test data files

Haven't used M::B for some time, so maybe this has been covered 
here and I missed it:  where should I place test *data* files for my 
unit tests to employ?

My present project is just a script, no libraries/modules, which needs 
to munge a set of files.  I need to copy some initial files into a working 
directory, have the script modify them and create some new files, and then 
check the contents.  

Thanks.