lib: Give TagStores Added and Removed publishers

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

lib/tagstore.py

@@ -1,15 +1,19 @@
 # Copyright 2021 (c) Anna Schumaker.
+from . import publisher
 from . import tag
 
 class TagStore:
     def __init__(self):
         self.store = dict()
+        self.Added = publisher.Publisher()
+        self.Removed = publisher.Publisher()
 
     def add(self, name, track=None):
         name = name.strip()
         if (t := self.store.get(name)) == None:
             t = tag.Tag(name)
             self.store[name] = t
+            self.Added.publish(t)
         if track:
             t.add_track(track)
         return t
@@ -19,3 +23,4 @@ class TagStore:
             t.remove_track(track)
         if (track==None or len(t) == 0) and t in self.store.values():
             self.store.pop(t.name)
+            self.Removed.publish(t)

lib/test_tagstore.py

@@ -1,27 +1,48 @@
 # Copyright 2021 (c) Anna Schumaker.
+from . import publisher
 from . import tagstore
 import unittest
 
 class TestTagStore(unittest.TestCase):
+    def setUp(self):
+        self.added = None
+        self.removed = None
+
+    def on_store_added(self, tag):
+        self.added = tag
+
+    def on_store_removed(self, tag):
+        self.removed = tag
+
     def test_tag_store(self):
         store = tagstore.TagStore()
         self.assertEqual(store.store, { })
+        self.assertIsInstance(store.Added, publisher.Publisher)
+        self.assertIsInstance(store.Removed, publisher.Publisher)
 
     def test_tag_store_add_remove(self):
         store = tagstore.TagStore()
+        store.Added.register(self.on_store_added)
+        store.Removed.register(self.on_store_removed)
+
         tag = store.add("test", 1)
+        self.assertEqual(self.added, tag)
         self.assertEqual(tag.tracks, [ 1 ])
 
+        self.added = None
         self.assertEqual(store.add("test  ", 2), tag)
         self.assertEqual(tag.tracks, [ 1, 2 ])
+        self.assertIsNone(self.added)
 
         store.remove(tag, 1)
         self.assertEqual(tag.tracks, [ 2 ])
         self.assertIn("test", store.store.keys())
+        self.assertIsNone(self.removed)
 
         store.remove(tag, 2)
         self.assertEqual(tag.tracks, [ ])
         self.assertNotIn("test", store.store.keys())
+        self.assertEqual(self.removed, tag)
 
     def test_tag_store_add_remove_none(self):
         store = tagstore.TagStore()