diff --git a/glib/gtestutils.c b/glib/gtestutils.c
index 88a6fc0d7..e67078d53 100644
--- a/glib/gtestutils.c
+++ b/glib/gtestutils.c
@@ -2680,7 +2680,11 @@ g_test_trap_fork (guint64        usec_timeout,
       close (stdout_pipe[0]);
       close (stderr_pipe[0]);
       if (!(test_trap_flags & G_TEST_TRAP_INHERIT_STDIN))
-        fd0 = g_open ("/dev/null", O_RDONLY, 0);
+        {
+          fd0 = g_open ("/dev/null", O_RDONLY, 0);
+          if (fd0 < 0)
+            g_error ("failed to open /dev/null for stdin redirection");
+        }
       if (sane_dup2 (stdout_pipe[1], 1) < 0 || sane_dup2 (stderr_pipe[1], 2) < 0 || (fd0 >= 0 && sane_dup2 (fd0, 0) < 0))
         g_error ("failed to dup2() in forked test program: %s", g_strerror (errno));
       if (fd0 >= 3)