make a SoundPlayer interface so we can mock it in the tests

this requires an annoying amount of scaffolding:
1. implement gst and mock classes to implement the SoundPlayer interface
2. modify notifier to take a SoundPlayer argument in its ctor
3. modify service to take a Notifier argument in its ctor instead of instantiating it on its own
4. change main to update the startup steps for player/notifier/service

13 files changed, 546 insertions, 60 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ed0e0ff..c99ce46 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -20,7 +20,9 @@ set(SERVICE_MANUAL_SOURCES
     testing.c
     service.c
     utils.c
-    sound.c)
+    sound-player.c
+    sound-player-gst.c
+    sound-player-mock.c)
 
 # generated sources
 include(GdbusCodegen)
diff --git a/src/main.c b/src/main.c
index 03e100d..2837b59 100644
--- a/src/main.c
+++ b/src/main.c
@@ -23,7 +23,9 @@
 #include <glib/gi18n.h>
 
 #include "device.h"
+#include "notifier.h"
 #include "service.h"
+#include "sound-player-gst.h"
 #include "testing.h"
 
 /***
@@ -40,6 +42,8 @@ on_name_lost (gpointer instance G_GNUC_UNUSED, gpointer loop)
 int
 main (int argc G_GNUC_UNUSED, char ** argv G_GNUC_UNUSED)
 {
+  IndicatorPowerSoundPlayer * sound_player;
+  IndicatorPowerNotifier * notifier;
   IndicatorPowerService * service;
   IndicatorPowerTesting * testing;
   GMainLoop * loop;
@@ -50,7 +54,9 @@ main (int argc G_GNUC_UNUSED, char ** argv G_GNUC_UNUSED)
   textdomain (GETTEXT_PACKAGE);
 
   /* run */
-  service = indicator_power_service_new (NULL);
+  sound_player = indicator_power_sound_player_gst_new ();
+  notifier = indicator_power_notifier_new (sound_player);
+  service = indicator_power_service_new(NULL, notifier);
   testing = indicator_power_testing_new (service);
   loop = g_main_loop_new (NULL, FALSE);
   g_signal_connect (service, INDICATOR_POWER_SERVICE_SIGNAL_NAME_LOST,
@@ -59,7 +65,9 @@ main (int argc G_GNUC_UNUSED, char ** argv G_GNUC_UNUSED)
 
   /* cleanup */
   g_main_loop_unref (loop);
-  g_clear_object (&service);
   g_clear_object (&testing);
+  g_clear_object (&service);
+  g_clear_object (&notifier);
+  g_clear_object (&sound_player);
   return 0;
 }
diff --git a/src/notifier.c b/src/notifier.c
index 63e7c89..b50f48c 100644
--- a/src/notifier.c
+++ b/src/notifier.c
@@ -22,10 +22,10 @@
 #include "dbus-shared.h"
 #include "notifier.h"
 #include "utils.h"
-#include "sound.h"
+#include "sound-player.h"
 
 #ifdef HAS_URLDISPATCHER
-# include <lomiri-url-dispatcher.h>
+#include <lomiri-url-dispatcher.h>
 #endif
 
 #include <libnotify/notify.h>
@@ -51,10 +51,12 @@ enum
 {
   PROP_0,
   PROP_BATTERY,
+  PROP_SOUND_PLAYER,
   LAST_PROP
 };
 
 #define PROP_BATTERY_NAME "battery"
+#define PROP_SOUND_PLAYER_NAME "sound-player"
 
 static GParamSpec * properties[LAST_PROP];
 
@@ -82,6 +84,8 @@ typedef struct
 
   gboolean caps_queried;
   gboolean actions_supported;
+
+  IndicatorPowerSoundPlayer * sound_player;
 }
 IndicatorPowerNotifierPrivate;
 
@@ -140,17 +144,19 @@ get_battery_power_level (IndicatorPowerDevice * battery)
 ***/
 
 static void
-play_low_battery_sound (void)
+play_low_battery_sound (IndicatorPowerNotifier * self)
 {
-  const gchar * key;
+  const gchar * const key = "Low battery.ogg";
   gchar * filename;
+  priv_t * const p = get_priv(self);
+
+  g_return_if_fail (p->sound_player != NULL);
 
