Write unit tests

[DamKast]

Write unit tests for the zigpy-zboss code.

[Hedda]

Any updates on your work to add some ZBOSS radio unit tests same/similar to unit tests in the other radio libraries for zigpy?

• https://github.com/zigpy/zigpy/blob/dev/CONTRIBUTING.md#unit-testing

puddly's reply to @e3c6a08b1f15492310b7e2912cc3552b in home-assistant/core#114828 indicate this is currently a showstopper.

"Merging support for an untested package would introduce an enormous maintenance burden, as we would not be able to update zigpy without also fixing zigpy-zboss and testing it by hand."

Please see the tests directory for bellows, zigpy-znp, zigpy-deconz, and zigpy-espzb radio libraries and add minimum of tests:

• https://github.com/zigpy/bellows/tree/dev/tests
• https://github.com/zigpy/zigpy-znp/tree/dev/tests
• https://github.com/zigpy/zigpy-deconz/tree/dev/tests
• https://github.com/lhespress/zigpy-espzb/tree/master/tests

PS: When add tests suggest also checking Home Assistant's "Development Checklist" to make sure checking all those boxes too:

• https://developers.home-assistant.io/docs/development_checklist/

• https://github.com/zigpy/zigpy/blob/dev/CONTRIBUTING.md#unit-testing