How to copy resources to test at build time with gradle

I have a gradle project that has an xslt file in resources:

src/main/resources/http://ift.tt/2nJjTyM

At time of build w/ gradle I'd like to use that file to overwrite:

src/test/resources/sec_report.xslt

That way my unit tests are always consuming the latest version/there is one source of truth for this file. What is the right way to make this happen? Write a shell script and execute it from gradle or maybe add it to the build task?