Monday, August 8, 2011

From the frontline, day 1

I've decided to start the campaign by ditching the existing PHP web app. I lost all confidence in it last Friday, when I found that it only worked by accident, due to a well-placed typo.
As I'm rewriting the web app anyway, I thought I could also ditch PHP altogether. Not that it's necessarily a bad language for web apps, but the rest of the code is perl or python, so getting rid of php means one less language to get confused by.
Because this is the War on Legacy Code, I'm not going to write untested code in this campaign. So first I need to brush up my python unit testing skills. I do have parts of a python version of the web app already (untested, that won't work later), but it's missing a user feedback form.
I don't want to send an email for every run of the test suite, so I need to mock up smtplib.SMTP. After some web research, I'll be using Ian Bicking's minimock to provide my mock objects. As I don't just run doctests (even though they're pretty cool), I decided to also throw in MiniMockUnit, which makes minimock print the output to a StringIO buffer instead of stdout. That way, you can easily put it in a normal unit test.
I usually run my tests using nosetests. Turns out, nosetests allows me to run both vanilla unit tests and doctests, and it also has a code coverage plugin. Thus,
nosetests -v --with-doctest --with-coverage --cover-html --cover-package="testmodule"
will get the module "testmodule" tested using available unit tests, doctests and the test coverage will be reported in html in the cover/ directory. The --cover-package part seems to be needed to stop the coverage code from trying (and failing) to create coverage information files in the standard lib paths.
To sum up, I didn't actually see much battle.. er.. code today but my arsenal is filled with testing tools, and I'm well prepared to jump into the fray tomorrow. Also, thanks to some help from the folks on #gsoc IRC on freenode, I now have decent syntax highlighting and formatting on my blog, so I might be able to post code samples for real now. Life is good so far.

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