增加文档 关于tests下文档介绍

实际开发中， 希望不需要启动socket服务就能进行模拟请求发送处理
类似于hyperf的http单元测试

Start by reviewing the tests directory and the current socket-service testing approach. Compare the desired no-socket request simulation with Hyperf's HTTP unit-test pattern; done means the tests documentation clearly explains whether and how requests can be simulated without starting the socket service.

索引モデルが issue の本文から書いたものです。