Index: Lib/test/test_genericpath.py
===================================================================
--- Lib/test/test_genericpath.py	(revision 82050)
+++ Lib/test/test_genericpath.py	(working copy)
@@ -194,7 +194,7 @@
     ]
 
     def test_normcase(self):
-        # Check that normcase() is idempotent
+        # check that normcase() is idempotent
         p = "FoO/./BaR"
         p = self.pathmodule.normcase(p)
         self.assertEqual(p, self.pathmodule.normcase(p))
@@ -203,6 +203,10 @@
         p = self.pathmodule.normcase(p)
         self.assertEqual(p, self.pathmodule.normcase(p))
 
+        # check that it accepts only strings and bytes
+        for path in (None, True, 0, 2.5, []):
+            self.assertRaises(TypeError, self.pathmodule.normcase, path)
+
     def test_splitdrive(self):
         # splitdrive for non-NT paths
         splitdrive = self.pathmodule.splitdrive