diff --git a/test/test_utils.py b/test/test_utils.py
index 17328a36..e9204515 100644
--- a/test/test_utils.py
+++ b/test/test_utils.py
@@ -77,10 +77,14 @@ class TestSetupReadline(unittest.TestCase):
         # There are minor differences, e.g. the dir doesn't include deleted
         # items as well as items that are not only available on linux.
         difference = set(self.completions(s)).symmetric_difference(goal)
-        difference = {x for x in difference if not x.startswith('from os import _')}
+        difference = {
+            x for x in difference
+            if all(not x.startswith('from os import ' + s)
+                   for s in ['_', 'O_', 'EX_', 'MFD_', 'SF_'])
+        }
         # There are quite a few differences, because both Windows and Linux
-        # (posix and nt) libraries are included.
-        assert len(difference) < 38
+        # (posix and nt) librariesare included.
+        assert len(difference) < 20
 
     @cwd_at('test')
     def test_local_import(self):