How to write a functional test for a DBUS service written in Python?

Question

(Title was: \"How to write a unit test for a DBUS service written in Python?\")

I\'ve started to write a DBUS service using dbus-python, but I\'m having trouble writ

Answer 1

With some help from Ali A's post, I have managed to solve my problem. The blocking event loop needed to be launched into a separate process, so that it can listen for events without blocking the test.

Please be aware my question title contained some incorrect terminology, I was trying to write a functional test, as opposed to a unit test. I was aware of the distinction, but didn't realise my mistake until later.

I've adjusted the example in my question. It loosely resembles the "test_pidavim.py" example, but uses an import for "dbus.glib" to handle the glib loop dependencies instead of coding in all the DBusGMainLoop stuff:

import unittest

import os
import sys
import subprocess
import time

import dbus
import dbus.service
import dbus.glib
import gobject

class MyDBUSService(dbus.service.Object):

    def __init__(self):
        bus_name = dbus.service.BusName('test.helloservice', bus = dbus.SessionBus())
        dbus.service.Object.__init__(self, bus_name, '/test/helloservice')

    def listen(self):
        loop = gobject.MainLoop()
        loop.run()

    @dbus.service.method('test.helloservice')
    def hello(self):
        return "Hello World!"


class BaseTestCase(unittest.TestCase):

    def setUp(self):
        env = os.environ.copy()
        self.p = subprocess.Popen(['python', './dbus_practice.py', 'server'], env=env)
        # Wait for the service to become available
        time.sleep(1)
        assert self.p.stdout == None
        assert self.p.stderr == None

    def testHelloService(self):
        bus = dbus.SessionBus()
        helloservice = bus.get_object('test.helloservice', '/test/helloservice')
        hello = helloservice.get_dbus_method('hello', 'test.helloservice')
        assert hello() == "Hello World!"

    def tearDown(self):
        # terminate() not supported in Python 2.5
        #self.p.terminate()
        os.kill(self.p.pid, 15)

if __name__ == '__main__':

    arg = ""
    if len(sys.argv) > 1:
        arg = sys.argv[1]

    if arg == "server":
        myservice = MyDBUSService()
        myservice.listen()

    else:
        unittest.main()