-  key = "Low battery.ogg";
   filename = datafile_find(DATAFILE_TYPE_SOUND, key);
   if (filename != NULL)
     {
       gchar * uri = g_filename_to_uri(filename, NULL, NULL);
-      sound_play_uri(uri);
+      indicator_power_sound_player_play_uri (p->sound_player, uri);
       g_free(uri);
       g_free(filename);
     }
@@ -330,7 +336,7 @@ on_battery_property_changed (IndicatorPowerNotifier * self)
       ((new_power_level != POWER_LEVEL_OK) && new_discharging && !old_discharging))
     {
       notification_show (self);
-      play_low_battery_sound();
+      play_low_battery_sound (self);
     }
   else if (!new_discharging || (new_power_level == POWER_LEVEL_OK))
     {
@@ -361,6 +367,10 @@ my_get_property (GObject     * o,
         g_value_set_object (value, p->battery);
         break;
 
+      case PROP_SOUND_PLAYER:
+        g_value_set_object (value, p->sound_player);
+        break;
+
       default:
         G_OBJECT_WARN_INVALID_PROPERTY_ID (o, property_id, pspec);
     }
@@ -380,6 +390,10 @@ my_set_property (GObject       * o,
         indicator_power_notifier_set_battery (self, g_value_get_object(value));
         break;
 
+      case PROP_SOUND_PLAYER:
+        indicator_power_notifier_set_sound_player (self, g_value_get_object(value));
+        break;
+
       default:
         G_OBJECT_WARN_INVALID_PROPERTY_ID (o, property_id, pspec);
     }
@@ -446,6 +460,13 @@ indicator_power_notifier_class_init (IndicatorPowerNotifierClass * klass)
     G_TYPE_OBJECT,
     G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
 
+  properties[PROP_SOUND_PLAYER] = g_param_spec_object (
+    PROP_SOUND_PLAYER_NAME,
+    "Sound Player",
+    "The current battery",
+    G_TYPE_OBJECT,
+    G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
+
   g_object_class_install_properties (object_class, LAST_PROP, properties);
 }
 
@@ -454,9 +475,11 @@ indicator_power_notifier_class_init (IndicatorPowerNotifierClass * klass)
 ***/
 
 IndicatorPowerNotifier *
-indicator_power_notifier_new (void)
+indicator_power_notifier_new (IndicatorPowerSoundPlayer * sound_player)
 {
-  GObject * o = g_object_new (INDICATOR_TYPE_POWER_NOTIFIER, NULL);
+  GObject * o = g_object_new (INDICATOR_TYPE_POWER_NOTIFIER,
+                              PROP_SOUND_PLAYER_NAME, sound_player,
+                              NULL);
 
   return INDICATOR_POWER_NOTIFIER (o);
 }
@@ -496,6 +519,26 @@ indicator_power_notifier_set_battery (IndicatorPowerNotifier * self,
 }
 
 void
+indicator_power_notifier_set_sound_player (IndicatorPowerNotifier * self,
+                                           IndicatorPowerSoundPlayer * sound_player)
+{
+  priv_t * p;
+
+  g_return_if_fail(INDICATOR_IS_POWER_NOTIFIER(self));
+  g_return_if_fail((sound_player == NULL) || INDICATOR_IS_POWER_SOUND_PLAYER(sound_player));
+
+  p = get_priv (self);
+
+  if (p->sound_player == sound_player)
+    return;
+
+  g_clear_object(&p->sound_player);
+
+  if (sound_player != NULL)
+      p->sound_player = g_object_ref(sound_player);
+}
+
+void
 indicator_power_notifier_set_bus (IndicatorPowerNotifier * self,
                                   GDBusConnection        * bus)
 {
diff --git a/src/notifier.h b/src/notifier.h
index 18e25d7..9625c07 100644
--- a/src/notifier.h
+++ b/src/notifier.h
@@ -23,6 +23,7 @@
 #include <gio/gio.h>
 
 #include "device.h"
+#include "sound-player.h"
 
 G_BEGIN_DECLS
 
@@ -55,7 +56,7 @@ struct _IndicatorPowerNotifierClass
 
 GType indicator_power_notifier_get_type (void);
 
