phpunit/dbunit is excellent, but you are stuck with one database. The guys at Etsy created very good extensions to fix this problem (MultipleDatabase), but it took me a while to figure out how to use it. Because PHPUnit is now available via Composer, you can fetch all dependencies with a single command.
He includes an example of a "composer.json" configuration file that pulls down tools including PHPUnit, dbunit, the Etsy extensions and Mockery for mock object testing. He suggests making a "parent class" to extend the DatabaseTest class to manage the database connections and includes an example of the code to get the connection and issue the method to check via the database assertions.