Andriod Emulator

CircleCI supports running the Android emulator through our Android machine image, which supports x86 Android emulator tests and nested virtualization. Documentation is available here:

https://circleci.com/docs/2.0/android-machine-image/.

We also recommend using the circleci/android orb in your config as it provides useful commands for emulator testing.

Note: The Android machine image is different from the Android docker convenience images, which do not support emulators

Common UI Test Failures 

Insufficient memory

We recommend using at least a resource class of at least "large" and above, as "medium" is usually insufficient to run the emulator and gradle processes.

Emulator configuration

Higher API levels and/or system images that come with Google APIs installed have been observed to be less stable, or require specific emulator options (e.g. no-window to be enabled/disabled). If UI tests are failing, we recommend trying out a different image. Please check a list of our Android machine images here:

https://circleci.com/developer/machine/image/android

Additional options such as partition-size can be set for the emulator via the Android orb's additional-emulator-args parameter.

Emulator animations

We recommend disabling of emulator animations to prevent interference with tests. This can be done through this orb command, disable-animations , or other commands from the orb that wrap it.

Flakiness

Some degree of flakiness may be expected from the emulator. We recommend using our android orb command, run-tests, (or other commands from the orb that wrap it, like start-emulator-and-run-tests) to run your tests with, as it supports retries