Always use x86 emulators (or x86_64 for testing 64-bit APKs). Although arm emulators exist, they are so slow that they are not worth your time.
You need to target the correct architecture via GN args:
target_cpu = "x86" # or "x64" if you have an x86_64 emulator
Chromium has a set of prebuilt images stored as CIPD packages. These are used by various builders to run tests on the emulator. Their configurations are currently stored in
You can use these configuration files to run the same emulator images locally.
The android test runner can run emulator instances on its own. In doing so, it starts the emulator instances, runs tests against them, and then shuts them down. This is how builders run the emulator.
To have the test runner run an emulator instance, use
$ out/Debug/bin/run_base_unittests \ --avd-config tools/android/avd/proto/generic_android28.textpb
The test runner will launch one instance by default. To have it run multiple instances, use
$ out/Debug/bin/run_base_unittests \ --avd-config tools/android/avd/proto/generic_android28.textpb \ --emulator-count 4
The test runner runs the emulator in headless mode by default. To have it run with a window, use
$ out/Debug/bin/run_base_unittests \ --avd-config tools/android/avd/proto/generic_android28.textpb \ --emulator-window
The test runner will set up and tear down the emulator on each invocation. To manage emulator lifetime independently, use
NOTE: You'll first need to install the emulator configuration you intend to use:
$ tools/android/avd/avd.py install \ --avd-config tools/android/avd/proto/generic_android28.textpb
This behaves the same as it does for the test runner.
$ tools/android/avd/avd.py start \ --avd-config tools/android/avd/proto/generic_android28.textpb
avd.py startwill start an emulator instance and then terminate. To shut down the emulator, use
adb emu stop.
Like the test runner,
avd.py runs the emulator in headless mode by default. To have it run with a window, use
$ tools/android/avd/avd.py start \ --avd-config tools/android/avd/proto/generic_android28.textpb \ --emulator-window
avd.py runs the emulator in read-only mode by default. To run a modifiable emulator, use
$ tools/android/avd/avd.py start \ --avd-config tools/android/avd/proto/generic_android28.textpb \ --no-read-only
By far the easiest way to set up emulator images is to use Android Studio. If you don't have an Android Studio project already, you can create a blank one to be able to reach the Virtual Device Manager screen.
Where files live:
Choose a skin with a small screen for better performance (unless you care about testing large screens).
Android Studio's image labels roughly translate to the following:
|AVD “Target”||Virtual Device Configuration tab||GMS?||Build Properties|
|Google Play||“Recommended” (the default tab)||This has GMS|
|Google APIs||“x86 Images”||This has GMS|
|No label||“x86 Images”||AOSP image, does not have GMS|
“Show Advanced Settings” > scroll down:
adb -s emulator-5554 shell mount(look for /sdcard)
hw.sdCard=noand set it to
emulatorcommand line tool.
$ # List virtual devices that you've created: $ ~/Android/Sdk/emulator/emulator -list-avds $ # Start a named device: $ ~/Android/Sdk/emulator/emulator @EMULATOR_ID
You can run an emulator without creating a window on your desktop (useful for
$ ~/Android/Sdk/emulator/emulator -no-window @EMULATOR_ID $ # This also works for new enough emulator builds: $ ~/Android/Sdk/emulator/emulator-headless @EMULATOR_ID
Tests are automatically sharded amongst available devices. If you run multiple emulators, then running test suites becomes much faster. Refer to the “Multiple AVD instances” section of these emulator release notes for more about how this works.
$ # Start 8 emulators. Press Ctrl-C to stop them all. $ ( for i in $(seq 8); do ~/Android/Sdk/emulator/emulator @EMULATOR_ID -read-only & done; wait ) $ # Start 12 emulators. More than 10 requires disabling audio on some OS's. Reducing cores increases parallelism. $ ( for i in $(seq 12); do ~/Android/Sdk/emulator/emulator @EMULATOR_ID -read-only -no-audio -cores 2 & done; wait )
Unlike physical devices, an emulator's
/system partition cannot be modified by default (even on rooted devices). If you need to do so (such as to remove a system app), you can start your emulator like so:
$ ~/Android/Sdk/emulator/emulator -writable-system @EMULATOR_ID
scpor ssh port forwarding to copy the APK from your workstation and install on a local device. Emulators run on your workstation, so there's no ssh slow-down.
engemulators don‘t come with the Play Store installed, so you can’t install third party applications. Sideloading is tricky, as not all third-party apps support x86.