ychescale9 / bitrise-ui-tests-workflow

Custom bitrise.io workflow for running instrumented tests on emulators

Bitrise UI Tests Workflow

Custom bitrise.io workflow for running instrumented tests on emulators.

⚠️ Update: 2020-04-26 - there have been a few improvements in Android Testing on CI for the last few months so some of the information presented below no longer be relevant. Specifically:

• many projects are migrating to GitHub Actions for Android CI and I created Android Emulator Runner, a custom GitHub Action that installs, configures and runs hardware-accelerated Android Emulators on macOS virtual machines.
• GitHub Actions' macos VMs are free for open-source projects but they are significantly more expensive than the Linux VMs for private repos. While Android Emulator Runner works with ubuntu VMs without hardware acceleration, I don't recommand it. Intead I'd encourage you to take a look at Cirrus CI which provides KVM-enabled Linux VMs and pricing seems pretty reasonable (100% free for opensource projects).

If you'd like to learn more about running Android instrumented tests on CI in general, I wrote a couple of articles:

• Running Android Emulators on CI - from bitrise.io to GitHub Actions - I explored my journey on finding the best solution for runing Android instrumented tests on CI, expecially opensource projects. I also covered how I migrated one of my opensource libraries from bitrise.io (using the workflow in this repo) to the custom Android Emulator Runner GitHub Action.
• Exploring Cirrus CI for Android - A deep dive into Cirrus CI and all the features relevant to Android and how you can optimize your pipeline etc. I also created some templates to help you get started.

Why do I need this?

Running proper automated UI tests on CI remains a challenge especially when operating with free plans for side projects. AFAIK Bitrise is the only service that supports running x86 emulators natively with -gpu swiftshader. They offer 1 free container for open-source projects. Other solutions I've looked at:

• CircleCI (and most other hosted CI providers) does not yet support running x86 emulators on their host machines which requires KVM support.
• Firebase Test Lab only allows 10 tests/day on virtual device and 5 tests/day on physical device with the Spark (free) Plan.
• Robolectric 4.x introduced support for running Espresso tests. While sharing test source between JVM and on-device tests mostly works, robolectric's shadowed environment is still too unstable / immature to be considered useful as they often have very different behaviors than when running on an emulator or real device.
• Emulator 28.1.8 Canary introduced a emulator-headless mode (replaced by emulator -no-window in Emulator 29.2.7 Canary) but with -no-accel on starting an emulator and installing APKs are still order of magnitude slower than running with host or swiftshader GPU acceleration.

Bitrise provides the Android Build for UI Testing and Virtual Device Testing for Android steps which use Firebase Test Lab to run tests for the chosen module / build variant with no limit on device hours / no. of test executions. But it has a couple of limitation:

• Only 1 build variant from 1 module can be run for each step. This means if you have multiple library modules with instrumented tests, you'll have to manually configure a Android Build for UI Testing or Virtual Device Testing for Android step for each module (or setup parallel workflows for running these in parallel if you wish to pay for additional containers).
• Running tests in a library module doesn't work unless an app APK is also present. The workaround is to also run app:assembleDebug for your library module tests.

You could also use the AVD Manager and Wait for Android emulator steps to spin up an Emulator on Bitrise locally and then run all your tests with gradle, but you don't have full control over the Emulator configs.

With a custom Workflow, we are able to control how we want to configure and run an Emulator on Bitrise with a custom shell script, and run all (or any) tests by running a single gradle command.

Steps

1. Copy start_emulator.sh into your ${projectRoot}/.bitrise/ (you could also just copy and paste it into a Script step in your Bitrise workflow directly).
2. Specify API_LEVEL and BUILD_TOOLS_VERSION in the script. You could also use environment variables for these.
3. Add a Script Runner step to your Bitrise workflow and specify .bitrise/start_emulator.sh for Script location
4. Add a Gradle Runner step to your Bitrise workflow and specify connectedDebugAndroidTest -Dorg.gradle.daemon=false -Dkotlin.incremental=false for Gradle task to run. You could also use more fine-grained commands to only run tests for certain modules / build variants.
5. Push your change to trigger the build.

A sample bitrise.yml can be found here.