anchor.diff:  
       sub ensureNoPartition {
         $machine->succeed("test ! -e /dev/$_[0]");
  +    }
  +
  +    sub ensureMountPoint {
  +      $machine->succeed("mountpoint $_[0]");
       }
   
       sub remount_and_check {
  
positive.code:       ensureNoPartition("vdb6");
        ensureNoPartition("vdc1");
        remount_and_check;
      };
  
      parttest "btrfs filesystem", sub {
  
negative.code:       ensureNoPartition("vdc4");
        ensureNoPartition("md2");
        remount_and_check;
        ensureMountPoint("/mnt/boot");
      };
  
      parttest "RAID1 with LUKS and LVM", sub {
  