Not sure what the problem is. Tox works fine locally but we've hit a few problems recently.
A sample TB can be found here http://build.adimian.com/job/openpyxl-2.0/26/console
But the key line is:
E ImportMismatchError: ('openpyxl.conftest', '/var/lib/jenkins/workspace/openpyxl-2.0/openpyxl/conftest.py', local('/var/lib/jenkins/workspace/openpyxl-2.0/.tox/py34/lib64/python3.4/site-packages/openpyxl/conftest.py'))
Looking at the source this relates to problems with file but what problems? Should the two files be the same?