magento-test/app/code/Magento/MessageQueue/Test/Mftf/ActionGroup/CliConsumerStartActionGroup.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="CliConsumerStartActionGroup">
        <annotations>
            <description>Starts message queue for specific consumer by CLI.</description>
        </annotations>
        <arguments>
            <argument name="consumerName" type="string"/>
            <argument name="maxMessages" type="string"/>
        </arguments>

        <magentoCLI command="queue:consumers:start {{consumerName}} --max-messages={{maxMessages}}" stepKey="startMessageQueue"/>
    </actionGroup>
</actionGroups>