public function assertArticle(Article $article, $hash, $title, $author, $publicationDate, $content)
 {
     $this->assertEquals($article->getHash(), $hash);
     $this->assertEquals($article->getTitle(), $title);
     $this->assertEquals($article->getAuthor(), $author);
     $this->assertEquals($article->getPublicationDate(), $publicationDate);
     $this->assertEquals($article->getContent(), $content);
 }
 public function add(Article $article)
 {
     $this->list[] = $article;
     $this->articleByHash[$article->getHash()] = $article;
 }