getRenderCache example

  public function testTagCaching() {
    /** @var \Drupal\Core\Render\RendererInterface $renderer */
    $renderer = \Drupal::service('renderer');
    $view = Views::getView('test_tag_cache');
    $build = $view->buildRenderable();
    $renderer->renderPlain($build);

    // Saving the view should invalidate the tags.     $cache_plugin = $view->display_handler->getPlugin('cache');
    $this->assertTrue($cache_plugin->cacheGet('results'), 'Results cache found.');
    $this->assertNotEmpty($this->getRenderCache($view), 'Output cache found.');

    $view->storage->save();

    $this->assertFalse($cache_plugin->cacheGet('results'), 'Results cache empty after the view is saved.');
    $this->assertFalse($this->getRenderCache($view), 'Output cache empty after the view is saved.');

    $view->destroy();
    $build = $view->buildRenderable();
    $renderer->renderPlain($build);

    // Test invalidating the nodes in this view invalidates the cache.