curds: Add the Previous playlist to the playlist manager

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

curds/playlist/manager.py

@@ -1,6 +1,7 @@
 # Copyright 2019 (c) Anna Schumaker.
 from . import collection
 from . import library
+from . import previous
 from .. import notify
 import os
 
@@ -27,10 +28,16 @@ class LibraryManager(list):
 class PlaylistManager(dict):
     def __init__(self):
         self["Collection"] = collection.CollectionPlaylist()
+        self["Previous"]   = previous.PreviousPlaylist()
         self["Library"]    = LibraryManager()
         self.current       = self["Collection"]
         self.track         = None
 
     def next(self):
         self.track = self.current.next()
+        self["Previous"].add(self.track)
+        return self.track
+
+    def previous(self):
+        self.track = self["Previous"].next()
         return self.track

curds/playlist/test_manager.py

@@ -3,6 +3,7 @@ from . import collection
 from . import library
 from . import manager
 from . import playlist
+from . import previous
 from .. import notify
 from .. import tags
 from .. import threadqueue
@@ -28,6 +29,7 @@ class TestPlaylistManager(unittest.TestCase):
         self.assertIsInstance(playman, manager.PlaylistManager)
         self.assertIsInstance(playman, dict)
         self.assertIsInstance(playman["Collection"], collection.CollectionPlaylist)
+        self.assertIsInstance(playman["Previous"],   previous.PreviousPlaylist)
         self.assertIsInstance(playman["Library"],    manager.LibraryManager)
         self.assertIsInstance(playman["Library"],    list)
 
@@ -77,17 +79,31 @@ class TestPlaylistManager(unittest.TestCase):
         self.assertEqual(len(alist), 12)
         self.assertEqual(len(playman["Collection"]), len(alist) + len(plist))
 
-    def test_manager_next(self):
+    def test_manager_next_prev(self):
         playman = manager.PlaylistManager()
         self.assertIsNone(playman.next())
         self.assertIsNone(playman.track)
 
         clist = playman["Collection"]
+        prev  = playman["Previous"]
         plist = playman["Library"].add(test_library)
         library.library_thread.join()
 
-        track = playman.next()
-        self.assertEqual(playman.track, track)
+        track1 = playman.next()
+        self.assertEqual(playman.track, track1)
         self.assertEqual(clist.current, 0)
-        self.assertEqual(track,   clist[0])
+        self.assertEqual(track1,  clist[0])
 
+        self.assertEqual(len(prev), 1)
+        self.assertEqual(prev[0], track1)
+
+        track2 = playman.next()
+        self.assertEqual(playman.track, track2)
+        self.assertEqual(clist.current, 1)
+        self.assertEqual(track2,  clist[1])
+
+        self.assertEqual(len(prev), 2)
+        self.assertEqual(prev[0], track2)
+        self.assertEqual(prev[1], track1)
+
+        self.assertEqual(playman.previous(), track1)