Fix one omission in r78359
diff --git a/Lib/test/test_shutil.py b/Lib/test/test_shutil.py
index 81c9036..270293a 100644
--- a/Lib/test/test_shutil.py
+++ b/Lib/test/test_shutil.py
@@ -515,6 +515,7 @@
 
         # check if the compressed tarball was created
         tarball = base_name + '.zip'
+        self.assertTrue(os.path.exists(tarball))
 
 
     def test_make_archive(self):