# iOS Prefetch Plugin Testing and Validation Enhancements - Applied

**Date:** 2025-11-15  
**Status:** ✅ Applied to codebase  
**Directive Source:** User-provided comprehensive enhancement directive

## Summary

This document tracks the application of comprehensive enhancements to the iOS prefetch plugin testing and validation system. All improvements from the directive have been systematically applied to the codebase.

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## 1. Technical Correctness Improvements ✅

### 1.1 Robust BGTask Scheduling & Lifecycle

**Applied to:** `ios/Plugin/DailyNotificationBackgroundTaskTestHarness.swift`

**Enhancements:**
- ✅ **Validation of Scheduling Conditions:** Added validation to ensure `earliestBeginDate` is at least 60 seconds in future (iOS requirement)
- ✅ **Simulator Error Handling:** Added graceful handling of Code=1 error (expected on simulator) with clear logging
- ✅ **One Active Task Rule:** Implemented `cancelPendingTask()` method to enforce only one prefetch task per notification
- ✅ **Debug Verification:** Added `verifyOneActiveTask()` helper method to verify only one task is pending
- ✅ **Schedule Next Task at Execution:** Updated handler to schedule next task IMMEDIATELY at start (Apple best practice)
- ✅ **Expiration Handler:** Enhanced expiration handler to ensure task completion even on timeout
- ✅ **Completion Guarantee:** Added guard to ensure `setTaskCompleted()` is called exactly once
- ✅ **Error Handling:** Enhanced error handling with proper logging and fallback behavior

**Code Changes:**
- Enhanced `schedulePrefetchTask()` with validation and one-active-task rule
- Updated `handlePrefetchTask()` to follow Apple's best practice pattern
- Added `cancelPendingTask()` and `verifyOneActiveTask()` methods
- Improved `PrefetchOperation` with failure tracking

### 1.2 Enhanced Scheduling and Notification Coordination

**Applied to:** Documentation in `IOS_TEST_APP_REQUIREMENTS.md`

**Enhancements:**
- ✅ Added "Technical Correctness Requirements" section
- ✅ Documented unified scheduling logic requirements
- ✅ Documented BGTask identifier constant verification
- ✅ Documented concurrency considerations for Phase 2
- ✅ Documented OS limits and tolerance expectations

---

## 2. Testing Coverage Expansion ✅

### 2.1 Edge Case Scenarios and Environment Conditions

**Applied to:** `doc/test-app-ios/IOS_PREFETCH_TESTING.md`

**Enhancements:**
- ✅ **Expanded Edge Case Table:** Added comprehensive table with 7 scenarios:
  - Background Refresh Off
  - Low Power Mode On
  - App Force-Quit
  - Device Timezone Change
  - DST Transition
  - Multi-Day Scheduling (Phase 2)
  - Device Reboot
- ✅ **Test Strategy:** Each scenario includes test strategy and expected outcome
- ✅ **Additional Variations:** Documented battery vs plugged, force-quit vs backgrounded, etc.

### 2.2 Failure Injection and Error Handling Tests

**Applied to:** `doc/test-app-ios/IOS_PREFETCH_TESTING.md` and `IOS_TEST_APP_REQUIREMENTS.md`

**Enhancements:**
- ✅ **Expanded Negative-Path Tests:** Added 8 new failure scenarios:
  - Storage unavailable
  - JWT expiration
  - Timezone drift
  - Corrupted cache
  - BGTask execution failure
  - Repeated scheduling calls
  - Permission revoked mid-run
- ✅ **Error Handling Section:** Added comprehensive error handling test cases to test app requirements
- ✅ **Expected Outcomes:** Each failure scenario includes expected plugin behavior

### 2.3 Automated Testing Strategies

**Applied to:** `doc/test-app-ios/IOS_PREFETCH_TESTING.md`

**Enhancements:**
- ✅ **Unit Tests Section:** Added comprehensive unit test strategy:
  - Time calculations
  - TTL validation
  - JSON mapping
  - Permission check flow
  - BGTask scheduling logic
- ✅ **Integration Tests Section:** Added integration test strategies:
  - Xcode UI Tests
  - Log sequence validation
  - Mocking and dependency injection
- ✅ **BGTask Expiration Coverage:** Added test strategy for expiration handler

---

## 3. Validation and Verification Enhancements ✅

### 3.1 Structured Logging and Automated Log Analysis

**Applied to:** `doc/test-app-ios/IOS_PREFETCH_TESTING.md`

**Enhancements:**
- ✅ **Structured Log Output (JSON):** Added JSON schema examples for:
  - Success events
  - Failure events
  - Cycle complete summary
- ✅ **Log Validation Script:** Added complete `validate-ios-logs.sh` script with:
  - Sequence marker detection
  - Automated validation logic
  - Usage instructions
- ✅ **Distinct Log Markers:** Documented log marker requirements

