I encourage wisdom seekers to present sample data and use Test::More in the example code of their question. Let's look at some examples.

How do I make the regex match?

#!/usr/bin/perl

use strict;
use warnings;
use Test::More;

my $data  = "Some string here";
my $regex = qr/ fancy regex here /mxis;

like( $data, $regex, "Matching my regex" );

done_testing;
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Your code fails, but readers can read this code and run it and make changes that will make it pass.

Why does my sub return an error?

#!/usr/bin/perl

use strict;
use warnings;
use Test::More;

sub mysub {
   return;
}

ok( mysub(), "Should return true" );

done_testing;
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Presenting Larger sample data as if you were reading a file line by line.

Use __DATA__.

#!/usr/bin/perl

use strict;
use warnings;
use Test::More;

my $wanted_matches = 2;
my $actual_matches = 0;
my $regex          = qr/ fancy regex here /mxis;

while ( my $line = <DATA> ) {
   chomp $line;

   if ( $line =~ $regex ){
      $actual_matches++;
   }
}

ok( $wanted_matches == $actual_matches, "Correct number of matches" );

done_testing;

__DATA__
line one..... 
line two..... 
....
line ten.....
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