diff --git a/mopidy/audio/scan.py b/mopidy/audio/scan.py
index 72c4bee6..f4efdb69 100644
--- a/mopidy/audio/scan.py
+++ b/mopidy/audio/scan.py
@@ -176,7 +176,7 @@ def _query_duration(pipeline):
     elif duration < 0:
         duration = None  # Stream without duration.
     else:
-        duration = duration // Gst.MSECOND
+        duration = int(duration // Gst.MSECOND)
     return success, duration
 
 
diff --git a/tests/m3u/test_playlists.py b/tests/m3u/test_playlists.py
index e0ea1ce4..e993f9b1 100644
--- a/tests/m3u/test_playlists.py
+++ b/tests/m3u/test_playlists.py
@@ -151,6 +151,9 @@ class M3UPlaylistsProviderTest(unittest.TestCase):
         self.assertEqual(playlist.name, result.name)
         self.assertEqual(track.uri, result.tracks[0].uri)
 
+    @unittest.skipIf(
+        platform.system() == 'Darwin',
+        'macOS 10.13 raises IOError "Illegal byte sequence" on open.')
     def test_load_playlist_with_nonfilesystem_encoding_of_filename(self):
         path = os.path.join(self.playlists_dir, 'øæå.m3u'.encode('latin-1'))
         with open(path, 'wb+') as f:
@@ -160,10 +163,7 @@ class M3UPlaylistsProviderTest(unittest.TestCase):
 
         self.assertEqual(len(self.core.playlists.as_list()), 1)
         result = self.core.playlists.as_list()
-        if platform.system() == 'Darwin':
-            self.assertEqual('%F8%E6%E5', result[0].name)
-        else:
-            self.assertEqual('\ufffd\ufffd\ufffd', result[0].name)
+        self.assertEqual('\ufffd\ufffd\ufffd', result[0].name)
 
     @unittest.SkipTest
     def test_playlists_dir_is_created(self):
diff --git a/tests/stream/test_library.py b/tests/stream/test_library.py
index 29348a6c..312feb69 100644
--- a/tests/stream/test_library.py
+++ b/tests/stream/test_library.py
@@ -60,4 +60,8 @@ def test_lookup_converts_uri_metadata_to_track(audio, config, track_uri):
     backend = actor.StreamBackend(audio=audio, config=config)
 
     result = backend.library.lookup(track_uri)
-    assert result == [Track(length=4406, uri=track_uri)]
+
+    assert len(result) == 1
+    track = result[0]
+    assert track.uri == track_uri
+    assert track.length == 4406