How We Test Calculators

Release validation workflow

1. Formula source review and implementation in typed utility modules.
2. Known-value test vectors for base and edge-case scenarios.
3. UI-level validation for invalid input handling and warning states.
4. Snapshot checks for saved scenario export and reopen paths.
5. Pre-release verification with `npm run test` and `npm run build`.

Update triggers

• IRS/tax-year changes for tax, paycheck, retirement contribution limits.
• Published reference updates for health and education calculators.
• User-reported discrepancies through the contact/report paths.
• Regression failures from automated tests.

Edge cases we explicitly check

• Zero and near-zero values, maximum/upper-bound values, and negative invalid inputs.
• Rounding and formatting behavior for currency, percent, and schedule outputs.
• Reopen consistency for saved scenarios and comparison metric mappings.
• Behavior under missing optional fields and unsupported combinations.