單元測試：修補的對象__base__

Question

從this question繼，我試圖修補A()類Mock()這樣，當B()被初始化，素被用作基本如：

class A(object): ... 
class B(A): ... 

def setUp(self): 
    with patch('A', new_callable=Mock) as MockObject: 
     self.b = B() 
     self.b.__class__.__base__ = MockOjbect 

不工作因爲基地是隻讀的。做這件事的正確方法是什麼？

更新：

>>> from mock import Mock 
>>> class A(object): 
...  pass 
... 
>>> class B(A): 
...  pass 
... 
>>> b.__class__.__bases__ = (Mock,) 
>>> b.__class__.__bases__ 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
    File "/opt/envs/myenv/local/lib/python2.7/site-packages/mock.py", line 656, in __getattr__ 
    elif self._mock_methods is not None: 
    File "/opt/envs/myenv/local/lib/python2.7/site-packages/mock.py", line 655, in __getattr__ 
    raise AttributeError(name) 
AttributeError: _mock_methods 

要清楚，我不相信這是要做到我想做的事情，我希望一半別人會拿出另一種方式的最佳途徑。

Answer 1

這是__bases__這是一個tuple。

修正版本：

class A(object): ... 
class B(A): ... 

def setUp(self): 
    with patch('A', new_callable=Mock) as MockObject: 
     self.b = B() 
     self.b.__class__.__bases__ = (MockOjbect,) 

參見：

>>> class Foo(object): 
...  pass 
... 
>>> Foo.__class__.__bases__ 
(<type 'object'>,) 

tuple的是不變但__bases__屬性肯定不是隻讀。