It happens that in tests somewhere deep in the object hierarchies and structures something has to be mocked. This especially happens with external services and their clients.
Problem
If cloudpickle happens to stumble upon a mock, it fails and it's very difficult to track down which object and which attribute contains the mocked object (especially when there are a bunch of mocks).
Example
requirements.txt
cloudpickle==2.0.0
test_pickle.py
import unittest
from unittest.mock import MagicMock
import cloudpickle
class ToMock:
a: str
def __init__(self):
self.something = "something"
class Mockable:
def __init__(self, to_mock=None):
self.not_mocked = "this is not mocked"
self.to_be_mocked = to_mock or ToMock()
class TestPickling(unittest.TestCase):
def test_no_mocking(self):
self.assertIsInstance(cloudpickle.dumps(Mockable()), bytes)
def test_simple_mock(self):
self.assertIsInstance(cloudpickle.dumps(Mockable(MagicMock())), bytes)
def test_specced_mock(self):
self.assertIsInstance(cloudpickle.dumps(Mockable(MagicMock(spec=ToMock))), bytes)
def test_autospecced_mock(self):
self.assertIsInstance(cloudpickle.dumps(Mockable(unittest.mock.create_autospec(ToMock))), bytes)
if __name__ == '__main__':
unittest.main()
output
python test_pickle.py
Testing started at 19:05 ...
Launching unittests with arguments python -m unittest test_pickle.TestPickling in /home/bumbum/PycharmProjects/pythonProject
Error
Traceback (most recent call last):
File "/home/bumbum/PycharmProjects/pythonProject/test_pickle.py", line 33, in test_autospecced_mock
self.assertIsInstance(cloudpickle.dumps(Mockable(unittest.mock.create_autospec(ToMock))), bytes)
File "/home/python/cloudpickle-magic-mock/lib/python3.9/site-packages/cloudpickle/cloudpickle_fast.py", line 73, in dumps
cp.dump(obj)
File "/home/python/cloudpickle-magic-mock/lib/python3.9/site-packages/cloudpickle/cloudpickle_fast.py", line 602, in dump
return Pickler.dump(self, obj)
_pickle.PicklingError: args[0] from __newobj__ args has the wrong class
Error
Traceback (most recent call last):
File "/home/python/cloudpickle-magic-mock/lib/python3.9/site-packages/cloudpickle/cloudpickle_fast.py", line 602, in dump
return Pickler.dump(self, obj)
File "/usr/lib64/python3.9/unittest/mock.py", line 2500, in __call__
return _Call((self._mock_name, args, kwargs), name=name, parent=self)
File "/usr/lib64/python3.9/unittest/mock.py", line 2404, in __new__
_len = len(value)
RecursionError: maximum recursion depth exceeded while calling a Python object
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/home/bumbum/PycharmProjects/pythonProject/test_pickle.py", line 27, in test_simple_mock
self.assertIsInstance(cloudpickle.dumps(Mockable(MagicMock())), bytes)
File "/home/python/cloudpickle-magic-mock/lib/python3.9/site-packages/cloudpickle/cloudpickle_fast.py", line 73, in dumps
cp.dump(obj)
File "/home/python/cloudpickle-magic-mock/lib/python3.9/site-packages/cloudpickle/cloudpickle_fast.py", line 609, in dump
raise pickle.PicklingError(msg) from e
_pickle.PicklingError: Could not pickle object as excessively deep recursion required.
Error
Traceback (most recent call last):
File "/home/bumbum/PycharmProjects/pythonProject/test_pickle.py", line 30, in test_specced_mock
self.assertIsInstance(cloudpickle.dumps(Mockable(MagicMock(spec=ToMock))), bytes)
File "/home/python/cloudpickle-magic-mock/lib/python3.9/site-packages/cloudpickle/cloudpickle_fast.py", line 73, in dumps
cp.dump(obj)
File "/home/python/cloudpickle-magic-mock/lib/python3.9/site-packages/cloudpickle/cloudpickle_fast.py", line 602, in dump
return Pickler.dump(self, obj)
_pickle.PicklingError: args[0] from __newobj__ args has the wrong class
Ran 4 tests in 0.043s
FAILED (errors=3)
Scenario
It happens that in tests somewhere deep in the object hierarchies and structures something has to be mocked. This especially happens with external services and their clients.
Problem
If
cloudpickle
happens to stumble upon a mock, it fails and it's very difficult to track down which object and which attribute contains the mocked object (especially when there are a bunch of mocks).Example
requirements.txt cloudpickle==2.0.0
test_pickle.py
output