Rumbo

Español · Build and tests

An Android app for browsing six fictional trips, saving favorites and keeping demo bookings on the device. When a refresh fails, the saved catalog remains available.

The implementation uses Kotlin, Compose, Navigation, Room and Retrofit, with domain logic in a separate core module. Places and prices are invented, and a demo booking does not reserve a real trip. No account, API key or backend is needed; the app has no Internet permission.

1. Search by trip title or region, with or without accents, and filter by category.
2. Open a trip. The heart saves a favorite independently of opening the detail.
3. Select Add demo booking. Find the booking and your favorites in My plan. Repeating a booking keeps its original reference.
4. In Lab, select Offline, Service error or Slow response, then return to Explore. A failed update preserves the saved catalog.
5. Choose Successful load in Lab to recover. Restart the process to check saved favorites and bookings.

The scenarios change local responses, not your device’s connection. To test a first load without saved data, use a fresh demo installation and start with the documented scenario argument. Replace DEVICE_ID with your device’s serial:

adb -s DEVICE_ID shell am start -n dev.navalcode.rumbo/.MainActivity --es demo_scenario OFFLINE

Values: CONNECTED, OFFLINE, SERVICE_ERROR, SLOW. Only this demo’s source is affected.

Use JDK 17, Android SDK 36, and an emulator or device with API 26+. Open the project in Android Studio or set the SDK path in an untracked local.properties file:

sdk.dir=/path/to/Android/sdk

From this directory:

./gradlew :core:test :app:testDebugUnitTest :app:lintDebug :app:assembleDebug
./gradlew :app:installDebug
./gradlew :app:connectedDebugAndroidTest
./gradlew :app:assembleRelease

Connected tests need an emulator or device. For an explicit serial and optional screenshots, see verification commands. Use :app:bundleRelease to generate an AAB. Release enables R8 and resource shrinking; production signing is not configured.

Gradle 8.14.3 is pinned with SHA-256; AGP 8.13.2, Kotlin 2.2.10 and library versions are fixed. Dependencies come from Google Maven and Maven Central.

• Trips.kt: source/store contracts, refresh deadline, cancellation, cached content and idempotent bookings, without Android dependencies.
• TripCatalogApi.kt: Retrofit DTO validation and mapping of HTTP/I/O failures.
• TripDatabase.kt: transactional catalog replacement and unique bookings in Room.
• TripsViewModel.kt: read-only flows, input methods and cancellation of a superseded refresh.
• RumboApp.kt: Compose, Navigation destinations, stable detail IDs and local actions.
• Landscape.kt: original Canvas illustrations.

Architecture explains the small manual dependency graph, alternatives and restoration limits. DESIGN.md describes the interface and locally bundled fonts.

Retrofit declares GET /v1/trips at https://demo.rumbo.invalid/. An OkHttp application interceptor answers every request locally without forwarding it. The scenario selects a response, I/O failure, HTTP 503 or cancellable delay. The repository applies a 3.5-second deadline and preserves the previous catalog and timestamp on expected failures.

MockWebServer tests use real loopback HTTP to check the contract and cancellation. This is a simulated travel source. Query/category state survives activity recreation through the ViewModel, but is not restored after process death; Room data persists independently.

The project has 32 JVM tests (16 core, 10 HTTP and six ViewModel) and eight Android tests for Room, booking, cached content, Back, independent favorites and activity recreation. Verification records the current runs, screenshots, artifact audits and any failed attempts; follow the workflow link above for hosted results.

Resources are Spanish with an English fallback. The app is a learning example: no real availability, payments, production signing or store distribution. Emulator checks and calculated layout checks do not establish physical-device behavior or formal accessibility certification.

Original code, documentation and artwork: MIT, Manuel Naval, 2026. Third-party notices retain the Gradle and dependency notices.