test-driven-univer-developmentlisted

# Test-Driven Univer Development Test-Driven Univer Development is package-local SaC TDD for Univer workbooks. Behavior is complete only when assertion contracts prove the changed packs through `univer sac verify`. This is not generic code TDD. The goal is correct Univer package behavior through source, runtime, and assertion evidence. For spreadsheet projects, that includes Excel domain semantics, range roles, formulas, computed values, formatting, validation, protection, preservation, and negative constraints. <EXTREMELY-IMPORTANT> NO MIGRATION PACK IMPLEMENTATION WITHOUT A PLAN-DERIVED FAILING ASSERTION FIRST. If you wrote migration source before the assertion failed for the intended workbook-visible reason: Delete or revert the migration source change and restart from the plan-derived assertion gate. No exceptions: - Do not keep it as reference. - Do not adapt it while writing assertions. - Do not leave it commented out. - Implement fresh from the plan-derived failing assertion. </EXTREMELY-IMPORTANT> ## When to Use Use this skill for: - new or changed Facade Migration Packs - `assertions.ts` coverage - `univer sac apply` or `univer sac verify` repair loops - workbook-visible behavior changes in package-local SaC source - refactoring SaC source while preserving workbook behavior Exceptions require explicit user agreement and must be recorded in the handoff. ## Operating Contract - Use `writing-univer-plans` first for complex workbook behavior. - Use `executing