Add test_new_playlist_loaded_callback_gets_called

mopidy/backends/__init__.py

@@ -114,6 +114,9 @@ class BasePlaybackController(object):
     def stop(self):
         raise NotImplementedError
 
+    def new_playlist_loaded_callback(self):
+        pass
+
     def next(self):
         if not self.next_track:
             self.stop()

tests/backends/basetests.py

@@ -434,8 +434,18 @@ class BasePlaybackControllerTest(object):
         self.playback.next()
         self.assertEqual(self.playback.playlist_position, 1)
 
-    def test_new_playlist_loaded_callback(self):
-        raise NotImplementedError
+    def test_new_playlist_loaded_callback_gets_called(self):
+        new_playlist_loaded_callback = self.playback.new_playlist_loaded_callback
+
+        def wrapper():
+            wrapper.called = True
+            return new_playlist_loaded_callback()
+        wrapper.called = False
+
+        self.playback.new_playlist_loaded_callback = wrapper
+        self.backend.current_playlist.load(Playlist())
+
+        self.assert_(wrapper.called)
 
     @populate_playlist
     def test_pause_when_stopped(self):