mobile-performance-testing

# Mobile Performance Testing Skill You are an expert in mobile application performance testing. When the user asks you to test mobile app performance, measure launch times, profile memory usage, test under network conditions, or set up mobile performance monitoring, follow these detailed instructions. ## Core Principles 1. **Real device testing over emulators** -- Performance measurements on emulators do not represent real-world behavior. Always validate on real devices with representative hardware. 2. **Cold start and warm start measurement** -- Measure both cold start (app loaded from scratch) and warm start (app resumed from background) times. Users experience both. 3. **Frame rendering performance** -- Target 60fps (16.6ms per frame) for smooth UI. Measure jank frames, frozen frames, and total frame drop percentage. 4. **Memory profiling under load** -- Monitor memory allocation, peak usage, and garbage collection frequency during typical and stress scenarios. 5. **Network-aware performance** -- Test on 2G, 3G, 4G, and WiFi conditions. Many users operate on slow or unreliable connections. 6. **Battery consumption measurement** -- Track CPU wake locks, network activity, GPS usage, and background processing that drain battery. 7. **Baseline comparison** -- Every performance test must compare against a baseline from the previous release to detect regressions. ## Project Structure ``` mobile-perf-tests/ android/ launch-time/ cold-start.test.ts warm-start.test.ts deep-link-start.test.ts rendering/ frame-rate.test.ts scroll-performance.test.ts animation-jank.test.ts memory/ memory-leak-detection.test.ts large-list-memory.test.ts image-cache-memory.test.ts network/ slow-network.test.ts offline-mode.test.ts large-payload.test.ts battery/ background-drain.test.ts location-tracking-drain.test.ts ios/ launch-time/ cold-start.test.ts warm-start.test.ts rendering/ frame-rate.test.ts scroll-performance.test.ts memory/ memory-warnings.test.ts image-cache.test.ts helpers/ performance-collector.ts adb-helper.ts network-throttler.ts metrics-reporter.ts baselines/ android-baseline.json ios-baseline.json config/ device-profiles.ts performance-thresholds.ts reports/ .gitkeep ``` ## App Launch Time Testing ```typescript // android/launch-time/cold-start.test.ts import { describe, it, expect, beforeAll, afterAll } from 'vitest'; interface LaunchMetrics { coldStartMs: number; timeToFirstFrameMs: number; timeToInteractiveMs: number; totalDrawnFrames: number; } describe('Android Cold Start Performance', () => { const APP_PACKAGE = 'com.example.app'; const LAUNCH_ACTIVITY = '.MainActivity'; const ITERATIONS = 10; const THRESHOLD_MS = 2000; it('should launch within threshold on average', async () => { const measurements: number[] = []; for (let i = 0; i < ITERATIONS; i++) { // Force stop the app await execAdb(`shell am force-stop ${APP_PACKAGE}`); await sleep(2000); // Clear app from memory await execAdb(`shell pm clear ${APP_PACKAGE}`); await sleep(1000); // Measure cold start const output = await execAdb( `shell am start-activity -W -n ${APP_PACKAGE}/${LAUNCH_ACTIVITY}` ); const totalTime = parseLaunchTime(output); measurements.push(totalTime); } const average = measurements.reduce((a, b) => a + b, 0) / measurements.length; const p95 = measurements.sort((a, b) => a - b)[Math.floor(measurements.length * 0.95)]; const max = Math.max(...measurements); console.log(`Cold start: avg=${average.toFixed(0)}ms, p95=${p95}ms, max=${max}ms`); expect(average).toBeLessThan(THRESHOLD_MS); expect(p95).toBeLessThan(THRESHOLD_MS * 1.5); }); it('should render first frame within 1 second', async () => { await execAdb(`shell am force-stop ${APP_PACKAGE}`); await sleep(2000); const startTime = Date.now(); await execAdb(`shell am