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

Brett Cannon brett at python.org
Thu Jul 8 21🔞17 CEST 2010

On Thu, Jul 8, 2010 at 07:59, Nick Coghlan <ncoghlan at gmail.com> wrote:

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): ============= pymoduletests = support.importfreshmodule('moduletester', fresh=['modulename'], blocked=['modulename']) cmoduletests = support.importfreshmodule('moduletester', fresh=['modulename', 'modulename']) testmodules = [pymoduletests, cmoduletests] suffixes = ["Py", "C"] for module, suffix in zip(testmodules, suffixes):  for obj in module.itervalues():  if isinstance(obj, unittest,TestCase):  obj.name += suffix  setattr(module, obj.name, obj) def testmain():  for module in testmodules:  module.testmain() =============

Very cool solution (assuming it works =) !

One issue I see with this is deciding how to organize tests that are specific to one version of a module compared to another. For instance, test_warnings has some tests specific to _warnings because of the hoops it has to jump through in order to get overriding showwarnings and friends to work. I guess I could try to make them generic enough that they don't require a specific module. Otherwise I would insert the module-specific tests into test_warnings to have that module also call gnostic_test_warnings to run the universal tests.

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