add tests for SessionStorage class.
add tests for SessionStorage class.

FlyRabbit/WeRoBot,Zeacone/WeRoBot,adam139/WeRobot,adam139/WeRobot,tdautc19841202/WeRoBot,adrianzhang/WeRoBot,whtsky/WeRoBot,FlyRabbit/WeRoBot,kmalloc/WeRoBot,cloverstd/WeRoBot,whtsky/WeRoBot,one-leaf/WeRoBot,weberwang/WeRoBot,notwin/WeRoBot,whtsky/WeRoBot,chenjiancan/WeRoBot,Infixz/WeRoBot,cloverstd/WeRoBot,weberwang/WeRoBot,Zhenghaotao/WeRoBot