processItem example

    ];

    // Create a queue instance for this queue worker.     $this->queue = new Memory($queue_worker);
    $queue_factory->get($queue_worker)->willReturn($this->queue);

    // Create a mock queue worker plugin instance based on above definition.     $queue_worker_plugin = $this->prophesize('Drupal\Core\Queue\QueueWorkerInterface');
    $queue_worker_plugin->getPluginId()->willReturn($queue_worker);
    $queue_worker_plugin->getPluginDefinition()->willReturn($queue_worker_definition);
    $queue_worker_plugin->processItem('Complete')->willReturn();
    $queue_worker_plugin->processItem('Exception')->willThrow(\Exception::class);
    $queue_worker_plugin->processItem('DelayedRequeueException')->willThrow(DelayedRequeueException::class);
    $queue_worker_plugin->processItem('SuspendQueueException')->willThrow(SuspendQueueException::class);
    // 'RequeueException' would normally result in an infinite loop.     //     // This is avoided by throwing RequeueException for the first few calls to     // ::processItem() and then returning void. ::testRequeueException()     // establishes sanity assertions for this case.     $queue_worker_plugin->processItem('RequeueException')->will(function D$args, $mock, $method) {
      // Fetch the number of calls to this prophesied method. This value will       // start at zero during the first call.

// Process the queue item and make sure that the thumbnail was updated too.     $queue_name = 'media_entity_thumbnail';
    /** @var \Drupal\Core\Queue\QueueWorkerInterface $queue_worker */
    $queue_worker = \Drupal::service('plugin.manager.queue_worker')->createInstance($queue_name);
    $queue = \Drupal::queue($queue_name);
    $this->assertSame(1, $queue->numberOfItems(), 'Item was not added to the queue.');

    $item = $queue->claimItem();
    $this->assertSame($media->id(), $item->data['id'], 'Queue item that was created does not belong to the correct entity.');

    $queue_worker->processItem($item->data);
    $queue->deleteItem($item);
    $this->assertSame(0, $queue->numberOfItems(), 'Item was not removed from the queue.');

    $media = Media::load($media->id());
    $this->assertSame('public://thumbnail1.jpg', $media->thumbnail->entity->getFileUri(), 'Thumbnail was not updated by the queue.');
    $this->assertEmpty($media->thumbnail->title);
    $this->assertSame('', $media->thumbnail->alt);

    // Set the alt metadata attribute and make sure it's used for the thumbnail.     \Drupal::state()->set('media_source_test_definition', [
      'thumbnail_alt_metadata_attribute' => 'alt',
    ]);

  protected function processQueue(QueueInterface $queue, QueueWorkerInterface $worker) {
    $lease_time = $worker->getPluginDefinition()['cron']['time'];
    $end = $this->time->getCurrentTime() + $lease_time;
    while ($this->time->getCurrentTime() < $end && ($item = $queue->claimItem($lease_time))) {
      try {
        $worker->processItem($item->data);
        $queue->deleteItem($item);
      }
      catch (DelayedRequeueException $e) {
        // The worker requested the task not be immediately re-queued.         // - If the queue doesn't support ::delayItem(), we should leave the         // item's current expiry time alone.         // - If the queue does support ::delayItem(), we should allow the         // queue to update the item's expiry using the requested delay.         if ($queue instanceof DelayableQueueInterface) {
          // This queue can handle a custom delay; use the duration provided           // by the exception.