### 3.2 Enhanced Verification Signals

**Applied to:** `doc/test-app-ios/IOS_PREFETCH_TESTING.md` and `IOS_TEST_APP_REQUIREMENTS.md`

**Enhancements:**
- ✅ **Telemetry Counters:** Documented all expected counters:
  - `dnp_prefetch_scheduled_total`
  - `dnp_prefetch_executed_total`
  - `dnp_prefetch_success_total`
  - `dnp_prefetch_failure_total{reason="NETWORK|AUTH|SYSTEM"}`
  - `dnp_prefetch_used_for_notification_total`
- ✅ **State Integrity Checks:** Added verification methods:
  - Content hash verification
  - Schedule hash verification
  - Persistence verification
- ✅ **Persistent Test Artifacts:** Added JSON schema for test run artifacts
- ✅ **UI Indicators:** Added requirements for status display and operation summary
- ✅ **In-App Log Viewer:** Documented Phase 2 enhancement for QA use

### 3.3 Test Run Result Template Enhancement

**Applied to:** `doc/test-app-ios/IOS_PREFETCH_TESTING.md`

**Enhancements:**
- ✅ **Enhanced Template:** Added fields for:
  - Actual execution time vs scheduled
  - Telemetry counters
  - State verification (content hash, schedule hash, cache persistence)
- ✅ **Persistent Artifacts:** Added note about test app saving summary to file

---

## 4. Documentation Updates ✅

### 4.1 Test App Requirements

**Applied to:** `doc/test-app-ios/IOS_TEST_APP_REQUIREMENTS.md`

**Enhancements:**
- ✅ **Technical Correctness Requirements:** Added comprehensive section covering:
  - BGTask scheduling & lifecycle
  - Scheduling and notification coordination
- ✅ **Error Handling Expansion:** Added 7 new error handling test cases
- ✅ **UI Indicators:** Added requirements for status display, operation summary, and dump prefetch status
- ✅ **In-App Log Viewer:** Documented Phase 2 enhancement
- ✅ **Persistent Schedule Snapshot:** Enhanced with content hash and schedule hash fields

### 4.2 Testing Guide

**Applied to:** `doc/test-app-ios/IOS_PREFETCH_TESTING.md`

**Enhancements:**
- ✅ **Edge Case Scenarios Table:** Comprehensive table with test strategies
- ✅ **Failure Injection Tests:** 8 new negative-path scenarios
- ✅ **Automated Testing Strategies:** Complete unit and integration test strategies
- ✅ **Validation Enhancements:** Log validation script, structured logging, verification signals
- ✅ **Test Run Template:** Enhanced with telemetry and state verification fields

---

## 5. Code Enhancements ✅

### 5.1 Test Harness Improvements

**File:** `ios/Plugin/DailyNotificationBackgroundTaskTestHarness.swift`

**Changes:**
- Enhanced `schedulePrefetchTask()` with validation and one-active-task enforcement
- Added `cancelPendingTask()` method
- Added `verifyOneActiveTask()` debug helper
- Updated `handlePrefetchTask()` to follow Apple best practices
- Enhanced `PrefetchOperation` with failure tracking
- Improved error handling and logging throughout

**Key Features:**
- Validates minimum 60-second lead time
- Enforces one active task rule
- Handles simulator limitations gracefully
- Schedules next task immediately at execution start
- Ensures task completion even on expiration
- Prevents double completion

---

## 6. Files Modified

1. ✅ `ios/Plugin/DailyNotificationBackgroundTaskTestHarness.swift` - Enhanced with technical correctness improvements
2. ✅ `doc/test-app-ios/IOS_PREFETCH_TESTING.md` - Expanded testing coverage and validation enhancements
3. ✅ `doc/test-app-ios/IOS_TEST_APP_REQUIREMENTS.md` - Added technical correctness requirements and enhanced error handling

---

## 7. Next Steps

### Immediate (Phase 1)
- [ ] Implement actual prefetch logic using enhanced test harness as reference
- [x] Create `validate-ios-logs.sh` script ✅ **COMPLETE** - Script created at `scripts/validate-ios-logs.sh`
- [ ] Add UI indicators to test app
- [ ] Implement persistent test artifacts export

### Phase 2
- [ ] Wire telemetry counters to production pipeline
- [ ] Implement in-app log viewer
- [ ] Add automated CI pipeline integration
- [ ] Test multi-day scenarios with varying TTL values

---

## 8. Validation Checklist

- [x] Technical correctness improvements applied to test harness
- [x] Edge case scenarios documented with test strategies
- [x] Failure injection tests expanded
- [x] Automated testing strategies documented
- [x] Structured logging schema defined
- [x] Log validation script provided ✅ **COMPLETE** - Script created at `scripts/validate-ios-logs.sh`
- [x] Enhanced verification signals documented
- [x] Test run template enhanced
- [x] Documentation cross-referenced and consistent
- [x] Code follows Apple best practices

---

## References

- **Main Directive:** `doc/directives/0003-iOS-Android-Parity-Directive.md`
- **Testing Guide:** `doc/test-app-ios/IOS_PREFETCH_TESTING.md`
- **Test App Requirements:** `doc/test-app-ios/IOS_TEST_APP_REQUIREMENTS.md`
- **Test Harness:** `ios/Plugin/DailyNotificationBackgroundTaskTestHarness.swift`
- **Glossary:** `doc/test-app-ios/IOS_PREFETCH_GLOSSARY.md`

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**Status:** All enhancements from the directive have been systematically applied to the codebase. The plugin is now ready for Phase 1 implementation with comprehensive testing and validation infrastructure in place.