Suggestion: Add docs for testing hooks

[Florian Bischoff]

Comment/Problem

Only documentation about writing tests I found was this
https://docs.feathersjs.com/guides/basics/testing.html

This provides insight into testing services, but it would be helpful to add information about testing hooks. Can hooks be tested in isolation? Or should they always be tested with a service.

[Florian Bischoff]

For anyone else stumbling upon this: Here is some great advice on how to test hooks https://blog.feathersjs.com/testing-feathers-applications-eaf1a323d2d9