[pitivi] titleeditor: Avoid traceback when getting values of enum props

[Alexandru Băluț <alexbalut src gnome org>]

commit 53197932ebd583f377cbcce19024fcc3ccc67749
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Mon Oct 7 00:23:05 2019 +0200

    titleeditor: Avoid traceback when getting values of enum props
    
    Traceback (most recent call last):
      File "/.../pitivi/pitivi/titleeditor.py", line 277, in _propertyChangedCb
        value = self.source.get_child_property(pspec.name)[1]
    TypeError: unknown type (null)

 pitivi/titleeditor.py       | 26 ++++++++++++++++++--------
 tests/test_titleeditor.py   | 31 ++++++++++++++++++++-----------
 tests/test_undo_timeline.py |  4 ++--
 3 files changed, 40 insertions(+), 21 deletions(-)
---
diff --git a/pitivi/titleeditor.py b/pitivi/titleeditor.py
index dadbf0d2..dfcd2394 100644
--- a/pitivi/titleeditor.py
+++ b/pitivi/titleeditor.py
@@ -238,7 +238,7 @@ class TitleEditor(Loggable):
             self.infobar.hide()
             self.editing_box.show()
             self._children_props_handler = self.source.connect('deep-notify',
-                                                               self._propertyChangedCb)
+                                                               self._source_deep_notify_cb)
         else:
             self.infobar.show()
             self.editing_box.hide()
@@ -259,47 +259,57 @@ class TitleEditor(Loggable):
                       "halignment": DEFAULT_HALIGNMENT}
         for prop, value in properties.items():
             res = source.set_child_property(prop, value)
-            assert res
-        # Select it so the Title editor becomes active.
+            assert res, prop
         self._selection.setSelection([title_clip], SELECT)
 
-    def _propertyChangedCb(self, source, unused_gstelement, pspec):
+    def _source_deep_notify_cb(self, source, unused_gstelement, pspec):
+        """Handles updates in the TitleSource backing the current TitleClip."""
         if self._setting_props:
             self._project.pipeline.commit_timeline()
             return
 
         control_binding = self.source.get_control_binding(pspec.name)
         if control_binding:
-            self.debug("Not handling %s as it is being interpollated",
+            self.debug("Not handling %s as it is being interpolated",
                        pspec.name)
             return
 
-        value = self.source.get_child_property(pspec.name)[1]
         if pspec.name == "text":
-            value = value or ""
-            if self.textbuffer.props.text == value:
+            res, value = self.source.get_child_property(pspec.name)
+            assert res, pspec.name
+            if self.textbuffer.props.text == value or "":
                 return
             self.textbuffer.props.text = value
         elif pspec.name in ["x-absolute", "y-absolute"]:
+            res, value = self.source.get_child_property(pspec.name)
+            assert res, pspec.name
             if self.settings[pspec.name].get_value() == value:
                 return
             self.settings[pspec.name].set_value(value)
         elif pspec.name in ["valignment", "halignment"]:
+            res, value = self.source.get_child_property(pspec.name)
+            assert res, pspec.name
             value = value.value_name
             if self.settings[pspec.name].get_active_id() == value:
                 return
             self.settings[pspec.name].set_active_id(value)
         elif pspec.name == "font-desc":
+            res, value = self.source.get_child_property(pspec.name)
+            assert res, pspec.name
             if self.font_button.get_font_desc() == value:
                 return
             font_desc = Pango.FontDescription.from_string(value)
             self.font_button.set_font_desc(font_desc)
         elif pspec.name == "color":
+            res, value = self.source.get_child_property(pspec.name)
+            assert res, pspec.name
             color = argb_to_gdk_rgba(value)
             if color == self.foreground_color_button.get_rgba():
                 return
             self.foreground_color_button.set_rgba(color)
         elif pspec.name == "foreground-color":
+            res, value = self.source.get_child_property(pspec.name)
+            assert res, pspec.name
             color = argb_to_gdk_rgba(value)
             if color == self.background_color_button.get_rgba():
                 return
diff --git a/tests/test_titleeditor.py b/tests/test_titleeditor.py
index 05afdd87..6c07fae8 100644
--- a/tests/test_titleeditor.py
+++ b/tests/test_titleeditor.py
@@ -24,27 +24,36 @@ from gi.repository import GES
 
 from pitivi.titleeditor import TitleEditor
 from tests import common
+from tests.test_undo_timeline import BaseTestUndoTimeline
 
 
-class TitleEditorTest(common.TestCase):
+class TitleEditorTest(BaseTestUndoTimeline):
     """Tests for the TitleEditor class."""
 
     def test_create(self):
         """Exercise creating a title clip."""
-        timeline_container = common.create_timeline_container(titleClipLength=1)
-        project = timeline_container._project
-        app = timeline_container.app
-
         # Wait until the project creates a layer in the timeline.
         common.create_main_loop().run(until_empty=True)
 
-        title_editor = TitleEditor(app)
-        title_editor._newProjectLoadedCb(None, project)
-        project.pipeline.getPosition = mock.Mock(return_value=0)
+        title_editor = TitleEditor(self.app)
+
+        from pitivi.timeline.timeline import TimelineContainer
+        timeline_container = TimelineContainer(self.app)
+        timeline_container.setProject(self.project)
+        self.app.gui.editor.timeline_ui = timeline_container
+
+        title_editor._newProjectLoadedCb(None, self.project)
+        self.project.pipeline.getPosition = mock.Mock(return_value=0)
 
         title_editor._createCb(None)
-        layers = timeline_container.ges_timeline.get_layers()
-        self.assertEqual(len(layers), 1, layers)
-        clips = layers[0].get_clips()
+        clips = self.layer.get_clips()
         self.assertEqual(len(clips), 1, clips)
         self.assertIsInstance(clips[0], GES.TitleClip)
+
+        self.action_log.undo()
+        clips = self.layer.get_clips()
+        self.assertEqual(len(clips), 0, clips)
+
+        self.action_log.redo()
+        clips = self.layer.get_clips()
+        self.assertEqual(len(clips), 1, clips)
diff --git a/tests/test_undo_timeline.py b/tests/test_undo_timeline.py
index 2c2fe4bf..db109434 100644
--- a/tests/test_undo_timeline.py
+++ b/tests/test_undo_timeline.py
@@ -43,8 +43,8 @@ class BaseTestUndoTimeline(common.TestCase):
     def setUp(self):
         super(BaseTestUndoTimeline, self).setUp()
         self.app = common.create_pitivi()
-        project = self.app.project_manager.new_blank_project()
-        self.timeline = project.ges_timeline
+        self.project = self.app.project_manager.new_blank_project()
+        self.timeline = self.project.ges_timeline
         self.layer = self.timeline.append_layer()
         self.action_log = self.app.action_log