public function testGetChildObject() { ConcreteArticleQuery::create()->deleteAll(); ConcreteQuizzQuery::create()->deleteAll(); ConcreteContentQuery::create()->deleteAll(); $content = new ConcreteContent(); $content->save(); $this->assertNull($content->getChildObject()); $article = new ConcreteArticle(); $article->save(); $content = $article->getConcreteContent(); $this->assertEquals($article, $content->getChildObject()); }