magento-test/app/code/Magento/Checkout/Test/Mftf/Section/CheckoutCartMessageSection.xml

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

<sections xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="urn:magento:mftf:Page/etc/SectionObject.xsd">
    <section name="CheckoutCartMessageSection">
        <element name="successMessage" type="text" selector=".message.message-success.success>div" />
        <element name="errorMessage" type="text" selector=".message-error.error.message>div" />
        <element name="emptyCartMessage" type="text" selector=".cart-empty>p"/>
        <element name="errorMessageText" type="text" selector="//div[contains(@class, 'message-error')]/div[text()='{{var}}']" parameterized="true"/>
    </section>
</sections>