diff -r d0b4be7d2134 Lib/test/test_cpickle.py
--- a/Lib/test/test_cpickle.py	Fri Jan 29 00:55:37 2016 +0200
+++ b/Lib/test/test_cpickle.py	Fri Jan 29 10:22:49 2016 +0200
@@ -175,12 +175,14 @@ for name in dir(AbstractPickleTests):
     if name.startswith('test_recursive_'):
         func = getattr(AbstractPickleTests, name)
         if '_subclass' in name and '_and_inst' not in name:
-            assert_args = RuntimeError, 'maximum recursion depth exceeded'
+            # Issue #25698: The copy_reg module becomes unexpectedly empty
+            def wrapper(self):
+                self.skipTest("import with a very deep stack is broken")
         else:
             assert_args = ValueError, "can't pickle cyclic objects"
-        def wrapper(self, func=func, assert_args=assert_args):
-            with self.assertRaisesRegexp(*assert_args):
-                func(self)
+            def wrapper(self, func=func, assert_args=assert_args):
+                with self.assertRaisesRegexp(*assert_args):
+                    func(self)
         functools.update_wrapper(wrapper, func)
         setattr(cPickleFastPicklerTests, name, wrapper)