ViewRenderTest.php

<?php

namespace Drupal\Tests\views\Kernel;

use Drupal\views\Views;

/**
 * Tests general rendering of a view.
 *
 * @group views
 */
class ViewRenderTest extends ViewsKernelTestBase {
    
    /**
     * {@inheritdoc}
     */
    public static $testViews = [
        'test_view_render',
    ];
    
    /**
     * Tests render functionality.
     */
    public function testRender() {
        $state = $this->container
            ->get('state');
        $state->set('views_render.test', 0);
        // Make sure that the rendering just calls the preprocess function once.
        $view = Views::getView('test_view_render');
        $output = $view->preview();
        $this->container
            ->get('renderer')
            ->renderRoot($output);
        $this->assertEquals(1, $state->get('views_render.test'));
    }

}