I don't want to sound like one of those old sourpussses who always grumble that the functionality of the module is covered, more robustly and in greater details, in an already-existing module, but... this functionality is already covered, more robustly and in greater details by Devel::Cover.
If you are using Module::Build to install your modules, all the hooks to use D::C are even already there. Reviewing your module for coverage can be as easy as:
Great module. Dead simple to use, and produces very pretty graphs.