totally untested decorator swap plugin

gistfile1.py

## the plugin

from nose.plugins import Plugin

import thedecorators
import thingtwo

class Swapper(Plugin):
    enableOpt = 'swap'

    def options(self, parser, env):
        """Register commandline options.
        """
        parser.add_option('--swap-implementation',
                          action='store_true',
                          dest=self.enableOpt,
                          default=env.get('SWAPS'),
                          help="Swap thingone for thingtwo")


    def begin(self):
        # only called if plugin is active
        thedecorators._implementation = thingtwo


## inside thedecorators

import thingone

_implementation = thingone

def somedecorator(func):
    return _implementation.somedecorator(func)