Python unit tests fail after collection due to result/API contract mismatches

[Rgeph]

Summary

After bypassing collection errors with --continue-on-collection-errors, many unit tests still fail because test expectations no longer match the current Python API contracts.

Reproduction

cd python
python -m pip install --user -e . pytest
python -m pytest tests/unit -q --tb=short -ra --continue-on-collection-errors

Current result

19 failed, 694 passed, 5 errors

Main failure groups

Spectrum metrics key mismatch

Several calibration tests call:

analyze_spectrum(...)["sndr_db"]

but the current spectrum API returns metrics using sndr_dbc.

Examples:

• tests/unit/calibration/test_verify_calibration_full.py
• tests/unit/calibration/test_verify_calibration_full_multi_datasets.py
• tests/unit/calibration/test_verify_calibration_lite.py

Polar/decomposition return shape mismatch

tests/unit/aout/test_verify_spec_plot_phase.py expects two return values from:

analyze_spectrum_polar(...)
analyze_decomposition_polar(...)

but the current functions return more values, causing:

ValueError: too many values to unpack (expected 2)

AOUT result field mismatch

tests/unit/aout/test_analyze_error_phase_plane.py expects fitted_sine, but the current result contains fitted_params and related fields instead.

Calibration/frequency edge case

tests/unit/calibration/test_verify_estimate_frequencies.py::test_freq_estimation_shuffled hits:

ZeroDivisionError: float division by zero

inside compute_spectrum when a degenerate/zero signal path reaches THD calculation.

Windows symlink privilege

One skill CLI test fails separately on Windows because editable installs use symlinks without checking privilege:

OSError: [WinError 1314] The client does not have a required privilege

That may deserve a platform-specific skip/fallback or its own fix.

Expected behavior

Unit tests should either:

• be updated to match the current public API, or
• the package should provide compatibility aliases/fields where those APIs are intended to remain supported.

Notes

This is separate from the test collection failures tracked in #27. Those collection errors prevent a normal test run from reaching these failures unless --continue-on-collection-errors is used.

[Arcadia-1]

PR #38 landed a partial fix for this issue: legacy spectrum metric aliases are available again, analyze_error_phase_plane() returns fitted_sine, and zero-signal spectrum analysis no longer raises ZeroDivisionError.

Remaining known failures after that patch are still in scope for this issue:

• calibration numeric/tolerance failures in the full calibration and lstsq tests;
• old polar phase tests expecting tuple returns while the current documented analyze_spectrum_polar() / analyze_decomposition_polar() APIs return dictionaries.

Recommendation: split the remaining work into two follow-ups: one for calibration numeric/test-contract review, and one for updating or explicitly compatibility-wrapping the polar phase tests/API.

[Arcadia-1]

Fixed by 23f8e93 (Fix remaining unit test contracts). Current Python unit suite now passes locally: 739 passed, 56 warnings with pytest tests/unit -q --tb=short --continue-on-collection-errors. The remaining broader test hygiene / comparison workflow / MATLAB environment items are tracked separately in #34, #35, #36, and #25.