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Mobile Testing Patterns

Mobile testing is NOT web testing. Different constraints, different strategies. This file teaches WHEN to use each testing approach and WHY. Code examples are minimal - focus on decision-making.

🧠 MOBILE TESTING MINDSET

Mobile testing differs from web:
├── Real devices matter (emulators hide bugs)
├── Platform differences (iOS vs Android behavior)
├── Network conditions vary wildly
├── Battery/performance under test
├── App lifecycle (background, killed, restored)
├── Permissions and system dialogs
└── Touch interactions vs clicks

🚫 AI MOBILE TESTING ANTI-PATTERNS

❌ AI Default	Why It's Wrong	✅ Mobile-Correct
Jest-only testing	Misses native layer	Jest + E2E on device
Enzyme patterns	Deprecated, web-focused	React Native Testing Library
Browser-based E2E (Cypress)	Can't test native features	Detox / Maestro
Mock everything	Misses integration bugs	Real device testing
Ignore platform tests	iOS/Android differ	Platform-specific cases
Skip performance tests	Mobile perf is critical	Profile on low-end device
Test only happy path	Mobile has more edge cases	Offline, permissions, interrupts
100% unit test coverage	False security	Pyramid balance
Copy web testing patterns	Different environment	Mobile-specific tools

1. Testing Tool Selection

Decision Tree

WHAT ARE YOU TESTING?
        │
        ├── Pure functions, utilities, helpers
        │   └── Jest (unit tests)
        │       └── No special mobile setup needed
        │
        ├── Individual components (isolated)
        │   ├── React Native → React Native Testing Library
        │   └── Flutter → flutter_test (widget tests)
        │
        ├── Components with hooks, context, navigation
        │   ├── React Native → RNTL + mocked providers
        │   └── Flutter → integration_test package
        │
        ├── Full user flows (login, checkout, etc.)
        │   ├── Detox (React Native, fast, reliable)
        │   ├── Maestro (Cross-platform, YAML-based)
        │   └── Appium (Legacy, slow, last resort)
        │
        └── Performance, memory, battery
            ├── Flashlight (RN performance)
            ├── Flutter DevTools
            └── Real device profiling (Xcode/Android Studio)

Tool Comparison

Tool	Platform	Speed	Reliability	Use When
Jest	RN	⚡⚡⚡	⚡⚡⚡	Unit tests, logic
RNTL	RN	⚡⚡⚡	⚡⚡	Component tests
flutter_test	Flutter	⚡⚡⚡	⚡⚡⚡	Widget tests
Detox	RN	⚡⚡	⚡⚡⚡	E2E, critical flows
Maestro	Both	⚡⚡	⚡⚡	E2E, cross-platform
Appium	Both	⚡	⚡	Legacy, last resort

2. Testing Pyramid for Mobile

                    ┌───────────────┐
                    │    E2E Tests  │  10%
                    │  (Real device) │  Slow, expensive, essential
                    ├───────────────┤
                    │  Integration  │  20%
                    │    Tests      │  Component + context
                    ├───────────────┤
                    │  Component    │  30%
                    │    Tests      │  Isolated UI
                    ├───────────────┤
                    │   Unit Tests  │  40%
                    │    (Jest)     │  Pure logic
                    └───────────────┘

Why This Distribution?

Level	Why This %
E2E 10%	Slow, flaky, but catches integration bugs
Integration 20%	Tests real user flows without full app
Component 30%	Fast feedback on UI changes
Unit 40%	Fastest, most stable, logic coverage

🔴 If you have 90% unit tests and 0% E2E, you're testing the wrong things.

3. What to Test at Each Level

Unit Tests (Jest)

✅ TEST:
├── Utility functions (formatDate, calculatePrice)
├── State reducers (Redux, Zustand stores)
├── API response transformers
├── Validation logic
└── Business rules

❌ DON'T TEST:
├── Component rendering (use component tests)
├── Navigation (use integration tests)
├── Native modules (mock them)
└── Third-party libraries

Component Tests (RNTL / flutter_test)

✅ TEST:
├── Component renders correctly
├── User interactions (tap, type, swipe)
├── Loading/error/empty states
├── Accessibility labels exist
└── Props change behavior

❌ DON'T TEST:
├── Internal implementation details
├── Snapshot everything (only key components)
├── Styling specifics (brittle)
└── Third-party component internals

Integration Tests

✅ TEST:
├── Form submission flows
├── Navigation between screens
├── State persistence across screens
├── API integration (with mocked server)
└── Context/provider interactions

❌ DON'T TEST:
├── Every possible path (use unit tests)
├── Third-party services (mock them)
└── Backend logic (backend tests)

E2E Tests

✅ TEST:
├── Critical user journeys (login, purchase, signup)
├── Offline → online transitions
├── Deep link handling
├── Push notification navigation
├── Permission flows
└── Payment flows

❌ DON'T TEST:
├── Every edge case (too slow)
├── Visual regression (use snapshot tests)
├── Non-critical features
└── Backend-only logic

4. Platform-Specific Testing

What Differs Between iOS and Android?

