magento-test/app/code/Magento/Indexer/Test/Mftf/ActionGroup/AdminSwitchAllIndexerToActionModeActionGroup.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="AdminSwitchAllIndexerToActionModeActionGroup">
        <arguments>
            <argument name="action" type="string" defaultValue="Update by Schedule"/>
        </arguments>
        <amOnPage url="{{AdminIndexManagementPage.url}}" stepKey="onIndexManagement"/>
        <waitForPageLoad stepKey="waitForManagementPage"/>
        <selectOption userInput="selectAll" selector="{{AdminIndexManagementSection.selectMassAction}}" stepKey="checkIndexer"/>
        <selectOption userInput="{{action}}" selector="{{AdminIndexManagementSection.massActionSelect}}" stepKey="selectAction"/>
        <click selector="{{AdminIndexManagementSection.massActionSubmit}}" stepKey="clickSubmit"/>
        <waitForPageLoad stepKey="waitForSubmit"/>
        <see userInput="indexer(s) are in &quot;{{action}}&quot; mode." stepKey="seeMessage"/>
    </actionGroup>
</actionGroups>