def METHOD_NAME(self):
    from relstorage.adapters.replica import ReplicaSelector
    rs = ReplicaSelector(self.fn, 600.0)
    self.assertEqual(rs.current(), 'example.com:1234')
    # change the file and get the new current replica
    with open(self.fn, 'w', encoding='utf-8') as f:
        f.write('localhost\nalternate\n')
    rs._config_checked = 0
    rs._config_modified = 0
    self.assertEqual(rs.current(), 'localhost')
    # switch to the alternate
    rs._select(1)
    self.assertEqual(rs.current(), 'alternate')
    # expire the alternate
    rs._expiration = 0
    self.assertEqual(rs.current(), 'localhost')