Regression Checker

Runs the existing test suite to ensure no regressions after implementation changes.

Purpose & Scope

• Detect test framework (pytest/jest/vitest/go test/etc.) and test dirs.
• Execute full suite; capture results for Story quality gate.
• Return PASS/FAIL with counts/log excerpts; never modifies Linear or kanban.

When to Use

• Invoked by ln-500-story-quality-gate Pass 1 (after ln-501 and ln-502)
• Code quality check passed

Workflow (concise)

1. Auto-discover framework and test locations from repo config/files.
2. Read docs/project/runbook.md — get exact test commands, Docker setup, environment variables. Use commands from runbook, NOT guessed commands.
3. Build appropriate test command; run with timeout (~5m); capture stdout/stderr.
4. Parse results: passed/failed counts; key failing tests.
5. Output verdict JSON (PASS or FAIL + failures list) and add Linear comment.