private function assertThatItsClear($reference = 'phpcr')
 {
     if ('phpcr' === $reference) {
         $this->documentManager->expects($this->once())->method('clear');
     } elseif ('dbal-orm' === $reference) {
         $this->objectManager->expects($this->once())->method('clear');
     }
     $this->UoW->clear();
     $this->assertCount(0, $this->UoW->getScheduledReferencesForUpdate());
     $this->assertCount(0, $this->UoW->getScheduledReferencesForRemove());
     $this->assertCount(0, $this->UoW->getScheduledReferencesForInsert());
     $this->assertCount(0, $this->UoW->getScheduledReferencesByManager());
 }