mobile-test-kit

Zero-friction mobile UI testing setup for React Native and Flutter apps.

One command installs everything:

npx create-mobile-test-kit

What you get

• Firebase Test Lab integration (real hardware, no emulators)
• Physical device routing (plugged-in phone takes priority automatically)
• Coverage drift detection (new screens with no tests → stubs appear instantly)
• Fastlane lanes for running, checking, and scheduling tests
• Full automation — GCP setup, build.gradle patches, Xcode targets, Fastlane merges

Works with React Native and Flutter.

What gets installed

| File | Purpose | |------|---------| | scripts/ui_test_coverage.sh | Scans all testIDs / ValueKeys in source, diffs against test files, appends stubs for gaps | | .claude/settings.json | PostToolUse hook — runs coverage check automatically on every source edit | | testlab/robo_script_android.json | Robo login script template for Android FTL crawl | | fastlane/FastFile-TestKit.rb | Fastlane lanes: testLabProd, localFullTest, checkTestCoverage |

Requirements

• Node ≥ 18
• Ruby + Bundler (for Fastlane lanes)
• gcloud CLI — install
• gsutil (bundled with gcloud)
• Firebase project on Blaze (pay-as-you-go) plan — required for iOS; free tier covers 60 min/day virtual + 30 min/day physical

Full FTL setup

1 — Firebase project

1. Go to console.firebase.google.com → Add project (or select existing)
2. Note your Project ID
3. Enable Blaze billing (⚙️ → Upgrade)

2 — Enable required APIs

gcloud config set project YOUR_PROJECT_ID

gcloud services enable \
  testing.googleapis.com \
  toolresults.googleapis.com \
  storage.googleapis.com \
  firebase.googleapis.com

3 — Create the GCS results bucket

gsutil mb -l us-central1 gs://YOUR_APP-test-lab-results

PROJECT_NUMBER=$(gcloud projects describe YOUR_PROJECT_ID --format="value(projectNumber)")
gsutil iam ch \
  serviceAccount:service-${PROJECT_NUMBER}@gcp-sa-firebase.iam.gserviceaccount.com:objectAdmin \
  gs://YOUR_APP-test-lab-results

4 — IAM roles

Local dev — your Google account needs:

gcloud projects add-iam-policy-binding YOUR_PROJECT_ID \
  --member="user:[email protected]" \
  --role="roles/firebase.qualityAdmin"

CI/CD — create a service account:

# Create SA
gcloud iam service-accounts create ftl-ci-runner \
  --display-name="Firebase Test Lab CI Runner" \
  --project=YOUR_PROJECT_ID

SA="ftl-ci-runner@YOUR_PROJECT_ID.iam.gserviceaccount.com"

# Grant roles
gcloud projects add-iam-policy-binding YOUR_PROJECT_ID \
  --member="serviceAccount:${SA}" --role="roles/cloudtestservice.testRunner"
gcloud projects add-iam-policy-binding YOUR_PROJECT_ID \
  --member="serviceAccount:${SA}" --role="roles/cloudtoolresults.editor"
gsutil iam ch serviceAccount:${SA}:objectAdmin gs://YOUR_APP-test-lab-results

# Key for CI secret
gcloud iam service-accounts keys create ftl-ci-key.json --iam-account="${SA}"

Never commit ftl-ci-key.json. Store as a CI secret.

5 — Activate on CI

gcloud auth activate-service-account --key-file="${FTL_KEY_JSON}"
gcloud config set project YOUR_PROJECT_ID

FTL pricing

Blaze plan (required for iOS):

| Device type | Free / day | Overage | |-------------|-----------|---------| | Android virtual | 60 min | $1.00 / hr | | Android physical | 30 min | $5.00 / hr | | iOS physical | 30 min | $5.00 / hr |

A typical 5-minute smoke test on 2 devices is free as long as daily usage stays under the allowance.

Coverage drift detection

Every time you edit a source file, the Claude Code hook runs ui_test_coverage.sh:

Edit App/Login/LoginScreen.js
  → hook fires
  → script scans all testID= values
  → "login-biometric-button" has no test → stub appended to Android + iOS test files
  → Claude: "Stubs added for login-biometric-button. Implement now?"

Manual run

bash scripts/ui_test_coverage.sh
# or via Fastlane:
bundle exec fastlane android checkTestCoverage
bundle exec fastlane ios checkTestCoverage

Physical device routing

When you plug in a phone:

• Android: adb devices detects it → API level checked (≥ 24) → tests run there
• iOS: xcrun xctrace list devices detects it → iOS version checked (≥ 15.1) → tests run there
• No device / older device → Firebase Test Lab takes over automatically

Fastlane lanes

# Run tests — physical device if connected, else FTL / simulator
bundle exec fastlane android testLabProd
bundle exec fastlane ios testLabProd

# Full local test run
bundle exec fastlane android localFullTest
bundle exec fastlane ios localFullTest

# Coverage gap report
bundle exec fastlane android checkTestCoverage
bundle exec fastlane ios checkTestCoverage

Troubleshooting

PERMISSION_DENIED on gcloud run — your account needs roles/firebase.qualityAdmin. Grant it in IAM & Admin → IAM.

BucketNotFound — run the bucket grant from Step 3 above.

No .xctestrun found — the UI test target isn't added to the scheme's Test action. Xcode → Manage Schemes → Edit → Test → add your UITests target.

iOS DEPLOYMENT_TARGET mismatch — your UI test target's IPHONEOS_DEPLOYMENT_TARGET must be ≤ 18.4 (FTL's current max).

Robo script doesn't fill the form — resource IDs don't match. Dump the UI: adb shell uiautomator dump /sdcard/dump.xml && adb pull /sdcard/dump.xml and search for resource-id or content-desc.

License

MIT