/**
  * @param Category $category
  */
 public function addReportMetrics(Category $category)
 {
     if (!isset($this->reportMetrics[$category->getName()])) {
         $this->reportMetrics[$category->getName()] = ['valid' => 0, 'invalid' => 0];
     }
     $currentReport =& $this->reportMetrics[$category->getName()];
     foreach ($category->getQuestions() as $question) {
         if ($question->isValid()) {
             $currentReport['valid']++;
         } else {
             $currentReport['invalid']++;
         }
     }
 }