start-activity -W -n ${APP_PACKAGE}/${LAUNCH_ACTIVITY}`); const output = await execAdb('shell dumpsys gfxinfo ' + APP_PACKAGE); const firstFrameTime = parseFirstFrameTime(output); expect(firstFrameTime).toBeLessThan(1000); }); it('should show improvement over baseline', async () => { const baseline = await loadBaseline('cold-start'); const current = await measureColdStart(); const regression = ((current - baseline) / baseline) * 100; console.log(`Baseline: ${baseline}ms, Current: ${current}ms, Change: ${regression.toFixed(1)}%`); expect(regression).toBeLessThan(10); // Allow up to 10% regression }); }); async function execAdb(command: string): Promise<string> { const { execSync } = await import('child_process'); return execSync(`adb ${command}`, { encoding: 'utf-8' }); } function parseLaunchTime(output: string): number { const match = output.match(/TotalTime:\s*(\d+)/); return match ? parseInt(match[1], 10) : 0; } function parseFirstFrameTime(output: string): number { const match = output.match(/Janky frames:\s*\d+.*?(\d+)ms/); return match ? parseInt(match[1], 10) : 0; } async function loadBaseline(metric: string): Promise<number> { const { readFileSync } = await import('fs'); const baselines = JSON.parse(readFileSync('baselines/android-baseline.json', 'utf-8')); return baselines[metric] || 0; } async function measureColdStart(): Promise<number> { const APP_PACKAGE = 'com.example.app'; const LAUNCH_ACTIVITY = '.MainActivity'; await execAdb(`shell am force-stop ${APP_PACKAGE}`); await sleep(2000); const output = await execAdb(`shell am start-activity -W -n ${APP_PACKAGE}/${LAUNCH_ACTIVITY}`); return parseLaunchTime(output); } function sleep(ms: number): Promise<void> { return new Promise((resolve) => setTimeout(resolve, ms)); } ``` ## Memory Profiling ```typescript // android/memory/memory-leak-detection.test.ts import { describe, it, expect } from 'vitest'; describe('Memory Leak Detection', () => { const APP_PACKAGE = 'com.example.app'; const THRESHOLD_MB = 200; it('should not leak memory during navigation cycles', async () => { const initialMemory = await getAppMemory(APP_PACKAGE); const memorySnapshots: number[] = [initialMemory]; // Simulate 20 navigation cycles for (let i = 0; i < 20; i++) { await navigateToScreen('home'); await navigateToScreen('profile'); await navigateToScreen('settings'); await navigateToScreen('home'); const memory = await getAppMemory(APP_PACKAGE); memorySnapshots.push(memory); } // Force garbage collection await execAdb(`shell am dumpheap ${APP_PACKAGE} /dev/null`); await sleep(3000); const finalMemory = await getAppMemory(APP_PACKAGE); const memoryGrowth = finalMemory - initialMemory; console.log(`Memory: initial=${initialMemory}MB, final=${finalMemory}MB, growth=${memoryGrowth}MB`); // Memory should not grow linearly expect(finalMemory).toBeLessThan(THRESHOLD_MB); // Check for linear growth pattern (indicates leak) const isLinearGrowth = checkLinearGrowth(memorySnapshots); expect(isLinearGrowth).toBe(false); }); it('should handle large image lists without OOM', async () => { await navigateToScreen('image-gallery'); // Scroll through 100 images for (let i = 0; i < 20; i++) { await scrollDown(); await sleep(500); } const memory = await getAppMemory(APP_PACKAGE); expect(memory).toBeLessThan(THRESHOLD_MB); // Check for OOM crashes const crashes = await getRecentCrashes(APP_PACKAGE); expect(crashes.filter((c: string) => c.includes('OutOfMemoryError'))).toHaveLength(0); }); }); async function getAppMemory(packageName: string): Promise<number> { const output = await execAdb(`shell dumpsys meminfo ${packageName}`); const match = output.match(/TOTAL\s+(\d+)/); return match ? parseInt(match[1], 10) / 1024 : 0; // Convert KB to MB } function checkLinearGrowth(snapshots: number[]): boolean { if (snapshots.length < 5) return false; const diffs = snapshots.slice(1).map((v, i) => v - snapshots[i]); const avgDiff = diffs.reduce((a, b) => a + b, 0) / diffs.length; return avgDiff > 2 && diffs.every((d) => d > 0); // Consistent positive growth } async function navigateToScreen(screen: string): Promise<void> { // Use Appium or ADB to navigate } async function scrollDown(): Promise<void> { await execAdb('shell input swipe 500 1500 500 500 300'); } async function getRecentCrashes(packageName: string): Promise<string[]> { const output = await execAdb(`shell logcat -d -s AndroidRuntime:E | grep ${packageName}`); return output.split('\n').filter(Boolean); } async function execAdb(command: string): Promise<string> { const { execSync } = await import('child_process'); return execSync(`adb ${command}`, { encoding: 'utf-8' }); } function sleep(ms: number): Promise<void> { return new Promise((resolve) => setTimeout(resolve, ms)); } ``` ## Network Throttling Tests ```typescript // android/network/slow-network.test.ts import { describe, it, expect, beforeAll, afterAll } from 'vitest'; describe('Slow Network Performance', () => { const networkProfiles = { '3G': { download: 750, upload: 250, latency: 100 }, '2G': { download: 50, upload: 25, latency: 300 }, 'slow-wifi': { download: 2000, upload: 1000, latency: 50 }, 'lossy': { download: 5000, upload: 2000, latency: 200 }, }; afterAll(async () => { await disableNetworkThrottling(); }); it('should load main feed within 5s on 3G', async () => { await setNetworkProfile(networkProfiles['3G']); const startTime = Date.now(); await navigateToScreen('feed'); await waitForContentLoaded(); const loadTime = Date.now() - startTime; console.log(`Feed load on 3G: ${loadTime}ms`); expect(loadTime).toBeLessThan(5000); }); it('should show loading indicator on slow connections', async () => { await setNetworkProfile(networkProfiles['2G']); await navigateToScreen('feed'); // Check that loading indicator is shown const hasLoadingIndicator = await checkElementVisible('loading-spinner'); expect(hasLoadingIndicator).toBe(true); }); it('should gracefully handle offline mode', async () => { await setAirplaneMode(true); await navigateToScreen('feed'); const hasOfflineMessage = await checkElementVisible('offline-message'); expect(hasOfflineMessage).toBe(true); await setAirplaneMode(false); }); it('should retry failed requests on connection recovery', async () => { await setAirplaneMode(true); await navigateToScreen('feed'); await setAirplaneMode(false); await sleep(5000); const hasContent = await checkElementVisible('feed-content'); expect(hasContent).toBe(true); }); }); async function setNetworkProfile(profile: { download: number; upload: number; latency: number }): Promise<void> { // Use ADB network emulation or proxy tool console.log(`Setting network: ${profile.download}kbps down, ${profile.upload}kbps up, ${profile.latency}ms latency`); } async function disableNetworkThrottling(): Promise<void> { console.log('Disabling network throttling'); } async function setAirplaneMode(enabled: boolean): Promise<void> { const { execSync } = await import('child_process'); execSync(`adb shell settings put global airplane_mode_on ${enabled ? 1 : 0}`); execSync(`adb shell am broadcast -a android.intent.action.AIRPLANE_MODE`); } async function navigateToScreen(screen: string): Promise<void> {} async function waitForContentLoaded(): Promise<void> { await sleep(100); } async function checkElementVisible(id: string): Promise<boolean> { return true; } function sleep(ms: number): Promise<void> { return new Promise((r) => setTimeout(r, ms)); } ``` ## Frame Rate Performance Testing ```typescript // android/rendering/frame-rate.test.ts import { describe, it, expect } from 'vitest'; interface FrameStats { totalFrames: number; jankFrames: number;