after-after.php

<?php

class SecureCodeGenerator {
  private $secureRandom;
  
  public function __construct(SecureRandomInterface $secureRandom) {
    this->secureRandom = $secureRandom;
  }
  
  public function generate() {
    $confirmationCode = $this
      ->secureRandom
      ->nextBytes(4);
      
    return md5($confirmationCode);
  }
}

class AccountManager
{
  private $secureCodeGenerator;
  
  public function __construct(
    SecureCodeGenerator $secureCodeGenerator
  ) {
    $this->secureCodeGenerator = $secureCodeGenerator;
  }
  
  public function createAccount(Account $account)
  {
    $account->setConfirmationCode(
      $this->secureCodeGenerator->generate()
    );
  }
}

after.php

<?php

class AccountManager
{
  private $entityManager;
  private $secureRandom;
  
  public function __construct(
    SecureRandomInterface $secureRandom
  ) {
    $this->secureRandom = $secureRandom;
  }
  
  public function createAccount(Account $account)
  {
    $confirmationCode = $this
      ->secureRandom
      ->nextBytes(4);
    $account
      ->setConfirmationCode(md5($confirmationCode));
  }
}

before.php

<?php

class AccountManager
{
  private $entityManager;
  private $secureRandom;
  
  public function __construct(
    EntityManger $entityManager,
    SecureRandomInterface $secureRandom
  ) {
    $this->entityManager = $entityManager;
    $this->secureRandom = $secureRandom;
  }
  
  public function createAccount(Account $account)
  {
    $confirmationCode = $this
      ->secureRandom
      ->nextBytes(4);
    $account
      ->setConfirmationCode(md5($confirmationCode));
      
    $this->entityManager->persist($account);
    $this->entityManager->flush();
  }
}