From Ravenware Software:
When I'm writing apps that means I'm using files to test the app with. Some of the files are mine, occasionally I'll need to use someone else's (like when writing PeekIt). I often need to have a test file of a certain size, or with some interesting content . I usually end up duplicating an existing file and modifying it manually (with PeekIt). That gets tedious. So I just wrote Test File Manager (TFM) for myself to manage the files I use for testing.
TFM is a central management app for all your test files. It also can create test files of any size, corrupt test files (to see how an app manages bad data), and places bytes in files to simulate certain conditions. All of these actions can be done repeatedly through Preset, and preset actions can be chained to make life a little easier. I still have quite a few more things I want to add to TFM, so check back regularly!