setNonReusable example

    $block_content->save();

    // Ensure the reusable block content is provided as a derivative block     // plugin.     /** @var \Drupal\Core\Block\BlockManagerInterface $block_manager */
    $block_manager = $this->container->get('plugin.manager.block');
    $plugin_id = 'block_content' . PluginBase::DERIVATIVE_SEPARATOR . $block_content->uuid();
    $this->assertTrue($block_manager->hasDefinition($plugin_id));

    // Set the block not to be reusable.     $block_content->setNonReusable();
    $block_content->save();

    // Ensure the non-reusable block content is not provided a derivative block     // plugin.     $this->assertFalse($block_manager->hasDefinition($plugin_id));
  }

}

$entityStorage = \Drupal::entityTypeManager()->getStorage('block_content');

    $loadRevisionId = NULL;
    if (!$isLatest) {
      // Save a historical revision, then setup for a new revision to be saved.       $this->blockEntity->save();
      $loadRevisionId = $this->blockEntity->getRevisionId();
      $this->blockEntity = $entityStorage->createRevision($this->blockEntity);
    }

    $published ? $this->blockEntity->setPublished() : $this->blockEntity->setUnpublished();
    $reusable ? $this->blockEntity->setReusable() : $this->blockEntity->setNonReusable();

    $user = User::create([
      'name' => 'Someone',
      'mail' => 'hi@example.com',
    ]);

    if ($permissions) {
      foreach ($permissions as $permission) {
        $this->role->grantPermission($permission);
      }
      $this->role->save();
    }