TestServiceProvider.php

<?php

namespace Drupal\KernelTests;

use Drupal\Core\DependencyInjection\ContainerBuilder;
use Drupal\Core\DependencyInjection\ServiceModifierInterface;
use Drupal\Core\DependencyInjection\ServiceProviderInterface;
use Symfony\Component\DependencyInjection\Definition;

/**
 * Provides special routing services for tests.
 */
class TestServiceProvider implements ServiceProviderInterface, ServiceModifierInterface {
    
    /**
     * @var \Drupal\simpletest\TestBase
     */
    public static $currentTest;
    
    /**
     * {@inheritdoc}
     */
    public function register(ContainerBuilder $container) {
        if (static::$currentTest && method_exists(static::$currentTest, 'containerBuild')) {
            static::$currentTest->containerBuild($container);
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function alter(ContainerBuilder $container) {
        if (static::$currentTest instanceof KernelTestBase) {
            static::addRouteProvider($container);
        }
    }
    
    /**
     * Add the on demand rebuild route provider service.
     *
     * @param \Drupal\Core\DependencyInjection\ContainerBuilder $container
     */
    public static function addRouteProvider(ContainerBuilder $container) {
        $route_provider_service_name = 'router.route_provider';
        // While $container->get() does a recursive resolve, getDefinition() does
        // not, so do it ourselves.
        $id = $route_provider_service_name;
        while ($container->hasAlias($id)) {
            $id = (string) $container->getAlias($id);
        }
        $definition = $container->getDefinition($id);
        $definition->clearTag('needs_destruction');
        $container->setDefinition("simpletest.{$route_provider_service_name}", $definition);
        $container->setDefinition($id, new Definition(RouteProvider::class));
    }

}