private function addAssignment(ilTestSkillQuestionAssignment $assignment)
 {
     if (!isset($this->assignments[$assignment->getQuestionId()])) {
         $this->assignments[$assignment->getQuestionId()] = array();
     }
     $this->assignments[$assignment->getQuestionId()][] = $assignment;
 }
 private function buildQuantifierInput(ilTestSkillQuestionAssignment $assignment)
 {
     $assignmentKey = implode(':', array($assignment->getSkillBaseId(), $assignment->getSkillTrefId(), $assignment->getQuestionId()));
     return "<input type\"text\" size=\"2\" name=\"quantifiers[{$assignmentKey}]\" value=\"{$assignment->getSkillPoints()}\" />";
 }