MPD: Handle 'play "-1"' in same way as 'playid "-1"'

mopidy/mpd/frontend.py

@@ -839,6 +839,7 @@ class MpdFrontend(object):
             raise MpdAckError(e[0])
 
     @handle_pattern(r'^play "(?P<songpos>\d+)"$')
+    @handle_pattern(r'^play "(?P<songpos>-1)"$')
     def _playback_playpos(self, songpos):
         """
         *musicpd.org, playback section:*
@@ -846,10 +847,17 @@ class MpdFrontend(object):
             ``play [SONGPOS]``
 
             Begins playing the playlist at song number ``SONGPOS``.
+
+        *MPoD:*
+
+        - issues ``play "-1"`` after playlist replacement.
         """
         songpos = int(songpos)
         try:
-            track = self.backend.current_playlist.playlist.tracks[songpos]
+            if songpos == -1:
+                track = self.backend.current_playlist.playlist.tracks[0]
+            else:
+                track = self.backend.current_playlist.playlist.tracks[songpos]
             return self.backend.playback.play(track)
         except IndexError:
             raise MpdAckError(u'Position out of bounds')

tests/mpd/frontend_test.py

@@ -461,6 +461,14 @@ class PlaybackControlHandlerTest(unittest.TestCase):
         self.assert_(u'ACK Position out of bounds' in result)
         self.assertEqual(self.b.playback.STOPPED, self.b.playback.state)
 
+    def test_play_minus_one_plays_first_in_playlist(self):
+        track = Track(id=0)
+        self.b.current_playlist.load(Playlist(tracks=[track]))
+        result = self.h.handle_request(u'play "-1"')
+        self.assert_(u'OK' in result)
+        self.assertEqual(self.b.playback.PLAYING, self.b.playback.state)
+        self.assertEqual(self.b.playback.current_track, track)
+
     def test_playid(self):
         self.b.current_playlist.load(Playlist(tracks=[Track(id=0)]))
         result = self.h.handle_request(u'playid "0"')