magento-test/app/code/Magento/Webapi/etc/di.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Magento\Webapi\Model\ConfigInterface" type="Magento\Webapi\Model\Config" />
    <preference for="Magento\Framework\Webapi\Rest\RequestValidatorInterface" type="Magento\Framework\Webapi\Rest\RequestMethodValidator" />
    <type name="Magento\Framework\App\AreaList">
        <arguments>
            <argument name="areas" xsi:type="array">
                <item name="webapi_rest" xsi:type="array">
                    <item name="frontName" xsi:type="string">rest</item>
                </item>
                <item name="webapi_soap" xsi:type="array">
                    <item name="frontName" xsi:type="string">soap</item>
                </item>
            </argument>
        </arguments>
    </type>
    <type name="Magento\Framework\Xml\Generator" shared="false" />
    <type name="Magento\Framework\Xml\Parser" shared="false" />
    <type name="Magento\Framework\Code\Scanner\DirectoryScanner" shared="false" />
    <type name="Magento\Integration\Model\ConfigBasedIntegrationManager">
        <plugin name="webapiSetup" type="Magento\Webapi\Model\Plugin\Manager" />
    </type>
    <type name="Magento\Webapi\Controller\Rest\ParamsOverrider">
        <arguments>
            <argument name="paramOverriders" xsi:type="array">
                <item name="%customer_id%" xsi:type="object">Magento\Webapi\Controller\Rest\ParamOverriderCustomerId</item>
            </argument>
        </arguments>
    </type>
    <type name="Magento\Framework\Webapi\Rest\Response\RendererFactory">
        <arguments>
            <argument name="renders" xsi:type="array">
                <item name="default" xsi:type="array">
                    <item name="type" xsi:type="string">*/*</item>
                    <item name="model" xsi:type="string">Magento\Framework\Webapi\Rest\Response\Renderer\Json</item>
                </item>
                <item name="application_json" xsi:type="array">
                    <item name="type" xsi:type="string">application/json</item>
                    <item name="model" xsi:type="string">Magento\Framework\Webapi\Rest\Response\Renderer\Json</item>
                </item>
                <item name="text_xml" xsi:type="array">
                    <item name="type" xsi:type="string">text/xml</item>
                    <item name="model" xsi:type="string">Magento\Framework\Webapi\Rest\Response\Renderer\Xml</item>
                </item>
                <item name="application_xml" xsi:type="array">
                    <item name="type" xsi:type="string">application/xml</item>
                    <item name="model" xsi:type="string">Magento\Framework\Webapi\Rest\Response\Renderer\Xml</item>
                </item>
                <item name="application_xhtml_xml" xsi:type="array">
                    <item name="type" xsi:type="string">application/xhtml+xml</item>
                    <item name="model" xsi:type="string">Magento\Framework\Webapi\Rest\Response\Renderer\Xml</item>
                </item>
            </argument>
        </arguments>
    </type>
    <type name="Magento\Webapi\Model\Config\Reader">
        <arguments>
            <argument name="converter" xsi:type="object">Magento\Webapi\Model\Config\Converter</argument>
            <argument name="schemaLocator" xsi:type="object">Magento\Webapi\Model\Config\SchemaLocator</argument>
            <argument name="fileName" xsi:type="string">webapi.xml</argument>
        </arguments>
    </type>
</config>