# Tests Audit Report

**Branch**: fix/issue-28-graph-corruption-shallow-copy
**Base**: main
**Date**: 2025-11-28 08:37:00
**Auditor**: Claude Code (Opus 4.5)

---

## Executive Summary

This branch addresses Issue #28 (Graph Corruption due to Shallow Copy) with a security fix in `dependency-graph.ts` and adds settling worker tracking to prevent resource over-allocation in `resource-monitor.ts`. The test coverage for the core fix is **excellent** - comprehensive regression tests were added. However, there are **test coverage gaps** for the resource monitor changes and worker handler integration.

**Key Findings:**
- The dependency graph fix (Issue #28) has 3 dedicated regression tests - WELL COVERED
- The settling workers feature (resource-monitor.ts) has NO dedicated tests - COVERAGE GAP
- The worker-handler.ts integration with `recordSpawn()` has NO tests - COVERAGE GAP
- Configuration changes (minSpawnDelayMs default) have NO tests - MINOR GAP

---

## Files Changed Analysis

| File | Lines Changed | Test Coverage Status |
|------|--------------|---------------------|
| `src/core/dependency-graph.ts` | 5 lines (deep copy fix) | EXCELLENT - 3 regression tests added |
| `src/implementations/resource-monitor.ts` | ~50 lines | POOR - No tests for settling workers |
| `src/services/handlers/worker-handler.ts` | 3 lines | POOR - No tests for recordSpawn integration |
| `src/core/configuration.ts` | 4 lines | NONE - Default value changes untested |
| `src/core/interfaces.ts` | 6 lines | N/A - Type definition only |

---

## BLOCKING: Issues in Your Changes

### 1. Missing Tests for Settling Workers Feature

**File**: `/workspace/delegate/src/implementations/resource-monitor.ts`
**Lines**: 27-31, 79-85, 108-167, 171-181

**Severity**: HIGH - This is a significant new feature with no test coverage

**Description**: 
The settling workers tracking feature adds substantial new logic to prevent resource over-allocation by tracking recently spawned workers that may not yet appear in system metrics. This includes:

- `SETTLING_WINDOW_MS` constant (15 seconds)
- `recentSpawnTimestamps` array tracking
- Timestamp cleanup logic
- Projected resource calculations
- `recordSpawn()` method

**What Should Be Tested**:
```typescript
// Missing test cases for resource-monitor.ts:
describe('Settling Workers Tracking', () => {
  it('should track recent spawn timestamps');
  it('should clean up spawn timestamps outside settling window');
  it('should include settling workers in effective worker count');
  it('should project CPU cores used by settling workers');
  it('should project memory used by settling workers');
  it('should reject spawn when effective worker count at max (including settling)');
  it('should expire settling workers after SETTLING_WINDOW_MS');
});

describe('recordSpawn', () => {
  it('should add current timestamp to recentSpawnTimestamps');
  it('should allow multiple spawn recordings');
});
```

**Risk**: Without tests, future refactoring could break the settling worker logic, leading to resource over-allocation and potential fork-bomb scenarios (the exact issue this code is meant to prevent).

---

### 2. Missing Tests for Worker Handler recordSpawn Integration

**File**: `/workspace/delegate/src/services/handlers/worker-handler.ts`
**Lines**: 295-296

**Severity**: MEDIUM - Integration point untested

**Description**:
The worker handler now calls `this.resourceMonitor.recordSpawn?.()` after spawning a worker. This integration is not tested.

**Current MockResourceMonitor in tests** (`/workspace/delegate/tests/unit/services/handlers/worker-handler.test.ts` lines 82-119) does NOT implement `recordSpawn()`, so the test cannot verify this behavior.

**What Should Be Tested**:
```typescript
// Add to worker-handler.test.ts MockResourceMonitor:
class MockResourceMonitor implements ResourceMonitor {
  recordSpawnCalls: number = 0;
  
  recordSpawn() {
    this.recordSpawnCalls++;
  }
}

// Add test:
it('should call recordSpawn after successful worker spawn', async () => {
  const task = new TaskFactory().build();
  resourceMonitor.setCanSpawn(true);
  eventBus.setRequestResponse('NextTaskQuery', ok(task));

  await eventBus.emit('TaskQueued', { taskId: task.id, task });
  await new Promise(resolve => setTimeout(resolve, 50));

  expect(resourceMonitor.recordSpawnCalls).toBe(1);
});
```

---

## Should Fix: Issues in Code You Touched

### 3. Configuration Default Value Change Not Validated

**File**: `/workspace/delegate/src/core/configuration.ts`
**Lines**: 32, 69

**Severity**: LOW - Default value changed but not verified in tests

**Description**:
The `minSpawnDelayMs` default was changed from 50ms to 1000ms (20x increase). While the configuration.test.ts has tests for minSpawnDelayMs validation, there is no test verifying the new default value of 1000ms.

