materio-base-d7/sites/all/modules/contrib/mail/smtp/tests/smtp_tests.module

<?php
/**
 * @file
 * Primary hook implementations for the SMTP test helper module.
 */

/**
 * Implements hook_mail().
 */
function smtp_tests_mail($key, &$message, $params) {
  // A very rudimentary test.
  if ($key == 'smtp_basic_test') {
    $message['subject'] = t('Test email subject');
    $message['body'][] = t('Test email body.');
  }
}