Re^5: Writing tests when you don't know what the output should be

OK, try adding something like


use FindBin;
use Test::More tests => 3;
use Test::Exception;

dies_ok { 'DupEventChecker'->new } 'dir_name not provided';

my $checker = 'DupEventChecker'->new(dir_name => $FindBin::Bin);
isa_ok $checker, 'DupEventChecker';

my ($itself) = grep { 0 <= index $0, $_ } $checker->dir->read;
ok $itself, 'test script found';
[download]

BTW, dir_name is required, but it isn't apparent from the declaration. dir could also have a default (e.g. '.', Cwd::getcwd or File::HomeDir->my_home).

    has 'dir'  => ( is => 'ro', isa => 'IO::Dir', required => 1 );

    around BUILDARGS => sub {
        $_ = shift for my ($orig, $class);
        my %args = @_;

        die 'required dir missing' unless exists $args{dir};

        return $class->$orig(dir => 'IO::Dir'->new($args{dir}))
    }
[download]

Or, maybe more clearly,

#!/usr/bin/perl
use warnings;
use strict;

{   package DupEventChecker;
    use IO::Dir;
    use Moose;
    use namespace::autoclean;

    has 'dir'   => ( is => 'ro', isa => 'Str', required => 1 );
    has '_dir'  => ( is       => 'ro',
                     isa      => 'IO::Dir',
                     lazy     => 1,
                     builder  => '_build_dir',
                     handles  => { read_dir => 'read' },
                     init_arg => undef,
                   );

    sub _build_dir { 'IO::Dir'->new(shift->dir) }
    __PACKAGE__->meta->make_immutable;
}

use FindBin;
use Test::More tests => 3;
use Test::Exception;

dies_ok { 'DupEventChecker'->new } 'dir not provided';

my $checker = 'DupEventChecker'->new(dir => $FindBin::Bin);
isa_ok $checker, 'DupEventChecker';

my $itself = grep $0 =~ m{(?:^|/)\Q$_\E$}x, $checker->read_dir;
is $itself, 1, 'test script found';
[download]

Update: Example added to the BTW. Update 2: The example was improved.

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]

Comment on Re^5: Writing tests when you don't know what the output should be Select or Download Code

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Re^6: Writing tests when you don't know what the output should be by nysus (Parson) on May 18, 2016 at 03:54 UTC
Thanks for this. Can you please help me understand why you used an internal and external accessor for `dir`? I'm new to Moose and I'm not quite sure why you did that. Thanks. $PM = "Perl Monk's"; $MCF = "Most Clueless ~~Friar~~ ~~Abbot~~ ~~Bishop~~ ~~Pontiff~~ ~~Deacon~~ Curate"; $nysus = $PM . ' ' . $MCF; Click here if you love Perl Monks	[reply] [d/l]
Re^7: Writing tests when you don't know what the output should be by choroba (Cardinal) on May 18, 2016 at 08:57 UTC
It depends on what you want. My solution expects the user only wants to supply the directory name and doesn't care about the internal implementation. It locks in a dependency, though, so another approach would be to accept just an object with a defined interface (dependency injection) - it's easier to test and extend. You should start with a picture, define the behaviours of the objects, and the implementation should emerge from the design, not vice versa. ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l]
Re^6: Writing tests when you don't know what the output should be by nysus (Parson) on May 19, 2016 at 15:43 UTC
One other question about your example if I might impose. That second to last line has me scratching my head. The `grep $0` is nothing I'm familiar with and the regex has me baffled as well. Thanks! $PM = "Perl Monk's"; $MCF = "Most Clueless ~~Friar~~ ~~Abbot~~ ~~Bishop~~ ~~Pontiff~~ ~~Deacon~~ Curate"; $nysus = $PM . ' ' . $MCF; Click here if you love Perl Monks	[reply] [d/l]
Re^7: Writing tests when you don't know what the output should be by choroba (Cardinal) on May 19, 2016 at 15:57 UTC
`my ($itself) = grep { 0 <= index $0, $_ } $checker->dir->read;` [download] See $0, index, grep. In other words, the `read` method returns the contents of the directory, `grep` then tries to find a file name $_ that's contained in the test script's path (it's buggy, as it doesn't check whether the preceding character is a slash). `m{(?:^\|/)\Q$_\E$}x` [download] The regex fixes the issue: it checks that the filename is present in the script's name from the beginning (^) or a slash to the end ($). `\Q` quotes special characters in the filename so it matches literally. ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l] [select]


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