Best way to refresh the test database with data from production database?

I have a test environment and a production environment. They are structurally identical. All I want to do is take the data from production and replace the test data with the production data. I want to keep the DB and instance names on Test as they are. Would someone please point me to a KB article that will tell me how to do this? I'm using RMAN for backup with catalogs stored outside of production. (In my development database to be clear.)

Thanks