMENT', 'productive');
 /**#@-*/
 
 $phpbb_root_path = (defined('PHPBB_ROOT_PATH')) ? PHPBB_ROOT_PATH : './../';