OSX File System Events - unit testing

I am working on unit tests for code that deals with the File System Events API. It creates a directory tree with random data in files and subdirectories, and then performs a few changes on these files and test that changes are handled properly.

However, this only works when the files are created in some user-space directory, such as on my own Desktop. When I try to pus the test files somewhere like /tmp or the location of NSTemporaryDirectory(), the listener does not receive any events. Are changes within directories such as /var and /tmp not recorded by the File System events API at all? Or is this an issue with permissions on those directories? I am not using the Sandbox for this portion of my app.