[ Python 常見問題 ] Python mock call_args_list unpacking tuples for assertion on arguments

Source From Here 
Question 
I'm having some trouble dealing with the nested tuple which Mock.call_args_list returns: 

view plaincopy to clipboardprint?

1. from unittest.mock import Mock  
2.   
3. def test_foo():  
4.     def foo(fn):  
5.         fn('PASS and some other stuff')  
6.   
7.     f = Mock(return_value=None)  
8.     foo(f)  
9.     foo(f)  
10.     foo(f)  
11.   
12.     for call in f.call_args_list:  
13.         pass  
14.         # make assertion here  

How-To 
I think that many of the difficulties here are wrapped up in the treatment of the "call" object. It can be thought of as a tuple with 2 members (args, kwargs) and so it's frequently nice to unpack it: 

view plaincopy to clipboardprint?

1. args, kwargs = call  

Once it's unpacked, then you can make your assertions separately for args and kwargs (since one is a tuple and the other a dict) 
- test.py 

view plaincopy to clipboardprint?

1. from unittest.mock import Mock  
2.   
3. cnt = 0  
4. names = ['John', 'Ken', 'Mary']  
5.   
6. def test_foo():  
7.     def foo(fn):  
8.         global cnt  
9.         fn('PASS and some other stuff ' + str(cnt), name=names[cnt])  
10.         cnt += 1  
11.   
12.     f = Mock(return_value=None)  
13.     foo(f)  
14.     foo(f)  
15.     foo(f)  
16.   
17.     for call in f.call_args_list:  
18.         args, kwargs = call  
19.         print('args={}; kwargs={}'.format(args, kwargs))  

Execution output: 

$ pytest -s test.py 
================================================================= test session starts ================================================================== 
platform linux -- Python 3.5.0, pytest-3.2.1, py-1.4.34, pluggy-0.4.0 
rootdir: /tmp, inifile: 
collected 1 item 

test.py args=('PASS and some other stuff 0',); kwargs={'name': 'John'} 
args=('PASS and some other stuff 1',); kwargs={'name': 'Ken'} 
args=('PASS and some other stuff 2',); kwargs={'name': 'Mary'}