-IndicatorPowerNotifier * indicator_power_notifier_new (void);
+IndicatorPowerNotifier * indicator_power_notifier_new (IndicatorPowerSoundPlayer * sound_player);
 
 void indicator_power_notifier_set_bus (IndicatorPowerNotifier  * self,
                                        GDBusConnection         * connection);
@@ -63,6 +64,9 @@ void indicator_power_notifier_set_bus (IndicatorPowerNotifier  * self,
 void indicator_power_notifier_set_battery (IndicatorPowerNotifier  * self,
                                            IndicatorPowerDevice    * battery);
 
+void indicator_power_notifier_set_sound_player (IndicatorPowerNotifier     * self,
+                                                IndicatorPowerSoundPlayer  * battery);
+
 #define POWER_LEVEL_STR_OK "ok"
 #define POWER_LEVEL_STR_LOW "low"
 #define POWER_LEVEL_STR_VERY_LOW "very_low"
diff --git a/src/service.c b/src/service.c
index 73fcf46..07f1106 100644
--- a/src/service.c
+++ b/src/service.c
@@ -52,6 +52,7 @@ enum
   PROP_0,
   PROP_BUS,
   PROP_DEVICE_PROVIDER,
+  PROP_NOTIFIER,
   LAST_PROP
 };
 
@@ -976,7 +977,8 @@ on_bus_acquired (GDBusConnection * connection,
   g_object_notify_by_pspec (G_OBJECT(self), properties[PROP_BUS]);
 
   /* export the battery properties */
-  indicator_power_notifier_set_bus (p->notifier, connection);
+  if (p->notifier != NULL)
+    indicator_power_notifier_set_bus (p->notifier, connection);
 
   /* export the actions */
   if ((id = g_dbus_connection_export_action_group (connection,
@@ -1118,6 +1120,10 @@ my_get_property (GObject     * o,
         g_value_set_object (value, p->device_provider);
         break;
 
+      case PROP_NOTIFIER:
+        g_value_set_object (value, p->notifier);
+        break;
+
       default:
         G_OBJECT_WARN_INVALID_PROPERTY_ID (o, property_id, pspec);
     }
@@ -1137,6 +1143,10 @@ my_set_property (GObject       * o,
         indicator_power_service_set_device_provider (self, g_value_get_object (value));
         break;
 
+      case PROP_NOTIFIER:
+        indicator_power_service_set_notifier (self, g_value_get_object (value));
+        break;
+
       default:
         G_OBJECT_WARN_INVALID_PROPERTY_ID (o, property_id, pspec);
     }
@@ -1179,6 +1189,7 @@ my_dispose (GObject * o)
   g_clear_object (&p->conn);
 
   indicator_power_service_set_device_provider (self, NULL);
+  indicator_power_service_set_notifier (self, NULL);
 
   G_OBJECT_CLASS (indicator_power_service_parent_class)->dispose (o);
 }
@@ -1200,8 +1211,6 @@ indicator_power_service_init (IndicatorPowerService * self)
 
   p->settings = g_settings_new ("org.ayatana.indicator.power");
 
-  p->notifier = indicator_power_notifier_new ();
-
   p->brightness = indicator_power_brightness_new();
   g_signal_connect_swapped(p->brightness, "notify::percentage",
                            G_CALLBACK(update_brightness_action_state), self);
@@ -1269,10 +1278,12 @@ indicator_power_service_class_init (IndicatorPowerServiceClass * klass)
 ***/
 
 IndicatorPowerService *
-indicator_power_service_new (IndicatorPowerDeviceProvider * device_provider)
+indicator_power_service_new (IndicatorPowerDeviceProvider * device_provider,
+                             IndicatorPowerNotifier * notifier)
 {
   GObject * o = g_object_new (INDICATOR_TYPE_POWER_SERVICE,
                               "device-provider", device_provider,
+                              "notifier", notifier,
                               NULL);
 
   return INDICATOR_POWER_SERVICE (o);
@@ -1311,6 +1322,25 @@ indicator_power_service_set_device_provider (IndicatorPowerService * self,
     }
 }
 
