Add test for CurrentPlaylistController load and implement on base class

mopidy/backends/__init__.py

@@ -25,6 +25,9 @@ class BaseCurrentPlaylistController(object):
         self.backend.playback.stop()
         self.playlist = Playlist()
 
+    def load(self, playlist):
+        self.playlist = playlist
+
 class BasePlaybackController(object):
     PAUSED = 'paused'
     PLAYING = 'playing'

tests/backends/__init__.py

@@ -1,4 +1,4 @@
-from mopidy.models import Track
+from mopidy.models import Track, Playlist
 
 class BaseCurrentPlaylistControllerTest(object):
     uris = []
@@ -50,6 +50,17 @@ class BaseCurrentPlaylistControllerTest(object):
 
         self.assertEqual(playback.state, playback.STOPPED)
 
+    def test_load(self):
+        controller = self.backend.current_playlist
+
+        new_playlist = Playlist()
+
+        self.assertNotEqual(new_playlist, controller.playlist)
+
+        controller.load(new_playlist)
+
+        self.assertEqual(new_playlist, controller.playlist)
+
 class BasePlaybackControllerTest(object):
     uris = []
     backend_class = None