Add pytest foundation and Zuul unit-test job

[berendt]

Sets up the test infrastructure so per-module unit tests for netbox_manager/ can be added incrementally (foundation work for #232, implements #233): pytest config in pyproject.toml, tests/ tree at repo root with a dynaconf settings stub in conftest.py and a smoke test, new netbox-manager-unit-tests Zuul job in check / periodic-daily, and dev deps mirrored in Pipfile + test-requirements.txt. Also extends .gitignore to exclude pycache/, *.egg-info/, and .pytest_cache/.

Closes #233

AI-assisted: Claude Code

[ideaship]

Review

Foundation is structurally sound: directory layout is correct, conftest.py handles the dynaconf import-time constraint cleanly, CI wiring is in place, and pipenv run pytest passes. Two items need to be fixed before merge.

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Correctness bugs

1. Stale Pipfile.lock

pipenv verify reports the lock is out of date. The committed _meta.hash.sha256 does not match the current Pipfile. The Zuul job runs pipenv install --dev (without --deploy), which silently re-resolves and relocks rather than failing — so CI will drift away from the committed lock whenever a dependency has a newer release. Fix: run pipenv lock and commit the result, or add --deploy to the CI command to hard-fail on stale locks.

2. pytest==9.0.3 requires Python >=3.10; project declares requires-python = ">=3.8"

pytest==9.0.3 has Requires-Python: >=3.10. Modern pip resolves this at download time and will reject the install on Python 3.8/3.9, so the README instructions (pip install -r requirements.txt -r test-requirements.txt) are broken for those versions. The Zuul job also does not pin a Python version — issue #233 explicitly listed this as in-scope and recommended 3.13.

Fix: either pin Python >=3.10 (or 3.13 per the issue) in .zuul.yaml and document that the test suite requires Python 3.10+, or drop to a pytest version that supports 3.8+. The former is the cleaner path.

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Missing / weak tests

3. get_leading_number has no behavioral test

test_main_module_imports only calls callable(main.get_leading_number). The function is pure and used in production paths (lines 975, 977 of main.py). A one-liner like assert main.get_leading_number("100-foo.yml") == "100" would provide an actual correctness check at zero extra cost.

4. test_main_module_imports — callable(main.deep_merge) is redundant

test_deep_merge_smoke already calls deep_merge directly; if it were missing or broken, that test would fail. The callable() check adds nothing.

5. test_dtl_module_imports checks class existence, not behavior

hasattr(dtl, "Repo") / hasattr(dtl, "NetBox") / hasattr(dtl, "DeviceTypes") verify that three class names are present in the module namespace. No method on any of them is called. Acceptable for a pure smoke test, but worth noting as coverage expands under #232.

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Minor

• pyproject.toml excludes tests/ from mypy entirely. Issue #233 (open question 4) recommended including it with disable_error_code = ["no-untyped-def"]. Either choice is defensible; worth an explicit decision in the PR description.