Are there any recommended pratctices how to configure hibernate.cfg.xml and\or HibernateUtil to run inside tomcat and standalone?

I have test-cases that run standalone against the hibernate-classes, and I use these classes from inside tomcat: In the first case, I use the hibernate.connection.pool, in the second case, I get my connections from a datasource. Are there any proposed best-practices how to achieve that switch? Apart from commenting/uncommenting parts of hibernate.cfg.xml?

thx for any help
stefan