gh-123780: Make test_pkgutil clean up `spam` module by mhsmith · Pull Request #123036 · python/cpython

mhsmith

When running the tests with --randomize, as is done by the buildbots, I came across this failure:

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ERROR: test_find_class (test.test_pickle.CUnpicklerTests.test_find_class)
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Traceback (most recent call last):
  File "/Users/msmith/git/python/cpython/Lib/test/pickletester.py", line 1265, in test_find_class
    self.assertRaises(ModuleNotFoundError, unpickler.find_class, 'spam', 'log')
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/unittest/case.py", line 804, in assertRaises
    return context.handle('assertRaises', args, kwargs)
           ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/unittest/case.py", line 238, in handle
    callable_obj(*args, **kwargs)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
AttributeError: module 'spam' has no attribute 'log'

======================================================================
ERROR: test_find_class (test.test_pickle.PyUnpicklerTests.test_find_class)
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Traceback (most recent call last):
  File "/Users/msmith/git/python/cpython/Lib/test/pickletester.py", line 1265, in test_find_class
    self.assertRaises(ModuleNotFoundError, unpickler.find_class, 'spam', 'log')
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/unittest/case.py", line 804, in assertRaises
    return context.handle('assertRaises', args, kwargs)
           ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/unittest/case.py", line 238, in handle
    callable_obj(*args, **kwargs)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/pickle.py", line 1620, in find_class
    return getattr(sys.modules[module], name)
AttributeError: module 'spam' has no attribute 'log'

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Ran 857 tests in 2.954s

FAILED (errors=2, skipped=31)
test test_pickle failed

This can be reproduced by running only test_pkgutil and test_pickle, in that order. test_pkgutil leaves behind a spam module in sys.modules, while test_pickle assumes there is no such module.