not possible to run unittests for a single charm

[Samuel Allan]

This is a quality of life request for development - when iterating on unittests for a single charm, it would be nice to be able to run tests and view test coverage for a single charm. Currently the process is slowed somewhat because tests for all charms are always run.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: main
Review: https://review.opendev.org/c/openstack/sunbeam-charms/+/906346

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/sunbeam-charms/+/906346
Committed: https://opendev.org/openstack/sunbeam-charms/commit/e7853633fab7758ba2949d83ac05a12c603d5d89
Submitter: "Zuul (22348)"
Branch: main

commit e7853633fab7758ba2949d83ac05a12c603d5d89
Author: Samuel Allan <email address hidden>
Date: Tue Jan 23 16:53:31 2024 +1030

    Allow running unit tests on a single charm

    This allows scoping a tox run of py3* and cover enviroments
    to a single charm or ops-sunbeam, to facilitate faster testing.

    Usage examples:

    ```
    tox -e py3 # test all
    tox -e py3 -- ops-sunbeam # just the ops sunbeam lib
    tox -e py3 -- barbican-k8s # only the barbican charm

    tox -e cover
    tox -e cover -- ops-sunbeam
    tox -e cover -- barbican-k8s
    ```

    Closes-Bug: #2050840

    Change-Id: Ieb3cd5ad85ee7a04a320cc41fbc3ad406e034a57