use strict;
use warnings;

sub test_exit {
  my ($subr, $exit_val) = @_;
  my $subp = fork;
  if ($subp) {
    my $done = waitpid($subp, 0);
    print "Process $done Exited with ".($?>>8).", expected $exit_val\n";
  }
  else {
    $subr->();
    warn "Did not exit\n";
    exit (~$exit_val);
  }
}

test_exit(sub{print "Process has run\n"; exit(42)}, 42);