Update tox.ini and fix install requirements

[ildyria]

Installing tox is done directly via pip install -r test-requirements.txt.
This ensures that a newer version of tox does not conflict with dependencies.

[mbyrnepr2]

Hi @ildyria 👋 .
I'm not sure about the rationale here - Let me know if I've gotten this all wrong :)

I think we can be flexible with the version of tox that is required -
So, in test-requirements.txt we should probably unpin the version specified currently for tox to be a range instead (e.g. any version higher than 4.0.0 should be fine for our tox commands to work). Otherwise when we ask users to install test-requirements.txt directly, we are forcing a particular version of tox on them, which isn't ideal, since you can use one globally-installed tox to manage multiple locally checked-out github projects.

Adding a new section at the top of tox.ini can also help with this:

[tox]
minversion = 4.0.0

[ildyria]

I think we can be flexible with the version of tox that is required

Well, I would have hoped so, but when I run this on my laptop with Tox 4.11.3 it was breaking due to that conflict.

[mbyrnepr2]

What sort of breaking output are you getting just so we are looking at the same thing?

I've performed 2 tests on resc-backend, using Python3.11 and python3.9. The below details describe the 3.11 test but the same versions of pip and tox are used in both tests. I haven't run into any issues with the setup as described here.

# I'm using the same version of tox (4.11.3) that you are using
# Tox was installed on my machine using Python 3.11
markbyrne@Marks-MacBook-Air-2 resc-backend % python3.11 -m tox --version
4.11.3 from /Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/tox/__init__.py

# pip version:
markbyrne@Marks-MacBook-Air-2 resc-backend % python3.11 -m pip --version
pip 23.2.1 from /Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/pip (python 3.11)

# Run tox `lint` environment
cd resc-backend
python3.11 -m tox -e lint
# flake8 & pylint complete

# Tox's site-packages contains the version of tox defined in test-requirements.txt:
markbyrne@Marks-MacBook-Air-2 resc-backend % ls .tox/lint/lib/python3.11/site-packages/tox
tox/                   tox-4.11.1.dist-info/

The one thing I did run into which could be fixed is when running tox by default with the tox command. Then I see a:
FileNotFoundError: [Errno 2] No such file or directory: 'requirements.txt'.
Note this was fixed for the resc-helm-wizard package.

[ildyria]

▶ python3 --version
Python 3.11.5

resc-repository-scanner/components/resc-vcs-scanner  update-tox-install-requirements ✗                       23h32m ◒
▶ python3 -m venv env

resc-repository-scanner/components/resc-vcs-scanner  update-tox-install-requirements ✗                       23h32m ◒
▶ source env/bin/activate
(env)
resc-repository-scanner/components/resc-vcs-scanner  update-tox-install-requirements ✗                       23h32m ◒
▶ pip3 install -r requirements.txt
Looking in indexes: nexus...
[...]
Successfully installed GitPython-3.1.32 Mako-1.2.4 MarkupSafe-2.1.3 aiofiles-0.8.0 aiohttp-3.8.5 aiosignal-1.3.1 alembic-1.11.2 amqp-5.1.1 asgiref-3.7.2 async-timeout-4.0.3 attrs-23.1.0 billiard-4.1.0 celery-5.3.1 certifi-2023.7.22 cffi-1.16.0 charset-normalizer-3.3.0 click-8.1.7 click-didyoumean-0.3.0 click-plugins-1.1.1 click-repl-0.3.0 cryptography-41.0.3 fastapi-0.66.1 fastapi-cache2-0.2.1 frozenlist-1.4.0 gitdb-4.0.10 greenlet-3.0.0 h11-0.14.0 idna-3.4 kombu-5.3.2 multidict-6.0.4 packaging-21.3 pendulum-2.1.2 prettytable-3.8.0 prompt-toolkit-3.0.39 pycparser-2.21 pydantic-1.8.2 pyjwt-2.8.0 pyparsing-3.1.1 python-dateutil-2.8.2 python-multipart-0.0.6 pytzdata-2020.1 redis-4.6.0 requests-2.31.0 resc-backend-2.0.0 six-1.16.0 smmap-5.0.1 sqlalchemy-1.4.37 starlette-0.14.2 tenacity-8.2.2 termcolor-2.3.0 tomlkit-0.12.1 typing-3.7.4.3 typing-extensions-4.8.0 tzdata-2023.3 urllib3-2.0.6 uvicorn-0.17.6 vine-5.0.0 waitress-2.1.2 wcwidth-0.2.8 yarl-1.9.2
(env)
resc-repository-scanner/components/resc-vcs-scanner  update-tox-install-requirements ✗     23h33m ◒
▶ pip install tox
[...]
cachetools, virtualenv, pyproject-api, tox
  Attempting uninstall: packaging
    Found existing installation: packaging 21.3
    Uninstalling packaging-21.3:
      Successfully uninstalled packaging-21.3
ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
resc-backend 2.0.0 requires packaging==21.3, but you have packaging 23.2 which is incompatible.
Successfully installed cachetools-5.3.1 chardet-5.2.0 colorama-0.4.6 distlib-0.3.7 filelock-3.12.4 packaging-23.2 platformdirs-3.11.0 pluggy-1.3.0 pyproject-api-1.6.1 tox-4.11.3 virtualenv-20.24.5
(env)

[mbyrnepr2]

Aha right :D. So I would say the root-cause here is that resc-backend is pinning all of it's dependencies too strictly.
resc-backend is a library (it's one of resc-vcs-scanner's dependencies) so it needs to be less restrictive since it's packages need to live side-by-side in your environment with any other packages you may have installed there.
So I would unpin those versions in resc-backend's requirements.txt (or give them a minimum required version which still minimises the chances for these kind of conflicts.)
This is likely to be a recurring issue until that action is taken.

https://caremad.io/posts/2013/07/setup-vs-requirement/