Issue on Travis with matplotlib backend on OSX

[guilgautier]

https://travis-ci.org/guilgautier/DPPy/jobs/400324355

from dppy.discrete_dpps import *
../../../.pyenv/versions/3.4.6/lib/python3.4/site-packages/dppy/discrete_dpps.py:9: in <module>
    import matplotlib.pyplot as plt
../../../.pyenv/versions/3.4.6/lib/python3.4/site-packages/matplotlib/pyplot.py:115: in <module>
    _backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
../../../.pyenv/versions/3.4.6/lib/python3.4/site-packages/matplotlib/backends/__init__.py:62: in pylab_setup
    [backend_name], 0)
../../../.pyenv/versions/3.4.6/lib/python3.4/site-packages/matplotlib/backends/backend_macosx.py:17: in <module>
    from matplotlib.backends import _macosx
E   RuntimeError: Python is not installed as a framework. The Mac OS X backend will not be able to function correctly if Python is not installed as a framework. See the Python documentation for more information on installing Python as a framework on Mac OS X. Please either reinstall Python as a framework, or try one of the other backends. If you are using (Ana)Conda please install python.app and replace the use of 'python' with 'pythonw'. See 'Working with Matplotlib on OSX' in the Matplotlib FAQ for more information.

[guilgautier]

Potential fix https://matplotlib.org/faq/osx_framework.html or https://stackoverflow.com/a/43015816

[Naereen]

I think a dirty fix can be indeed https://stackoverflow.com/questions/3285193/how-to-switch-backends-in-matplotlib-python/43015816#43015816

See https://matplotlib.org/api/matplotlib_configuration_api.html#matplotlib.use

[guilgautier]

I tried the first option and it seems to have done job. The first option will only fix general issues with matplotlib on OSX for Travis, but not for local installation. What do you think @Naereen ?

[Naereen]

I don't think there is a problem with local installation, but cannot test it (no OSX at hand)

[guilgautier]

Should not be a problem you're right, @rbardenet wrote and ran the test locally on his Mac, closing the issue.