bluez: Implement unpair() method

[projectgus]

Operates by calling RemoveDevice on the Adapter object, which can be done regardless of the device's connection status.

If the device is connected then calling this method will cause Bluez to disconnect. Calling this method will also cause Bluez to delete any bonding information and GATT attribute cache.

As noted in the previous version of this function, there doesn't seem to be a more direct way to unpair a device in Bluez. It's possible to set the Trusted parameter (readwrite) on a Device object, but not the Paired parameter.

[dlech]

Nice one! It would be helpful to have some comments explaining the preconditions that lead to the various cases of having/not having self._device_info, etc. How many of these cases have you tested? (unpair while connected, unpair before connected with address arg, unpair before connected with BLEDevice, with/without adapter arg, did I miss any combos?)

[projectgus]

@dlech Thanks for quick review!

Have fixed the issue you found with setting adapter in the constructor, and refactored a little.

I've tested with permutations of the following:

• BleakClient(str) and BleakClient(BLEDevice)
• Device previously paired vs device paired as part of the client session
• unpair() while connected vs unpair() before initiating any connection
• Passing adapter kwarg to BleakClient() vs not passing (default adapter)

Also added some code to explicitly reset the internal state of the connection after unpairing. Although Bluez sends property changes to update some of this, it seems like calling unpair() and then connect() in the same client object can still fail as the client thinks it doesn't need to re-run discovery but Bluez requires this.

[projectgus]

@dlech Thanks for the careful review and explanatory comments, much appreciated!

I think this should be good to go now. I noticed another quirk while re-testing, which is that even if the RemoveDevice attempt fails (i.e. nothing to remove), any existing BlueZ object still needs to be re-Discovered - so I've reordered the unpair() coroutine a little.

[dlech]

merged, thanks!