tomevault-io Dev Fuzz Testing (Gate 4)
Overview
Ensure critical parsing and input handling code has fuzz tests to discover crashes and edge cases through random input generation.
Core principle: Fuzz tests find bugs you didn't think to test for. They're mandatory for all code that handles external input.
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 |
Standards Reference
MANDATORY: Load testing-fuzz.md standards via WebFetch.
Step 1: Validate Input
REQUIRED INPUT:
- unit_id: [task/subtask being tested]
- implementation_files: [files from Gate 0]
- language: [go only for native fuzz]
OPTIONAL INPUT:
- gate3_handoff: [full Gate 3 output]
if any REQUIRED input is missing:
→ STOP and report: "Missing required input: [field]"
if language != "go":
→ STOP and report: "Native fuzz testing only supported for Go (Go 1.18+)"
Step 2: Dispatch QA Analyst Agent (Fuzz Mode)
Task tool:
subagent_type: "ring:qa-analyst"
prompt: |
**MODE:** FUZZ TESTING (Gate 4)
**Standards:** Load testing-fuzz.md
**Input:**
- Unit ID: {unit_id}
- Implementation Files: {implementation_files}
- Language: {language}
**Requirements:**
1. Create fuzz functions (FuzzXxx naming)
2. Add seed corpus (minimum 5 entries per function)
3. Run fuzz tests for 30 seconds
4. Report any crashes found
**Output Sections Required:**
- ## Fuzz Testing Summary
- ## Corpus 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 fuzz tests (max 3 iterations)
→ If still failing: ESCALATE to user
Step 4: Generate Output
## Fuzz Testing Summary
**Status:** {PASS|FAIL}
**Fuzz Functions:** {count}
**Corpus Entries:** {count}
**Crashes Found:** {count}
## Corpus Report
| Function | Entries | Crashes |
|----------|---------|---------|
| {function_name} | {count} | {count} |
## Handoff to Next Gate
- Ready for Gate 5 (Property Testing): {YES|NO}
- Iterations: {count}
Severity Calibration
| Severity | Criteria | Examples |
|---|---|---|
| CRITICAL | Crash found, security vulnerability discovered | Panic on input, buffer overflow, memory corruption |
| HIGH | No fuzz functions, missing corpus | Zero FuzzXxx functions, empty seed corpus |
| MEDIUM | Insufficient corpus, naming issues | Less than 5 corpus entries, non-standard function names |
| LOW | Coverage gaps, optimization | Missing edge case seeds, fuzz duration improvements |
Report all severities. CRITICAL = immediate fix and re-fuzz. HIGH = fix before gate pass. MEDIUM = fix in iteration. LOW = document.
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. Fuzz finds unknowns. | Write fuzz tests |
| "Code is too simple for fuzz" | Simple code can still crash on malformed input. | Write fuzz tests |
| "Fuzz testing is slow" | 30 seconds per function. Crashes in production are slower. | Write fuzz tests |
| "We validate input anyway" | Validation can have bugs too. Fuzz tests the validators. | Write fuzz tests |
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