<?php

use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\entity_test\Entity\EntityTest;
use Drupal\entity_test\Entity\EntityTestMul;
use Drupal\field\Entity\FieldConfig;
use Drupal\field\Entity\FieldStorageConfig;
\Drupal::service('module_installer')->install(['entity_test', 'dynamic_entity_reference']);

$field_storage = FieldStorageConfig::create(array(
  'entity_type' => 'entity_test',
  'field_name' => 'field_test',
  'type' => 'dynamic_entity_reference',
  'settings' => array(
    'exclude_entity_types' => FALSE,
    'entity_type_ids' => [
      'entity_test',
      'entity_test_mul',
    ],
  ),
  'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
));
$field_storage->save();

$field = FieldConfig::create(array(
  'entity_type' => 'entity_test',
  'field_name' => 'field_test',
  'bundle' => 'entity_test',
  'settings' => array(),
));
$field->save();

$field_storage = FieldStorageConfig::create(array(
  'entity_type' => 'entity_test_mul',
  'field_name' => 'field_test_mul',
  'type' => 'dynamic_entity_reference',
  'settings' => array(
    'exclude_entity_types' => FALSE,
    'entity_type_ids' => [
      'entity_test',
      'entity_test_mul',
    ],
  ),
  'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
));
$field_storage->save();

$field = FieldConfig::create(array(
  'entity_type' => 'entity_test_mul',
  'field_name' => 'field_test_mul',
  'bundle' => 'entity_test_mul',
  'settings' => array(),
));
$field->save();


// Create some test entities which link each other.
$referenced_entity = EntityTest::create();
$referenced_entity->save();
$referenced_entity_mul = EntityTestMul::create();
$referenced_entity_mul->save();

$entity = EntityTest::create();
$entity->field_test[] = $referenced_entity;
$entity->field_test[] = $referenced_entity_mul;
$entity->save();

$entity = EntityTest::create();
$entity->field_test[] = $referenced_entity;
$entity->field_test[] = $referenced_entity_mul;
$entity->save();


$entity = EntityTestMul::create();
$entity->field_test_mul[] = $referenced_entity;
$entity->field_test_mul[] = $referenced_entity_mul;
$entity->save();

$entity = EntityTestMul::create();
$entity->field_test_mul[] = $referenced_entity;
$entity->field_test_mul[] = $referenced_entity_mul;
$entity->save();