How to use python-mock library

Question

I have problems with understanding mock library in python. Here is example: A have two files test.py and another.py

test.py

#!
from mock import patch
from another import C


class A(object):
    def method(self):
        return 2


@patch('another.C')
@patch('test.A')
class TestB(object):

    def test1(self, mA, mC):
        print mA, A
        print mC, C

another.py

class C(object):

    def a(self):
        return 3

So, question is "Why A have in output:

<MagicMock name='A' id='13985040'> <MagicMock name='A' id='13985040'>
<MagicMock name='C' id='13993936'> <class 'another.C'>

Why class from another.py can't be patched? In my case I have heavy function to test, and it imports classes from other files. So I cant understand how to them right.

Thanks

aychedee · Accepted Answer · 2012-07-15 15:24:18Z

2

With the Python mock library you always patch (mock) the function or class in the location that you are actually using it.

Since you are importing 'C' into 'test' and using it there you would patch it like this:

@patch('test.C')
@patch('test.A')
class TestB(object):

    def test1(self, mA, mC):
        print mA, A
        print mC, C

Which will give you output like this:

<MagicMock name='A' id='3070076204'> <MagicMock name='A' id='3070076204'>
<MagicMock name='C' id='3070084940'> <MagicMock name='C' id='3070084940'>

You can mock any class, method, or function that you want. But You need to mock the object in the location that it is actually being used.

answered Jul 15, 2012 at 15:24

aychedee

25.7k8 gold badges82 silver badges83 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How to use python-mock library

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related