+void
+indicator_power_service_set_notifier (IndicatorPowerService  * self,
+                                      IndicatorPowerNotifier * notifier)
+{
+  priv_t * p;
+
+  g_return_if_fail (INDICATOR_IS_POWER_SERVICE (self));
+  g_return_if_fail (!notifier || INDICATOR_IS_POWER_NOTIFIER (notifier));
+  p = self->priv;
+
+  if (p->notifier != notifier)
+    {
+      g_clear_object (&p->notifier);
+      p->notifier = g_object_ref (notifier);
+      indicator_power_notifier_set_bus (p->notifier, p->conn);
+    }
+}
+
+
 /* If a device has multiple batteries and uses only one of them at a time,
    they should be presented as separate items inside the battery menu,
    but everywhere else they should be aggregated (bug 880881).
diff --git a/src/service.h b/src/service.h
index 76ed10f..00ed3e6 100644
--- a/src/service.h
+++ b/src/service.h
@@ -24,6 +24,7 @@
 #include <glib-object.h>
 
 #include "device-provider.h"
+#include "notifier.h"
 
 G_BEGIN_DECLS
 
@@ -64,11 +65,15 @@ struct _IndicatorPowerServiceClass
 
 GType indicator_power_service_get_type (void);
 
-IndicatorPowerService * indicator_power_service_new (IndicatorPowerDeviceProvider * provider);
+IndicatorPowerService * indicator_power_service_new (IndicatorPowerDeviceProvider * provider,
+                                                     IndicatorPowerNotifier       * notifier);
 
 void indicator_power_service_set_device_provider (IndicatorPowerService        * self,
                                                   IndicatorPowerDeviceProvider * provider);
 
+void indicator_power_service_set_notifier (IndicatorPowerService  * self,
+                                           IndicatorPowerNotifier * notifier);
+
 IndicatorPowerDevice * indicator_power_service_choose_primary_device (GList * devices);
 
 
diff --git a/src/sound.c b/src/sound-player-gst.c
index 37c2a8d..9b3f11a 100644
--- a/src/sound.c
+++ b/src/sound-player-gst.c
@@ -1,5 +1,8 @@
 /*
- * Copyright 2015 Canonical Ltd.
+ * Copyright 2013 Canonical Ltd.
+ *
+ * Authors:
+ *   Charles Kerr <charles.kerr@canonical.com>
  *
  * This program is free software: you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 3, as published
@@ -12,17 +15,48 @@
  *
  * You should have received a copy of the GNU General Public License along
  * with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * Authors:
- *   Charles Kerr <charles.kerr@canonical.com>
  */
 
-#include "sound.h"
-
-#include <glib.h>
+#include "sound-player.h"
+#include "sound-player-gst.h"
 
 #include <gst/gst.h>
 
+
+/***
+****  private struct
+***/
+
+typedef struct
+{
+  int unused;
+}
+IndicatorPowerSoundPlayerGSTPrivate;
+
+typedef IndicatorPowerSoundPlayerGSTPrivate priv_t;
+
+#define get_priv(o) ((priv_t*)indicator_power_sound_player_gst_get_instance_private(o))
+
+
+/***
+****  GObject boilerplate
+***/
+
+static void indicator_power_device_provider_interface_init (
+                                IndicatorPowerSoundPlayerInterface * iface);
+
+G_DEFINE_TYPE_WITH_CODE (
+  IndicatorPowerSoundPlayerGST,
+  indicator_power_sound_player_gst,
+  G_TYPE_OBJECT,
+  G_ADD_PRIVATE(IndicatorPowerSoundPlayerGST)
+  G_IMPLEMENT_INTERFACE (INDICATOR_TYPE_POWER_SOUND_PLAYER,
+                         indicator_power_device_provider_interface_init))
+
+/***
+****  GSTREAMER
+***/
+
 static void
 gst_init_once(void)
 {
@@ -81,14 +115,17 @@ static gboolean bus_callback(GstBus* bus G_GNUC_UNUSED, GstMessage* msg, gpointe
   return G_SOURCE_CONTINUE;
 }
 
-void
-sound_play_uri(const char* uri)
+/***
+****  IndicatorPowerSoundPlayer virtual functions
+***/
+
+static void
+my_play_uri (IndicatorPowerSoundPlayer * self G_GNUC_UNUSED, const gchar * uri)
 {
   GstElement * element;
   GstBus * bus;
 
-  gst_init_once();
-
+  /* create the element */
   element = gst_element_factory_make("playbin", NULL);
 
   /* start listening for gst events */
@@ -102,3 +139,35 @@ sound_play_uri(const char* uri)
   gst_element_set_state(element, GST_STATE_PLAYING);
 }
 
