diff --git a/tests/unit/classes/frontendfile/FrontEndFileHandlerTest.php b/tests/unit/classes/frontendfile/FrontEndFileHandlerTest.php
index f85b1dabc..541f50887 100644
--- a/tests/unit/classes/frontendfile/FrontEndFileHandlerTest.php
+++ b/tests/unit/classes/frontendfile/FrontEndFileHandlerTest.php
@@ -13,6 +13,8 @@ class FrontEndFileHandlerTest extends \Codeception\TestCase\Test
 	public function testFrontEndFileHandler()
 	{
 		$handler = new FrontEndFileHandler();
+		HTMLDisplayHandler::$reservedCSS = '/xxx$/';
+		HTMLDisplayHandler::$reservedJS = '/xxx$/';
 		$db_info = Context::getDBInfo() ?: new stdClass;
 		$db_info->minify_scripts = 'N';
 		Context::setDBInfo($db_info);