Issue #3553664 by phenaproxima, alexpott, nicxvan: BootableCommandTrait...

    $kernel->setSitePath($this->getSitePath());

    Settings::initialize($kernel->getAppRoot(), $kernel->getSitePath(), $this->classLoader);

    $kernel->boot();

    $request = Request::createFromGlobals();

    // The request needs to be created with a URL that, even if not actually

    // reachable, at least has a valid *form*, so that Drupal can correctly

    // generate links and URLs.

    $request = Request::create('http://' . basename($kernel->getSitePath()) . '/core/scripts/drupal');

    $kernel->preHandle($request);

    // Try to register an event listener to properly terminate the Drupal kernel

<?php

declare(strict_types=1);

namespace Drupal\Tests\Core\Command;

use Composer\Autoload\ClassLoader;

use Drupal\Core\Command\BootableCommandTrait;

use Drupal\Core\Database\Database;

use Drupal\Tests\UnitTestCase;

use PHPUnit\Framework\Attributes\CoversTrait;

use PHPUnit\Framework\Attributes\Group;

use PHPUnit\Framework\Attributes\RequiresPhpExtension;

use Symfony\Component\Console\Application;

use Symfony\Component\Console\Command\Command;

use Symfony\Component\Console\Input\InputInterface;

use Symfony\Component\Console\Output\OutputInterface;

use Symfony\Component\Console\Tester\CommandTester;

/**

 * Tests the trait that helps console commands boot Drupal.

 */

#[Group('Command')]

#[CoversTrait(BootableCommandTrait::class)]

#[RequiresPhpExtension('pdo_sqlite')]

class BootableCommandTraitTest extends UnitTestCase {

  /**

   * The class loader, which is needed to boot Drupal.

   */

  private readonly object $classLoader;

  /**

   * A console application to manage the commands under test.

   */

  private readonly Application $application;

  /**

   * {@inheritdoc}

   */

  protected function setUp(): void {

    parent::setUp();

    // To boot Drupal, we need a database. For the purposes of this test, an

    // in-memory SQLite database is sufficient.

    Database::addConnectionInfo('default', 'default', [

      'driver' => 'sqlite',

      'namespace' => 'Drupal\\sqlite\\Driver\\Database\\sqlite',

      'autoload' => 'core/modules/sqlite/src/Driver/Database/sqlite/',

      'database' => ':memory:',

    ]);

    $class_loaders = ClassLoader::getRegisteredLoaders();

    $this->classLoader = reset($class_loaders);

    $this->application = new Application('drupal', \Drupal::VERSION);

  }

  /**

   * Tests that commands are initialized with a reasonable base URL.

   */

  public function testRequestUrlIsValid(): void {

    // Create a fake command that boots Drupal and outputs the base URL.

    $this->application->add(new class ($this->classLoader) extends Command {

      use BootableCommandTrait;

      public function __construct(object $classLoader) {

        parent::__construct('test');

        $this->classLoader = $classLoader;

      }

      /**

       * {@inheritdoc}

       */

      protected function execute(InputInterface $input, OutputInterface $output): int {

        $this->boot();

        $output->write($GLOBALS['base_url']);

        // Symfony Console apparently changes the error and exception handlers,

        // which will anger PHPUnit.

        restore_error_handler();

        restore_exception_handler();

        return 0;

      }

    });

    $tester = new CommandTester($this->application->find('test'));

    $tester->execute([]);

    $this->assertSame('http://default', $tester->getDisplay());

  }

}