magento-test/app/code/Magento/Checkout/Test/Mftf/ActionGroup/StorefrontSelectAddressInCheckoutAddressDropDownActionGroup.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
 /**
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
-->

<actionGroups xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:noNamespaceSchemaLocation="urn:magento:mftf:Test/etc/actionGroupSchema.xsd">
    <actionGroup name="StorefrontSelectAddressInCheckoutAddressDropDownActionGroup">
        <annotations>
            <description>Selects the specified option in the address selection drop down on the storefront Checkout page.</description>
        </annotations>
        <arguments>
            <argument name="address" defaultValue="New Address" type="string"/>
        </arguments>
        <waitForElementVisible selector="{{CheckoutPaymentSection.addressDropdown}}" stepKey="waitForAddressDropDownToBeVisible"/>
        <selectOption selector="{{CheckoutPaymentSection.addressDropdown}}" userInput="{{address}}" stepKey="selectAddressOption"/>
        <waitForPageLoad stepKey="waitForAddressLoad"/>
    </actionGroup>
</actionGroups>