magento-test/app/code/Magento/Elasticsearch/Test/Mftf/ActionGroup/ModifyCustomAttributeValueActionGroup.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="ModifyCustomAttributeValueActionGroup">
        <annotations>
            <description>Update value for custom attribute</description>
        </annotations>
        <arguments>
            <argument name="attributeValue" defaultValue="3.5" type="string"/>
            <argument name="product" type="string" defaultValue="SKU0001"/>
        </arguments>
        <click selector="{{AdminProductGridSection.productRowBySku(product)}}" stepKey="clickOnSimpleProductRow"/>
        <waitForPageLoad stepKey="waitForPageLoad1"/>
        <click selector="{{AdminProductMultiselectAttributeSection.option(attributeValue)}}" stepKey="selectFirstOption"/>
        <click selector="{{AdminProductFormSection.save}}" stepKey="save"/>
        <waitForPageLoad stepKey="waitForProductSaved"/>
    </actionGroup>
</actionGroups>