From: Alex Young <alex@...>
Date: 2007-08-16T15:48:05+09:00
Subject: Re: Unit tests and destructive methods

darren kirby wrote:
> Hello all,
> 
> As my flac library approaches 1000 lines of code I decided it would be prudent 
> to finally get around to writing some unit tests, which I have done. Now: I 
> have created a 'reference' flac file with known values, which I then read to 
> see if my lib parses it correctly.
> 
> That works great for the 'read' part of the library, however, I am now adding 
> methods which write/rewrite values in the flac file (tags, padding blocks 
> etc) making permanent changes in the file, and I am wondering how best to 
> write tests for these.
> 
> I am thinking that I need to write code which makes a copy of the reference 
> file, write the changes, read the copy to ensure the changes were written 
> correctly, then delete the copy.
> 
> Does this seem reasonable? Is there a better way?
In addition to the other suggestions, you could write to a StringIO 
instead of to a File - that way you don't need to worry about touching 
the filesystem at all, and the changes stay in memory.

-- 
Alex