From: Michael Malone <michael.malone@...>
Date: 2009-04-02T13:10:25+09:00
Subject: Re: official poll - unit testing

john maclean wrote:
> Hello,
> My name is Mr Official and I am hereby asking you to participating in
> my poll. "Do you really do unit testing?"
>
> Acceptable answers;
>
> * Janet Jackme does my dishes cos I unit test all of the time
> * I only unit test when < insert reason for testing>
>
>
>   
In truth, I only unit test after something breaks.  I guess I start 
doing things thinking "this will only be a one or two line change" and 
before I know it, I've added an extra module of code that is largely 
based on old code, but just different enough to break it.  I also find 
that working in Ruby is counter-productive to working up the mental 
drive to unit test.  This is not me getting all fanatic about ruby (ok, 
much) but it's true of other dynamic languages.  I grew up on Java and C 
and with that, one tends to get bogged down in so much detail trying to 
translate behaviour into code, that testing is a nice, high-level view 
of your program that validates your design to some degree.  In dynamic 
languages, things are already pretty high-level and the tendency here is 
to believe that writing code correctly every time is about as difficult 
as writing english sentences with correct grammar each time.  A quick 
run through the spell checker (ruby -wc) and everything's done, right? 

So yes, it's probably the confidence I get from a dynamic language 
_after_ C and the like that lets me believe that I've become a brilliant 
coder overnight because I can suddenly parse strings quickly without 
worrying about memory leaks, pointers and NUL chars (when I was at 
university we had a 10% test dedicated to doing just that!).  In short, 
the bug minefields I trained to be extra-worried about no longer exist, 
so setting up a Unit Test for the 'easy bits' mentally seems like more 
effort than it's worth.  Until it breaks.  Part of solving the problem 
is obviously defining the solution, to me, which is exactly where the 
test comes!

It might be a slightly contradictory way of looking at things, but it's 
certainly honest!

Michael

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