Yes, you are right with the replacement of real DBI object with the fake one.

I found the Perl Practical Test-Driven Development Presentation on the Internet where it is nicely described. (Thank you Google!) The presentation is about TDD but it covers also database tests. It can be freely downloaded from here:

http://cdn.oreillystatic.com/en/assets/1/event/12/Practical Test-driven Development Presentation.pdf

Well, I think my problem is solved. When I'll have next problem I'll let you know about it :-)

Thank you.