/**
  * {@inheritdoc}
  */
 public function save(File $file, Adapter $adapter)
 {
     $datetime = $file->getLastModification();
     if (null !== $datetime) {
         $adapter->writeLastModification($file->getName(), $datetime->format('U'));
     }
     return $this;
 }
 function let(KnowsLastModification $adapter, Adapter $other, File $file)
 {
     $date = new \DateTime('2015-01-01', new \DateTimeZone("Europe/Paris"));
     $adapter->implement('Gaufrette\\Core\\Adapter');
     $adapter->readLastModification('file.png')->willReturn(1234566000);
     $file->getName()->willReturn('file.png');
     $file->getLastModification()->willReturn($date);
 }