+/***
+****  Instantiation
+***/
+
+static void
+indicator_power_sound_player_gst_class_init (IndicatorPowerSoundPlayerGSTClass * klass)
+{
+  gst_init_once();
+}
+
+static void
+indicator_power_device_provider_interface_init (IndicatorPowerSoundPlayerInterface * iface)
+{
+  iface->play_uri = my_play_uri;
+}
+
+static void
+indicator_power_sound_player_gst_init (IndicatorPowerSoundPlayerGST * self G_GNUC_UNUSED)
+{
+}
+
+/***
+****  Public API
+***/
+
+IndicatorPowerSoundPlayer *
+indicator_power_sound_player_gst_new(void)
+{
+  gpointer o = g_object_new (INDICATOR_TYPE_POWER_SOUND_PLAYER_GST, NULL);
+
+  return INDICATOR_POWER_SOUND_PLAYER (o);
+}
diff --git a/src/sound-player-gst.h b/src/sound-player-gst.h
new file mode 100644
index 0000000..6ef8866
--- /dev/null
+++ b/src/sound-player-gst.h
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2013 Canonical Ltd.
+ *
+ * Authors:
+ *   Charles Kerr <charles.kerr@canonical.com>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __INDICATOR_POWER_SOUND_PLAYER_GST__H__
+#define __INDICATOR_POWER_SOUND_PLAYER_GST__H__
+
+#include <glib-object.h> /* parent class */
+
+#include "device-provider.h"
+
+G_BEGIN_DECLS
+
+#define INDICATOR_TYPE_POWER_SOUND_PLAYER_GST \
+  (indicator_power_sound_player_gst_get_type())
+
+#define INDICATOR_POWER_SOUND_PLAYER_GST(o) \
+  (G_TYPE_CHECK_INSTANCE_CAST ((o), \
+                               INDICATOR_TYPE_POWER_SOUND_PLAYER_GST, \
+                               IndicatorPowerSoundPlayerGST))
+
+#define INDICATOR_POWER_SOUND_PLAYER_GST_GET_CLASS(o) \
+ (G_TYPE_INSTANCE_GET_CLASS ((o), \
+                             INDICATOR_TYPE_POWER_SOUND_PLAYER_GST, \
+                             IndicatorPowerSoundPlayerGSTClass))
+
+#define INDICATOR_IS_POWER_SOUND_PLAYER_GST(o) \
+  (G_TYPE_CHECK_INSTANCE_TYPE ((o), \
+                               INDICATOR_TYPE_POWER_SOUND_PLAYER_GST))
+
+typedef struct _IndicatorPowerSoundPlayerGST
+                IndicatorPowerSoundPlayerGST;
+typedef struct _IndicatorPowerSoundPlayerGSTClass
+                IndicatorPowerSoundPlayerGSTClass;
+
+/**
+ * An IndicatorPowerSoundPlayer which gets its devices from GST.
+ */
+struct _IndicatorPowerSoundPlayerGST
+{
+  GObject parent_instance;
+};
+
+struct _IndicatorPowerSoundPlayerGSTClass
+{
+  GObjectClass parent_class;
+};
+
+GType indicator_power_sound_player_gst_get_type (void);
+
+IndicatorPowerSoundPlayer * indicator_power_sound_player_gst_new (void);
+
+G_END_DECLS
+
+#endif /* __INDICATOR_POWER_SOUND_PLAYER_GST__H__ */
diff --git a/src/sound-player-mock.c b/src/sound-player-mock.c
new file mode 100644
index 0000000..17eff21
--- /dev/null
+++ b/src/sound-player-mock.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *   Charles Kerr <charles.kerr@canonical.com>
+ */
+
+#include "sound-player.h"
+#include "sound-player-mock.h"
+
+enum
+{
+  SIGNAL_URI_PLAYED,
+  LAST_SIGNAL
+};
+
+static guint signals[LAST_SIGNAL] = { 0 };
+
+/***
+****  GObject boilerplate
+***/
+
+static void indicator_power_sound_player_interface_init (
+                                IndicatorPowerSoundPlayerInterface * iface);
+
+G_DEFINE_TYPE_WITH_CODE (
+  IndicatorPowerSoundPlayerMock,
+  indicator_power_sound_player_mock,
+  G_TYPE_OBJECT,
+  G_IMPLEMENT_INTERFACE (INDICATOR_TYPE_POWER_SOUND_PLAYER,
+                         indicator_power_sound_player_interface_init))
+
+/***
+****  IndicatorPowerSoundPlayer virtual functions
