Use different google-service.json for testing in Android

I am building an Android application using Firebase. Thus, I have a google-services.json file in my root app directory. I'd like to tell Android to use a different google-services.json file when running tests, but I'm not sure how to do this. I don't want to run tests against the production database. Can anyone provide a step-by-step guide on how to configure product flavors or something to use a different google-services.json according to whether or not I am testing?