$|=1;
print "1..2\n";

use Coro;
use Coro::Semaphore;

{
   my $sem = new Coro::Semaphore 2;

   my $rand = 0;

   sub xrand {
      $rand = ($rand * 121 + 2121) % 212121;
      $rand / 212120
   }

   my $counter;

   $_->join for
      map {
         async {
            my $current = $Coro::current;
            for (1..100) {
               cede if 0.2 > xrand;
               Coro::async_pool { $current->ready } if 0.2 > xrand;
               $counter += $sem->count;
               my $guard = $sem->guard;
               cede; cede; cede; cede;
            }
         }
      } 1..15
   ;

   print $counter == 998 ? "" : "not ", "ok 1 # $counter\n";
}

{
   my $sem = new Coro::Semaphore 0;

   $as1 = async {
      my $g = $sem->guard;
      print "not ok 2\n";
   };    

   $as2 = async {
      my $g = $sem->guard;
      print "ok 2\n";
   };    

   cede;

   $sem->up; # wake up as1
   $as1->cancel; # destroy as1 before it could ->guard
   $as1->join;
   $as2->join;
}