""" Helpers for working with Zope and its components. """ import atexit import warnings from typing import Set from zope.component import getSiteManager from zope.interface.registry import Components class TestComponents: """ A helper for providing a sterile registry when testing with ``zope.component``. Instantiation will install an empty registry that will be returned by :func:`zope.component.getSiteManager`. """ __test__: bool = False instances: Set['TestComponents'] = set() atexit_setup: bool = False def __init__(self): self.registry: Components = Components('Testing') self.old: Components = getSiteManager.sethook(lambda: self.registry) self.instances.add(self) if not self.__class__.atexit_setup: atexit.register(self.atexit) self.__class__.atexit_setup = True def uninstall(self): """ Remove the sterile registry and replace it with the one that was in place before this :class:`TestComponents` was instantiated. """ getSiteManager.sethook(self.old) self.instances.remove(self) @classmethod def atexit(cls): if cls.instances: warnings.warn( 'TestComponents instances not uninstalled by shutdown!' )