BeforeCartMergeEvent example

    public function testReturnsCorrectProperties(): void
    {
        $customerCart = new Cart('customerCart');
        $guestCart = new Cart('customerCart');
        $mergeableLineItems = new LineItemCollection();
        $salesChannelContext = $this->createMock(SalesChannelContext::class);

        $context = Context::createDefaultContext();
        $salesChannelContext->method('getContext')->willReturn($context);

        $event = new BeforeCartMergeEvent(
            $customerCart,
            $guestCart,
            $mergeableLineItems,
            $salesChannelContext
        );

        static::assertSame($customerCart, $event->getCustomerCart());
        static::assertSame($guestCart, $event->getGuestCart());
        static::assertSame($mergeableLineItems, $event->getMergeableLineItems());
        static::assertSame($salesChannelContext, $event->getSalesChannelContext());
        static::assertSame($context, $event->getContext());
    }

if (!$customerContext->getDomainId()) {
            $customerContext->setDomainId($currentContext->getDomainId());
        }

        return $this->enrichCustomerContext($customerContext, $currentContext, $currentContext->getToken(), $customerId);
    }

    private function mergeCart(Cart $customerCart, Cart $guestCart, SalesChannelContext $customerContext): Cart
    {
        $mergeableLineItems = $guestCart->getLineItems()->filter(fn (LineItem $item) => ($item->getQuantity() > 0 && $item->isStackable()) || !$customerCart->has($item->getId()));

        $this->eventDispatcher->dispatch(new BeforeCartMergeEvent(
            $customerCart,
            $guestCart,
            $mergeableLineItems,
            $customerContext
        ));

        $errors = $customerCart->getErrors();
        $customerCart->setErrors(new ErrorCollection());

        $customerCartClone = clone $customerCart;
        $customerCart->setErrors($errors);