/**
  * @param string $username
  * @param string $email
  * @param string $password
  * @return User
  * @throws \yii\base\Exception
  * @throws \yii\base\InvalidConfigException
  * @throws \yii\db\Exception
  */
 private function insertUser($username = '******', $email = '*****@*****.**', $password = '******')
 {
     $user = new User(['username' => $username, 'email' => $email, 'password' => $password]);
     $user->activateAndSave();
     return $user;
 }