[Python-Dev] Python equivalents in stdlib Was: Include datetime.py in stdlib or not?

[Nick Coghlan]

On Thu, Jul 8, 2010 at 9:13 AM, Benjamin Peterson <benjamin at python.org> wrote:
> 2010/7/7 Nick Coghlan <ncoghlan at gmail.com>:
>> On Thu, Jul 8, 2010 at 7:56 AM, Michael Foord <fuzzyman at voidspace.org.uk> wrote:
>>> Using a class decorator to duplicate each _test_ into two test_* methods
>>> sounds  like a good approach.
>>
>> Note that parameterised methods have a similar problem to
>> parameterised modules - unittest results are reported in terms of
>> "testmodule.testclass.testfunction", so proper attribution of results
>> in the test output will require additional work. The separate
>> subclasses approach doesn't share this issue, since it changes the
>> value of the second item in accordance with the module under test.
>
> A good parameterized implementation, though, gives the repr() of the
> parameters in failure output.

That would qualify as "additional work" if your tests aren't already
set up that way (and doesn't cover the case of unexpected exceptions
in a test, where the test method doesn't get to say much about the way
the error is reported).

I realised during the day that my suggested approach was more
complicated than is actually necessary - once the existing tests have
been moved to a separate module, *that test module* can itself be
imported twice, once with the python version of the module to be
tested and once with the C version. You can then do some hackery to
distinguish the test classes without having to modify the test code
itself (note, the below code should work in theory, but isn't actually
tested):

=============
py_module_tests = support.import_fresh_module('moduletester',
fresh=['modulename'], blocked=['_modulename'])
c_module_tests = support.import_fresh_module('moduletester',
fresh=['modulename', '_modulename'])

test_modules = [py_module_tests, c_module_tests]
suffixes = ["_Py", "_C"]

for module, suffix in zip(test_modules, suffixes):
    for obj in module.itervalues():
        if isinstance(obj, unittest,TestCase):
            obj.__name__ += suffix
            setattr(module, obj.__name__, obj)

def test_main():
    for module in test_modules:
        module.test_main()
=============

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia