<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
declare(strict_types=1);

use Magento\Framework\Api\SearchCriteriaBuilder;
use Magento\Sales\Api\Data\OrderInterface;
use Magento\Sales\Api\OrderRepositoryInterface;
use Magento\TestFramework\Helper\Bootstrap;

$om = Bootstrap::getObjectManager();
/** @var OrderRepositoryInterface $orderRepository */
$orderRepository = $om->get(OrderRepositoryInterface::class);
/** @var SearchCriteriaBuilder $searchCriteriaBuilder */
$searchCriteriaBuilder = $om->get(SearchCriteriaBuilder::class);

foreach ([['SKU-1', 'eu-1'], ['SKU-2', 'us-1'], ['SKU-6', 'eu-1']] as $skuSource) {
    /** @var OrderInterface $order */
    $order = current(
        $orderRepository->getList(
            $searchCriteriaBuilder
                ->addFilter(OrderInterface::INCREMENT_ID, 'in_store_pickup_test_order-' . $skuSource[0])
                ->create()
        )->getItems()
    );

    $order->getExtensionAttributes()
          ->setPickupLocationCode($skuSource[1]);

    $orderRepository->save($order);
}