[gnome-settings-daemon/wip/benzea/backlight] power: Add test to check backlight brightness is updated after uevent

[Benjamin Berg <bberg src gnome org>]

commit 8b7e7d184395163b08cf95dccfa08c45981bb751
Author: Benjamin Berg <bberg redhat com>
Date:   Fri Apr 20 19:16:29 2018 +0200

    power: Add test to check backlight brightness is updated after uevent
    
    A simple test to check that gsd-power will notice an update to the
    brightness.

 plugins/power/gsd-backlight.c |  1 +
 plugins/power/test.py         | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)
---
diff --git a/plugins/power/gsd-backlight.c b/plugins/power/gsd-backlight.c
index 3193c3f8..ce5fb927 100644
--- a/plugins/power/gsd-backlight.c
+++ b/plugins/power/gsd-backlight.c
@@ -165,6 +165,7 @@ gsd_backlight_udev_idle_update_cb (GsdBacklight *backlight)
                 return FALSE;
         }
         brightness = atoi(contents);
+        g_debug ("GsdBacklight: New brightness value after uevent is %d", brightness);
 
         /* Only notify if brightness has changed. */
         if (brightness == priv->brightness_val)
diff --git a/plugins/power/test.py b/plugins/power/test.py
index 9c13a7f2..c039b0fb 100755
--- a/plugins/power/test.py
+++ b/plugins/power/test.py
@@ -1051,6 +1051,24 @@ class PowerPluginTest(gsdtestcase.GSDTestCase):
         time.sleep(1.0)
         self.assertEqual(self.get_brightness(), 90)
 
+    def test_brightness_uevent(self):
+        obj_gsd_power = self.session_bus_con.get_object(
+            'org.gnome.SettingsDaemon.Power', '/org/gnome/SettingsDaemon/Power')
+        obj_gsd_power_prop_iface = dbus.Interface(obj_gsd_power, dbus.PROPERTIES_IFACE)
+
+        brightness = obj_gsd_power_prop_iface.Get('org.gnome.SettingsDaemon.Power.Screen', 'Brightness')
+        self.assertEqual(50, brightness)
+
+        # Check that the brightness is updated if it was changed through some
+        # other mechanism (e.g. firmware).
+        # Set to 80+1 because of the GSD offset (see add_backlight).
+        self.testbed.set_attribute(self.backlight, 'brightness', '81')
+
+        self.check_plugin_log('GsdBacklight: New brightness value after uevent is 81', 1, 'gsd-power did not 
process uevent correctly')
+
+        brightness = obj_gsd_power_prop_iface.Get('org.gnome.SettingsDaemon.Power.Screen', 'Brightness')
+        self.assertEqual(80, brightness)
+
     def test_brightness_step(self):
         # We cannot use check_plugin_log here because the startup check already
         # read the relevant message.