Begin testing sysfs port recognition

[kurtmckee]

Note

This PR is broken into two commits, and should likely be reviewed one at-a-time.

• f5cb780 introduces a new command, pyserial-generate-test-asset, which can generate a JSON output of a user's sysfs-based device information, and introduces a test framework for recreating the device's sysfs filesystem as it existed on the user's device in-memory.

  This will help with debugging sysfs-based device recognition, as well as locking valuable information into the test suite to help evaluate future code changes.

  Three devices from my own testing, representing the usb, usb-serial, and serial-base sysfs subsystems, are now tested.

• 323c81f updates/modernizes the code in list_ports_linux.py, which is where the sysfs-based device recognition code lives. The code was run through pyupgrade, isort, and has had type annotations added. A cursory run of mypy was made and some issues were resolved, but type annotations are not guaranteed to be correct until more of the code has been type-annotated.

This introduces the following changes:

• Add a pytest-generate-test-asset command.

  The command produces a detailed JSON output
  to capture the state of a device on a system
  that can be used to diagnose issues with device recognition
  and can be added directly to the test suite for permanence.

  This command only works on sysfs systems so far.

• Add test assets generated from an Ubuntu 24.04 system
  running kernel 6.14.0 with real devices plugged in.

  These assets demonstrate the following subsystems:

  • serial-base
  • usb
  • usb-serial

  and demonstrate globbing of the following /dev patterns:

  • /dev/ttyACM*
  • /dev/ttyS*
  • /dev/ttyUSB*

• Increase the code coverage fail-under value to 30%.
  Previously the value was 20%.

• mypy was run against the new CLI command and passes.

  However, type annotations are not yet guaranteed
  until more of the project is type annotated
  and mypy is passing in CI.

• Type annotations have been added to list_ports_linux.py.

• The list_ports_linux.py code has been run through mypy.
  Some issues were found and fixed,
  but others will require additional work.

• The code has been run through pyupgrade and isort.

• Device patterns (like /dev/ttyS*) have been moved,
  and have been reordered to reflect which patterns have tests
  and which are currently untested.

• The if __name__ == "__main__" condition has been removed.
  If seeing the device subsystem is valuable,
  the pyserial-ports command can be updated for that purpose.

• Some typos were fixed.