Another way to do it is with FindBin, i.e.

use FindBin ();
use File::Spec::Functions qw/catfile/;
...
$p->parse_file(catfile($FindBin::Bin,qw/ .. lib Pod Simple Select.pm /
+));
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I do this in the tests for several of my modules (example) and it's worked great so far across all of CPAN Testers*.

The same thing goes for lib, e.g. use lib $FindBin::Bin;.

* Update: Sorry, I should not have made that specific claim that that code works across all of CPAN Testers, I forgot that those are author tests that don't get run there. However, I do have a few very similar lines of code where I can make that claim instead (from here):

use FindBin ();
use lib $FindBin::Bin;
...
my $script = catfile($FindBin::Bin, 'test_opts_usage.pl');
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