I usually deploy them as SQL files. I keep my SQL statements as close to standard as possible, so a change in Database Engine (say MySQL-->Postgres) results in

I usually deploy them as SQL files. I keep my SQL statements as close to standard as possible, so a change in Database Engine (say MySQL-->Postgres) results in a simple step. The unit tests can be performed as a bunch of SQL statements passed as input to the database client and verify that it works as expected. This level (the unit test) can also be done with any programming language of choice, to make the task easier.