Hi,
The numbered SQL scripts (1.sql, 2.sql, ...) are
database evolutions. An application developer writes them and places them in the designated directory. The Play framework determines when the database schema doesn't reflect recently added scripts and runs them.
In principal, then, since evolutions are about going from an empty schema to a working application database, it seems like they could be used to set up (and tear down) a database for testing purposes. The main technical matter you'd have to resolve is, how to move the responsibility of running the scripts from the framework into your test code.
Dan