When testing applications, often you find yourself needing to provide
functionality in your test environment that would usually be provided by
external modules. Rather than munging the %INC by hand to mark these external
modules as loaded, so they are not attempted to be loaded by perl, this module
offers you a very simple way to mark modules as loaded and/or unloaded.

WWW: http://search.cpan.org/dist/Module-Loaded/