"...thoughts on how to test..."

Consider Test::More:

#!/usr/bin/env perl

use strict;
use warnings;
use Test::More tests => 3;
use feature qw(say);

my $string = q(Lorem ipsum kizuaheli);

say $string;

$string =~ m/^.+(.{3})(ipsum)(.{3}).+$/;

ok( $1 eq q(em ),   qq(\$1: $1) );
ok( $2 eq q(ipsum), qq(\$2: $2) );
ok( $3 eq q( ki),   qq(\$3: $3) );

__END__

karls-mac-mini:monk karl$ ./tryna.pl
1..3
Lorem ipsum kizuaheli
ok 1 - $1: em 
ok 2 - $2: ipsum
ok 3 - $3:  ki
[download]

The more test-driven monks may forgive me.

Best regards, Karl