UuuuNyaaa!

Acme-UuuuNyaaa.pm

package Acme::UuuuNyaaa;

use strict;
use warnings;

sub new{
	my $class = shift;
	my $self = bless {}, $class;

	return $self;
}

sub u{
	return "(」・ω・)」うー！";
}

sub n{
	return "(／・ω・)／にゃー！";
}

sub un{
	my $self = shift;
	return $self->u.$self->n;
}

sub ln{
	return "Let's＼(・ω・)／にゃー！";
}

sub response{
    my ($self,$text) = @_;
    if ($text =~ m{う[〜ー]}msix) {
        return $self->n;
    }
    else {
        return $self->ln;
    }
}

1;

test.pl

use strict;
use Test::More;

BEGIN{
	use_ok('Acme::UuuuNyaaa');
}

my $unya = Acme::UuuuNyaaa->new;
ok($unya->u eq "(」・ω・)」うー！", "うー！");
ok($unya->n eq "(／・ω・)／にゃー！", "にゃー！");
ok($unya->un eq "(」・ω・)」うー！(／・ω・)／にゃー！", "うー！にゃー！");
ok($unya->ln eq "Let's＼(・ω・)／にゃー！", "Lets!にゃー！");

subtest "response to u" => sub {
    for my $text ("うー", "う〜") {
        ok($unya->response($text) eq $unya->n);
    }
};

subtest "fallback" => sub {
    ok($unya->response("no match") eq $unya->ln);
};
done_testing;