The plan is, that I am going to write a lot of tests accessing the live search.cpan.org web site and use those tests as a suite of acceptance tests for the search.cpan.org clone project.

Download: mp4 webm

YouTube

While working on the next step, I noticed that the swap-files used by vim show up as untracked file by git. In order to avoid adding them to Git, I added *.swp to the .gitignore file. commit.

Testing search.cpan.org

There are a couple of ways to test web site, and using WWW::Mechanize is a great way to do that. WWW::Mechanize is basically a web client (it is a subclass of LWP::UserAgent that understand HTML. So you can tell it to click on a link or fill a form.

In itself WWW::Mechanize is great to automate interaction with web sites, but if we want to write unit-test (even if in this case we call them acceptance tests) it is much better to use Test::WWW::Mechanize which is a wrapper around Mechanize providing test-functions using Test::Builder backend. Exactly the same way as it was explained in the testing mini-series that ended when we created a test module.

Using Test::WWW::Mechanize is a bit different than the test module we created. This module provides an object oriented interface. First we create an instance of this class and then use its methods to interact with a web site. As a start we call get_ok with a URL. This will fetch the page on that URL and check if the fetching was successful. (If it returned 200 ok.) Then we can use all kinds of methods to check the content of this page. In this case I went for a very minimalistic test, I used the title_is method to check if the page has the expected title.

At this point I already started to have concerns: In the clone, am I going to have the same title or will it explicitly say it is a clone? Am I going to be able to reuse these tests with the clone? I did not have an answer to these, but I kept going and added another subtest. The follow_link_ok method clicks on the link that says "Authors", checks if there was such a link and if the new page was loaded successfully.

use strict;
use warnings;

use Test::More;
use Test::WWW::Mechanize;

plan tests => 2;

my $w = Test::WWW::Mechanize->new;

my $url = 'http://search.cpan.org/';

subtest home => sub {
    $w->get_ok($url);
    $w->title_is('The CPAN Search Site - search.cpan.org');
};

subtest authors => sub {
    $w->follow_link_ok( {text => 'Authors'}, 'Authors link' );
};

$ git add .
$ git commit -m "first tests of live search.cpan.org site"

commit

Add some more tests

Once I had the skeleton of the tests I could add some more checks.

On the home-page there is a form. The parameters of submit_form_ok method gets help identify one specific form. In our case it is quite easy, as there is only one form on this page. (I checked it by looking at the HTML source of the page and looking for the word "form".) So we identify the form by being the first (and only) form on this page: form_number => 1. Then we supply the values to the fields. In order to know the names of the fields I had to look at the HTML source of the page again. The query is some free-text field, while the mode is a selector. The submit_form_ok method will fill the form, click on the submit button, and check if the resulting page returned 200 ok.

Then we have two methods checking the content of the resulting page. content_contains check if the given string can be found in the source of the HTML file and content_lacks checks if the given string is not in the HTML.

This test actually is even more problematic than the one checking the title. When searching for "sz" among the authors, I was expecting to see all the authors that have "sz" in their name. It turns out search.cpan.org does not show all of them. Specifically I did not see my own name. This is disturbing on many levels, besides hurting my ago. Does this mean there is a bug in search.cpan.org or is there something more subtle in this search, I am not aware of. Should the clone try to show the exact same list, or shall we consider this a bug and fix it?

Can we even understand why specific people are listed here and others not?

How can I write a test that will pass on both search.cpan.org and on the clone, if they will show different results?

use strict;
use warnings;

use Test::More;
use Test::WWW::Mechanize;

plan tests => 2;

my $w = Test::WWW::Mechanize->new;

my $url = 'http://search.cpan.org/';

subtest home => sub {
    $w->get_ok($url);
    $w->title_is('The CPAN Search Site - search.cpan.org');
    $w->submit_form_ok( {
            form_number => 1,
            fields      => {
                query => 'sz',
                mode  => 'author', 
            },
        }, 'search "sz" in author'
    );
    $w->content_contains('Arpad Szasz');
    $w->content_lacks('Szabo');
};

subtest authors => sub {
    $w->follow_link_ok( {text => 'Authors'}, 'Authors link' );
    $w->title_is('The CPAN Search Site - search.cpan.org');
    $w->follow_link_ok( {text => 'A'}, 'A link' );
    $w->title_is('The CPAN Search Site - search.cpan.org');
    $w->content_contains('Andy Adler');
    $w->content_contains('Sasha Kovar');

    $w->follow_link_ok( {text => 'AADLER'}, 'Link to author AADLER');
};

The second subtest was also extended with a couple of additional checks. I checked the title here too, and then followed the link that has A on it. Checked the title again and used content_contains to make sure two names appear in the list. Then followed one of the links.

These tests are also slightly problematic. What if one of the people changes her name. Will the test fail then? Is this ok to have test that are dependent on the environment?

$ git add .
$ git commit -m "add some more tests"

commit