bee:dev-fuzz-testing

Dev Fuzz Testing (Gate 4)

Overview

Ensure critical parsing and input handling code has mutation tests (via Infection) to discover weaknesses in test suites through code mutation.

Core principle: Mutation testing finds weaknesses in your tests that traditional coverage metrics miss. They're mandatory for all code that handles external input.

<block_condition>

• No Infection config = FAIL
• MSI (Mutation Score Indicator) < 80% = FAIL
• Escaped mutants in critical paths = FAIL (add tests and re-run) </block_condition>

CRITICAL: Role Clarification

This skill ORCHESTRATES. QA Analyst Agent (fuzz mode) EXECUTES.

Who	Responsibility
This Skill	Gather requirements, dispatch agent, track iterations
QA Analyst Agent	Write fuzz tests, generate corpus, run fuzz

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Standards Reference

MANDATORY: Load testing-mutation.md standards via WebFetch.

<fetch_required> https://raw.githubusercontent.com/luanrodrigues/ia-frmwrk/master/dev-team/docs/standards/php/testing-mutation.md </fetch_required>

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Step 1: Validate Input

REQUIRED INPUT:
- unit_id: [task/subtask being tested]
- implementation_files: [files from Gate 0]
- language: [php for mutation testing with Infection]

OPTIONAL INPUT:
- gate3_handoff: [full Gate 3 output]

if any REQUIRED input is missing:
  → STOP and report: "Missing required input: [field]"

if language != "php":
  → STOP and report: "Mutation testing via Infection is supported for PHP only"

Step 2: Dispatch QA Analyst Agent (Fuzz Mode)

Task tool:
  subagent_type: "bee:qa-analyst"
  model: "opus"
  prompt: |
    **MODE:** MUTATION TESTING (Gate 4)

    **Standards:** Load testing-mutation.md

    **Input:**
    - Unit ID: {unit_id}
    - Implementation Files: {implementation_files}
    - Language: {language}

    **Requirements:**
    1. Configure Infection (infection.json5) for source directories
    2. Run `./vendor/bin/infection --min-msi=80 --min-covered-msi=90`
    3. Analyze escaped mutants in critical code paths
    4. Add tests to kill escaped mutants

    **Output Sections Required:**
    - ## Mutation Testing Summary
    - ## Mutation Report
    - ## Handoff to Next Gate

Step 3: Evaluate Results

Parse agent output:

if "Status: PASS" in output:
  → Gate 4 PASSED
  → Return success with metrics

if "Status: FAIL" in output:
  → Dispatch fix to implementation agent
  → Re-run mutation tests (max 3 iterations)
  → If still failing: ESCALATE to user

Step 4: Generate Output

## Mutation Testing Summary
**Status:** {PASS|FAIL}
**Mutants Generated:** {count}
**Mutants Killed:** {count}
**MSI:** {percentage}%

## Mutation Report
| Source Directory | Mutants | Killed | Escaped | MSI |
|-----------------|---------|--------|---------|-----|
| {directory} | {count} | {count} | {count} | {percentage}% |

## Handoff to Next Gate
- Ready for Gate 5 (Property Testing): {YES|NO}
- Iterations: {count}

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Anti-Rationalization Table

Rationalization	Why It's WRONG	Required Action
"Unit tests cover edge cases"	You can't test what you don't think of. Mutation testing finds weaknesses.	Run mutation tests
"Code is too simple for mutation testing"	Simple code can still have untested paths.	Run mutation tests
"Mutation testing is slow"	Minutes per run. Production bugs from weak tests are slower.	Run mutation tests
"We have high coverage anyway"	Coverage != quality. Mutation testing verifies test assertions.	Run mutation tests

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