[p4] trying to keep my changes but also test the versions submitted to perforce??

[adam question]

I am working on several files, sometimes I need to test some of my
friends changes to those files submitted after I started my work. In
order to do that, I go manually to all my changed files, and copy them
to some names like filename.copylater, update my whole directory from
perforce. When I am done with testing and go back to my work; manually
copy my files filename.copylater and recompile. It is a painful
process, but I dont want my unfinalized changes to be submitted into
perforce, but at the same time I have to check my friends changes
which are submitted after I started working on my files.

Is there a way to automate this process without submitting my files??

Thanks