Hypothesis weird error

error.txt

cory@corymbp:hyper-h2/ % tox -e py27                      5d25507|twisted✓ [0m]
GLOB sdist-make: /Users/cory/Documents/Python/hyper-h2/setup.py
py27 inst-nodeps: /Users/cory/Documents/Python/hyper-h2/.tox/dist/h2-0.1.0.zip
py27 runtests: PYTHONHASHSEED='3864724170'
py27 runtests: commands[0] | py.test -n 4 --cov h2 /Users/cory/Documents/Python/hyper-h2/test/
============================= test session starts ==============================
platform darwin -- Python 2.7.10 -- py-1.4.30 -- pytest-2.7.2
rootdir: /Users/cory/Documents/Python/hyper-h2, inifile: 
plugins: hypothesis-pytest, cov, xdist, xdist, xdist
gw0 [33] / gw1 [31] / gw2 [31] / gw3 [33]
scheduling tests via LoadScheduling
collecting 0 items / 4 errors
==================================== ERRORS ====================================
_________________ ERROR collecting test/test_state_machines.py _________________
test/test_state_machines.py:18: in <module>
    class TestConnectionStateMachine(object):
test/test_state_machines.py:23: in TestConnectionStateMachine
    input_=sampled_from(h2.connection.ConnectionInputs))
.tox/py27/lib/python2.7/site-packages/hypothesis/core.py:456: in run_test_with_generator
    test.__name__, argspec
.tox/py27/lib/python2.7/site-packages/hypothesis/internal/reflection.py:431: in accept
    u'invocation': u', '.join(invocation_parts)
.tox/py27/lib/python2.7/site-packages/hypothesis/internal/reflection.py:359: in source_exec_as_module
    assert r.read() == source
E   assert '' == 'from hypothesis.utils.conventions import not_set\n\ndef accept(f):\n    def test_state_transitions(self, state=not_set, input_=not_set):\n        return f(self, state, input_)\n    return test_state_transitions\n'
E    +  where '' = <built-in method read of file object at 0x106b51030>()
E    +    where <built-in method read of file object at 0x106b51030> = <open file u'/Users/cory/Documents/Python/hyper-h2/.hypothesis/eval_source/hyp...y_module_29641d823094e91fb6f7a85e6fe7aca197c90b0e.py', mode 'r' at 0x106b51030>.read
------------------------------- Captured stderr --------------------------------
/Users/cory/Documents/Python/hyper-h2/.tox/py27/lib/python2.7/site-packages/hypothesis/core.py:662: HypothesisDeprecationWarning: You have an obsolete version of the hypothesis-pytest plugin installed. Please update to a more recent version.
  load_entry_points()
_________________ ERROR collecting test/test_state_machines.py _________________
test/test_state_machines.py:14: in <module>
    from hypothesis import given
.tox/py27/lib/python2.7/site-packages/hypothesis/__init__.py:29: in <module>
    from hypothesis.core import given, assume, find, example
.tox/py27/lib/python2.7/site-packages/hypothesis/core.py:32: in <module>
    import hypothesis.strategies as sd
.tox/py27/lib/python2.7/site-packages/hypothesis/strategies.py:179: in <module>
    def floats(min_value=None, max_value=None):
.tox/py27/lib/python2.7/site-packages/hypothesis/strategies.py:58: in defines_strategy
    @proxies(strategy_definition)
.tox/py27/lib/python2.7/site-packages/hypothesis/internal/reflection.py:443: in accept
    copy_argspec(target.__name__, inspect.getargspec(target))(proxy))
.tox/py27/lib/python2.7/site-packages/hypothesis/internal/reflection.py:431: in accept
    u'invocation': u', '.join(invocation_parts)
.tox/py27/lib/python2.7/site-packages/hypothesis/internal/reflection.py:359: in source_exec_as_module
    assert r.read() == source
E   assert '' == 'from hypothesis.utils.conventions import not_set\n\ndef accept(f):\n    def floats(min_value=not_set, max_value=not_set):\n        return f(min_value, max_value)\n    return floats\n'
E    +  where '' = <built-in method read of file object at 0x106e10930>()
E    +    where <built-in method read of file object at 0x106e10930> = <open file u'/Users/cory/Documents/Python/hyper-h2/.hypothesis/eval_source/hyp...y_module_1eba03841185292c6018ae372c9f399bb5b99054.py', mode 'r' at 0x106e10930>.read
_____________________________ ERROR collecting gw1 _____________________________
Different tests were collected between gw3 and gw1. The difference is:
--- gw3

+++ gw1

@@ -29,5 +29,3 @@

 test/test_basic_logic.py::TestBasicServer::()::test_no_preamble_errors
 test/test_basic_logic.py::TestBasicServer::()::test_headers_event
 test/test_basic_logic.py::TestBasicServer::()::test_data_event
-test/test_state_machines.py::TestConnectionStateMachine::()::test_state_transitions
-test/test_state_machines.py::TestStreamStateMachine::()::test_state_transitions
_____________________________ ERROR collecting gw2 _____________________________
Different tests were collected between gw3 and gw2. The difference is:
--- gw3

+++ gw2

@@ -29,5 +29,3 @@

 test/test_basic_logic.py::TestBasicServer::()::test_no_preamble_errors
 test/test_basic_logic.py::TestBasicServer::()::test_headers_event
 test/test_basic_logic.py::TestBasicServer::()::test_data_event
-test/test_state_machines.py::TestConnectionStateMachine::()::test_state_transitions
-test/test_state_machines.py::TestStreamStateMachine::()::test_state_transitions
--------------- coverage: platform darwin, python 2.7.10-final-0 ---------------
Name              Stmts   Miss  Cover
-------------------------------------
h2/__init__           2      0   100%
h2/connection       162    109    33%
h2/events            17      8    53%
h2/exceptions         3      0   100%
h2/frame_buffer      20     13    35%
h2/stream           142     96    32%
-------------------------------------
TOTAL               346    226    35%
=========================== 4 error in 3.09 seconds ============================
ERROR: InvocationError: '/Users/cory/Documents/Python/hyper-h2/.tox/py27/bin/py.test -n 4 --cov h2 /Users/cory/Documents/Python/hyper-h2/test/'
___________________________________ summary ____________________________________
ERROR:   py27: commands failed

Hi, did you ever find the cause of this problem?

could be this bug: HypothesisWorks/hypothesis#66