SharePoint 2016 Cloud Hybrid Search - test environment

I'm setting up two SharePoint 2016 environments, one for TEST (UAT/QA) and the other for PRODUCTION.  I would like to know if it is possible to set up the TEST environment in a way that we can test the search capabilities separate from production.  I don't want to pollute the Office 365 indexes with TEST farm content.  Is there a way to configure a separate TEST search index pool in Office 365?  If not, how do companies handle this?