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Diffstat (limited to 'cloudinit/tests/test_persistence.py')
-rw-r--r-- | cloudinit/tests/test_persistence.py | 127 |
1 files changed, 0 insertions, 127 deletions
diff --git a/cloudinit/tests/test_persistence.py b/cloudinit/tests/test_persistence.py deleted file mode 100644 index ec1152a9..00000000 --- a/cloudinit/tests/test_persistence.py +++ /dev/null @@ -1,127 +0,0 @@ -# Copyright (C) 2020 Canonical Ltd. -# -# Author: Daniel Watkins <oddbloke@ubuntu.com> -# -# This file is part of cloud-init. See LICENSE file for license information. -""" -Tests for cloudinit.persistence. - -Per https://docs.python.org/3/library/pickle.html, only "classes that are -defined at the top level of a module" can be pickled. This means that all of -our ``CloudInitPickleMixin`` subclasses for testing must be defined at -module-level (rather than being defined inline or dynamically in the body of -test methods, as we would do without this constraint). - -``TestPickleMixin.test_subclasses`` iterates over a list of all of these -classes, and tests that they round-trip through a pickle dump/load. As the -interface we're testing is that ``_unpickle`` is called appropriately on -subclasses, our subclasses define their assertions in their ``_unpickle`` -implementation. (This means that the assertions will not be executed if -``_unpickle`` is not called at all; we have -``TestPickleMixin.test_unpickle_called`` to ensure it is called.) - -To avoid manually maintaining a list of classes for parametrization we use a -simple metaclass, ``_Collector``, to gather them up. -""" - -import pickle -from unittest import mock - -import pytest - -from cloudinit.persistence import CloudInitPickleMixin - - -class _Collector(type): - """Any class using this as a metaclass will be stored in test_classes.""" - - test_classes = [] - - def __new__(cls, *args): - new_cls = super().__new__(cls, *args) - _Collector.test_classes.append(new_cls) - return new_cls - - -class InstanceVersionNotUsed(CloudInitPickleMixin, metaclass=_Collector): - """Test that the class version is used over one set in instance state.""" - - _ci_pkl_version = 1 - - def __init__(self): - self._ci_pkl_version = 2 - - def _unpickle(self, ci_pkl_version: int) -> None: - assert 1 == ci_pkl_version - - -class MissingVersionHandled(CloudInitPickleMixin, metaclass=_Collector): - """Test that pickles without ``_ci_pkl_version`` are handled gracefully. - - This is tested by overriding ``__getstate__`` so the dumped pickle of this - class will not have ``_ci_pkl_version`` included. - """ - - def __getstate__(self): - return self.__dict__ - - def _unpickle(self, ci_pkl_version: int) -> None: - assert 0 == ci_pkl_version - - -class OverridenVersionHonored(CloudInitPickleMixin, metaclass=_Collector): - """Test that the subclass's version is used.""" - - _ci_pkl_version = 1 - - def _unpickle(self, ci_pkl_version: int) -> None: - assert 1 == ci_pkl_version - - -class StateIsRestored(CloudInitPickleMixin, metaclass=_Collector): - """Instance state should be restored before ``_unpickle`` is called.""" - - def __init__(self): - self.some_state = "some state" - - def _unpickle(self, ci_pkl_version: int) -> None: - assert "some state" == self.some_state - - -class UnpickleCanBeUnoverriden(CloudInitPickleMixin, metaclass=_Collector): - """Subclasses should not need to override ``_unpickle``.""" - - -class VersionDefaultsToZero(CloudInitPickleMixin, metaclass=_Collector): - """Test that the default version is 0.""" - - def _unpickle(self, ci_pkl_version: int) -> None: - assert 0 == ci_pkl_version - - -class VersionIsPoppedFromState(CloudInitPickleMixin, metaclass=_Collector): - """Test _ci_pkl_version is popped from state before being restored.""" - - def _unpickle(self, ci_pkl_version: int) -> None: - # `self._ci_pkl_version` returns the type's _ci_pkl_version if it isn't - # in instance state, so we need to explicitly check self.__dict__. - assert "_ci_pkl_version" not in self.__dict__ - - -class TestPickleMixin: - def test_unpickle_called(self): - """Test that self._unpickle is called on unpickle.""" - with mock.patch.object( - CloudInitPickleMixin, "_unpickle" - ) as m_unpickle: - pickle.loads(pickle.dumps(CloudInitPickleMixin())) - assert 1 == m_unpickle.call_count - - @pytest.mark.parametrize("cls", _Collector.test_classes) - def test_subclasses(self, cls): - """For each collected class, round-trip through pickle dump/load. - - Assertions are implemented in ``cls._unpickle``, and so are evoked as - part of the pickle load. - """ - pickle.loads(pickle.dumps(cls())) |