Are there any tools that can tell me what percentage of a XSL document get actually executed during tests?
UPDATE
I could not find anything better than Oxygen's XSL debugger and profiler, so I'm accepting Mladen's answer.
Not sure about code coverage itself, but you can find an XML debugger and profiler from Oxygen which might help you out.
This didn't exist back when this question was asked, but now there is ONE option for finding code coverage of XSLT documents:
http://code.google.com/p/cakupan/
I'll admit that I haven't used it yet, as I'm still gathering information right now, but as far as I'm aware, this is IT.
If anyone is still interested, Saxon has a performance analysis, which has a functionality that gives you a breakdown of each template and the number of times they are used (which is great for optimisation).
This is how my output looks like:
