Fix crash in local backend when looking up unknown path

docs/changes.rst

@@ -71,6 +71,8 @@ v0.8 (in development)
 - Created a Spotify track proxy that will switch to using loaded data as soon
   as it becomes available. Fixes :issue:`72`.
 
+- Fixed crash on lookup of unknown path when using local backend.
+
 
 v0.7.3 (2012-08-11)
 ===================

mopidy/backends/local/__init__.py

@@ -203,7 +203,8 @@ class LocalLibraryProvider(BaseLibraryProvider):
         try:
             return self._uri_mapping[uri]
         except KeyError:
-            raise LookupError('%s not found.' % uri)
+            logger.debug(u'Failed to lookup "%s"', uri)
+            return None
 
     def find_exact(self, **query):
         self._validate_query(query)

tests/backends/base/library.py

@@ -34,8 +34,8 @@ class LibraryControllerTest(object):
         self.assertEqual(track, self.tracks[0])
 
     def test_lookup_unknown_track(self):
-        test = lambda: self.library.lookup('fake uri')
-        self.assertRaises(LookupError, test)
+        track = self.library.lookup('fake uri')
+        self.assertEquals(track, None)
 
     def test_find_exact_no_hits(self):
         result = self.library.find_exact(track=['unknown track'])