magento-test/app/code/Magento/Cms/Test/Mftf/ActionGroup/AdminExpandMediaGalleryFolderActionGroup.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="AdminExpandMediaGalleryFolderActionGroup">
        <annotations>
            <description>Expands the provided Folder Name in the Media Gallery.</description>
        </annotations>
        <arguments>
            <argument name="FolderName" type="string"/>
        </arguments>
        <conditionalClick selector="{{MediaGallerySection.mediaGalleryFolderTreeIconCollapsed(FolderName)}}" dependentSelector="{{MediaGallerySection.mediaGalleryFolderTreeIconCollapsed(FolderName)}}" visible="true" stepKey="clickFolderIfCollapsed"/>
        <waitForPageLoad stepKey="waitForPageLoad"/>
        <waitForElement selector="{{MediaGallerySection.mediaGalleryFolderTreeIconExpanded(FolderName)}}" stepKey="waitForExpandedFolder"/>
    </actionGroup>
</actionGroups>