will close some of the cost-center tickets - how to compare .perf outputs?

I'm trying to write some tests for some profiling-related tickets and I don't understand how do I compare .prof outputs. Can anyone help? I tried generating a .prof.sample and it worked, but somehow if I delete a random line from .prof.sample, my test still succeeds! If I delete the whole file or keep the file but delete the contents, it fails. I have no idea what's going on. Any ideas? Thanks