Mock Data Finder

Purpose

Find Android and iOS screens that silently fall back to mock data when API calls fail, hiding real errors from users and developers.

Why This Matters

Silent mock data fallbacks:

• Hide API errors making debugging difficult
• Show fake data to users (misleading)
• Prevent proper error handling/retry UI
• Make it impossible to know if API is working

Detection Patterns

Android (Kotlin)

Look for catch blocks that load mock data:

// BAD: Silent fallback to mock
} catch (e: Exception) {
    state = state.copy(
        loading = false,
        data = getMockData()  // User sees fake data!
    )
}

// GOOD: Show error, let user retry
} catch (e: Exception) {
    Log.e("Screen", "API failed", e)
    state = state.copy(
        loading = false,
        error = "Failed to load: ${e.message}"
    )
}

Search Commands

Find mock data in Android:

# Find getMock functions
grep -r "getMock" apps/android/ --include="*.kt"

# Find mock fallbacks in catch blocks
grep -rn "catch.*Exception" apps/android/ --include="*.kt" -A 5 | grep -i mock

# Find hardcoded test data
grep -rn "listOf\|arrayOf" apps/android/*/ui/screens/ --include="*.kt" | grep -E "(id.*=.*\".*-\"|test|mock|fake)"

Find mock data in iOS:

# Find mock/preview data
grep -r "mock\|Mock\|preview\|Preview" apps/ios/ --include="*.swift"

# Find catch blocks with fallbacks
grep -rn "catch" apps/ios/ --include="*.swift" -A 3

Common Mock Data Patterns

Pattern 1: getMockXxx() Function

fun getMockDashboard(): Dashboard {
    return Dashboard(
        items = listOf(
            Item(id = "mock-1", name = "Test Item")
        )
    )
}

Pattern 2: Inline Mock in Catch

catch (e: Exception) {
    val mockData = listOf(
        User(id = "u1", name = "John Doe"),
        User(id = "u2", name = "Jane Doe")
    )
    state = state.copy(users = mockData)
}

Pattern 3: Conditional Mock Fallback

val data = apiResponse ?: getMockData()
// or
val data = if (apiResponse.isEmpty()) getMockData() else apiResponse

Fix Pattern

Replace mock fallbacks with proper error handling:

// BEFORE
fun loadData() {
    scope.launch {
        state = state.copy(loading = true)
        try {
            val data = apiService.getData()
            state = state.copy(loading = false, data = data)
        } catch (e: Exception) {
            // Silent mock fallback - BAD!
            state = state.copy(loading = false, data = getMockData())
        }
    }
}

// AFTER
fun loadData() {
    scope.launch {
        state = state.copy(loading = true, error = null)
        try {
            val data = apiService.getData()
            state = state.copy(loading = false, data = data)
        } catch (e: Exception) {
            // Log error and show to user - GOOD!
            Log.e("ScreenName", "Failed to load data", e)
            state = state.copy(
                loading = false,
                error = "Failed to load data: ${e.message}"
            )
        }
    }
}

Checklist

When reviewing a screen:

• No getMock*() functions called in production code
• Catch blocks log errors with Log.e()
• Catch blocks set error state, not mock data
• UI has error state display (error banner, retry button)
• No hardcoded test IDs ("test-1", "mock-id", etc.)

Files to Check

Common locations for mock data:

Android:

• apps/android/**/ui/screens/*.kt - Screen composables
• apps/android/**/ui/viewmodels/*.kt - ViewModels
• apps/android/**/data/repository/*.kt - Repositories

iOS:

• apps/ios/**/Views/*.swift - SwiftUI views
• apps/ios/**/ViewModels/*.swift - ViewModels
• apps/ios/**/Services/*.swift - API services