1 files changed, 12 insertions, 1 deletions
diff --git a/t/spawn.t b/t/spawn.t
index 6168c1f6..5fc99a2a 100644
--- a/t/spawn.t
+++ b/t/spawn.t
@@ -24,7 +24,18 @@ SKIP: {
          is(waitpid($pid, 0), $pid, 'waitpid succeeds on spawned process');
          is($?, 0, 'true exited successfully');
          pipe(my ($r, $w)) or BAIL_OUT;
-        $pid = eval { spawn(['true'], undef, { pgid => 1, 2 => $w }) };
+
+        # Find invalid PID to try to join its process group.
+        my $wrong_pgid = 1;
+        for (my $i=0x7fffffff; $i >= 2; $i--) {
+                if (kill(0, $i) == 0) {
+                        $wrong_pgid = $i;
+                        last;
+                }
+        }
+
+        # Test spawn behavior when it can't join the requested process group.
+        $pid = eval { spawn(['true'], undef, { pgid => $wrong_pgid, 2 => $w }) };
          close $w;
          my $err = do { local $/; <$r> };
          # diag "$err ($@)";