# Folio A minimal Kotlin Multiplatform personal-ledger app: login with demo credentials, create accounts, add credits and debits. Shared UI across Android and iOS via Compose Multiplatform. 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 ```sh just install # build + install on a booted emulator / device just uninstall just clean ``` ## iOS ```sh 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. ## Demo credentials ``` email: demo@folio.app password: ledger123 ``` ## Run a sanderling test (Android) ```sh just test ``` If no device is connected, sanderling boots the single AVD it finds. With multiple AVDs, pick one: ```sh AVD=Pixel_7 just test ``` Persistent settings can live in `.env` alongside the justfile: ``` AVD=Pixel_7 DURATION=5m ``` Traces land in `./sanderling/runs//`. ## 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.