我可以在python unittests中伪造/模拟我的模拟对象的类型吗 [英] Can I fake/mock the type of my mock objects in python unittests

问题描述

在我的python代码中，我检查了其中一个参数的类型，以确保它属于我期望的类型.例如:

def myfunction(dbConnection):
    if (type(dbConnection)<>bpgsql.Connection):
        r['error'] += ' invalid database connection'

我想通过模拟连接来进行测试.有没有办法使模拟对象假装为正确的类型?

解决方案

以所有应有的尊重，看来你们不太正确！

我可以使用鸭子输入，但是首先有一种方法可以完成我打算做的事情:

来自 http://docs.python.org/dev/library/unittest .mock.html

使用类或实例作为spec或spec_set的模拟对象能够通过isintance测试:

>>>
>>> mock = Mock(spec=SomeClass)
>>> isinstance(mock, SomeClass)
True
>>> mock = Mock(spec_set=SomeClass())
>>> isinstance(mock, SomeClass)
True

所以我的示例代码如下:

m = mock.MagicMock(spec=bpgsql.Connection)
isinstance(m, bpgsql.Connection) 

这将返回True

所有这些，我并不是说要在python中进行严格的类型检查，我说如果您需要检查它就可以做到，它也可以与测试和模拟一起工作.

In my python code I check the type of one of the parameters to make sure it is of the type I expect. For instance:

def myfunction(dbConnection):
    if (type(dbConnection)<>bpgsql.Connection):
        r['error'] += ' invalid database connection'

I want to pass a mock connection for testing purposes. Is there a way to make the mock object pretend to be of the correct type?

解决方案

With all due respect, It looks like you guys are not quite right!

I can use duck typing as said, but there is a way to do what I intended to do in the first place:

from http://docs.python.org/dev/library/unittest.mock.html

Mock objects that use a class or an instance as a spec or spec_set are able to pass isintance tests:

>>>
>>> mock = Mock(spec=SomeClass)
>>> isinstance(mock, SomeClass)
True
>>> mock = Mock(spec_set=SomeClass())
>>> isinstance(mock, SomeClass)
True

so my example code would be like:

m = mock.MagicMock(spec=bpgsql.Connection)
isinstance(m, bpgsql.Connection) 

this returns True

All that said, I am not arguing for strict type checking in python, I say if you need to check it you can do it and it works with testing and mocking too.

这篇关于我可以在python unittests中伪造/模拟我的模拟对象的类型吗的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！