CLI

The most extensible and flexible way to run your Android instrumentation tests on emulator.wtf is via our command line client.

Assuming you have $HOME/bin on your PATH:

curl https://maven.emulator.wtf/releases/ew-cli -o $HOME/bin/ew-cli && \
  chmod a+x $HOME/bin/ew-cli

Run ew-cli with your API token and point it to your app & androidTest apks:

ew-cli --token YOUR_API_TOKEN --app path/to/app.apk --test path/to/test.apk

Run with --help to see all the possible options:

ew-cli --help

ew-cli has various exit codes to indicate the type of failure that occurred:

You can pass your API token in via an the EW_API_TOKEN env var instead of a command-line argument, i.e. when using in a CI job:

export EW_API_TOKEN="YOUR_API_TOKEN"
ew-cli --app path/to/app.apk --test path/to/test.apk

Use --outputs-dir to store run results locally, useful for things like exporting the JUnit XML report to your CI system or storing run logcat as a build artifact.

ew-cli --app path/to/app.apk --test path/to/test.apk --outputs-dir out

Add --record-video to store a video recording of the test. It will be downloaded into --outputs-dir once the test has finished. When running tests with multiple shards or devices then you will get a separate video per shard-device combination.

By default emulator.wtf runs tests on a Pixel2-like emulator with API 27 (Android 8.1). If you want to run on a different version or device profile you can use --device to do so:

ew-cli --app path/to/app.apk --test path/to/test.apk --device model=NexusLowRes,version=23

You can add repeated --device arguments to run on a combination of devices.

ew-cli --app path/to/app.apk --test path/to/test.apk \
  --device model=NexusLowRes,version=23 --device model=Pixel2,version=27

You can list all available device profiles by invoking ew-cli with the --models argument:

ew-cli --models

You can limit maximum test runtime with --timeout to ensure the tests don’t get stuck for too long. For example, to run tests up to 10 minutes:

ew-cli --app path/to/app.apk --test path/to/test.apk --timeout 10m

You can use Android Test Orchestrator to run the tests - this will create a new app VM from scratch for each test. Slower to run, but will ensure no static state leakage between tests. Add the optional --clear-package-data flag to clear app persisted state between each run. Read more about orchestrator here.

ew-cli --use-orchestrator --clear-package-data --app path/to/app.apk \
  --test path/to/test.apk

Use the --with-coverage flag to capture test run coverage data and store the results (one or more .exec files) in the path specified by --outputs-dir:

ew-cli --with-coverage --app path/to/app.apk --test path/to/test.apk \
  --outputs-dir out

The following example runs 3 separate shards and stores the outputs from each in a separate folder under out:

ew-cli --app path/to/app.apk --test path/to/test.apk --outputs-dir out --num-shards 3

Sometimes you want to add data like fixtures to the device to be consumed by the device. The following command pushes the fixtures.json file so it’s readable at runtime in /sdcard/fixtures.json:

ew-cli --app path/to/app.apk --test path/to/test.apk \
  --other-files /sdcard/fixtures.json=fixtures.json

Instead of passing all arguments via command-line you can pass them in via a YAML file instead. The file should contain named groups of arguments (which can be composed via a special include key). The keys inside each argument group are the same as they would be on the command line.

Example file:

atd:
  device:
    - model: Pixel2Atd
      version: 30
      
myapp:
  app: path/to/app.apk
  test: path/to/test.apk

pr-check:
  include: [atd, myapp]

And invocation:

ew-cli tests.yaml:pr-check

Results in the exactly same ew-cli invoke as:

ew-cli --app path/to/app.apk --test path/to/test.apk \
  --device model=Pixel2Atd,version=30

Application APK to test.

Test APK, containing Android instrumentation tests (i.e. Espresso).

Your API token. Can alternatively use the EW_API_TOKEN environment variable to pass this in.

