unit testing CGI scripts?

[Richard Wesley]

In article <mailman.1415.1076423956.12720.python-list at python.org>,
 "Lee, Dustin" <dlee at rightnow.com> wrote:

> How about testing CGI scripts that access a database (I expect this is the 
> norm)?
> 
> I find writing unittests with non-cgi and non-database code very beneficial 
> and pretty straight forward.  I have yet to figure out how to do this with 
> cgi and database coding.  I'm starting to appreciate why pure functional 
> languages (Haskell, etc) really laud the praises of doing "side-effect free" 
> programming.  Of course it's hard conceive of using a database with out 
> actually changing it....
> 
> So who out there is doing cgi/db programming and actually testing it?

Layering is very helpful.  Have the cgi script entrypoint routine 
initialize a configuration class containing all the relevant information 
(database connection, host configuration, etc.).  Then call a routine 
that does all the work and returns the output in some structured 
representation (e.g. a dictionary).  Then have another standard routine 
that generates the output from that representation and maybe a style 
sheet.  

To test the code, you now need to check three interfaces:  the 
configuration object constructor, the page generator and the cgi 
implementation code.  The tests for the first two can be separate from 
the tests for an individual cgi entrypoint.  To test a particular API, 
all you need to do then is construct a variant of the configuration 
object that uses predefined data for each setUp e.g. it talks to a clean 
test database, it uses a clean section of the filesystem (I use 
tempdirs), it has "fake" hostname information (I use 
unittest.ourdomain.com).  Then you can look at the structured output, do 
diffs on the database, explore the filesystem and so on.

As you can see, the old dictum that you should design your code to be 
tested comes in here.  Good luck!

HTH,

-- 

- rmgw

<http://www.trustedmedianetworks.com/>

----------------------------------------------------------------------------
Richard Wesley                                  Trusted Media Networks, Inc.

"'You don't know how to manage Looking-glass cakes,' the Unicorn remarked.
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