curds: Clear the current list when selecting the Collection playlist

The collection playlist always has loop=True, so we'll never pop it from
the stack under normal conditions. Let's clear the list when selecting
this playlist so we don't keep a list of unreachable playlists.

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

curds/playlist/manager.py

@@ -149,6 +149,8 @@ class PlaylistManager(PlaylistManagerBase):
         self.track   = None
 
     def select(self, plist):
-        if plist in self.current:
+        if plist == self.lookup("Collection"):
+            self.current = [ ]
+        elif plist in self.current:
             self.current.remove(plist)
         self.current.insert(0, plist)

curds/playlist/test_manager.py

@@ -256,5 +256,11 @@ class TestPlaylistManager(unittest.TestCase):
         self.assertEqual(self.playman.next(), glist[0])
         self.assertEqual(self.playman.current, [ glist, clist ])
 
+        self.playman.select(plist)
+        self.assertEqual(self.playman.current, [ plist, glist, clist ])
+        self.playman.select(clist)
+        self.assertEqual(self.playman.current, [ clist ])
+
+        self.playman.select(plist)
         self.playman.reset()
         self.assertEqual(self.playman.current, [ clist ])