Restore running tests on Python 3.9 (oldest supported Python version)

[Avasam (Avasam)]

As title says.
Done by force-installing a compatible-enough version of scipy-stubs. Conditions should make it easy to grep and remove once Python 3.9 support is dropped from PyLance stubs.

As other PRs, requires #397 first.

---

Alternatively, if maintainers make the call that 3.9 is no longer supported (due to being EOL, even 3.10 is EOL soon !), then I'll close this PR in favor of bumping the min-supported version in configs.

[Bill Schnurr (bschnurr)]

🔒 Automated review in progress — Bill Schnurr (@bschnurr) is auto-reviewing this PR.

[Bill Schnurr (bschnurr)]

Result: ⚠️ needs-more-tests

Verification details

Verification: The relevant tests could not be fully run in the isolated environment; this review is not fully verified.

Summary: The sandbox only provided Python 3.13, and offline dependency setup was blocked by a missing `docopt-ng` wheel, so the Python 3.9 CI matrix could not be exercised. An ad-hoc check confirmed the dependency marker, workflow fallback, and both `run_tests.py` version branches. A mypy control passed, but the available unpinned mypy 2.3.1 cannot target Python 3.9. No tests were added for the new installer branch.

Test runs: 3 passed, 4 not run

• ⚠️ Not run | Mypy Python 3.9 smoke test | python -m mypy tests/run_tests.py --python-version=3.9
• ⚠️ Not run | Python 3.9 Pyright workflow test | python -m pyright
• ⚠️ Not run | Stubtest workflow suite | python tests/run_stubtest.py
• ⚠️ Not run | Offline dependency bootstrap | python -m venv --system-site-packages .venv && .venv/bin/python -m pip install --no-index --find-links="$PIP_FIND_LINKS" --group tests
• ✅ Passed | Mypy Python 3.10 control | python -m mypy --version && python -m mypy tests/run_tests.py --python-version=3.10
• ✅ Passed | Environment and test discovery | printf 'sandbox_profile=%s\n' "$AUTOMATION_SANDBOX_PROFILE"; printf '%s\n' '--- changed files ---'; git diff --name-status HEAD^ HEAD; printf '%s\n' '--- available Python/tooling ---'; command -v python3.9 || true; command -v python3.13 || true; command -v python || true; python --version 2>&1 || true; command -v uv || true; printf '%s\n' '--- environments/dependencies ---'; test -d .venv && echo '.venv present' || echo '.venv absent'; python - <<'PY'
import importlib.util
for name in ('pytest', 'mypy', 'pyright', 'scipy', 'scipy-stubs', 'optype'):
print(f'{name}: {bool(importlib.util.find_spec(name))}')
PY
printf '%s\n' '--- test entrypoints ---'; find tests -maxdepth 2 -type f -print | sort
• ✅ Passed | Python-version dependency fallback assertions | python - <<'PY'
import importlib.util
import pathlib
import tomllib
from packaging.requirements import Requirement
root = pathlib.Path('.')
data = tomllib.loads((root / 'pyproject.toml').read_text())
tests = data['dependency-groups']['tests']
scipy_req = next(Requirement(item) for item in tests if item.startswith('scipy-stubs'))
assert not scipy_req.marker.evaluate({'python_version': '3.9'})
assert scipy_req.marker.evaluate({'python_version': '3.10'})
assert 'pip' in data['dependency-groups']['dev']
workflow = (root / '.github/workflows/test.yml').read_text()
assert 'python-version: ["3.9", "3.13"]' in workflow
assert "if: ${{ matrix.python-version == '3.9' }}" in workflow
assert "python -m pip install 'scipy-stubs<1.16' 'optype<0.10' --ignore-requires-python" in workflow
spec = importlib.util.spec_from_file_location('run_tests_under_test', root / 'tests/run_tests.py')
module = importlib.util.module_from_spec(spec)
spec.loader.exec_module(module)
original_version = module.sys.version_info
try:
calls = []
module.subprocess.check_call = calls.append
module.sys.version_info = (3, 9)
module.install_requirements()
assert calls[-1] == (module.sys.executable, '-m', 'pip', 'install', 'scipy-stubs<1.16', 'optype<0.10', '--ignore-requires-python')
assert len(calls) == 3
calls.clear()
module.sys.version_info = (3, 10)
module.install_requirements()
assert len(calls) == 2
finally:
module.sys.version_info = original_version
print('PASS: dependency marker, workflow Python 3.9 fallback, and run_tests version branches')
PY

⚠️ Mypy Python 3.9 smoke test diagnostic output

mypy: error: argument --python-version: Python 3.9 is not supported (must be 3.10 or higher)

⚠️ Python 3.9 Pyright workflow test diagnostic output

Python 3.9 and pyright were unavailable after offline dependency setup failed.

⚠️ Stubtest workflow suite diagnostic output

Required runtime and stub dependencies could not be installed offline.

⚠️ Offline dependency bootstrap diagnostic output

Looking in links: /opt/python-wheelhouse, /opt/python-wheelhouse
ERROR: Could not find a version that satisfies the requirement docopt-ng
ERROR: No matching distribution found for docopt-ng

[Bill Schnurr (bschnurr)]

Approved via Review Center.