audio: Add dummy implementation of the audio actor

mopidy/audio/__init__.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 # flake8: noqa
 from .actor import Audio
+from .dummy import DummyAudio
 from .listener import AudioListener
 from .constants import PlaybackState
 from .utils import (calculate_duration, create_buffer, millisecond_to_clocktime,

mopidy/audio/dummy.py

@@ -0,0 +1,62 @@
+from __future__ import unicode_literals
+
+import pykka
+
+from .constants import PlaybackState
+from .listener import AudioListener
+
+
+class DummyAudio(pykka.ThreadingActor):
+    def __init__(self):
+        super(DummyAudio, self).__init__()
+        self.state = PlaybackState.STOPPED
+        self._position = 0
+
+    def set_on_end_of_track(self, callback):
+        pass
+
+    def set_uri(self, uri):
+        pass
+
+    def set_appsrc(self, *args, **kwargs):
+        pass
+
+    def emit_data(self, buffer_):
+        pass
+
+    def emit_end_of_stream(self):
+        pass
+
+    def get_position(self):
+        return self._position
+
+    def set_position(self, position):
+        self._position = position
+        return True
+
+    def start_playback(self):
+        return self._change_state(PlaybackState.PLAYING)
+
+    def pause_playback(self):
+        return self._change_state(PlaybackState.PAUSED)
+
+    def prepare_change(self):
+        return True
+
+    def stop_playback(self):
+        return self._change_state(PlaybackState.STOPPED)
+
+    def get_volume(self):
+        return 0
+
+    def set_volume(self, volume):
+        pass
+
+    def set_metadata(self, track):
+        pass
+
+    def _change_state(self, new_state):
+        old_state, self.state = self.state, new_state
+        AudioListener.send(
+            'state_changed', old_state=old_state, new_state=new_state)
+        return True