curds: Add save() and load() functions

These functions pickle out the entire tag map onto disk. I also add a
stress test for the entire tags module that scans tracks using the
threadqueue, since that's how I intend everything to be used.

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

curds/tags.py

@@ -1,4 +1,5 @@
 # Copyright 2019 (c) Anna Schumaker.
+import data
 import mutagen
 import os
 import re
@@ -61,3 +62,12 @@ class Track(Tag):
     def add(path):
         track = Track(path)
         return track if Tag.lookup(track) == track else None
+
+
+def save():
+    with data.DataFile("tags.pickle", data.WRITE) as f:
+        f.pickle(tag_map)
+
+def load():
+    with data.DataFile("tags.pickle", data.READ) as f:
+        tag_map.update(f.unpickle())

curds/test_tags.py

@@ -0,0 +1,65 @@
+# Copyright 2019 (c) Anna Schumaker.
+import data
+import tags
+import threadqueue
+import unittest
+import os
+
+test_library = os.path.abspath("./trier/Test Library")
+test_tracks  = os.path.abspath("./trier/Test Album")
+
+class TestTags(unittest.TestCase):
+    def setUp(self):
+        data.DataFile("tags.pickle", data.WRITE).remove()
+        tags.tag_map.clear()
+
+    def test_tags_save_load(self):
+        dfile = data.DataFile("tags.pickle", data.READ)
+
+        self.assertFalse(dfile.exists())
+        tags.load()
+        self.assertEqual(len(tags.tag_map), 0)
+
+        t = tags.Track.add(os.path.join(test_tracks, "01 - Test Track.ogg"))
+        self.assertFalse(dfile.exists())
+        tags.save()
+        self.assertTrue(dfile.exists())
+
+        tags.tag_map.clear()
+        self.assertFalse(hash(t) in tags.tag_map)
+        self.assertFalse(hash(t.album) in tags.tag_map)
+
+        tags.load()
+        self.assertTrue(hash(t) in tags.tag_map)
+        self.assertTrue(hash(t.album) in tags.tag_map)
+
+    def test_tags_stress(self):
+        dfile    = data.DataFile("tags.pickle", data.READ)
+        tq       = threadqueue.ThreadQueue()
+        tracks   = 0
+        albums   = 0
+        tag_list = list(tags.tag_map)
+
+        self.assertFalse(dfile.exists())
+
+        for dirname, subdirs, files in os.walk(test_library):
+            save = False
+            for f in files:
+                tq.push(tags.Track.add, os.path.join(dirname, f))
+                tracks += 1
+                save    = True
+            if save == True:
+                tq.push(tags.save)
+                albums += 1
+
+        self.assertLess(len(tags.tag_map), tracks + albums)
+        tq.join()
+        tq.stop()
+        self.assertEqual(len(tags.tag_map), tracks + albums)
+        self.assertTrue(dfile.exists())
+
+        tags.tag_map.clear()
+        tags.load()
+        self.assertEqual(len(tags.tag_map), tracks + albums)
+        for tag in tag_list:
+            self.assertIn(hash(tag), tags.tag_map)