Top tip: if you use Test::More your tests will automatically tell you how the condition fails. eg:

use strict;
use warnings;

use Test::More tests => 1;

my $param_value='123456789';
is (length($param_value), 5, 'Length of $param_value') or
    diag "\$param_value = >$param_value<";
[download]

See How to ask better questions using Test::More and sample data and SSCCE for further hints.

PS. In case it wasn't clear, I've changed the expected length to 5 so the test deliberately fails. Testing against an expected length of 9 would succeed, of course.