Can 2 Meteor environments share the same Compose deployment?

I’m migrating Mongo from a Compose “Mongo Classic” (2.6.x) to a Compose modern Mongo 3.2.x instance.

I used to have a single Mongo Classic deployment, with 2 databases : one for production, the other for testing. Each had its own separate oplog user.

Now, Compose only allows a single, deployment-wide oplog user. Won’t using that single oplog user for both my prod & test environments lead to catastrophe ? What workarounds are available ? Do I absolutely need two deployments now ? Compose is expensive enough as it is…

I’m running Meteor 1.5.x.

AFAIK, as long as each _id is unique it won’t matter.