class UserCreateFailMailTest

class UserCreateFailMailTest extends BrowserTestBase {
  
  /**
   * Modules to enable.
   *
   * @var array
   */
  protected static $modules = [
    'system_mail_failure_test',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected $defaultTheme = 'stark';
  
  /**
   * Tests the create user administration page.
   */
  public function testUserAdd() {
    $user = $this->drupalCreateUser([
      'administer users',
    ]);
    $this->drupalLogin($user);
    // Replace the mail functionality with a fake, malfunctioning service.
    $this->config('system.mail')
      ->set('interface.default', 'test_php_mail_failure')
      ->save();
    // Create a user, but fail to send an email.
    $name = $this->randomMachineName();
    $edit = [
      'name' => $name,
      'mail' => $this->randomMachineName() . '@example.com',
      'pass[pass1]' => $pass = $this->randomString(),
      'pass[pass2]' => $pass,
      'notify' => TRUE,
    ];
    $this->drupalGet('admin/people/create');
    $this->submitForm($edit, 'Create new account');
    $this->assertSession()
      ->pageTextContains('Unable to send email. Contact the site administrator if the problem persists.');
    $this->assertSession()
      ->pageTextNotContains('A welcome message with further instructions has been emailed to the new user ' . $edit['name'] . '.');
  }

}