- is_deeply([grep(/\bpipe\b/, @lsof)], [], 'no extra pipes with -W0');
+
+ # filter out pipes inherited from the parent
+ my @this = `lsof -p $$`;
+ my $bad;
+ my $extract_inodes = sub {
+ map {;
+ my @f = split(' ', $_);
+ my $inode = $f[-2];
+ $bad = $_ if $inode !~ /\A[0-9]+\z/;
+ $inode => 1;
+ } grep (/\bpipe\b/, @_);
+ };
+ my %child = $extract_inodes->(@lsof);
+ my %parent = $extract_inodes->(@this);
+ skip("inode not in expected format: $bad", 1) if defined($bad);
+ delete @child{(keys %parent)};
+ is_deeply([], [keys %child], 'no extra pipes with -W0');