Mobile Testing

Mobile Testing (Maestro for iOS + Android)

Maestro drives the iOS Simulator and Android Emulator with simple YAML flows. Use it to verify functionality after changes to ios-app/ or android-app/.

Quick Start

1. Verify builder.config.json exists in the repo root with the required allowedCommands (see "Verify builder.config.json" below); create or update it if missing.
2. Confirm Maestro is installed (maestro --version); if not, install it.
3. Build and launch the relevant app on a simulator/emulator.
4. Run an existing flow from maestro/ or create one for the new feature.
5. Report pass/fail plus screenshot/log paths back to the user.

Verify builder.config.json

Before running any Maestro commands, ensure builder.config.json exists in the repository root and contains the following allowedCommands list. Without these entries the required shell commands (maestro, xcrun, xcodebuild, ./gradlew, adb, etc.) will be blocked by ACL policy.

{
  "allowedCommands": [
    "npm *",
    "pnpm *",
    "yarn *",
    "yarn",
    "bun *",
    "bun",
    "gh *",
    "wc *",
    "gradle *",
    "gradle",
    "rg *",
    "./gradlew *",
    "./gradlew",
    "adb *",
    "adb",
    "vp *",
    "vp",
    "git *",
    "export *",
    "rails *",
    "gem *",
    "bundle *",
    "rake *",
    "echo *",
    "cd *",
    "find *",
    "ls *",
    "rm *",
    "cp *",
    "mv *",
    "pwd",
    "curl *",
    "npx tsc *",
    "head *",
    "lsof *",
    "kill *",
    "ps *",
    "tr *",
    "awk *",
    "cat *",
    "grep *",
    "sed *",
    "tail *",
    "touch *",
    "mkdir *",
    "tee *",
    "true",
    "uniq *",
    "test *",
    "false",
    "npx *",
    "sort *",
    "env",
    "dirname",
    "basename *",
    "realpath *",
    "readlink *",
    "stat *",
    "file *",
    "diff *",
    "xargs *",
    "chmod *",
    "which *",
    "whoami",
    "uname *",
    "uname",
    "date",
    "date *",
    "printenv *",
    "sleep *",
    "netlify *",
    "node *",
    "tsx *",
    "builderio *",
    "builder *",
    "open *",
    "xcrun *",
    "xcodebuild *",
    "xcode-select *",
    "xed *",
    "agvtool *",
    "maestro *",
    "maestro"
  ]
}

If the file is missing, create it. If it exists but lacks any of the entries above, merge them in without removing existing allowed commands.

1. Install Maestro

Run only if maestro --version fails.

curl -Ls "https://get.maestro.mobile.dev" | bash
export PATH="$PATH:$HOME/.maestro/bin"
maestro --version

Platform prerequisites:

• iOS: Xcode + at least one iOS Simulator runtime.
• Android: Android SDK, an emulator AVD, adb on PATH.

2. Build the Apps

iOS (simulator build):

cd ios-app
xcodebuild -project movie-rater.xcodeproj \
  -scheme movie-rater \
  -sdk iphonesimulator \
  -configuration Debug \
  -derivedDataPath build

Resulting .app: ios-app/build/Build/Products/Debug-iphonesimulator/movie-rater.app

Android (debug APK):

cd android-app
./gradlew :app:assembleDebug

Resulting .apk: android-app/app/build/outputs/apk/debug/app-debug.apk

3. Boot a Simulator/Emulator and Install

iOS:

xcrun simctl boot "iPhone 15" || true
open -a Simulator
xcrun simctl install booted <path-to>.app

Android:

emulator -list-avds
emulator -avd <AvdName> &
adb wait-for-device
adb install -r <path-to>.apk

4. Run Tests

maestro test maestro/ios/smoke.yaml
maestro test maestro/android/smoke.yaml
maestro test maestro/                   # run all flows

Useful flags:

• --format junit --output report.xml for CI.
• maestro studio opens an interactive inspector (great for finding selectors when authoring a new flow).
• maestro hierarchy dumps the current screen's view tree.

5. Create a New Test Flow

Directory layout to follow:

maestro/
  ios/        # iOS-specific entry flows
  android/    # Android-specific entry flows
  shared/     # reusable sub-flows

Minimum flow shape:

appId: com.example.movierater   # iOS bundle id or Android package
---
- launchApp:
    clearState: true
- assertVisible: "Movies"
- tapOn:
    id: "movie-card-title"
- assertVisible: "Details"

Authoring steps:

1. Open maestro studio against a running app to discover selectors.
2. Prefer id: selectors backed by stable accessibility identifiers.
3. If identifiers are missing, add them in app code:
   • SwiftUI: .accessibilityIdentifier("movie-card-title")
   • Android Views: android:contentDescription or resource id
   • Jetpack Compose: Modifier.testTag("movie-card-title") with semantics { testTagsAsResourceId = true }
4. Keep one user journey per flow file; extract shared steps to maestro/shared/ and runFlow: them.
5. Re-run the flow until it passes deterministically.

6. Reporting Back

After running tests, surface to the user:

• The flow file(s) executed.
• Pass/fail summary and the failing step if any.
• Paths to screenshots, recordings, and ~/.maestro/tests/<run>/ logs.
• Any code changes made (e.g., added accessibility identifiers).

Gotchas

• appId differs per platform — use the iOS bundle id in maestro/ios/ flows and the Android package name in maestro/android/ flows.
• The app must already be installed on the booted simulator/emulator before maestro test runs; Maestro does not build apps.
• Tests that rely on visible text break when copy changes; prefer id: selectors with accessibility identifiers.
• Compose testTag is invisible to Maestro unless testTagsAsResourceId = true is set on the semantics root.
• Only one iOS Simulator can be "booted" target at a time; if commands hit the wrong device, shut others down with xcrun simctl shutdown all.
• Android emulator boot is slow; always adb wait-for-device before installing or testing.
• Flaky network calls cause flaky tests — seed deterministic data or mock the network in debug builds rather than retrying.
• Don't introduce a custom back button in SwiftUI just to make a test easier; it breaks the swipe-back gesture. Fix the selector instead.