Testing an event subscriber

CartManagerTest.php

<?php

namespace Drupal\Tests\commerce_cart\Kernel;

use Drupal\commerce_order\Entity\OrderItem;
use Drupal\commerce_price\Price;
use Drupal\commerce_order\Entity\OrderInterface;
use Drupal\commerce_product\Entity\ProductVariation;
use Drupal\Tests\commerce\Kernel\CommerceKernelTestBase;

/**
 * Tests the cart manager.
 *
 * @coversDefaultClass \Drupal\commerce_cart\CartManager
 * @group commerce
 */
class CartManagerTest extends CommerceKernelTestBase {

  use CartManagerTestTrait;

  /**
   * The cart manager.
   *
   * @var \Drupal\commerce_cart\CartManager
   */
  protected $cartManager;

  /**
   * The cart provider.
   *
   * @var \Drupal\commerce_cart\CartProvider
   */
  protected $cartProvider;

  /**
   * A sample user.
   *
   * @var \Drupal\user\UserInterface
   */
  protected $user;

  /**
   * A product variation.
   *
   * @var \Drupal\commerce_product\Entity\ProductVariation
   */
  protected $variation1;

  /**
   * A product variation.
   *
   * @var \Drupal\commerce_product\Entity\ProductVariation
   */
  protected $variation2;

  /**
   * A product variation.
   *
   * @var \Drupal\commerce_product\Entity\ProductVariation
   */
  protected $variation3;

  /**
   * Modules to enable.
   *
   * @var array
   */
  public static $modules = [
    'entity_reference_revisions',
    'path',
    'profile',
    'state_machine',
    'commerce_product',
    'commerce_order',
  ];

  /**
   * {@inheritdoc}
   */
  protected function setUp() {
    parent::setUp();

    $this->installEntitySchema('commerce_order');
    $this->installConfig(['commerce_order']);
    $this->installConfig(['commerce_product']);

    $this->variation1 = ProductVariation::create([
      'type' => 'default',
      'sku' => 'variation1',
      'title' => $this->randomString(),
      'price' => new Price('1.00', 'USD'),
      'status' => 1,
    ]);

    $this->variation2 = ProductVariation::create([
      'type' => 'default',
      'sku' => 'variation2',
      'title' => $this->randomString(),
      'price' => new Price('2.00', 'USD'),
      'status' => 1,
    ]);

    $this->variation3 = ProductVariation::create([
      'type' => 'default',
      'sku' => 'variation3',
      'title' => $this->randomString(),
      'price' => new Price('3.00', 'USD'),
      'status' => 1,
    ]);

