Kordant/tasks/ios-production/18-performance-testing.md

18. Performance Testing (XCTestMetric)

meta: id: ios-production-18 feature: ios-production priority: P2 depends_on: [] tags: [testing, performance, quality]

objective:

• Implement performance testing using XCTestMetric to ensure consistent 60fps and fast response times

deliverables:

• Performance tests for critical flows
• XCTMetric measurements
• Baseline performance documentation
• Performance regression detection in CI

steps:

1. Set up performance tests:
   • Create XCTestCase with measure blocks
   • Use XCTClockMetric for time measurements
   • Use XCTCPUMetric for CPU usage
   • Use XCTMemoryMetric for memory usage
2. Test critical flows:
   • App launch time (cold and warm)
   • Dashboard scroll performance (60fps)
   • Alert list scroll performance
   • Service screen transitions
   • API response time (with mocked data)
   • Image loading performance
3. Establish baselines:
   • Run tests 10 times to establish baseline
   • Document expected ranges for each metric
   • Set performance budgets
4. Add regression detection:
   • Configure XCTest to fail on 10% regression
   • Add to CI pipeline
   • Alert on performance degradation
5. Test on physical devices:
   • iPhone SE (2nd gen) — minimum supported device
   • iPhone 12 — mid-range target
   • iPhone 15 Pro — high-end target
6. Document performance:
   • Create docs/PERFORMANCE.md
   • List all measured metrics and baselines
   • Document optimization techniques used

tests:

• Performance: All metrics within budget
• Regression: 10% regression triggers failure
• Device: Tests pass on physical devices

acceptance_criteria:

• 10+ performance test cases
• App launch time measured and baselined
• Scroll performance tested (target 60fps)
• API response time measured
• Memory usage tracked during key flows
• Baselines established for iPhone SE, 12, and 15 Pro
• 10% regression threshold configured
• Performance tests run in CI
• Performance budget documented
• No performance regressions in release builds

validation:

• Run performance tests → all within budget
• Introduce slow animation → test fails
• Check CI → performance tests passing
• Review docs → baselines documented

notes:

• Performance tests should run on physical devices, not simulators
• Simulators don't reflect real-world performance accurately
• Use Xcode's Metrics tab to track performance over time
• Consider using Firebase Performance Monitoring for real-world data