Fixture definition

fixture.php

class LoadMediaData extends AbstractFixture implements OrderedFixtureInterface
{
    public function load(ObjectManager $manager)
    {
        $certification = new Certification();
        $certification->setCode('PG-13');
        $manager->persist($certification);
        
        $person = new Person();
        $person->setName('Test person');
        $manager->persist($person);
        
        $movie = new Movie();
        $movie->setOriginalName('Test movie');
        $manager->persist($movie);
        
        $cast = new MovieHasPerson();
        $cast->setPerson($person);
        $cast->setMovie($movie);
        $cast->setCharacterName('Test name');
        $manager->persist($cast);
        
        $manager->flush();
        
        
        $this->addReference('movie-test', $movie);
    }
    
    public function getOrder()
    {
        return 1;
    }
}

Fixture example