[pitivi] clipproperties: Update widgets when switching clips

[Alexandru Băluț <alexbalut src gnome org>]

commit 187ecc8bec4abb3f7b6bee0c86ed933c1b0be897
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Mon Feb 15 22:11:19 2021 +0100

    clipproperties: Update widgets when switching clips
    
    The speed widgets were not being updated when selecting a different
    clip.

 pitivi/clipproperties.py     | 13 +++++++++++++
 tests/test_clipproperties.py | 21 +++++++++++++++++++++
 2 files changed, 34 insertions(+)
---
diff --git a/pitivi/clipproperties.py b/pitivi/clipproperties.py
index 8660ba76c..ead9e5cd2 100644
--- a/pitivi/clipproperties.py
+++ b/pitivi/clipproperties.py
@@ -362,6 +362,10 @@ class TimeProperties(Gtk.Expander, Loggable):
     @rate.setter  # type: ignore
     def rate(self, value: float) -> None:
         self._set_rate(value)
+        # We assume the "rate" has been set as an effect of the binding between
+        # the self._speed_adjustment and the "rate" property.
+        # Signal the "rate_linear" property is updated so
+        # self._speed_scale_adjustment is also updated.
         self.notify("rate_linear")
 
     @GObject.Property(type=float)
@@ -373,6 +377,10 @@ class TimeProperties(Gtk.Expander, Loggable):
     def rate_linear(self, linear: float) -> None:
         value = self._linear_to_rate(linear)
         self._set_rate(value)
+        # We assume the "rate_linear" has been set as an effect of the binding
+        # between the self._speed_scale_adjustment and the "rate" property.
+        # Signal the "rate" property is updated so the self._speed_adjustment
+        # is also updated.
         self.notify("rate")
 
     def _set_rate(self, value: float):
@@ -475,6 +483,11 @@ class TimeProperties(Gtk.Expander, Loggable):
         self._time_effects = self.__get_time_effects(self._clip)
 
         if self._clip:
+            # Signal the properties changed so the Adjustments bound to them
+            # and the widgets using these are updated.
+            self.notify("rate")
+            self.notify("rate_linear")
+
             self._clip.connect("deep-notify", self.__child_property_changed_cb)
             self.show_all()
         else:
diff --git a/tests/test_clipproperties.py b/tests/test_clipproperties.py
index e01734a34..af5cc89ae 100644
--- a/tests/test_clipproperties.py
+++ b/tests/test_clipproperties.py
@@ -522,6 +522,27 @@ class SpeedPropertiesTest(common.TestCase):
     def test_clip_speed_v(self):
         self._check_clip_speed(video=True)
 
+    @common.setup_project_with_clips(assets_names=["mp3_sample.mp3", "30fps_numeroted_frames_blue.webm"])
+    @common.setup_clipproperties
+    def test_widgets_updated_when_switching_clips(self):
+        clip1, clip2 = self.layer.get_clips()
+        clip1_duration = clip1.props.duration
+        clip2_duration = clip2.props.duration
+
+        self.timeline_container.timeline.selection.select([clip1])
+        self.assertIs(self.speed_box._clip, clip1)
+        self.assert_applied_rate(0, 1.0, clip1_duration)
+
+        self.speed_box._speed_adjustment.props.value = 2.0
+        self.assert_applied_rate(1, 2.0, clip1_duration / 2)
+
+        self.timeline_container.timeline.selection.select([clip2])
+        self.assertIs(self.speed_box._clip, clip2)
+        self.assert_applied_rate(0, 1.0, clip2_duration)
+
+        self.timeline_container.timeline.selection.select([clip1])
+        self.assert_applied_rate(1, 2.0, clip1_duration / 2)
+
     @common.setup_project_with_clips
     @common.setup_clipproperties
     def test_load_project_clip_speed(self):