python - 创建无法 pickle 的对象

如何在rpc代码中轻松创建无法 pickle 以测试边缘情况的对象？

它必须是:

简单

可靠(在将来的python或pickle版本中不会中断)

跨平台

编辑:预期用途看起来像这样:

class TestRPCServer:
    def foo(self):
        return MagicalUnpicklableObject()

def test():
    with run_rpc_server_and_connect_to_it() as proxy:
        with nose.assert_raises(pickle.PickleError):
            proxy.foo()

最佳答案

如果您只需要一个在 pickle 时将引发异常的对象，则出于测试目的，您可以炸毁 __getstate__ method。

>>> class C:
...     def __getstate__(self):
...         raise Exception
...
>>> pickle.dumps(C())
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 1374, in dumps
    Pickler(file, protocol).dump(obj)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 224, in dump
    self.save(obj)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 723, in save_inst
    stuff = getstate()
  File "<stdin>", line 3, in __getstate__
Exception

如果您希望减少人为的情况，请考虑使用OS资源的对象，例如文件句柄，套接字或线程等。

>>> with open('spam.txt', 'w') as f:
...     pickle.dumps(f)
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 1374, in dumps
    Pickler(file, protocol).dump(obj)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 224, in dump
    self.save(obj)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 306, in save
    rv = reduce(self.proto)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/copy_reg.py", line 70, in _reduce_ex
    raise TypeError, "can't pickle %s objects" % base.__name__
TypeError: can't pickle file objects

关于python - 创建无法 pickle 的对象，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/35724255/