Amaury, yes, it would be nice if pickle were more reliable here.  But
that should be the topic of a different tracker issue.  Despite the
Title, this issue is really about sporadic pickletools.py failures, and
the pickletools tests are trying to test pickletools, not pickle.py (or
cPickle).  Changing the test as suggested makes it reliably test what
it's trying to test (namely that pickletools.dis() produces sensible
output for pickle's GLOBAL opcode).  Whether pickle/cPickle should do a
better job of building GLOBAL opcodes in the first place is a distinct
issue.

In any case, since pickle/cPickle have worked this way forever, and the
only known bad consequence to date is accidental sporadic test failures
in pickletools.py, the underlying pickle/cPickle issue shouldn't be a
release blocker regardless.