Yesterday I receipted an email answering this question:
coverage.py (the tool coveralls uses to measure coverage in Python programs) has a "coverage combine" command.
Yesterday, I got the global coverage executing something like this:
coverage erase
tox
coverage combine
coveralls
In tox.ini I added the "p" param:
python {envbindir}/coverage run -p testing/run_tests.py
python {envbindir}/coverage run -p testing/run_tests.py testing.settings_no_debug
I fixed the problem with these commits: