'Keep only genres that are in the whitelist.'

def test_whitelist_custom(self):

    self._setup_config(whitelist=set(['blues', 'rock', 'jazz']), count=2)
    self.assertEqual(self.plugin._resolve_genres(['pop', 'blues']), u'Blues')
    self._setup_config(canonical='', whitelist=set(['rock']))
    self.assertEqual(self.plugin._resolve_genres(['delta    blues']), u'')
