When using Postgres and running tests with yarn rw test api, I receive the following error:

error: Error validating datasource `DS`: The URL for datasource `DS` must start with the protocol `postgresql://`.

Taking a look at the cli command source, it's expecting a test database url (TEST_DATABASE_URL) to be defined if the Prisma provider is Postgres.

If this is intended, it might be a useful to mention this behaviour in the docs and/or add it to .env.example to save some time.