Issue 19572: More silently skipped tests explicitly skipped.
diff --git a/Lib/test/test_zipimport.py b/Lib/test/test_zipimport.py
index f7cb8b9..37603b9 100644
--- a/Lib/test/test_zipimport.py
+++ b/Lib/test/test_zipimport.py
@@ -111,7 +111,7 @@
         # so we'll simply skip it then. Bug #765456.
         #
         if "zlib" in sys.builtin_module_names:
-            return
+            self.skipTest('zlib is a builtin module')
         if "zlib" in sys.modules:
             del sys.modules["zlib"]
         files = {"zlib.py": (NOW, test_src)}