Testing framework for functional/system testing for C/C++?

For C++, there are lots of good unit test frameworks out there, but I couldn't find a good one for functional testing. With functional testing, I mean stuff which touches the disk, requires the whole application to be in place etc.

Point in case: What framework helps with testing things like whether your I/O works? I've got a hand-rolled system in place, which creates temporary folders, copies around a bunch of data, so the tests are always done in the same environment, but before I spend more time on my custom framework -- is there a good one out there already?