Subj : Re: Not debugging?
To   : comp.programming,comp.lang.java.programmer,comp.lang.lisp
From : Peter Ammon
Date : Thu Aug 25 2005 11:29 pm

Phlip wrote:
> Tim X wrote:
> 
> 
>>I'm guessing he was referring to the irritating development of
>>programmers who are not able to debug code without a high level IDE
>>which includes a debugger which allows them to step/trace through the
>>code one line at a time and watch what happens to variables in a watch
>>window.
> 
> 
> No. I'm talking about developers who don't write unit tests as they write 
> code. These provide the option of using Undo, instead of debugging, when the 
> tests fail unexpectedly.
> 
> This leads to a development cycle with highly bug-resistant code, and 
> without proactive debugging to implement new functions.
> 
> Yes, you still need the debugger - typically for legacy situations - and you 
> still need elaborate debugging skills. New code stays ahead of them.
> 
> The idea that we can implement without debugging is incomprehensible to most 
> programmers. But that really is what I meant.

I've been waiting for someone to make this claim about unit testing. 
Guess I'll pick on you :)

I don't believe that unit testing eliminates debugging.  I'll give a 
real life example.

We had a bug where an update to our library disabled some features of a 
  client program.  After some investigating, it was determined that the 
client program was doing this:

if (library_version == 3)

instead of this:

if (library_version >= 3)

Our fix for this bug was to detect the client and report 3 for the 
version if the client was the offending program, and otherwise report 
the true version.

This is the sort of bug that gets caught in integration testing.  I 
can't think of any way that unit testing would have helped this 
situation.  I'd be very interested in hearing how this sort of bug would 
be approached in the test-first "no debugging" philosophy.

-Peter

-- 
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.