ENH: GH-35611 Tests for top-level Pandas functions serializable (#35692)

Author: ikedaosushi

pandas/tests/test_common.py

@@ -10,6 +10,7 @@
 
 import pandas as pd
 from pandas import Series, Timestamp
+import pandas._testing as tm
 from pandas.core import ops
 import pandas.core.common as com
 
@@ -157,3 +158,12 @@ def test_version_tag():
         raise ValueError(
             "No git tags exist, please sync tags between upstream and your repo"
         )
+
+
+@pytest.mark.parametrize(
+    "obj", [(obj,) for obj in pd.__dict__.values() if callable(obj)]
+)
+def test_serializable(obj):
+    # GH 35611
+    unpickled = tm.round_trip_pickle(obj)
+    assert type(obj) == type(unpickled)