This is physically impossible. You had no risk.
This is an impossible scenario you are worried about, so the answer is a penis can't poke through denim and penetrate a vagina. You are totally safe and definitely don't need to test.
It is understandable that she wouldn't take a test for that kind of behavior as there couldn't be any risk otherwise everyone in America would have it from infection transmitted through clothes, because we all have cuts and touch others by mistake. So relax and move on from HIV fears.