In addition to haukex's comments here, I would say that the
    @required = keys %{{ map { $_ => 1 } @required }};
and
    @notthere = keys %{{ map { $_ => 1 } @notthere }};
statements are unnecessary. All they do is rearrange the order of elements in the respective arrays in a more-or-less random way, and this rearrangement has no useful effect.

c:\@Work\Perl>perl -wMstrict -le
"my @allwords = qw(this is a list of words that is required for tests)
+;
 my @required = qw(this is a list of words that is required);
 ;;
 my %hash = map { $_ => 1 } @allwords;
 ;;
 print 'do stuff'
   if @required == grep { defined $_ } @hash{@required};
 ;;
 my @notthere = qw(this list is not there in allwords);
 ;;
 print 'do not do stuff'
   unless @notthere == grep { defined $_ } @hash{@notthere};
"
do stuff
do not do stuff
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