test google drive account - can I get one for free for dev / test?

We need a test "google drive business sandbox" or some way to mock a realistic Google Drive Business account. As a security SaaS startup, our goal is to call the Google Drive (Business) APIs and retrieve information about access and permissions. We want to test 15-20 users for scale testing

However, there seems to be no way to set up a sandbox test account without setting up a full enterprise account - which is expensive at $10/user/month for a startup to afford.

This means in order to write tests we need an Business google account to connect to. But that's pretty expensive and not possible from a budget standpoint.

How can we get something to run tests against that doesn't cost us a fortune?