# 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 via Compose Multiplatform. Doubles as the example uatu runs its property-based specs against. ## Stack - Kotlin Multiplatform + Compose Multiplatform (shared UI) - kotlinx.serialization for file-backed persistence - kotlinx.coroutines for state flows - uatu `sdk-android` for harness integration on Android ## 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 `iosApp/iosApp.xcodeproj` from `iosApp/project.yml`, builds the KMP framework, links it into the SwiftUI host, installs, and launches. ## Demo credentials ``` email: demo@folio.app password: ledger123 ``` ## Run a uatu test (Android) ```sh just test ``` If no device is connected, uatu 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 `./uatu/runs//`. ## How it connects to uatu - `composeApp/src/androidMain/.../FolioApplication.kt` calls `Uatu.start(this)` and registers snapshot extractors (`logged_in`, `account_count`, `total_balance`, `route`) - `uatu/spec.ts` imports `@uatu/spec`, reads those snapshots, asserts properties, and weights the actions the fuzzer picks from - `just test` invokes `uatu test` against the installed APK