"""
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!'
)
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