[Python-Dev] regrtest.py mystery (original) (raw)

Tim Peters tim.one@home.com
Sun, 16 Dec 2001 00:23:43 -0500

[Fred]

Perhaps it should hold onto the module as well? That would avoid it getting cleaned up before possibly dependent modules. For the test case problem, perhaps there should be a list of exceptional modules that don't get cleaned up by regrtest once they appear. encodings and warnings would probably both need to be on the list. This list should probably be in the sys module; it would also be useful for the RollbackImporter in the unittestgui.py script that comes with the separate PyUnit package.

I expect the problem is intractable. Here's a revealing experiment: add this block to the start of test___all__.check_all():

if modname in sys.modules:
    del sys.modules[modname]

That is, just prior to test___all__ trying to import a module, remove only that module from sys.modules if it's already there. Sounds pretty harmless, right? But on Windows, it causes 28 standard tests to fail (possibly more on Linux):

28 tests failed: test___all__ test_difflib test_email test_fileinput test_fnmatch test_future test_gettext test_glob test_global test_htmllib test_htmlparser test_inspect test_mimetypes test_mmap test_os test_pyclbr test_re test_regex test_repr test_scope test_sre test_strftime test_strop test_sundry test_tokenize test_urllib2 test_xmllib test_xmlrpc

Trying to figure which modules "hurt" turns out to be a nightmare. Here's the minimal set that allows the test suite to pass again on Windows, using the default test order:

if modname in sys.modules:
    if modname not in (

"copy_reg", "os", "sgmllib", "sre", "tempfile", "tokenize", "warnings", ): del sys.modules[modname]

Am I gonna check that in? Fat chance .