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TOKUHIROM / Web-Query-0.15 / t / 03_traverse.t 
use strict;
use warnings;
use utf8;
use Test::More;
use Web::Query qw/wq/;
use Scalar::Util qw/refaddr/;

my $html = <<'...';
<html><body><div id="foo"><div id="bar"><div id="baz"></div></div></div></body></html>
...
subtest 'parent' => sub {
    is wq($html)->find('#baz')->parent()->attr('id'), 'bar';
    is wq($html)->find('#bar')->parent()->attr('id'), 'foo';
};

subtest 'first/last return new instance' => sub {
    subtest 'first' => sub {
        my $q = wq($html)->find('div');
        my $first = $q->first;
        isnt(refaddr($first), refaddr($q));
    };
    subtest 'last' => sub {
        my $q = wq($html)->find('div');
        my $last = $q->last;
        isnt(refaddr($last), refaddr($q));
    };
};
subtest 'size' => sub {
    is wq($html)->find('div')->size,  3;
    is wq($html)->find('body')->size, 1;
    is wq($html)->find('li')->size,   0;
    is wq($html)->find('.null')->first->size, 0;
    is wq($html)->find('.null')->last->size,  0;
};
subtest 'map' => sub {
    is_deeply wq($html)->find('div')->map(sub {$_[0]}), [0, 1, 2];
    is_deeply wq($html)->find('div')->map(sub {$_->attr('id')}), [qw/foo bar baz/];
};
subtest 'filter' => sub {
    is wq($html)->filter('div')->size,                                          3;
    is wq($html)->filter('body')->size,                                         1;
    is wq($html)->filter('li')->size,                                           0;
    is wq($html)->find('div')->filter(sub {$_->attr('id') =~ /ba/})->size,      2;
    is wq($html)->find('div')->filter(sub {my $i = shift; $i % 2 == 0})->size,  2;
};
done_testing;