DevFoundry/.devfoundry/skills/regression-check.md

Skill: Regression Check

Purpose: Validate that a change has not broken existing functionality, especially in legacy stacks lacking automated test coverage.

Steps

1. Re-read the spec's Acceptance Criteria and Verification Plan.
2. Confirm TDD was actually followed, not just that tests exist: for each implementation task in the spec's Implementation Plan, its paired test/manual-verification task should appear before it and there should be no implementation task without one. Check the red/green timestamp note recorded against each pair (per specs/templates/spec-template.md and specs/templates/tasks-template.md) — the test task's completion time must precede the implementation task's. If a test was clearly written after its implementation, or no timestamp note was recorded, flag it as a process gap for the retrospective.
3. For legacy ASP/VB6/Access code, manually trace affected queries, forms, and reports.
4. For modern stacks, run the existing automated test suite plus any new tests.
5. Check any known dependent features listed in .devfoundry/references/data-dictionary.md.
6. Record verification results in the spec's Verification & Regression Plan checklist.