/**
  * {@inheritdoc}
  */
 public function transform($collection)
 {
     // process any empty value (string, array)
     if (empty($collection)) {
         return array();
     }
     return parent::transform($collection);
 }
 public function testReverseTransformNull()
 {
     $this->assertEquals(new ArrayCollection(), $this->transformer->reverseTransform(null));
 }