simplenews-3.0.0-alpha1/tests/modules/simplenews_test/simplenews_test.module

<?php

/**
 * @file
 * Hook implementations for the Simplenews Test module.
 */

use Drupal\simplenews\AbortSendingException;
use Drupal\simplenews\SkipMailException;
use Drupal\simplenews\SubscriberInterface;

/**
 * Implements hook_mail_alter().
 */
function simplenews_test_mail_alter(&$message) {
  if ($message['id'] == 'simplenews_node') {
    /** @var \Drupal\simplenews\Mail\MailInterface $mail */
    $mail = $message['params']['simplenews_mail'];
    $issue = $mail->getIssue();
    if (!empty($issue->body->value)) {
      if ($issue->body->value == 'Nothing interesting') {
        throw new SkipMailException('There was nothing interesting to send.');
      }
    }
  }
}

/**
 * Implements hook_simplenews_mail_result_alter().
 */
function simplenews_test_simplenews_mail_result_alter(&$result, array $message) {
  if ($results_alter = \Drupal::state()->get('simplenews.test_result_alter')) {
    $result = array_shift($results_alter);
    \Drupal::state()->set('simplenews.test_result_alter', $results_alter);

    if ($result == -1) {
      throw new AbortSendingException('Testing abort sending');
    }
  }
}

/**
 * Implements hook_simplenews_subscribe().
 */
function simplenews_test_simplenews_subscribe(SubscriberInterface $subscriber, string $newsletter_id) {
  $results = \Drupal::state()->get('simplenews.test_hook_results');
  if (!is_null($results)) {
    $results[] = ['add', $subscriber->getMail(), $newsletter_id];
    \Drupal::state()->set('simplenews.test_hook_results', $results);
  }
}

/**
 * Implements hook_simplenews_unsubscribe().
 */
function simplenews_test_simplenews_unsubscribe(SubscriberInterface $subscriber, string $newsletter_id) {
  $results = \Drupal::state()->get('simplenews.test_hook_results');
  if (!is_null($results)) {
    $results[] = ['remove', $subscriber->getMail(), $newsletter_id];
    \Drupal::state()->set('simplenews.test_hook_results', $results);
  }
}