diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -215,10 +215,10 @@ class PosixTester(unittest.TestCase):
         try:
             posix.mknod(support.TESTFN,
                         stat.S_IFIFO | stat.S_IRUSR | stat.S_IWUSR, 0)
-        except OSError:
+        except OSError as e:
             # Some old systems don't allow unprivileged users to use
             # mknod(), or only support creating device nodes.
-            pass
+            self.assertIn(e.errno, (errno.EPERM, errno.EINVAL))
         else:
             self.assertTrue(stat.S_ISFIFO(posix.stat(support.TESTFN).st_mode))