Ln 513 Regression Checker

---
name: ln-513-regression-checker
description: Worker that runs existing tests to catch regressions. Auto-detects framework, reports pass/fail. No status changes or task creation.
license: MIT
---

> **Paths:** File paths (`shared/`, `references/`, `../ln-*`) are relative to skills repo root. If not found at CWD, locate this SKILL.md directory and go up one level for repo root.

# Regression Checker

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

## Inputs

| Input | Required | Source | Description |
|-------|----------|--------|-------------|
| `storyId` | Yes | args, git branch, kanban, user | Story to process |

**Resolution:** Story Resolution Chain.
**Status filter:** To Review

## Purpose & Scope
- Detect test framework (pytest/jest/vitest/go test/etc.) and test dirs.
- Execute full suite; capture stdout/stderr for Story quality gate.
- Return PASS/FAIL with counts/log excerpts; never modifies Linear or kanban.
- Preserve full stdout/stderr output for downstream log analysis.

## When to Use
- After code quality checks pass
- Code quality check passed

## Workflow

### Phase 0: Resolve Inputs

**MANDATORY READ:** Load `shared/references/input_resolution_pattern.md`, `shared/references/ci_tool_detection.md`

1. **Resolve storyId:** Run Story Resolution Chain per guide (status filter: [To Review]).

### Phase 1: Execute Tests

**MANDATORY READ:** Load `docs/project/infrastructure.md`, `docs/project/runbook.md`, `shared/references/output_normalization.md`

1) Auto-discover test framework per ci_tool_detection.md Command Registry (Test Frameworks section).
2) Get service endpoints, port allocation from infrastructure.md. Get exact test commands, Docker setup, environment variables from runbook.md. Runbook commands take priority over auto-detection (per ci_tool_detection.md Discovery Hierarchy).
3) Build appropriate test command; run with timeout (5min per ci_tool_detection.md); capture stdout/stderr.
4) Parse results: passed/failed counts; key failing tests.
5) **Normalize + group failures:** Apply `shared/references/output_normalization.md` §1-§3 to test output. Group failing tests by error category (Import/Module, Assertion, Timeout, Type, Connection, Runtime). Report grouped: e.g., "3 Import errors in auth/, 2 Assertion mismatches in payment/".
6) Output verdict JSON (PASS or FAIL + grouped failures list) and add Linear comment.

## Critical Rules
- No selective test runs; run full suite.
- Do not fix tests or change status; only report.
- Language preservation in comment (EN/RU).

## Definition of Done

- [ ] Framework detected; command executed
- [ ] Results parsed; verdict produced with failing tests (if any)
- [ ] Linear comment posted with summary

## Reference Files
- Risk-based limits used downstream: `shared/references/risk_based_testing_guide.md`
- **CI tool detection:** `shared/references/ci_tool_detection.md`
- **Output normalization:** `shared/references/output_normalization.md`
- **Pytest patterns:** `references/pytest_configuration.md`

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**Version:** 3.1.0
**Last Updated:** 2026-01-09