diff --git a/lib/classes/component.php b/lib/classes/component.php
index c0eba687b43..98b59625026 100644
--- a/lib/classes/component.php
+++ b/lib/classes/component.php
@@ -155,7 +155,7 @@ class core_component {
             return;
         }
 
-        if (PHPUNIT_TEST) {
+        if (defined('PHPUNIT_TEST') && PHPUNIT_TEST) {
             // For unit tests we support classes in `\frankenstyle_component\tests\` to be loaded from
             // `path/to/frankenstyle/component/tests/classes` directory.
             // Note: We do *not* support the legacy `\frankenstyle_component_tests_style_classnames`.