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From: Cecil Westerhof <Cecil@decebal.nl>
Newsgroups: comp.lang.python
Subject: Re: Is this a good way to implement testing
Organization: Decebal Computing
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Date: Sun, 03 May 2015 11:49:44 +0200
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Op Sunday 3 May 2015 10:45 CEST schreef Peter Otten:

> Cecil Westerhof wrote:
>
>> Another question. Is it acceptable to have it in the module itself,
>> or should I put it in something like test_<module>.py? The code for
>> testing is bigger as the code for the implementation, so I am
>> leaning to putting it in a separate file.
>
> Definitely use an established testing framework instead of rolling
> your own, and definitely put it into a separate file -- by the time
> there is good coverage the test code is usually much bigger than the
> tested code.

Yep, the module already has 370 lines of testing code and only 225 of
working code. And I just started.


> Be aware that there is also doctest which scans docstrings for text
> resembling interactive Python sessions. Doctests are both tests and
> usage examples, so I think it's good to put a few of these into the
> module. Here's how it works:
>
> $ cat factorial.py
> def factorial(n):
> """Calculate the factorial 1 * 2 * ... * n.
>
>>>> factorial(0)
> 1
>>>> factorial(1)
> 1
>>>> factorial(10)
> 3628800 """ return 1 $ python3 -m doctest factorial.py
> **********************************************************************
> File "/home/peter/clpy/factorial.py", line 8, in factorial.factorial
> Failed example: factorial(10) Expected: 3628800 Got: 1
> **********************************************************************
> 1 items had failures: 1 of 3 in factorial.factorial ***Test
> Failed*** 1 failures. $

That looks very promising. But I use the test to verify the
correctness and show the performance. Is that also possible? Or should
I split those out.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof