Android Emulator

Tenki Linux x64 Runners support KVM nested virtualization, which makes them a first-class home for Android emulator-based CI, Espresso, instrumented tests, screenshot tests, Detox, and similar UI-test workloads.

Nested virtualization (KVM)

KVM is available on request for x64 runners. Once enabled on your workspace, your jobs can boot Android emulators using the standard Android SDK system images, including:

• system-images;android-34;google_apis;x86_64
• Older API levels (29–33) for legacy test matrices
• Google Play variants of the above

End-to-end UI tests (Espresso, instrumented JUnit, screenshot tests) run on the booted emulator within the runner.

Example workflow

The workflow below uses reactivecircus/android-emulator-runner on a Tenki Linux runner. The only line that differs from a GitHub-hosted runner workflow is runs-on.

jobs:
  ui-tests:
    runs-on: tenki-standard-large-8c-16g
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-java@v4
        with:
          distribution: temurin
          java-version: 17

      - name: Cache AVD
        uses: actions/cache@v4
        with:
          path: |
            ~/.android/avd/*
            ~/.android/adb*
          key: avd-android-34

      - name: Run instrumented tests
        uses: reactivecircus/android-emulator-runner@v2
        with:
          api-level: 34
          target: google_apis
          arch: x86_64
          script: ./gradlew connectedCheck

Picking a runner size

Android emulator workloads are memory-hungry and benefit from more cores during APK compilation. Recommended starting points:

See Which Runner to use? for general sizing guidance.

Caching the emulator

Use the Tenki cache (a drop-in replacement for actions/cache) to persist the AVD between runs. The first cold boot of a new API level takes a few minutes; subsequent runs with a warm AVD are dramatically faster.