R23-T056: Move test_abs_val into doctests and reach 100% coverage for maths/abs.py - #66

Description

Explores how CI collects and reports on maths/abs.py (doctests vs the test_abs_val() function) and closes the coverage gap: test_abs_val's assertions become doctests, and the __main__ block, which pytest never runs, is marked # pragma: no cover.

Related Issue

Fixes: #56

Type of Change

• Bug Fix
• New Feature
• UI/UX Improvement
• Performance Improvement
• Tests
• Documentation
• Refactoring / Maintenance
• CI/CD

Changes Made

• maths/abs.py: added doctests to abs_val, abs_min, abs_max, abs_max_sort (the cases from test_abs_val), removed test_abs_val() and its call in __main__, marked the __main__ block # pragma: no cover (same convention as ciphers/skytale_cipher.py).
• work/R23-T056/CI_NOTES.md: how CI runs pytest (flags, --ignore, coverage), the collected test IDs, DIRECTORY.md / build_directory_md.py / validate_filenames.py behaviour, and the coverage before/after output.
• work/R23-T056/coverage_before.txt, coverage_after.txt: full pytest-cov output.

Screenshots / Recordings

Not applicable (no UI changes).

Testing

• python -m pytest maths/abs.py --cov=maths --cov-report=term-missing -v -> before: 6 items, abs.py below 100% (lines 89-94 missing); after: 4 items, abs.py 100%
• python -m pytest maths/test_abs.py -q -> passed
• ruff check maths/abs.py -> all checks passed

Checklist

• I have tested my changes locally.
• I have added or updated tests, if needed.
• I have updated documentation, if needed.
• I have followed the project's coding guidelines.
• I have run the relevant tests and checks.
• I have addressed previous review feedback, if applicable.

Additional Notes

Findings: pytest maths/abs.py collects both the doctests and the test_abs_val function (6 items), but CI-style collection (pytest .) collects only the doctests: abs.py does not match test_*.py, and --doctest-modules is what picks it up, so test_abs_val ran only through its >>> test_abs_val() doctest. The coverage gap was the __main__ block. Side note: abs_val(-0.0) returns -0.0 while built-in abs(-0.0) is 0.0 (not changed). Details in work/R23-T056/CI_NOTES.md.