magento-test/app/code/Magento/Newsletter/Test/Mftf/ActionGroup/CheckSubscribedNewsletterActionGroup.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="CheckSubscribedNewsletterActionGroup">
        <annotations>
            <description>Goes to the Storefront Newsletter Management page. Validates that the 'Subscription' checkbox is checked.</description>
        </annotations>

        <amOnPage url="{{StorefrontNewsletterManagePage.url}}" stepKey="goToNewsletterManage"/>
        <seeCheckboxIsChecked selector="{{StorefrontNewsletterManageSection.subscriptionCheckbox}}" stepKey="checkSubscribedNewsletter"/>
    </actionGroup>
</actionGroups>