Use tox to run tests on multiple versions of python

[xrotwang]

Running tests with tox [1] has some advantages:

• Running tests with multiple versions of python is simple.
• Proper package installation is tested as well. So for example
  the presence of README.rst when setup.py is run can only be
  guaranteed when this file is packaged with pygbif. tox will discover
  issues like this.

[1] https://pypi.python.org/pypi/tox

[coveralls]

Coverage remained the same at 57.878% when pulling a44b99b on xrotwang:master into 9ee5980 on sckott:master.

[sckott]

thanks, having a look

[sckott]

@xrotwang a few questions:

• how does integration with Travis happen? do we change this https://github.com/sckott/pygbif/blob/master/.travis.yml#L14-L15
• ever run into problems with PYTHONPATH? I often have this problem, where when I want to switch from python 2 to 3 and vice versa, I have to unset PYTHONPATH, then I can use python3, but after that python2 can't be found correctly - Any solutions?

[xrotwang]

No, Travis integration stays the same. tox does only help with running the tests locally. Basically, Travis and tox do the same thing: Create a virtualenv per python version, and run the tests there. But tox - unlike Travis - first creates a dist package from the sources and installs this dist package in each virtualenv. This is why I spotted the missing MANIFEST.in.

Since tox uses virtualenv to isolate test environements for each python version, problems with PYTHONPATH should not occur. This is taken care of by the virtualenv after all.

[sckott]

Hmm, i've always had a borked local python setup, so i'll just keep testing manually - and try to sort it out some day