Add tests for artist_sort as lyrics search fallback

Adjust doc comment to highlight that artist_sort is used as a fallback

beetsplug/lyrics.py

@@ -187,6 +187,9 @@ def search_pairs(item):
     In addition to the artist and title obtained from the `item` the
     method tries to strip extra information like paranthesized suffixes
     and featured artists from the strings and add them as candidates.
+    The artist sort name is added as a fallback candidate to help in
+    cases where artist name includes special characters or is in a
+    non-latin script.
     The method also tries to split multiple titles separated with `/`.
     """
     def generate_alternatives(string, patterns):

test/test_lyrics.py

@@ -95,6 +95,27 @@ class LyricsPluginTest(unittest.TestCase):
         self.assertEqual(('Alice and Bob', ['song']),
                          list(lyrics.search_pairs(item))[0])
 
+    def test_search_artist_sort(self):
+        item = Item(artist='CHVRCHΞS', title='song', artist_sort='CHVRCHES')
+        self.assertIn(('CHVRCHΞS', ['song']),
+                      lyrics.search_pairs(item))
+        self.assertIn(('CHVRCHES', ['song']),
+                      lyrics.search_pairs(item))
+
+        # Make sure that the original artist name is still the first entry
+        self.assertEqual(('CHVRCHΞS', ['song']),
+                         list(lyrics.search_pairs(item))[0])
+
+        item = Item(artist='横山克', title='song', artist_sort='Masaru Yokoyama')
+        self.assertIn(('横山克', ['song']),
+                      lyrics.search_pairs(item))
+        self.assertIn(('Masaru Yokoyama', ['song']),
+                      lyrics.search_pairs(item))
+
+        # Make sure that the original artist name is still the first entry
+        self.assertEqual(('横山克', ['song']),
+                         list(lyrics.search_pairs(item))[0])
+
     def test_search_pairs_multi_titles(self):
         item = Item(title='1 / 2', artist='A')
         self.assertIn(('A', ['1 / 2']), lyrics.search_pairs(item))