Archiv für September 2012

Announcing D-Bus mocker library

I was working on writing tests for gnome-settings-daemon a week or so ago, and finally got blocked on being unable to set up upower/ConsoleKit/etc. the way I need them. Also, doing so needs root privileges, I don’t want my test suite to actually suspend my machine, and using the real service is generally not suitable for test suites that are supposed to run during “make check”, in jhbuild, and the like — these do not have the polkit privileges to do all that, and may not even have a system D-Bus running in the first place.

So I wrote a little test_upower.py helper, then realized that I need another one for systemd/ConsoleKit (for the “system idle” property), also looked at the mock polkit in udisks and finally sat down for two days to generalize this and do this properly.

The result is python-dbusmock, I just released the first tarball. With this you can easily create mock objects on D-Bus from any programming language with a D-Bus binding, or even from the shell.

The mock objects look like the real API (or at least the parts that you actually need), but they do not actually do anything (or only some action that you specify yourself). You can configure their state, behaviour and responses as you like in your test, without making any assumptions about the real system status.

When using a local system/session bus, you can do unit or integration testing without needing root privileges or disturbing a running system. The Python API offers some convenience functions like “start_session_bus()“ and “start_system_bus()“ for this, in a “DBusTestCase“ class (subclass of the standard “unittest.TestCase“).

Surprisingly I found very little precedence here. There is a Perl module, but that’s not particuarly helpful for test suites in C/Vala/Python. And there is Phil’s excellent Bendy Bus, but this has a different goal: If you want to thoroughly test a particular D-BUS service, such as ensuring that it does the right thing, doesn’t crash on bad input, etc., then Bendy Bus is for you (and python-dbusmock isn’t). However, it is too much overhead and rather inconvenient if you want to test a client-side program and just need a few system services around it which you want to set up in different states for each test.

You can use python-dbusmock with any programming language, as you can run the mocker as a normal program. The actual setup of the mock (adding objects, methods, properties, etc.) all happen via D-Bus methods on the “org.freedesktop.DBus.Mock“ interface. You just don’t have the convenience D-Bus launch API.

The simplest possible example is to create a mock upower with a single Suspend() method, which you can set up like this from Python:

import dbus
import dbusmock

class TestMyProgram(dbusmock.DBusTestCase):
[...]
    def setUp(self):
        self.p_mock = self.spawn_server('org.freedesktop.UPower',
                                        '/org/freedesktop/UPower',
                                        'org.freedesktop.UPower',
                                        system_bus=True,
                                        stdout=subprocess.PIPE)

        # Get a proxy for the UPower object's Mock interface
        self.dbus_upower_mock = dbus.Interface(self.dbus_con.get_object(
            'org.freedesktop.UPower', '/org/freedesktop/UPower'),
            'org.freedesktop.DBus.Mock')

        self.dbus_upower_mock.AddMethod('', 'Suspend', '', '', '')

[...]

    def test_suspend_on_idle(self):
        # run your program in a way that should trigger one suspend call
        
        # now check the log that we got one Suspend() call
        self.assertRegex(self.p_mock.stdout.readline(), b'^[0-9.]+ Suspend$')

This doesn’t depend on Python, you can just as well run the mocker like this:

python3 -m dbusmock org.freedesktop.UPower /org/freedesktop/UPower org.freedesktop.UPower

and then set up the mocks through D-Bus like

gdbus call --system -d org.freedesktop.UPower -o /org/freedesktop/UPower \
      -m org.freedesktop.DBus.Mock.AddMethod '' Suspend '' '' ''

If you use it with Python, you get access to the dbusmock.DBusTestCase class which provides some convenience functions to set up and tear down local private session and system buses. If you use it from another language, you have to call dbus-launch yourself.

Please see the README for some more details, pointers to documentation and examples.

Update: You can now install this via pip from PyPI or from the daily builds PPA.

Update 2: Adjusted blog entry for version 0.0.3 API, to avoid spreading now false information too far.

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PyGObject 3.3.92 released

I just released PyGObject 3.3.92, for GNOME 3.5.92.

There is nothing too exciting in this release; a couple of small bug fixes and a lot of new test cases. See the detailled list of changes below.

Thanks to all contributors!

