UserCreateFailMailTest.php

<?php

namespace Drupal\Tests\user\Functional;

use Drupal\Tests\BrowserTestBase;

/**
 * Tests the create user administration page.
 *
 * @group user
 */
class UserCreateFailMailTest extends BrowserTestBase {
    
    /**
     * Modules to enable
     *
     * @var array
     */
    public 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->drupalPostForm('admin/people/create', $edit, t('Create new account'));
        $this->assertText(t('Unable to send email. Contact the site administrator if the problem persists.'));
        $this->assertNoText(t('A welcome message with further instructions has been emailed to the new user @name.', [
            '@name' => $edit['name'],
        ]));
    }

}