Integration tests

[timrid]

This adds integration tests for bleak. It works by emulating a BLE device with bumble in conjunction with an nRF52840 Dongle.

I currently only tested this with a MacBook and the CoreBluetooth backend. But in principle this should also work similar on Linux and Windows. I dont think that it will be possible to get 100% coverage (e.g. permission handling is not automatically testable), but it will catch many cases. I think, that it should also be possible to add tox to automatically test all supported python versions.

I am sharing this as a draft to get high level feedback on whether integration tests are interesting in this way. Then I would continue working on this to test the other platforms as well. I developed this, because I need some way to test my work on an rubicon-objc backend (see #1833).

[dlech]

Yeah, having something like this would be really great. And I already have one of these dongles already.

It would help speed things up if we could split this into multiple pull requests, ideally not changing much more than 500 lines at a time. 2000+ lines is just too much to try to review all at once.

And I wouldn't worry about testing different Python versions as we generally haven't had issues related to that.

[dlech]

I do not want to have binary files committed to the source tree. We can replace this with a URL to download it from a trusted source and commit a hash to source to verify that the file at the URL hasn't changed.

[dlech]

This could be a new group in the pyproject.toml file so that it gets installed in the virtual environment instead of globally.

[dlech]

We'll need some links on where to get these tools.