Changes:

  • release-news: Generate HTML changelog (Martin Pitt)
  • [API add] Add ObjectInfo.get_abstract method (Simon Feltman) (#675581)
  • Add deprecation warning when setting gpointers to anything other than int. (Simon Feltman) (#683599)
  • test_properties: Test accessing a property from a superclass (Martin Pitt) (#684058)
  • test_properties.py: Consistent test names (Martin Pitt)
  • test_everything: Ensure TestSignals callback does get called (Martin Pitt)
  • argument: Fix 64bit integer convertion from GValue (Nicolas Dufresne) (#683596)
  • Add Simon Feltman as a project maintainer (Martin Pitt)
  • test_signals.py: Drop global type variables (Martin Pitt)
  • test_signals.py: Consistent test names (Martin Pitt)
  • Add test cases for GValue signal arguments (Martin Pitt) (#683775)
  • Add test for GValue signal return values (Martin Pitt) (#683596)
  • Improve setting pointer fields/arguments to NULL using None (Simon Feltman) (#683150)
  • Test gint64 C signal arguments and return values (Martin Pitt)
  • Test in/out int64 GValue method arguments. (Martin Pitt) (#683596)
  • Bump g-i dependency to 1.33.10 (Martin Pitt)
  • Fix -uninstalled.pc.in file (Thibault Saunier) (#683379)

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PostgreSQL 9.2 final available for Debian and Ubuntu

PostgreSQL 9.2 has just been released, after a series of betas and a release candidate. See for yourself what’s new, and try it out!

Packages are available in Debian experimental as well as my PostgreSQL backports PPA for Ubuntu 10.04 to 12.10, as usual.

Please note that 9.2 will not land any more in the feature frozen Debian Wheezy and Ubuntu Quantal (12.10) releases, as none of the server-side extensions are packaged for 9.2 yet.

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PyGObject 3.3.91 released

I just released PyGObject 3.3.91, for GNOME 3.5.91.

The big new feature in this release (thanks to the release team for granting an exception) is Simon Feltman’s new Signal helper class, which makes defining custom signals a whole lot simpler and more obvious. In the past, you had to do

 class C(GObject.GObject):
    __gsignals__ = {
        'my_signal': (GObject.SIGNAL_RUN_FIRST, GObject.TYPE_NONE,
                      (GObject.TYPE_INT,))
    }

    def do_my_signal(self, arg):
        print("my_signal called with %i" % arg)

whereas now this looks like

class C(GObject.GObject):
    @GObject.Signal(arg_types=(int,))
    def my_signal(self, arg):
        print("my_signal called with %i" % arg)

or even more elegantly when using Python 3 and its new type annotations:

class C(GObject.GObject):
    @GObject.Signal
    def my_signal(self, arg:int):
        print("my_signal called with %i" % arg)

Check out the updated example and docstring for other ways how to use it.

Overrides can now be in a directory different from the one that pygobject installs itself into. These overrides need to put this into their __init__.py at the top:

from pkgutil import extend_path
__path__ = extend_path(__path__, __name__)

and put themselves somewhere into the default PYTHONPATH. This should make it a lot easier for library packages to ship their own overrides for Python.

This new version also comes with a couple of new overrides and bug fixes. See the detailled list of changes below.

Thanks to all contributors!

  • Fix exception test case for Python 2 (Martin Pitt)
  • Bump g-i dependency to >= 1.3.9 (Martin Pitt)
  • Show proper exception when trying to allocate a disguised struct (Martin Pitt) (#639972)
  • Support marshalling GParamSpec signal arguments (Mark Nauwelaerts) (#683099)
  • Add test for a signal that returns a GParamSpec (Martin Pitt) (#683265)
  • [API add] Add Signal class for adding and connecting custom signals. (Simon Feltman) (#434924)
  • Fix pygtkcompat’s Gtk.TreeView.insert_column_with_attributes() (Martin Pitt)
  • Add override for Gtk.TreeView.insert_column_with_attributes() (Marta Maria Casetti) (#679415)
  • .gitignore: Add missing built files (Martin Pitt)
  • Ship tests/gi in tarball (Martin Pitt)
  • Split test_overrides.py (Martin Pitt) (#683188)
  • _pygi_argument_to_object(): Clean up array unmarshalling (Martin Pitt)
  • Fix memory leak in _pygi_argument_to_object() (Alban Browaeys) (#682979)
  • Fix setting pointer fields/arguments to NULL using None. (Simon Feltman) (#683150)
  • Fix for python 2.6, officially drop support for < 2.6 (Martin Pitt) (#682422)
  • Allow overrides in other directories than gi itself (Thibault Saunier) (#680913)
  • Clean up sys.path handling in tests (Simon Feltman) (#680913)
  • Fix dynamic creation of enum and flag gi types for Python 3.3 (Simon Feltman) (#682323)
  • [API add] Override g_menu_item_set_attribute (Paolo Borelli) (#682436)

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