playlist: Create a TagModel as a custom GListModel

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

lib/fake.py

@@ -1,9 +1,11 @@
 # Copyright 2021 (c) Anna Schumaker.
+from gi.repository import GObject
 
 tracks = { }
 
-class FakeTrack:
+class FakeTrack(GObject.GObject):
     def __init__(self, n, tag=None):
+        GObject.GObject.__init__(self)
         self.trackid = n
         self.length  = n
         self.tag     = tag

playlist/model.py

@@ -0,0 +1,19 @@
+# Copyright 2021 (c) Anna Schumaker.
+from gi.repository import GObject, Gio
+
+class TagModel(GObject.GObject, Gio.ListModel):
+    def __init__(self, tag):
+        GObject.GObject.__init__(self)
+        self.tag = tag
+
+    def do_get_item_type(self):
+        return GObject.TYPE_PYOBJECT
+
+    def do_get_n_items(self):
+        return len(self.tag)
+
+    def do_get_item(self, n):
+        return self.tag[n]
+
+    def do_get_object(self, n):
+        return self.tag[n]

playlist/test_model.py

@@ -0,0 +1,23 @@
+# Copyright 2021 (c) Anna Schumaker.
+from . import model
+from lib import fake
+from lib import tag
+from gi.repository import GObject, Gio
+import unittest
+
+
+class TestTagModel(unittest.TestCase):
+    def test_tag_model_init(self):
+        t = tag.Tag("Test")
+        m = model.TagModel(t)
+
+        self.assertIsInstance(m, GObject.Object)
+        self.assertIsInstance(m, Gio.ListModel)
+
+        self.assertEqual(m.get_item_type(), GObject.TYPE_PYOBJECT)
+        self.assertEqual(m.get_n_items(), 0)
+        self.assertIsNone(m.get_item(0))
+
+        t.add_track(fake.Track(1))
+        self.assertEqual(m.get_n_items(), 1)
+        self.assertEqual(m.get_item(0), fake.Track(1))