composer require --dev doctrine/doctrine-fixtures-bundle

 $bundles[] = new Doctrine\Bundle\FixturesBundle\DoctrineFixturesBundle();

namespace App\DataFixtures;use App\Entity\Product;
use Doctrine\Bundle\FixturesBundle\Fixture;
use Doctrine\Common\Persistence\ObjectManager;class AppFixtures extends Fixture
{public function load(ObjectManager $manager){// create 20 products! Bam!for ($i = 0; $i < 20; $i++) {$product = new Product();$product->setName('product '.$i);$product->setPrice(mt_rand(10, 100));$manager->persist($product);}$manager->flush();}
}

php bin/console doctrine:fixtures:load

use Symfony\Component\Security\Core\Encoder\UserPasswordEncoderInterface;// ...
private $encoder;public function __construct(UserPasswordEncoderInterface $encoder)
{$this->encoder = $encoder;
}// ...
public function load(ObjectManager $manager)
{$user = new User();$user->setUsername('admin');$password = $this->encoder->encodePassword($user, 'pass_1234');$user->setPassword($password);$manager->persist($user);$manager->flush();
}

this->addReference(self::ADMIN_USER_REFERENCE, $userAdmin);

$userGroup->addUser($this->getReference(UserFixtures::ADMIN_USER_REFERENCE));

// src/DataFixtures/UserFixtures.php
// ...
class UserFixtures extends Fixture
{public const ADMIN_USER_REFERENCE = 'admin-user';public function load(ObjectManager $manager){$userAdmin = new User('admin', 'pass_1234');$manager->persist($userAdmin);$manager->flush();// other fixtures can get this object using the UserFixtures::ADMIN_USER_REFERENCE constant$this->addReference(self::ADMIN_USER_REFERENCE, $userAdmin);}
}// src/DataFixtures/GroupFixtures.php
// ...
class GroupFixtures extends Fixture
{public function load(ObjectManager $manager){$userGroup = new Group('administrators');// this reference returns the User object created in UserFixtures$userGroup->addUser($this->getReference(UserFixtures::ADMIN_USER_REFERENCE));$manager->persist($userGroup);$manager->flush();}
}