magento-test/app/code/Magento/Sales/Test/Mftf/ActionGroup/AdminOpenOrderCommentsHistoryActionGroup.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="AdminOpenOrderCommentsHistoryActionGroup">
        <annotations>
            <description>Clicks on the 'Comments History' on Admin View Order page.</description>
        </annotations>
        <click selector="{{AdminOrderDetailsOrderViewSection.commentsHistory}}" stepKey="clickOnTabCommentsHistory"/>
        <waitForPageLoad stepKey="waitForComments"/>
    </actionGroup>
</actionGroups>