diff --git a/tests/locallib_test.php b/tests/locallib_test.php
index 0205c47..7486c21 100644
--- a/tests/locallib_test.php
+++ b/tests/locallib_test.php
@@ -83,6 +83,11 @@ class locallib_test extends \advanced_testcase {
     public $assign;
     private int $courseid;
 
+    /**
+     * @var int the id of the generated course
+     */
+    private int $courseid;
+
     /**
      * Extract and install the mbz backup of a course
      * containing assignments using the advanced grading