Yes, regarding PERLLIB, you read it right. To be exact, there are 439 entries, which collectively radiate cold shafts of broken glass in every direction imaginable. :-/
Could you kindly shed some light on what you mean by a test suite? I am asking because, typically, Perl scripts are run to initialize a chip-building environment by parsing configuration files and settings, etc., and then a non-Perl compiled binary is fired up for what can sometimes be a multi-day run. Now, I could skip the non-Perl compiled binary activity for testing purposes. The different Perl scripts, though, are run from one wildly different location to another. Are you saying a master/test Perl script should be used to appropriately augment @INC as each chip-building Perl script fails? In other words, at the start of test suite activity, empty @INC and build it out to include only what is necessary.
Pardon my ignorance, but I am not familiar with setting up test suites in Perl. Typical Perl scripts that I author, for example, require only a handful of custom modules, so this is turning out to be quite the learning experience for me...