@Override
    public Collection<RedisServer> masters() {
        List<Map<String, String>> masters = connection.sync(StringCodec.INSTANCE, RedisCommands.SENTINEL_MASTERS);
        return toRedisServersList(masters);
    }
@Test
    public void testMasters() {
        Collection<RedisServer> masters = connection.masters();
        assertThat(masters).hasSize(1);
    }