sanderling/examples/folio

Folio

A minimal Kotlin Multiplatform personal-ledger app: login with demo credentials, create accounts, add credits and debits. Shared UI across Android, iOS, and web (wasmJs via Compose for Web). Doubles as the example sanderling runs its property-based specs against.

Stack

• Kotlin Multiplatform + Compose Multiplatform (shared UI)
• SQLDelight for the data layer (unified across platforms)
• kotlinx.coroutines for state flows
• kotlinx.serialization for @Serializable route types

Prerequisites

• just
• JDK 17
• Android SDK (auto-discovered under $ANDROID_HOME, ~/Library/Android/sdk, or the Homebrew cask)
• Xcode 16+ and xcodegen (brew install xcodegen) for iOS

Android

just install      # build + install on a booted emulator / device
just uninstall
just clean

iOS

just ios                          # default device: iPhone 17 Pro
IOS_DEVICE="iPhone 15" just ios   # pick a different simulator

just ios regenerates app/iosApp/iosApp.xcodeproj from app/iosApp/project.yml, builds the KMP framework (Shared.framework from :app:shared), links it into the SwiftUI host, installs, and launches.

Web

just web         # webpack dev server with COOP/COEP headers
just web-build   # produce a webpack distributable bundle

just web runs :app:webApp:wasmJsBrowserDevelopmentRun --continuous, so edits to shared code reload in the browser.

Demo credentials

email:    [email protected]
password: ledger123

Run a sanderling test (Android)

just test

If no device is connected, sanderling boots the single AVD it finds. With multiple AVDs, pick one:

AVD=Pixel_7 just test

Persistent settings can live in .env alongside the justfile:

AVD=Pixel_7
DURATION=5m

Traces land in ./sanderling/runs/<timestamp>/.

Run a sanderling test (iOS)

just test-ios                          # default simulator: iPhone 17 Pro
IOS_DEVICE="iPhone 15" just test-ios   # pick a different simulator

just test-ios boots the simulator if needed, runs just ios to install and launch the app, then invokes sanderling test --platform ios. Same DURATION, SEED, and OUTPUT env vars as the Android target.

How it connects to sanderling

• Each screen sets a stable Compose testTag (HomeScreen, AccountCard, LedgerRow, TxnAmount, ...). The Sanderling SDK resolves testTag to resource-id on Android and accessibilityIdentifier on iOS.
• Identity for list items is the visible text content (account name; txn note + amount). No synthetic IDs encoded in semantics.
• contentDescription is reserved for real accessibility labels, never as a data carrier.
• sanderling/spec.ts imports @sanderling/spec, reads state via s.ax.*, asserts properties, and weights the actions the fuzzer picks from.
• just test invokes sanderling test against the installed APK.