Actually, MakeMaker will make it just work.
Just cd into Client/Graph, do your perl Makefile.PL, make,
make test, and make install, and it will be in the correct
directory such that you can `use Client::Graph'.
in reply to h2xs again
If your problem is that you can't use it from the build
directory, look at the way the autogenerated test.pl uses it,
and copy that. In fact, why not just put the code into
the test.pl. You are writing unit tests, right?
Finally: when you go to package up your distribution,
rename the Client directory Client-Graph and then tar it up.
That's the style most modules on the CPAN use.