Add 'play -1' support, which fixes resume in MPoD

docs/changes.rst

@@ -19,6 +19,8 @@ No description yet.
     commands. This makes media library browsing in ncmpcpp work, though very
     slow due to all the meta data requests to Spotify.
 
+  - Add support for ``play "-1"``, which fixes resume in MPoD.
+
 - Settings:
 
   - Fix crash on ``--list-settings`` on clean installation. Thanks to Martins

mopidy/frontends/mpd/protocol/playback.py

@@ -132,10 +132,13 @@ def playid(frontend, cpid):
 
         Begins playing the playlist at song ``SONGID``.
 
-    *GMPC:*
+    *Clarifications:*
 
-    - issues ``playid "-1"`` after playlist replacement to start playback
-      at the first track.
+    - ``playid "-1"`` when paused resumes playback.
+    - ``playid "-1"`` when stopped with a current track starts playback at the
+      current track.
+    - ``playid "-1"`` when stopped without a current track, e.g. after playlist
+      replacement, starts playback at the first track.
     """
     cpid = int(cpid)
     paused = (frontend.backend.playback.state ==
@@ -161,17 +164,23 @@ def playpos(frontend, songpos):
 
         Begins playing the playlist at song number ``SONGPOS``.
 
-    *Many clients:*
+    *Clarifications:*
 
-    - issue ``play "-1"`` after playlist replacement to start the current
-      track. If the current track is not set, start playback at the first
-      track.
+    - ``playid "-1"`` when paused resumes playback.
+    - ``playid "-1"`` when stopped with a current track starts playback at the
+      current track.
+    - ``playid "-1"`` when stopped without a current track, e.g. after playlist
+      replacement, starts playback at the first track.
 
     *BitMPC:*
 
     - issues ``play 6`` without quotes around the argument.
     """
     songpos = int(songpos)
+    paused = (frontend.backend.playback.state ==
+        frontend.backend.playback.PAUSED)
+    if songpos == -1 and paused:
+        return frontend.backend.playback.resume()
     try:
         if songpos == -1:
             cp_track = _get_cp_track_for_play_minus_one(frontend)

tests/frontends/mpd/playback_test.py

@@ -257,6 +257,18 @@ class PlaybackControlHandlerTest(unittest.TestCase):
         self.assertEqual(self.b.playback.STOPPED, self.b.playback.state)
         self.assertEqual(self.b.playback.current_track, None)
 
+    def test_play_minus_one_resumes_if_paused(self):
+        self.b.current_playlist.append([Track(length=40000)])
+        self.b.playback.seek(30000)
+        self.assert_(self.b.playback.time_position >= 30000)
+        self.assertEquals(self.b.playback.PLAYING, self.b.playback.state)
+        self.b.playback.pause()
+        self.assertEquals(self.b.playback.PAUSED, self.b.playback.state)
+        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.assert_(self.b.playback.time_position >= 30000)
+
     def test_playid(self):
         self.b.current_playlist.append([Track()])
         result = self.h.handle_request(u'playid "0"')