Test automatici2
per
applicazioni Web
Stefano Rodighiero - larsen@perl.it

Scrivere software
=
Gestire la complessità

Complessità
You might think of this as mental juggling - the more mental
balls the program requires you to keep in the air at once, the
more likely you’ll drop one of the balls, leading to a design or
coding error.
-- Steve McConnell

Gestire la complessità
• Loose coupling
• Tecniche standard
• KISS
• Test?

Test?
«Testing by itself does not improve software quality. [...]
Trying to improve software by increasing the amount of testing
is like trying to lose weight by weighting yourself more often»
-- Steve McConnell

Test!
• Aumenta indirettamente la qualità del
software
• Design for testing
• Refactoring
• Wishful thinking
• Confidenza con il proprio codice

Esempio
#!/usr/bin/perl -w
use Test::Simple tests => 2;
use Date::ICal;
my $ical = Date::ICal->new; # make an object
ok( defined $ical ); # check we got something
ok( $ical->isa('Date::ICal') ); # and it's the right class

Gradualmente
• prova.pl → t/01_base.t
• diag()
• Usare gli occhi
• map <F8> :! prove %<C-M>
• YMMV :)

Applicazioni web

Paradigma MVC
Presentazione Model
Controllo

Test di videogame
• Situazioni difficili da riprodurre
• Grande complessità
• Chi effettua il test non è il programmatore

?

Test di applicazioni web
• Workflow complessi
• Quello che non è automatico tende a non
essere fatto

WWW::Mechanize
#!/usr/bin/perl
use strict;
use warnings;
use WWW::Mechanize;
my $agent = WWW::Mechanize->new();
$agent->get( 'http://www.google.com' );
print $agent->content();

Test::WWW::Mechanize
#!/usr/bin/perl
use strict;
use warnings;
use Test::More qw/ no_plan /;
use Test::WWW::Mechanize;
my $agent = Test::WWW::Mechanize->new();
$agent->get_ok( 'http://www.google.com' );
$agent->title_is( 'Google' );

WWW::Mechanize::Shell
calvin:~ larsen$ perl -MWWW::Mechanize::Shell -e shell
>g http://www.google.com
Retrieving http://www.google.com(200)
http://www.google.com>script mech3.pl
http://www.google.com>quit
calvin:~ larsen$

WWW::Mechanize::Shell
#!perl -w
use strict;
use WWW::Mechanize;
use WWW::Mechanize::FormFiller;
use URI::URL;
my $agent = WWW::Mechanize->new( autocheck => 1 );
my $formfiller = WWW::Mechanize::FormFiller->new();
$agent->env_proxy();
$agent->get('http://www.google.com');
$agent->form(1) if $agent->forms
and scalar @{$agent->forms};
mech3.pl

HTTP::Recorder

proxy.pl
#!/usr/bin/perl
use strict;
use warnings;
use HTTP::Proxy qw/ :log /;
use HTTP::Recorder;
my $proxy = HTTP::Proxy->new;
my $agent = HTTP::Recorder->new( file => \"/tmp/tmpfile\"
, showwindow => 1
);
$proxy->logmask( STATUS | PROCESS | HEADERS );
$proxy->port( 3128 );
$proxy->host( '' );
$proxy->agent( $agent );
$proxy->start();

Demo

Idee
• Usare proxy.pl con un sistema di bugtracking
(il ticket contiene il codice per riprodurre
l’errore)
• Testare applicazioni non scritte in Perl
• Screenscraping

Conclusioni
• Integrate le pratiche di testing nel vostro
workflow lavorativo
• Gradualmente!
• Sono pratiche che pagano da subito
• Come posso progettare il codice per
facilitarne il test?

Monday, I could wait till Tuesday
If I make up my mind
Wednesday would be fine, Thursday’s on my mind
Friday’d give me time, Saturday could wait
But Sunday’d be too late
-- Sting

Grazie :)
larsen@perl.it
http://larsen.perlmonk.org/blog

Riferimenti
• Web Testing with HTTP::Recorder
http://www.perl.com/pub/a/2004/06/04/recorder.html
• Test di applicazioni web
http://www.perl.it/blog/archives/000036.html
• A Perl Testing Tutorial (PDF)
http://www.wgz.org/chromatic/perl/IntroTestMore.pdf
• Migliorare la navigazione sul web con Perl
http://www.perl.it/blog/archives/000076.html
• Documentazione dei vari moduli menzionati
http://search.cpan.org/