ContainerTest.php

<?php

namespace Drupal\Tests\Core\DependencyInjection;

use Drupal\Core\DependencyInjection\Container;
use Drupal\Tests\UnitTestCase;

/**
 * @coversDefaultClass \Drupal\Core\DependencyInjection\Container
 * @group DependencyInjection
 */
class ContainerTest extends UnitTestCase {
    
    /**
     * Tests serialization.
     */
    public function testSerialize() {
        $container = new Container();
        $this->expectException(\AssertionError::class);
        serialize($container);
    }

}