Does hash contain minimum keys?

[GotToBTru]

Testing a hash to see if it has values for all required keys. Extraneous keys are okay.

use strict;
use warnings;
use Test::More tests => 3;

my (%required,%over,%under,%partial);
$required{$_} = 1 for qw/header detail trailer/;

$over{$_} = $_ for qw/title header subject detail trailer postscript/;
$under{$_} = $_ for qw/header trailer/;
$partial{$_} = $_ for qw/header trailer/;
$partial{detail} = undef;

ok(test_it(%over),'checking %over for required keys');
ok(test_it(%under),'checking %under for required keys');
ok(test_it(%partial),'checking %partial for required keys');

sub test_it {
  my %h = @_;
#  return (grep {$required{$_} && $h{$_}} keys %h) == (keys %required)
+;
   return (grep {$required{$_} && defined $h{$_}} keys %h) == (keys %r
+equired);
}

Update: use of defined suggested by choroba. I would have run into this because 0 is a value I would encounter.

[choroba]

Maybe add a defined after the && if zero is a valid value? See also HASH COMPARISONS in Test::Deep .

[emshach]

In this example %required doesn't need to be a hash, and since that's what you're checking against, that's what you should search. You could also use prototyping to avoid building a whole new hash each time, so we'd end up with something like:

sub test_it (\%) {
  my ($h) = @_;
  return (keys (%$h) >= @required
          && !grep { !defined($h->{$_}) } @required);
  # return true if the list of missing required keys is empty
}