'Run collectstatic, and capture and return the output. We want to run
the command at highest verbosity, which is why we can\'t
just call e.g. BaseCollectionTestCase.run_collectstatic()'

def _collectstatic_output(self, **kwargs):

    out = StringIO()
    call_command('collectstatic', interactive=False, verbosity=3, stdout=out, **kwargs)
    return out.getvalue()