+***/
+
+static void
+my_play_uri (IndicatorPowerSoundPlayer * self, const gchar * uri)
+{
+  g_signal_emit (self, signals[SIGNAL_URI_PLAYED], 0, uri, NULL);
+}
+
+/***
+****  Instantiation
+***/
+
+static void
+indicator_power_sound_player_mock_class_init (IndicatorPowerSoundPlayerMockClass * klass G_GNUC_UNUSED)
+{
+  signals[SIGNAL_URI_PLAYED] = g_signal_new (
+    "uri-played",
+    G_TYPE_FROM_CLASS(klass),
+    G_SIGNAL_RUN_LAST,
+    G_STRUCT_OFFSET (IndicatorPowerSoundPlayerMockClass, uri_played),
+    NULL, NULL,
+    g_cclosure_marshal_VOID__STRING,
+    G_TYPE_NONE, 1, G_TYPE_STRING);
+}
+
+static void
+indicator_power_sound_player_interface_init (IndicatorPowerSoundPlayerInterface * iface)
+{
+  iface->play_uri = my_play_uri;
+}
+
+static void
+indicator_power_sound_player_mock_init (IndicatorPowerSoundPlayerMock * self G_GNUC_UNUSED)
+{
+}
+
+/***
+****  Public API
+***/
+
+IndicatorPowerSoundPlayer *
+indicator_power_sound_player_mock_new (void)
+{
+  gpointer o = g_object_new (INDICATOR_TYPE_POWER_SOUND_PLAYER_MOCK, NULL);
+
+  return INDICATOR_POWER_SOUND_PLAYER (o);
+}
+
diff --git a/src/sound-player-mock.h b/src/sound-player-mock.h
new file mode 100644
index 0000000..f7f2653
--- /dev/null
+++ b/src/sound-player-mock.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *   Charles Kerr <charles.kerr@canonical.com>
+ */
+
+#ifndef __INDICATOR_POWER_SOUND_PLAYER_MOCK__H__
+#define __INDICATOR_POWER_SOUND_PLAYER_MOCK__H__
+
+#include <glib-object.h> /* parent class */
+
+#include "sound-player.h"
+
+G_BEGIN_DECLS
+
+#define INDICATOR_TYPE_POWER_SOUND_PLAYER_MOCK \
+  (indicator_power_sound_player_mock_get_type())
+
+#define INDICATOR_POWER_SOUND_PLAYER_MOCK(o) \
+  (G_TYPE_CHECK_INSTANCE_CAST ((o), \
+                               INDICATOR_TYPE_POWER_SOUND_PLAYER_MOCK, \
+                               IndicatorPowerSoundPlayerMock))
+
+#define INDICATOR_POWER_SOUND_PLAYER_MOCK_GET_CLASS(o) \
+ (G_TYPE_INSTANCE_GET_CLASS ((o), \
+                             INDICATOR_TYPE_POWER_SOUND_PLAYER_MOCK, \
+                             IndicatorPowerSoundPlayerMockClass))
+
+#define INDICATOR_IS_POWER_SOUND_PLAYER_MOCK(o) \
+  (G_TYPE_CHECK_INSTANCE_TYPE ((o), \
+                               INDICATOR_TYPE_POWER_SOUND_PLAYER_MOCK))
+
+typedef struct _IndicatorPowerSoundPlayerMock
+                IndicatorPowerSoundPlayerMock;
+typedef struct _IndicatorPowerSoundPlayerMockPriv
+                IndicatorPowerSoundPlayerMockPriv;
+typedef struct _IndicatorPowerSoundPlayerMockClass
+                IndicatorPowerSoundPlayerMockClass;
+
+/**
+ * An IndicatorPowerSoundPlayer which gets its devices from Mock.
+ */
+struct _IndicatorPowerSoundPlayerMock
+{
+  GObject parent_instance;
+};
+
+struct _IndicatorPowerSoundPlayerMockClass
+{
+  GObjectClass parent_class;
+
+  /* signals */
+  void (*uri_played) (IndicatorPowerSoundPlayer * self, const gchar* uri);
+};
+
+GType indicator_power_sound_player_mock_get_type (void);
+
+IndicatorPowerSoundPlayer * indicator_power_sound_player_mock_new (void);
+
+G_END_DECLS
+
+#endif /* __INDICATOR_POWER_SOUND_PLAYER_MOCK__H__ */
diff --git a/src/sound-player.c b/src/sound-player.c
new file mode 100644
index 0000000..f6421ad
--- /dev/null
+++ b/src/sound-player.c
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2013 Canonical Ltd.
+ *
+ * Authors:
+ *   Charles Kerr <charles.kerr@canonical.com>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "sound-player.h"
