Re: [Zope-dev] zope.testrunner test failures on windows

15 Aug 2008

      On Tue, Aug 12, 2008 at 09:17:39PM +0100, Chris Withers wrote:
...
I could have sworn I reported this before but couldn't find anything in 
the archives so apologies if I have posted this before...
I have a feeling of deja vu about this...
...
Anyway, running zope.testrunner's trunk's tests on windows seems to have 
some problems. These don't occur when running them on Linux.
I'm vaguely interested in fixing these, but I don't do Windows.
...
File "zope.testing\src\zope\testing\testrunner\testrunner-debugging-
layer-setup.test", line 45, in testrunner-debugging-layer-setup.test
...
       File "zope.testing\src\zope\testing\testrunner\find.py", line
103, in find_suites
         suite = StartUpFailure(
Let's look at this statement closer:

                try:
                    module = import_name(module_name)
                except KeyboardInterrupt:
                    raise
                except:
-->                 suite = StartUpFailure(
                        options, module_name,
                        sys.exc_info()[:2]
                        + (sys.exc_info()[2].tb_next.tb_next,),
                        )

It would appear that the traceback is shallower than the code expects.  I don't
know why it is trying to strip the first two frames of the stack, either.
...
File "zope.testing\src\zope\testing\testrunner\find.py", line
36, in __init__
         post_mortem(exc_info)
       File "zope.testing\src\zope\testing\testrunner\runner.py", lin
e 717, in post_mortem
         pdb.post_mortem(exc_info[2])
       File "Python24\lib\pdb.py", line 1016, in post_mortem
         while t.tb_next is not None:
Apparently the traceback was exactly two frames deep, and with those stripped,
the code passed None to pdb.post_mortem().

It would be good if someone who has Windows and Linux could compare the
tracebacks in question.

I'd also suggest extracting the stack frame stripping into a function
that would be a bit more defensive:

    def strip_tb_frames((exc_type, exc_value, tb), count):
        while tb.tb_next is not None and count > 0:
            tb = tb.tb_next
            count -= 1
        return (exc_type, exc_value, tb)

and call it like this

                    suite = StartUpFailure(
                        options, module_name,
                        strip_tb_frames(sys.exc_info(), 2)
                        )

(Why oh why does Guido want to take away my beloved implicit argument
tuple unpacking in Python 3.0?)
...
AttributeError: 'NoneType' object has no attribute 'tb_next'
Next error:
...
Failure in test zope.testing\src\zope\testing\testrunner\testrunner-
coverage-win32.txt
Failed doctest test for testrunner-coverage-win32.txt
   File "zope.testing\src\zope\testing\testrunner\testrunner-coverage
-win32.txt", line 0
The name of this test suggests it's only run under Win32, so any refactoring
done on Linux is likely to break it without anyone noticing.
...
----------------------------------------------------------------------
File "zope.testing\src\zope\testing\testrunner\testrunner-coverage-w
in32.txt", line 14, in testrunner-coverage-win32.txt
Failed example:
     ignore = testrunner.TestIgnore(WinOptions())
Exception raised:
     Traceback (most recent call last):
       File "zope.testing\src\zope\testing\doctest.py", line 1356, in
  __run
         compileflags, 1) in test.globs
       File "<doctest testrunner-coverage-win32.txt[2]>", line 1, in ?
     AttributeError: 'module' object has no attribute 'TestIgnore'
TestIgnore moved from zope.testing.testrunner to
zope.testing.testrunner.coverage.  It should be simple to fix the test.
...
Ran 183 tests with 2 failures and 0 errors in 43.094 seconds.
Tearing down left over layers:
   Tear down zope.testing.testrunner.layer.UnitTests in 0.000 seconds.
Marius Gedminas
-- 
An NT server can be run by an idiot, and usually is.