Recently at work my coworker Shinya Okano came across Modipyd written by Takanori Ishikawa. Modipyd is a module dependency monitoring framework which can build module dependency trees and monitor when modules have been changed. But most interesting feature it provides is the pyautotest tool.

pyautotest is a small daemon that will monitor modules in a project and automatically run tests that depend on a particular module when the module changes. This comes in really handy when writing python libraries and tools.

When run on the console it looks something like this:

ian@macbook-ian:~/src/mylib$ pyautotest
....
----------------------------------------------------------------------
Ran 4 tests in 0.002s

OK
..........
----------------------------------------------------------------------
Ran 10 tests in 0.001s

OK

Here I edited a couple files and pyautotest ran the tests that are dependent on those files.

Now to the really cool part. My other coworker Yosuke Ikeda wrote a test runner that will invoke growlnotify and show a growl message with the results of each test run. Inspired by this I went ahead and added support for libnotify on Linux using pynotify and Shinya Okano added support for Windows with Snarl.

When combined with pyautotest this makes for a really cool test driven development tool. Every time you save a file you get a notification if you did something dumb and broke a dependent test. Just install growltestrunner:

hg clone https://bitbucket.org/ae35/growltestrunner/
cd growltestrunner
python setup.py install

… and invoke pyautotest in your project directory like below

For growl:

pyautotest -r growltestrunner.GrowlTestRunner

For pynotify:

pyautotest -r growltestrunner.PynotifyTestRunner

For Snarl:

pyautotest -r growltestrunner.SnarlTestRunner