chore: clean up ops-testing project file

[dimaqq]

Fixes #2311 -- switches the build backend to Hatchling, better links, etc.

Open questions:

• I've renamed testing/src/scenario to testing/src/ops_scenario. The alternative would be to tweak some project setting to our setup (package name doesn't match directory)
• If we go renaming things, how about dropping the src layout?

[tonyandrewmeyer]

• I've renamed testing/src/scenario to testing/src/ops_scenario. The alternative would be to tweak some project setting to our setup (package name doesn't match directory)

I'm pretty sure this is wrong, whether it's src layout or not. The PyPI package name is ops-scenario, but the package is scenario (it's "import scenario" not "import ops_scenario"). The filesystem should match the namespace not the PyPI package.

• If we go renaming things, how about dropping the src layout?

What about adopting it instead? It still seems to be that this is the current common practice, and it makes it simpler for the monorepo with tooling, based on the experimentation last year.

[dimaqq]

I'm pretty sure this is wrong, whether it's src layout or not. The PyPI package name is ops-scenario, but the package is scenario (it's "import scenario" not "import ops_scenario"). The filesystem should match the namespace not the PyPI package.

I tried that, but uv-build disagrees:

🦐/c/operator (chore-clean-up-ops-testing-project-file)> tox -e unit -- -vx
unit: uv-sync> uv sync --locked --python-preference system --no-default-groups --group unit --group xdist -p /Users/dima/.local/share/uv/tools/tox/bin/python
Resolved 59 packages in 3ms
  × Failed to build `ops-scenario @ file:///code/operator/testing`
  ├─▶ The build backend returned an error
  ╰─▶ Call to `uv_build.build_editable` failed (exit status: 1)

      [stderr]
      Error: Expected a Python module at: src/ops_scenario/__init__.py

P.S. and weirdly your advice works if I move everything under packages/.
So confusing!

P.P.S. I think there's a subtle difference between editable install and sdist build.
One wants it one way, the other, the opposite way.