Python模拟类实例变量

Question

我正在使用Python的mock库。我知道如何通过遵循document嘲笑一个类的实例方法：

>>> def some_function(): 
...  instance = module.Foo() 
...  return instance.method() 
... 
>>> with patch('module.Foo') as mock: 
...  instance = mock.return_value 
...  instance.method.return_value = 'the result' 
...  result = some_function() 
...  assert result == 'the result' 

然而，试图嘲笑一个类的实例变量，但（在下面的例子中instance.labels）不工作：

>>> with patch('module.Foo') as mock: 
...  instance = mock.return_value 
...  instance.method.return_value = 'the result' 
...  instance.labels = [1, 1, 2, 2] 
...  result = some_function() 
...  assert result == 'the result' 

基本上我想instance.labels根据some_function得到我想要的值。任何提示？

Answer 1

这的some_function()打印版本嘲笑labels属性：

def some_function(): 
    instance = module.Foo() 
    print instance.labels 
    return instance.method() 

我module.py：

class Foo(object): 

    labels = [5, 6, 7] 

    def method(self): 
     return 'some' 

补丁是一样的你：

with patch('module.Foo') as mock: 
    instance = mock.return_value 
    instance.method.return_value = 'the result' 
    instance.labels = [1,2,3,4,5] 
    result = some_function() 
    assert result == 'the result 

完全控制台会话：

>>> from mock import patch 
>>> import module 
>>> 
>>> def some_function(): 
...  instance = module.Foo() 
...  print instance.labels 
...  return instance.method() 
... 
>>> some_function() 
[5, 6, 7] 
'some' 
>>> 
>>> with patch('module.Foo') as mock: 
...  instance = mock.return_value 
...  instance.method.return_value = 'the result' 
...  instance.labels = [1,2,3,4,5] 
...  result = some_function() 
...  assert result == 'the result' 
...  
... 
[1, 2, 3, 4, 5] 
>>> 

对我来说你的代码是的工作。