Ouzo\Model::getRelation PHP Method

    public function getRelation($name)
    {
        return $this->_modelDefinition->relations->getRelation($name);
    }

 /**
  * @test
  */
 public function shouldThrowExceptionIfNoRelation()
 {
     $model = new Model(array('fields' => array('field1')));
     //when
     try {
         $model->getRelation('invalid');
         $this->fail();
     } catch (InvalidArgumentException $e) {
     }
 }