test_pkgutil should clean up spam module#123780
Description
When running the tests with --randomize, as is done by the buildbots, @mhsmith came across this failure:
====================================================================== ERROR: test_find_class (test.test_pickle.CUnpicklerTests.test_find_class) ---------------------------------------------------------------------- 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) ---------------------------------------------------------------------- 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' ---------------------------------------------------------------------- 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.