test: #3397420 Add a way to capture mails sent through the mailer transport service during tests

<?php

declare(strict_types=1);

namespace Drupal\Core\Test;

use Symfony\Component\Mailer\SentMessage;

use Symfony\Component\Mime\Email;

use Symfony\Component\Mime\RawMessage;

/**

 * Provides methods for testing emails sent during test runs.

 *

 * @see \Drupal\mailer_capture\Transport\CaptureTransport

 */

trait MailerCaptureTrait {

  /**

   * Gets an array containing all emails sent during this test case.

   *

   * @return \Symfony\Component\Mime\Email[]

   *   An array containing email messages captured during the current test.

   */

  protected function getEmails(): array {

    $messages = array_map(fn (SentMessage $m) => $m->getOriginalMessage(), $this->getCapturedMessages());

    return array_filter($messages, fn (RawMessage $m) => $m instanceof Email);

  }

  /**

   * Gets an array containing all messages sent during this test case.

   *

   * @return \Symfony\Component\Mailer\SentMessage[]

   *   An array containing messages captured during the current test.

   */

  protected function getCapturedMessages(): array {

    return \Drupal::keyValue('mailer_capture')->get('messages', []);

  }

  /**

   * Clears all messages sent during this test case.

   */

  protected function clearCapturedMessages(): void {

    \Drupal::keyValue('mailer_capture')->delete('messages');

  }

}

name: 'Mailer capture'

type: module

description: 'Activates mailer transport capturing all mail in a key value store.'

package: Testing

version: VERSION

<?php

declare(strict_types=1);

namespace Drupal\mailer_capture;

use Drupal\Core\DependencyInjection\ContainerBuilder;

use Drupal\Core\DependencyInjection\ServiceModifierInterface;

use Drupal\Core\KeyValueStore\KeyValueFactoryInterface;

use Drupal\mailer_capture\Transport\CaptureTransport;

use Psr\EventDispatcher\EventDispatcherInterface;

use Symfony\Component\DependencyInjection\Definition;

use Symfony\Component\DependencyInjection\Reference;

use Symfony\Component\Mailer\Transport\TransportInterface;

/**

 * Enforce mailer transport which captures sent messages in a key value store.

 *

 * Enforces CaptureTransport as the mailer transport service implementation,

 * sidestepping mailer transport factory. As a result, the contents of the

 * system.mail mailer_dsn is irrelevant for transport service construction.

 */

class MailerCaptureServiceProvider implements ServiceModifierInterface {

  /**

   * {@inheritdoc}

   */

  public function alter(ContainerBuilder $container): void {

    $definition = new Definition(CaptureTransport::class, [

      new Reference(EventDispatcherInterface::class),

    ]);

    $definition->addMethodCall('setKeyValueFactory', [

      new Reference(KeyValueFactoryInterface::class),

    ]);

    $container->setDefinition(TransportInterface::class, $definition->setPublic(TRUE));

  }

}

<?php

declare(strict_types=1);

namespace Drupal\mailer_capture\Transport;

use Drupal\Core\KeyValueStore\KeyValueFactoryInterface;

use Symfony\Component\Mailer\SentMessage;

use Symfony\Component\Mailer\Transport\AbstractTransport;

use Symfony\Component\Mailer\Transport\TransportInterface;

use Symfony\Contracts\Service\Attribute\Required;

/**

 * Defines a mail transport that captures sent messages in a key value store.

 *

 * This class is for running tests or for development.

 */

class CaptureTransport extends AbstractTransport implements TransportInterface {

  /**

   * Key value factory.

   */

  protected KeyValueFactoryInterface $keyValueFactory;

  /**

   * Set key value factory.

   */

  #[Required]

  public function setKeyValueFactory(KeyValueFactoryInterface $keyValueFactory): void {

    $this->keyValueFactory = $keyValueFactory;

  }

  /**

   * {@inheritdoc}

   */

  protected function doSend(SentMessage $message): void {

    $keyValueStore = $this->keyValueFactory->get('mailer_capture');

    $capturedMails = $keyValueStore->get('messages', []);

    $capturedMails[] = $message;

    $keyValueStore->set('messages', $capturedMails);

  }

  /**

   * {@inheritdoc}

   */

  public function __toString(): string {

    return 'drupal.test-capture';

  }

}

name: 'Mailer capture test'

type: module

description: 'Support module for mailer capture testing.'

package: Testing

version: VERSION