Python watch for modified files and run tests

watch

#!/usr/bin/env python

"""
-Thanks to Shawn Milochik for this - saved for future reference
Run unit test suite every time a Python file
is modified.

Requires pyinotify:
    https://github.com/seb-m/pyinotify
"""
import os
from time import sleep

import pyinotify

from django.core.management import call_command

watch_manager = pyinotify.WatchManager()

class EventHandler(pyinotify.ProcessEvent):

    #we use IN_CLOSE_WRITE instead of IN_MODIFY
    #because it happens only once per file save
    def process_IN_CLOSE_WRITE(self, event):

        #ignore non-Python files
        if event.pathname.split(os.extsep)[-1] != 'py':
            return False

        try:
            call_command('test',
                'myapp1', 'myapp2',
            )
        except SystemExit as ex:
            """
            needed in case the the test runner
            calls sys.exit(), which it does if
            there are any test failures
            """
            pass

        #let's not run tests like crazy -- 
        #I like to hit 'save' pretty frequently.
        sleep(30)

handler = EventHandler()
notifier = pyinotify.Notifier(watch_manager, handler)
watch_dir = watch_manager.add_watch('.', pyinotify.IN_CLOSE_WRITE, rec = True)
notifier.loop()