Drop PyPI mock dependency; use unittest.mock instead

[musicinmybrain]

This is available in the Python standard library from version 3.3; sure advertises support for 3.6 and later in setup.py

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Summary

Since unittest.mock is in the Python standard library, the external dependency is unnecessary.

See also https://fedoraproject.org/wiki/Changes/DeprecatePythonMock; furthermore, an effort is underway to retire the python-mock package from Fedora Linux in a near-future release.

[musicinmybrain]

This PR only handles the mock/unittest.mock change. Removing the nose dependency and supporting pytest as in #161 would be even nicer, of course!

[musicinmybrain]

See also https://fedoraproject.org/wiki/Changes/DeprecatePythonMock; furthermore, an effort is underway to retire the python-mock package from Fedora Linux in a near-future release.

This is happening in the upcoming Fedora 40 release (F40 Change Proposal: Remove Python Mock Usage (System-Wide)), so I’m applying this PR as a downstream patch in Fedora Linux.

[gabrielfalcao]

@musicinmybrain the master branch presently moves code related to mock into sure.doubles.mocks along with a brief reasoning as to why.

[musicinmybrain]

@musicinmybrain the master branch presently moves code related to mock into sure.doubles.mocks along with a brief reasoning as to why.

I think I understand what you are doing there with respect to typing, but I am still working to understand the full context:

• Why work around two possible “flavors” of _CallList rather than removing the mock dependency and always using unittest.mock? Is it because you expect that some users have code with mock.mock._CallList and you need to integrate with that?
• Are you planning to remove the PyPI mock dependency soon? Can it at least be downgraded to a test dependency that can be more easily patched out?

[gabrielfalcao]

@musicinmybrain the master branch presently moves code related to mock into sure.doubles.mocks along with a brief reasoning as to why.

I think I understand what you are doing there with respect to typing, but I am still working to understand the full context:

• Why work around two possible “flavors” of _CallList rather than removing the mock dependency and always using unittest.mock? Is it because you expect that some users have code with mock.mock._CallList and you need to integrate with that?

The primary hypothesis in this case is that in supporting only unittest.mock._CallList, an inconsistent behavior could emerge in codebases using mock.mock._CallList. Nevertheless, the only logical reasoning applied in deciding to keep supporting mock._CallList entirely based on the following test:

from unittest.mock import _CallList as _CallList_
from mock.mock import _CallList
assert _CallList_ != _CallList

• Are you planning to remove the PyPI mock dependency soon? Can it at least be downgraded to a test dependency that can be more easily patched out?

Sure, that sounds reasonable.

[gabrielfalcao]

Fixed on release 3.0a1