/**
  * constructs tutor management and configure it according to parameters,
  * invoking parent constructor
  *
  * @param string $what 'test' or 'survey' string
  * @param Course $courseObj course object reference
  * @param Course_instance $course_instanceObj course instance object reference
  * @param int $id_student id student
  * @param int $id_test id test
  * @param int $id_history_test id history test
  */
 public function __construct($what, $courseObj, $course_instanceObj, $id_student = null, $id_test = null, $id_history_test = null)
 {
     parent::__construct($what, $courseObj, $course_instanceObj, $id_student, $id_test, $id_history_test);
     $this->id_student = $id_student;
 }