    $user = $this->createUser();
    $this->user = $this->reloadEntity($user);
  }

//  /**
//   * Tests the cart manager.
//   *
//   * @covers ::addEntity
//   * @covers ::createOrderItem
//   * @covers ::addOrderItem
//   * @covers ::updateOrderItem
//   * @covers ::removeOrderItem
//   * @covers ::emptyCart
//   */
//  public function testCartManager() {
//    $this->installCommerceCart();
//
//    $cart = $this->cartProvider->createCart('default', $this->store, $this->user);
//    $this->assertInstanceOf(OrderInterface::class, $cart);
//    $this->assertEmpty($cart->getItems());
//
//    $order_item1 = $this->cartManager->addEntity($cart, $this->variation1);
//    $order_item1 = $this->reloadEntity($order_item1);
//    $this->assertNotEmpty($cart->hasItem($order_item1));
//    $this->assertEquals(1, $order_item1->getQuantity());
//    $this->assertEquals(new Price('1.00', 'USD'), $cart->getTotalPrice());
//
//    $order_item1->setQuantity(2);
//    $this->cartManager->updateOrderItem($cart, $order_item1);
//    $this->assertNotEmpty($cart->hasItem($order_item1));
//    $this->assertEquals(2, $order_item1->getQuantity());
//    $this->assertEquals(new Price('2.00', 'USD'), $cart->getTotalPrice());
//
//    $order_item2 = $this->cartManager->addEntity($cart, $this->variation2, 3);
//    $order_item2 = $this->reloadEntity($order_item2);
//    $this->assertNotEmpty($cart->hasItem($order_item1));
//    $this->assertNotEmpty($cart->hasItem($order_item2));
//    $this->assertEquals(3, $order_item2->getQuantity());
//    $this->assertEquals(new Price('8.00', 'USD'), $cart->getTotalPrice());
//
//    $this->cartManager->removeOrderItem($cart, $order_item1);
//    $this->assertNotEmpty($cart->hasItem($order_item2));
//    $this->assertEmpty($cart->hasItem($order_item1));
//    $this->assertEquals(new Price('6.00', 'USD'), $cart->getTotalPrice());
//
//    $this->cartManager->emptyCart($cart);
//    $this->assertEmpty($cart->getItems());
//    $this->assertEquals(NULL, $cart->getTotalPrice());
//  }
//
//  /**
//   * Tests that order items without purchasable entities do not cause crashes.
//   */
//  public function testAddOrderItem() {
//    $this->installCommerceCart();
//    $cart = $this->cartProvider->createCart('default', $this->store, $this->user);
//
//    $order_item = OrderItem::create([
//      'type' => 'default',
//      'quantity' => 2,
//      'unit_price' => new Price('12.00', 'USD'),
//    ]);
//    $order_item->save();
//    $this->cartManager->addOrderItem($cart, $order_item);
//    $this->assertEquals(1, count($cart->getItems()));
//  }

  /**
   * Tests that order items added in an event subscriber get added to the order.
   */
  public function testEventAddOrderItem() {
    $this->installCommerceCart();
    $this->enableModules(['commerce_cart_test_event_subscriber']);

    $cart = $this->cartProvider->createCart('default', $this->store, $this->user);

    $order_item = OrderItem::create([
      'type' => 'default',
      'quantity' => 1,
      'unit_price' => new Price('12.00', 'USD'),
      'purchased_entity' => $this->variation3,
    ]);
    $order_item->save();
    $this->cartManager->addOrderItem($cart, $order_item);
    $this->assertEquals(2, count($cart->getItems()));
  }

}

TestCartEventSubscriber.php

<?php

namespace Drupal\commerce_cart_test_event_subscriber\EventSubscriber;

use Drupal\commerce\PurchasableEntityInterface;
use Drupal\commerce_cart\CartManagerInterface;
use Drupal\commerce_cart\CartProviderInterface;
use Drupal\commerce_cart\Event\CartEntityAddEvent;
use Drupal\commerce_cart\Event\CartEvents;
use Drupal\commerce_cart\Event\CartOrderItemRemoveEvent;
use Drupal\commerce_order\Entity\OrderInterface;
use Drupal\commerce_order\Entity\OrderItemInterface;
use Drupal\commerce_product\Entity\ProductInterface;
use Drupal\commerce_product\Entity\ProductVariation;
use Drupal\commerce_product\ProductVariationStorage;
use Drupal\commerce_store\CurrentStoreInterface;
use Drupal\commerce_store\Entity\StoreInterface;
use Drupal\Core\Entity\EntityStorageException;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\user\UserInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Responds to cart events.
 */
class CartEventSubscriber implements EventSubscriberInterface {

  /**
   * The cart manager.
   *
   * @var \Drupal\commerce_cart\CartManagerInterface
   */
  protected $cartManager;

  /**
   * The cart provider.
   *
   * @var \Drupal\commerce_cart\CartProviderInterface
   */
  protected $cartProvider;

  /**
   * The current store.
   *
   * @var \Drupal\commerce_store\CurrentStoreInterface
   */
  protected $currentStore;

  /**
   * The order item storage.
   *
   * @var \Drupal\commerce_order\OrderItemStorageInterface
   */
  protected $orderItemStorage;

  /**
   * Product variation storage.
   *
   * @var \Drupal\commerce_product\ProductVariationStorageInterface
   */
  protected $variationStorage;

