lib/mana.pm
get '/' => sub {
    template 'index.tt' => { login => session('user')};
};

post '/login' => sub {
    redirect '/login' unless
        Mana::Interface::checkLogin({ params });
    session user => params->{ login };
    redirect '/';
};

t/002.pm
use strict;
use warnings;


use Mana;
use Test::More tests => 3;
use Plack::Test;
use HTTP::Request::Common;
use HTTP::Cookies;

my $jar  = HTTP::Cookies->new;
my $app = Mana->to_app;
is( ref $app, 'CODE', 'Got app' );

my $test = Plack::Test->create($app);

my $req = POST "/login?login=bapt&password=mdp";
$jar->add_cookie_header($req);

my $res  = $test->request($req);
ok( $res->is_redirect, "[GET /login] successful" );

$res  = $test->request( GET "/" );
ok( $res->is_success, "[GET /] successful" );