Skip test that requires zlib when zlib is not available.

Lib/test/test_zipfile.py

diff --git a/Lib/test/test_zipfile.py b/Lib/test/test_zipfile.py
index 8d51528..90aab86 100644
--- a/Lib/test/test_zipfile.py
+++ b/Lib/test/test_zipfile.py
@@ -489,6 +489,7 @@
         except zipfile.BadZipFile:
             self.assertTrue(zipfp2.fp is None, 'zipfp is not closed')
 
+    @skipUnless(zlib, "requires zlib")
     def test_unicode_filenames(self):
         # bug #10801
         fname = findfile('zip_cp437_header.zip')