  /**
   * CartEventSubscriber constructor.
   *
   * @param \Drupal\commerce_cart\CartManagerInterface $cart_manager
   *   The cart manager.
   * @param \Drupal\commerce_cart\CartProviderInterface $cart_provider
   *   The cart provider.
   * @param \Drupal\commerce_store\CurrentStoreInterface $current_store
   *   The current store.
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   *   The entity type manager.
   *
   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
   */
  public function __construct(CartManagerInterface $cart_manager, CartProviderInterface $cart_provider, CurrentStoreInterface $current_store, EntityTypeManagerInterface $entity_type_manager) {
    $this->cartManager = $cart_manager;
    $this->cartProvider = $cart_provider;
    $this->currentStore = $current_store;
    $this->orderItemStorage = $entity_type_manager->getStorage('commerce_order_item');
    $this->variationStorage = $entity_type_manager->getStorage('commerce_product_variation');
  }

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() {
    return [
      CartEvents::CART_ENTITY_ADD => 'onAddToCart',
    ];
  }

  /**
   * Responds to Add to cart events.
   *
   * @param \Drupal\commerce_cart\Event\CartEntityAddEvent $event
   *   The entity add to cart event.
   *
   * @throws \Exception
   */
  public function onAddToCart(CartEntityAddEvent $event) {
    $order_item = $event->getOrderItem();
    echo 'FOO';
    /** @var \Drupal\commerce_product\Entity\ProductVariationInterface $purchased_entity */
    $purchased_entity = $order_item->getPurchasedEntity();
    if ($purchased_entity->getSku() === 'variation3') {
      $store = $this->selectStore($purchased_entity);
      $cart = $this->getCart($store, 'default');
      $variation2_id = $this->variationStorage->getQuery()
        ->condition('sku', 'variation2')
        ->execute();
      $variation2 = $this->variationStorage->load($variation2_id);
      $order_item = $this->cartManager->addEntity($cart, $variation2, 1);
      try {
        $order_item->save();
        // @todo: BUG: Sessions don't get added to cart on a fresh cart (after
        // checkout).  Once cart is initialized, it looks like, then will session
        // products be added.  WTF?
      }
      catch (EntityStorageException $e) {
        drupal_set_message(t(':variation could not be added to cart.  Please contact customer support.', [
          ':variation' => $variation2->label(),
        ]));
      }
    }
  }

  /**
   * Gets or creates a cart for the given store and order type.
   *
   * @param \Drupal\commerce_store\Entity\StoreInterface $store
   *   The store.
   * @param string $order_type_id
   *   The order type id.
   *
   * @return \Drupal\commerce_order\Entity\OrderInterface
   *   A cart.
   */
  protected function getCart(StoreInterface $store, $order_type_id) {
    $cart = $this->cartProvider->getCart($order_type_id, $store);
    if (!$cart) {
      $cart = $this->cartProvider->createCart($order_type_id, $store);
    }

    return $cart;
  }

  /**
   * Selects the store for the given purchasable entity.
   *
   * If the entity is sold from one store, then that store is selected.
   * If the entity is sold from multiple stores, and the current store is
   * one of them, then that store is selected.
   *
   * @param \Drupal\commerce\PurchasableEntityInterface $entity
   *   The entity being added to cart.
   *
   * @throws \Exception
   *   When the entity can't be purchased from the current store.
   *
   * @return \Drupal\commerce_store\Entity\StoreInterface
   *   The selected store.
   */
  protected function selectStore(PurchasableEntityInterface $entity) {
    $stores = $entity->getStores();
    if (count($stores) === 1) {
      $store = reset($stores);
    }
    elseif (count($stores) === 0) {
      // Malformed entity.
      throw new \Exception('The given entity is not assigned to any store.');
    }
    else {
      $store = $this->currentStore->getStore();
      if (!in_array($store, $stores)) {
        // Indicates that the site listings are not filtered properly.
        throw new \Exception("The given entity can't be purchased from the current store.");
      }
    }

    return $store;
  }

}