Running Tests On Gradle Managed Devices — Gradle Owns The Emulator

Gradle Managed Devices (GMD) move the emulator into the build: you declare devices in build.gradle.kts, and ./gradlew <device>DebugAndroidTest downloads the system image, boots a fresh emulator, runs androidTest, collects results, and shuts it down. The payoff is reproducibility — CI and every machine run the exact same device — and no hand-managed emulators. This skill covers the DSL, the generated tasks, ATD images for cheap CI, sharding, and where GMD sits relative to connectedAndroidTest and raw am instrument (see ../../../adb/tests/running-instrumented-tests-via-adb/SKILL.md).

When to use this skill

• The user wants instrumented tests to run on a defined, reproducible emulator in CI without adb-managing a device.
• The user mentions managedDevices, allDevicesCheck, ManagedVirtualDevice, or a generated task like pixel2api30DebugAndroidTest.
• The user wants the test matrix (which API levels / form factors) to live in version control, not in someone's local AVD list.
• CI emulator runs are slow/flaky and the user asks about ATD ("Automated Test Device") images.
• The user wants to shard a slow instrumented suite across several emulator copies.

When NOT to use this skill

• The user wants to run tests on a physical device or an emulator they already have running — that is ./gradlew connectedAndroidTest / connectedDebugAndroidTest; GMD is for emulators Gradle creates.
• The user is invoking the runner directly without Gradle (adb shell am instrument -w -r …, sharding via -e numShards, Test Orchestrator wiring) — use ../../../adb/tests/running-instrumented-tests-via-adb/SKILL.md and ../../../adb/automation/scripting-adb-for-ci/SKILL.md.
• The user is choosing the AndroidJUnit4 runner / writing the test class itself — use ../../runner/running-instrumented-tests-with-androidjunit4/SKILL.md.
• The user wants Compose UI tests specifically — those still run as instrumented tests; GMD just hosts them. See ../../../compose/setup/setting-up-host-vs-device-tests/SKILL.md for host-vs-device choice first.