Code review comment for ~andersson123/autopkgtest-cloud:revive_unit_tests

I'm not able to use the test_app.py test because I don't have some flask package installed:

    from flask import Flask, redirect, request, session
ModuleNotFoundError: No module named 'flask'

I then installed python3-pytest-flask but that was insufficient:

    from flask_openid import OpenID
ModuleNotFoundError: No module named 'flask_openid'

I then installed python3-flask-openid and ran into a different issue:

  File "/home/bdmurray/source-trees/autopkgtest-cloud/autopkgtest-cloud/charms/focal/autopkgtest-web/webcontrol/request/tests/.
./../request/app.py", line 114, in <module>
    os.makedirs(PATH, exist_ok=True)
  File "<frozen os>", line 225, in makedirs
PermissionError: [Errno 13] Permission denied: '/run/autopkgtest_webcontrol'

Could you please document how to run the tests?