所有的hook函数，都需要pytest_开头命名。
参考：https://www.cnblogs.com/pingguo-softwaretesting/p/9620121.html
https://www.cnblogs.com/sunshine-blog/p/10069680.html
pytest官方文档：https://docs.pytest.org/en/latest/writing_plugins.html#firstresult-stop-at-first-non-none-result