diff --git a/classes/structure.php b/classes/structure.php
index 022bda6..d45b58f 100644
--- a/classes/structure.php
+++ b/classes/structure.php
@@ -42,6 +42,9 @@ class mod_attendance_structure {
     /** @var stdclass course module record */
     public $cm;
 
+    /** @var int cmid - needed for calendar internal tests (see Issue #473) */
+    public $cmid;
+
     /** @var stdclass course record */
     public $course;
 
@@ -125,6 +128,9 @@ class mod_attendance_structure {
             }
         }
         $this->cm           = $cm;
+        if (empty($this->cmid)) {
+            $this->cmid = $cm->id;
+        }
         $this->course       = $course;
         if (is_null($context)) {
             $this->context = context_module::instance($this->cm->id);
diff --git a/tests/generator/lib.php b/tests/generator/lib.php
index 858759e..674753d 100644
--- a/tests/generator/lib.php
+++ b/tests/generator/lib.php
@@ -65,7 +65,7 @@ class mod_attendance_generator extends testing_module_generator {
         $att = parent::create_instance($record, (array)$options);
         $cm = $DB->get_record('course_modules', array('id' => $att->cmid), '*', MUST_EXIST);
         $course = $DB->get_record('course', array('id' => $cm->course), '*', MUST_EXIST);
-        unset($att->cmid);
+
         return new mod_attendance_structure($att, $cm, $course);
     }
 }