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Direktori : /lib/python3/dist-packages/keyring/testing/ |
Current File : //lib/python3/dist-packages/keyring/testing/util.py |
import contextlib import os import sys import random import string class ImportKiller: "Context manager to make an import of a given name or names fail." def __init__(self, *names): self.names = names def find_module(self, fullname, path=None): if fullname in self.names: return self def load_module(self, fullname): assert fullname in self.names raise ImportError(fullname) def __enter__(self): self.original = {} for name in self.names: self.original[name] = sys.modules.pop(name, None) sys.meta_path.insert(0, self) def __exit__(self, *args): sys.meta_path.remove(self) for key, value in self.original.items(): if value is not None: sys.modules[key] = value @contextlib.contextmanager def NoNoneDictMutator(destination, **changes): """Helper context manager to make and unmake changes to a dict. A None is not a valid value for the destination, and so means that the associated name should be removed.""" original = {} for key, value in changes.items(): original[key] = destination.get(key) if value is None: if key in destination: del destination[key] else: destination[key] = value yield for key, value in original.items(): if value is None: if key in destination: del destination[key] else: destination[key] = value def Environ(**changes): """A context manager to temporarily change the os.environ""" return NoNoneDictMutator(os.environ, **changes) ALPHABET = string.ascii_letters + string.digits def random_string(k, source=ALPHABET): """Generate a random string with length <i>k</i>""" result = '' for i in range(0, k): result += random.choice(source) return result