Issue #19572: More silently skipped tests explicitly skipped.
diff --git a/Lib/test/test_site.py b/Lib/test/test_site.py
index f4b5fc6..0898449 100644
--- a/Lib/test/test_site.py
+++ b/Lib/test/test_site.py
@@ -343,6 +343,7 @@
             self.assertNotIn(path, seen_paths)
             seen_paths.add(path)
 
+    @unittest.skip('test not implemented')
     def test_add_build_dir(self):
         # Test that the build directory's Modules directory is used when it
         # should be.