gistfile1.py

from tox import hookimpl

class GlobinterpreterPlugin:

    @hookimpl
    def tox_configure(self, config):
        self.config = config
        # postprocess config

    @hookimpl
    def tox_get_python_executable(self, name):
        return path-to-pyhon-executable

    @hookimpl
    def tox_addoption(self, parser):
        add command line options

I tried this::

from tox import hookimpl

print ('GIP loading ....')

class GlobInterpreterPlugin:

    @hookimpl
    def tox_configure(self, config):
        print('......... postprocess config')
        self.config = config

    @hookimpl
    def tox_get_python_executable(self, name):
        print('......... path-to-pyhon-executable')
        return None

    @hookimpl
    def tox_addoption(self, parser):
        print('......... add command line options')


gip = GlobInterpreterPlugin()

But I only get the "GIP loading ...." message. When I make the methods into global functions (and dropping the self parameter) they all get called. Am I missing something obvious? I can move forward, so this is not urgent.