Added simple test case for the issue

tests/cloudpickle_test.py

@@ -680,6 +680,22 @@ def foo():
         finally:
             sys.modules.pop("_fake_module", None)
 
+    def test_dynamic_pytest_module(self):
+        # Test case for pull request https://github.com/cloudpipe/cloudpickle/pull/116
+        import py
+
+        def f():
+            s = py.builtin.set([1])
+            return s.pop()
+
+        # some setup is required to allow pytest apimodules to be correctly serializable.
+        from cloudpickle import CloudPickler
+        from py._apipkg import ApiModule
+        CloudPickler.dispatch[ApiModule] = CloudPickler.save_module
+        g = cloudpickle.loads(cloudpickle.dumps(f))
+
+        result = g()
+        self.assertEqual(1, result)
 
 if __name__ == '__main__':
     unittest.main()