Greenlet dict wrapper behaves surprisingly on Travis

[hynek]

The addition of unrelated code led to a test failure: https://travis-ci.org/hynek/structlog/builds/11921511

=================================== FAILURES ===================================
_______________ TestThreadLocalDict.test_non_dunder_proxy_works ________________
self = <tests.test_threadlocal.TestThreadLocalDict object at 0x23a7c50>
D = <class 'structlog.threadlocal.WrappedDict-f561929d-5fca-4b25-afcf-956a40968ad0'>
    def test_non_dunder_proxy_works(self, D):
        d = D({'a': 42})
>       assert 1 == len(d)
E       assert 1 == 2
E        +  where 2 = len(<WrappedDict-f561929d-5fca-4b25-afcf-956a40968ad0({'a': 42, 'b': 23})>)
tests/test_threadlocal.py:131: AssertionError

It appears that the greenlet wrapper does not create distinct dict classes on each call but just one that shares the same data store within one greenlet.

That shouldn’t be a problem in practice, but it’s contrary to what the docs say.

I wasn’t able to trigger this bug locally. The test is commented out as of 1995a8b.

/cc @hpk42

[hynek]

Making tox use actually Python 3.3 made it go away. This is really odd so I’m keeping this bug open.

[hynek]

Fixed by 7de1f06