I was curious about how well behaved my new classes were and wrote this to find what new symbols were being added to the symbol table.

Just change 'use Posix' to whatever module you would like to check.

Update:Changed the first comment to show the modules in my example are all optional.

use strict;
use warnings;

# Load any modules you don't want tested before the BEGIN
# You don't have to load the modules above - just any
# you want to load and exclude before the tested module(s)

    my %before;
    @before{keys %::} = (1) x keys %::;
    $before{DATA} = 1;
    sub before { $before{$_[0]} }

# Put the module(s) you're testing here.
use POSIX;

for ( sort keys %:: ) {
    printf "% 25s => %s\n", $_, $::{$_} unless before $_;