In what fashion doesn't work? Generates an error or warning? Just doesn't do anything? Causes the CPU to overheat then explode?

Because you don't declare $test anywhere in test.pl Perl makes it global to everything. If you use strict the strictures require $test to be declared. If you do that it becomes local. You can use strictures and require by declaring the variable with our:

#!/usr/bin/perl -w
#test.pl
use strict;
use warnings;

require 'noname1.pl';

our $test;

print $test;
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use strict;
use warnings;

our $test = 'This works!';
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Prints:

This works!
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