magento-test/app/code/Magento/MediaGalleryUi/Test/Mftf/ActionGroup/AdminEnhancedMediaGalleryEnableMassActionModeActionGroup.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="AdminEnhancedMediaGalleryEnableMassActionModeActionGroup">
        <annotations>
            <description>Activate massaction mode by click on Delete Selected..</description>
        </annotations>

        <wait stepKey="waitBefore" time="5" />
        <waitForElementVisible selector="{{AdminEnhancedMediaGalleryMassActionSection.deleteImages}}" stepKey="waitForMassActionButton"/>
        <click selector="{{AdminEnhancedMediaGalleryMassActionSection.deleteImages}}" stepKey="clickOnMassActionButton"/>
        <waitForPageLoad stepKey="waitForPageLoaded" />
        <wait stepKey="waitAfter" time="5" />
    </actionGroup>
</actionGroups>