+
+G_DEFINE_INTERFACE (IndicatorPowerSoundPlayer,
+                    indicator_power_sound_player,
+                    0)
+
+static void
+indicator_power_sound_player_default_init (IndicatorPowerSoundPlayerInterface * klass G_GNUC_UNUSED)
+{
+}
+
+/***
+****  PUBLIC API
+***/
+
+void
+indicator_power_sound_player_play_uri (IndicatorPowerSoundPlayer * self,
+                                       const gchar               * uri)
+{
+  IndicatorPowerSoundPlayerInterface * iface;
+
+  g_return_if_fail (INDICATOR_IS_POWER_SOUND_PLAYER (self));
+  iface = INDICATOR_POWER_SOUND_PLAYER_GET_INTERFACE (self);
+  g_return_if_fail (iface->play_uri != NULL);
+  iface->play_uri (self, uri);
+}
diff --git a/src/sound-player.h b/src/sound-player.h
new file mode 100644
index 0000000..ac7e261
--- /dev/null
+++ b/src/sound-player.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2013 Canonical Ltd.
+ *
+ * Authors:
+ *   Charles Kerr <charles.kerr@canonical.com>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __INDICATOR_POWER_SOUND_PLAYER__H__
+#define __INDICATOR_POWER_SOUND_PLAYER__H__
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define INDICATOR_TYPE_POWER_SOUND_PLAYER \
+  (indicator_power_sound_player_get_type ())
+
+#define INDICATOR_POWER_SOUND_PLAYER(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST ((obj), \
+                               INDICATOR_TYPE_POWER_SOUND_PLAYER, \
+                               IndicatorPowerSoundPlayer))
+
+#define INDICATOR_IS_POWER_SOUND_PLAYER(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE ((obj), INDICATOR_TYPE_POWER_SOUND_PLAYER))
+
+#define INDICATOR_POWER_SOUND_PLAYER_GET_INTERFACE(inst) \
+  (G_TYPE_INSTANCE_GET_INTERFACE ((inst), \
+                                  INDICATOR_TYPE_POWER_SOUND_PLAYER, \
+                                  IndicatorPowerSoundPlayerInterface))
+
+typedef struct _IndicatorPowerSoundPlayer
+                IndicatorPowerSoundPlayer;
+
+typedef struct _IndicatorPowerSoundPlayerInterface
+                IndicatorPowerSoundPlayerInterface;
+
+/**
+ * An interface class for an object that plays sounds.
+ */
+struct _IndicatorPowerSoundPlayerInterface
+{
+  GTypeInterface parent_iface;
+
+  /* virtual functions */
+  void (*play_uri) (IndicatorPowerSoundPlayer * self,
+                    const gchar * uri);
+};
+
+GType indicator_power_sound_player_get_type (void);
+
+/***
+****
+***/
+
+void indicator_power_sound_player_play_uri (IndicatorPowerSoundPlayer * self,
+                                            const gchar * uri);
+
+G_END_DECLS
+
+#endif /* __INDICATOR_POWER_SOUND_PLAYER__H__ */
diff --git a/src/sound.h b/src/sound.h
deleted file mode 100644
index f201fe9..0000000
--- a/src/sound.h
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * Copyright 2015 Canonical Ltd.
- *
- * This program is free software: you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 3, as published
- * by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranties of
- * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
- * PURPOSE.  See the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * Authors:
- *   Charles Kerr <charles.kerr@canonical.com>
- */
-
-#ifndef __INDICATOR_POWER_SOUND_H__
-#define __INDICATOR_POWER_SOUND_H__
-
-#include <gio/gio.h>
-
-G_BEGIN_DECLS
-
-void sound_play_uri(const char* uri);
-
-G_END_DECLS
-
-#endif /* __INDICATOR_POWER_SOUND_H__ */