**Recommendation**: Add explicit test for default value:
```typescript
it('should default minSpawnDelayMs to 1000ms', () => {
  const config = createConfiguration({});
  expect(config.minSpawnDelayMs).toBe(1000);
});
```

---

### 4. Interface Change Without Corresponding Type Tests

**File**: `/workspace/delegate/src/core/interfaces.ts`
**Lines**: 47-52

**Severity**: LOW - Documentation only, but optional method not enforced

**Description**:
The `ResourceMonitor` interface now has an optional `recordSpawn?()` method. While this is intentionally optional for backward compatibility, there's no test ensuring implementors handle the optional nature correctly.

**Note**: The TestResourceMonitor in `/workspace/delegate/src/implementations/resource-monitor.ts` does NOT implement `recordSpawn()`, which is fine because it's optional. However, this could lead to silent failures if tests rely on this behavior.

---

## Pre-existing Issues (Not Blocking)

### 5. Existing Test Doubles Missing Interface Methods

**File**: `/workspace/delegate/tests/unit/implementations/system-resource-monitor.test.ts`

**Severity**: INFORMATIONAL

**Description**:
The existing resource monitor tests do not test the `recordSpawn()` method because it's new. This is expected for a new feature but should be addressed.

---

### 6. Skipped Tests in Resource Monitor

**File**: `/workspace/delegate/tests/unit/implementations/system-resource-monitor.test.ts`
**Lines**: 216-287

**Severity**: INFORMATIONAL - Pre-existing

**Description**:
There are 3 skipped tests (`it.skip`) related to threshold event emission that were already skipped before this PR. These are marked with TODO comments indicating the feature is not yet implemented.

---

## Positive Findings

### Excellent Coverage: Dependency Graph Immutability Tests

**File**: `/workspace/delegate/tests/unit/core/dependency-graph.test.ts`
**Lines**: 248-338 (NEW)

The branch adds **3 comprehensive regression tests** for Issue #28:

1. **`should not mutate graph when checking for cycles with existing task`** (lines 249-291)
   - Tests the exact bug scenario
   - Verifies state before and after cycle check
   - CRITICAL assertion: `expect(depsBAfter.value).not.toContain(TaskId('task-A'))`
   - Well-documented with comments explaining the bug

2. **`should not mutate graph when checking non-cycle with existing task`** (lines 293-314)
   - Tests immutability even when no cycle detected
   - Verifies graph.size() unchanged

3. **`should not mutate graph with multiple cycle checks`** (lines 316-337)
   - Tests accumulated corruption prevention
   - Multiple successive cycle checks

**Test Quality Assessment**:
- Clear test names
- Proper Arrange-Act-Assert pattern
- Well-documented with comments explaining the bug
- Multiple assertion types (size, contains, length)
- Covers both positive and negative cycle detection paths

---

## Summary

| Category | Count | Items |
|----------|-------|-------|
| BLOCKING (Must Fix) | 2 | Missing settling worker tests, Missing recordSpawn integration test |
| Should Fix | 2 | Configuration default test, Interface type test |
| Pre-existing (Informational) | 2 | Test doubles incomplete, Skipped tests |

---

## Tests Score: 6/10

**Breakdown:**
- Dependency Graph Fix: 10/10 (excellent regression tests)
- Settling Workers Feature: 2/10 (no tests)
- Worker Handler Integration: 2/10 (no test for recordSpawn call)
- Configuration Changes: 5/10 (validation tested, default not)
- Overall Quality: 7/10 (good patterns where tests exist)

---

## Merge Recommendation

**REVIEW REQUIRED**

The core bug fix (Issue #28) is well-tested and safe to merge. However, the settling workers feature adds significant new logic (~50 lines) with no test coverage. This creates risk for a feature specifically designed to prevent system instability.

**Recommended Actions Before Merge:**
1. Add tests for `recordSpawn()` method in SystemResourceMonitor
2. Add tests for settling worker tracking logic (timestamp cleanup, projected resources)
3. Add test for worker handler calling `recordSpawn()` after spawn
4. Update MockResourceMonitor in worker-handler tests to implement `recordSpawn()`

**Alternative (Conditional Approval):**
If time-constrained, the dependency graph fix could be merged separately from the settling workers feature, as they address different concerns. The graph fix is well-tested and low-risk.

---

## Appendix: Changed Lines Reference

### /workspace/delegate/src/core/dependency-graph.ts
```diff
-    const tempGraph = new Map(this.graph);
+    // SECURITY FIX (Issue #28): Deep copy required to prevent graph corruption
+    // Shallow copy (new Map(this.graph)) only copies Map structure - Set values are REFERENCES
+    // When we modify temp graph's Sets, we would mutate the original graph's Sets
+    const tempGraph = new Map(
+      Array.from(this.graph.entries()).map(([k, v]) => [k, new Set(v)])
+    );
```

### /workspace/delegate/src/implementations/resource-monitor.ts (Key Changes)
```diff
+  // SETTLING WORKERS TRACKING (Issue: load average is lagging indicator)
+  private readonly SETTLING_WINDOW_MS = 15000; // 15 seconds for worker to "settle"
+  private recentSpawnTimestamps: number[] = [];
+
+  recordSpawn(): void {
+    this.recentSpawnTimestamps.push(Date.now());
+  }
```

### /workspace/delegate/src/services/handlers/worker-handler.ts
```diff
+      // Record spawn for settling worker tracking (accounts for lag in load average)
+      this.resourceMonitor.recordSpawn?.();
```
