# Testing

## Regression Test Precision

Regression tests use percentage-based relative tolerances (`rtol`) for numerical comparison:

- **High precision** (`rtol=1e-6` = 0.0001%): Efficiency analysis, load sweep, wrapper parity
- **Medium precision** (`rtol=1e-3` = 0.1%): RXC filter values  
- **Lower precision** (`rtol=1e-2` = 1%): LCR fitting parameters, R² values

Relative tolerance means the allowed difference is proportional to the magnitude of the values being compared.

## Windows Compatibility

LCR fitting tests are `@pytest.mark.xfail` on Windows due to numerical precision differences in optimization algorithms. This is expected behavior.

```python
@pytest.mark.xfail(
    condition=sys.platform == "win32",
    reason="LCR fitting results differ significantly on Windows due to numerical precision differences",
    strict=False,
)
```

## Archive System

Tests use binary pickle archives (`tests/data/analysis_regression_results.pkl`) for precise numerical comparison with automatic creation and updates.

## Coverage Reports

### Excluded Files

Files excluded from coverage analysis are listed in `pyproject.toml`:

```toml
[tool.coverage.run]
omit = ["wpt_tools/plotter.py"]
```

### Viewing Coverage

- **Terminal**: `uv run pytest tests/ --cov=wpt_tools --cov-report=term-missing`
- **Direct**: `uv run coverage report --show-missing`

Excluded files are not shown in coverage reports.