How to deal with `JwtUtils.getUserInfo()` when writing unit tests?

[Kunshuai Zhu]

Hi friends,
I ran into trouble while writing unit tests. You can see
`PermissionServiceImpl#getPermissionMenu`.
The code in 74th line is `UserInfo userInfo = JwtUtils.getUserInfo();`
Here comes the problem that it will throw NullPointerException. So
that the following lines can't be test.
What should i do? Can I import "powermock" to mock `JwtUtils.getUserInfo()`?