Module::Install is a good option for including test and other modules with your distribution so that they are used for testing but not installed. The documentation is not quite complete yet, but there was a Perl Journal article in June 2003 that explains it quite nicely.

You can also use it to create bundles that include everything in the distribution file. This is better than the standard CPAN bundle mechanism in some cases (for example, when you want to install a bunch of modules in a machine without network connectivity or you can't use CPAN.pm for some reason).