magento-test/app/code/Magento/Search/Test/Mftf/ActionGroup/AssertStorefrontVerifySearchButtonIsDisabledActionGroup.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">
    <!-- Filter by search query and select -->
    <actionGroup name="AssertStorefrontVerifySearchButtonIsDisabledActionGroup">
        <annotations>
            <description>Verify search button has disabled attribute</description>
        </annotations>

        <grabAttributeFrom selector="{{StorefrontQuickSearchSection.searchButton}}" userInput="disabled" stepKey="grabSearchButtonDisabledAttribute"/>

        <assertEquals stepKey="assertSearchButtonDisabled">
            <actualResult type="const">$grabSearchButtonDisabledAttribute</actualResult>
            <expectedResult type="string">true</expectedResult>
        </assertEquals>
    </actionGroup>
</actionGroups>