Area	iOS Behavior	Android Behavior	Test Both?
Back navigation	Edge swipe	System back button	✅ YES
Permissions	Ask once, settings	Ask each time, rationale	✅ YES
Keyboard	Different appearance	Different behavior	✅ YES
Date picker	Wheel/modal	Material dialog	⚠️ If custom UI
Push format	APNs payload	FCM payload	✅ YES
Deep links	Universal Links	App Links	✅ YES
Gestures	Some unique	Material gestures	⚠️ If custom

Platform Testing Strategy

FOR EACH PLATFORM:
├── Run unit tests (same on both)
├── Run component tests (same on both)
├── Run E2E on REAL DEVICE
│   ├── iOS: iPhone (not just simulator)
│   └── Android: Mid-range device (not flagship)
└── Test platform-specific features separately

5. Offline & Network Testing

Offline Scenarios to Test

Scenario	What to Verify
Start app offline	Shows cached data or offline message
Go offline mid-action	Action queued, not lost
Come back online	Queue synced, no duplicates
Slow network (2G)	Loading states, timeouts work
Flaky network	Retry logic, error recovery

How to Test Network Conditions

APPROACH:
├── Unit tests: Mock NetInfo, test logic
├── Integration: Mock API responses, test UI
├── E2E (Detox): Use device.setURLBlacklist()
├── E2E (Maestro): Use network conditions
└── Manual: Use Charles Proxy / Network Link Conditioner

6. Performance Testing

What to Measure

Metric	Target	How to Measure
App startup	< 2 seconds	Profiler, Flashlight
Screen transition	< 300ms	React DevTools
List scroll	60 FPS	Profiler, feel
Memory	Stable, no leaks	Instruments / Android Profiler
Bundle size	Minimize	Metro bundler analysis

When to Performance Test

PERFORMANCE TEST:
├── Before release (required)
├── After adding heavy features
├── After upgrading dependencies
├── When users report slowness
└── On CI (optional, automated benchmarks)

WHERE TO TEST:
├── Real device (REQUIRED)
├── Low-end device (Galaxy A series, old iPhone)
├── NOT on emulator (lies about performance)
└── With production-like data (not 3 items)

7. Accessibility Testing

What to Verify

Element	Check
Interactive elements	Have accessibilityLabel
Images	Have alt text or decorative flag
Forms	Labels linked to inputs
Buttons	Role = button
Touch targets	≥ 44x44 (iOS) / 48x48 (Android)
Color contrast	WCAG AA minimum

How to Test

AUTOMATED:
├── React Native: jest-axe
├── Flutter: Accessibility checker in tests
└── Lint rules for missing labels

MANUAL:
├── Enable VoiceOver (iOS) / TalkBack (Android)
├── Navigate entire app with screen reader
├── Test with increased text size
└── Test with reduced motion

8. CI/CD Integration

What to Run Where

Stage	Tests	Devices
PR	Unit + Component	None (fast)
Merge to main	+ Integration	Simulator/Emulator
Pre-release	+ E2E	Real devices (farm)
Nightly	Full suite	Device farm

Device Farm Options

Service	Pros	Cons
Firebase Test Lab	Free tier, Google devices	Android focus
AWS Device Farm	Wide selection	Expensive
BrowserStack	Good UX	Expensive
Local devices	Free, reliable	Limited variety

📝 MOBILE TESTING CHECKLIST

Before PR

Unit tests for new logic
Component tests for new UI
No console.logs in tests
Tests pass on CI

Before Release

E2E on real iOS device
E2E on real Android device
Tested on low-end device
Offline scenarios verified
Performance acceptable
Accessibility verified

What to Skip (Consciously)

100% coverage (aim for meaningful coverage)
Every visual permutation (use snapshots sparingly)
Third-party library internals
Backend logic (separate tests)

🎯 Testing Questions to Ask

Before writing tests, answer:

What could break? → Test that
What's critical for users? → E2E test that
What's complex logic? → Unit test that
What's platform-specific? → Test on both platforms
What happens offline? → Test that scenario

Remember: Good mobile testing is about testing the RIGHT things, not EVERYTHING. A flaky E2E test is worse than no test. A failing unit test that catches a bug is worth 100 passing trivial tests.

11 KiB Raw Blame History

Mobile Testing Patterns

🧠 MOBILE TESTING MINDSET

🚫 AI MOBILE TESTING ANTI-PATTERNS

1. Testing Tool Selection

Decision Tree

Tool Comparison

2. Testing Pyramid for Mobile

Why This Distribution?

3. What to Test at Each Level

Unit Tests (Jest)

Component Tests (RNTL / flutter_test)

Integration Tests

E2E Tests

4. Platform-Specific Testing

What Differs Between iOS and Android?

Platform Testing Strategy

5. Offline & Network Testing

Offline Scenarios to Test

How to Test Network Conditions

6. Performance Testing

What to Measure

When to Performance Test

7. Accessibility Testing

What to Verify

How to Test

8. CI/CD Integration

What to Run Where

Device Farm Options

📝 MOBILE TESTING CHECKLIST

Before PR

Before Release

What to Skip (Consciously)

🎯 Testing Questions to Ask

11 KiB

Raw Blame History