Protobuf error on OS X: KeyError ('DESCRIPTOR')

[fritzo]

On OS X

$ uname -a
Darwin fritz-air 15.2.0 Darwin Kernel Version 15.2.0: Fri Nov 13 19:56:56 PST 2015; root:xnu-3248.20.55~2/RELEASE_X86_64 x86_64

$ make test
...
pomagma.workers_test.test_structure_queue ... ok

======================================================================
ERROR: Failure: KeyError ('DESCRIPTOR')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/fritz/.virtualenvs/pomagma/lib/python2.7/site-packages/nose/loader.py", line 523, in makeTest
    return self._makeTest(obj, parent)
  File "/Users/fritz/.virtualenvs/pomagma/lib/python2.7/site-packages/nose/loader.py", line 568, in _makeTest
    obj = transplant_class(obj, parent.__name__)
  File "/Users/fritz/.virtualenvs/pomagma/lib/python2.7/site-packages/nose/util.py", line 642, in transplant_class
    class C(cls):
  File "/Users/fritz/.virtualenvs/pomagma/lib/python2.7/site-packages/google/protobuf/internal/python_message.py", line 131, in __new__
    descriptor = dictionary[GeneratedProtocolMessageType._DESCRIPTOR_KEY]
KeyError: 'DESCRIPTOR'

----------------------------------------------------------------------
Ran 337 tests in 218.073s

FAILED (SKIP=8, errors=1)

[caimaoy]

Yes, I have the same problem

[drielsma]

I've been banging my head against this for a while and finally realized that this error arises when nose is trying to discover whether there are any tests in compiled python files that were generated by protoc (test models that I load in my unit tests). Excluding them via -e does the trick, ie nosetests -e _pb2.py

[fritzo]

Thanks, @drielsma ! I've switched from nose to pytest, so hopefully this error will no longer arise.