updateThumbnails example

        $criteria = new Criteria();
        $criteria->addAssociation('mediaFolder.configuration.mediaThumbnailSizes');
        $criteria->addFilter(new EqualsAnyFilter('media.id', $msg->getMediaIds()));

        /** @var MediaCollection $entities */
        $entities = $this->mediaRepository->search($criteria, $context)->getEntities();

        if ($msg instanceof UpdateThumbnailsMessage) {
            foreach ($entities as $media) {
                $this->thumbnailService->updateThumbnails($media, $context, $msg->isStrict());
            }
        } else {
            $this->thumbnailService->generate($entities, $context);
        }
    }
}

public function testThumbnailGeneration(): void
    {
        $this->setFixtureContext($this->context);
        $media = $this->getPngWithFolder();

        $filePath = $this->urlGenerator->getRelativeMediaUrl($media);
        $resource = fopen(__DIR__ . '/../fixtures/shopware-logo.png', 'rb');

        \assert($resource !== false);
        $this->getPublicFilesystem()->writeStream($filePath, $resource);

        $this->thumbnailService->updateThumbnails(
            $media,
            $this->context,
            false
        );

        $this->runWorker();

        $searchCriteria = new Criteria();
        $searchCriteria->setLimit(1);
        $searchCriteria->addFilter(new EqualsFilter('media.id', $media->getId()));
        $searchCriteria->addAssociation('mediaFolder.configuration.mediaThumbnailSizes');

        

    private function generateThumbnails(RepositoryIterator $iterator, Context $context): array
    {
        $generated = 0;
        $skipped = 0;
        $errored = 0;
        $errors = [];

        while (($result = $iterator->fetch()) !== null) {
            foreach ($result->getEntities() as $media) {
                try {
                    if ($this->thumbnailService->updateThumbnails($media, $context, $this->isStrict) > 0) {
                        ++$generated;
                    } else {
                        ++$skipped;
                    }
                } catch (\Throwable $e) {
                    ++$errored;
                    $errors[] = [sprintf('Cannot process file %s (id: %s) due error: %s', $media->getFileName(), $media->getId(), $e->getMessage())];
                }
            }
            $this->io->progressAdvance($result->count());
        }