Merge lp:~veebers/autopilot/custom_emulator_lp-1191164 into lp:autopilot

[Christopher Lee]

Make sure the Custom emulators _Backend is set when creating an introspection object.

CustomEmulator cls._Backend wasn't being set. Make sure it's set when creating an introspection object.

[Christopher Lee (veebers)]

I can't help but feel that this is a bandaid and that I'm missing a more fundamental fix.

[Leo Arias (elopio)]

<elopio> veebers: I think it will work.
<elopio> when I read this code in autopilot I got the feeling that a lot is black magic, not really clear.
<elopio> but I don't have an alternate solution. If the test added passes, I'm happy.
<veebers> elopio: it works at the moment (i.e. all the autopilot tests pass, I'm just going to run the Unity tests) but I'm not sure that it is as intended
<veebers> elopio: aye, It's not the easiest to read (with metaclasses et. al). If all the tests pass I'll get it merged in. I'll hit up thomi once he gets back to check if there is a better option too
<elopio> veebers: +1
<elopio> let me leave an approve comment.

review: Approve (code review)

[Thomi Richards (thomir-deactivatedaccount)]

review: Approve

[PS Jenkins bot (ps-jenkins)]

review: Approve (continuous-integration)

=== modified file 'autopilot/introspection/dbus.py'
--- autopilot/introspection/dbus.py	2013-05-23 23:09:52 +0000
+++ autopilot/introspection/dbus.py	2013-06-20 21:26:23 +0000
@@ -475,6 +475,8 @@
         name = get_classname_from_path(path)
         try:
             class_type = _object_registry[cls._id][name]
+            if class_type._Backend is None:
+                class_type._Backend = cls._Backend
         except KeyError:
             logger.warning("Generating introspection instance for type '%s' based on generic class.", name)
             # override the _id attr from cls, since we don't want generated types
 
=== modified file 'autopilot/tests/functional/test_introspection_features.py'
--- autopilot/tests/functional/test_introspection_features.py	2013-05-23 05:05:58 +0000
+++ autopilot/tests/functional/test_introspection_features.py	2013-06-20 21:26:23 +0000
@@ -22,6 +22,7 @@
 from tempfile import mktemp
 from testtools.matchers import Equals
 
+from autopilot.matchers import Eventually
 from autopilot.testcase import AutopilotTestCase
 from autopilot.introspection.dbus import CustomEmulatorBase
 
@@ -73,3 +74,16 @@
 
         self.assertThat(type(test_widget), Equals(MouseTestWidget))
 
+    def test_can_access_custom_emulator_properties(self):
+        """Must be able to access properties of a custom emulator."""
+
+        class EmulatorBase(CustomEmulatorBase):
+            pass
+
+        class MouseTestWidget(EmulatorBase):
+            pass
+
+        app = self.start_mock_app(EmulatorBase)
+        test_widget = app.select_single(MouseTestWidget)
+
+        self.assertThat(test_widget.visible, Eventually(Equals(True)))