How do you test scripts (i.e. not a module)? The OP may not be able or want to change the scripts. The scripts may or may not be interactive, they may or may not need arguments supplied etc.

Those are great questions, and I'm hoping the OP can tell us more about their situation.

So far, the only thing I know about these scripts is that they access a database and that the code is a little crufty. Apart from that, I know nothing.

I don't know if these scripts are web-based or if they're command-line based. I don't know if the scripts are batch or interactive. I don't know what platform is involved, and I don't know what the database is.

Therefore, I've tried to make my answers as useful as possible, while also being as generic as possible.