Specify device(s) to run test with, use repeated values to test on a combination of devices. Possible keys:

• device - the device profile to use, one of Pixel2, NexusLowRes
• version - the API version to use, currently supported values: 23, 27

Fail if the test runtime exceeds the given timeout value. Values are in the format of number + suffix where suffix is either s, m or h (seconds, minutes or hours). Examples: 10m, 2h. Defaults to 15m.

Run only a subset of matching test targets, these will be forwarded to AndroidJUnitRunner. See full list of configuration options here.

Some examples:

• run all tests in a class: --test-targets "class com.example.Foo"
• run a single test called bar: --test-targets "class com.example.Foo#bar"
• run all tests in a package: --test-targets "package com.example"
• run all tests annotated with @MediumTest: --test-targets "size medium"
• run all tests in a package annotated with @MediumTest: --test-targets "size medium package com.example"

Path to college test run outputs to (JUnit report, logcat, any pulled directories). Tip: when sharding, use a different outputs dir for each shard.

Specifies what to download into the path specified by --outputs-dir.

Available options:

• summary - machine-readable summary about test results and outputs, similar output to --json
• merged_results_xml - merged JUnit XML from all emulator instances (devices and shards)
• coverage - coverage files gathered from tests
• pulled_dirs - pulled directories from emulator instances
• results_xml - all JUnit XML files, separate per emulator instance
• logcat - logcat files, separate per emulator instance
• captured_video - captured test video, separate per emulator instance

Default: merged_results_xml,coverage,pulled_dirs

A list of additional APKs to install, in addition to those being directly tested.

Any sort of random data you want to send to the device before the tests are run. In the form of remote-path=local-path, where remote-path must start with either /sdcard/ or /data/local/tmp. Separate with commas if you want to send multiple files.

Add this flag to use Android Test Orchestrator.

Clear package data (any persistent state) between app test runs. Only works together with --use-orchestrator.

Collect test coverage execution data and store it in the outputs folder. Only makes sense if you also specify --outputs-dir.

Add repeat attempts of devices and/or shards where there were test failures. Maximum number of flaky test attempts is 10. The test attempts will be started in parallel, e.g. with --num-flaky-test-attempts 3 an extra 3 attempts will be started in case of a test failure.

Splits your tests evenly across multiple devices. Emulator.wtf will try to balance the number of tests in each shard. Individual test times are not taken into account so this can lead to uneven shard times but should still provide better results compared to --num-uniform-shards.

Splits your tests across multiple emulator instances by runtime. Emulator.wtf will try to assign tests to devices based on their historical runtime. This will give you the most even spread between shards for large test suites.

If historical data is not available then falls back to --num-shards (heuristic sharding so that each emulator instance has roughly the same number of tests).

Splits your tests randomly across multiple devices.

Specify --test-targets-for-shard multiple times to spread tests into shards manually. Possibly options to split: by package, class or single test method.

To specify all tests in a package, use --test-targets-for-shard "package com.foo".

To specify all tests in a class, use --test-targets-for-shard "class com.foo.MyTestClass".

To specify a single test method, use --test-targets-for-shard "class com.foo.MyTestClass#myTestMethod".

The arguments can be repeated in a comma separated list, e.g. the following argument will run both classes com.example.Foo and com.example.Bar in a single shard:

--test-targets-for-shard "class com.example.Foo,com.example.Bar"

To mix argument types, separate them with a semicolon ;, i.e. to run all tests in the package com.example and also class com.foo.MyTestClass:

--test-targets-for-shard "package com.example;class com.foo.MyTestClass"

A comma-separated list of key-value pairs that are passed to AndroidJUnitRunner.

A comma-separated list of directories to pull from the device and store in the path specified by --outputs-dir. The path in --outputs-dir will have the same relative path as the absolute path on the device, i.e. --directories-to-pull /sdcard/acmeapp/screenshots --outputs-dir out will pull the contents of /sdcard/acmeapp/screenshots on the device to out/sdcard/acmeapp/screenshots.

Print machine readable test result into STDOUT, useful when wrapping ew-cli with your own scripts.

Suppress any logging (sent to STDERR), use this together with --json to only get json output in STDOUT.

List available device models. Works together with --json to get the models list in a machine-readable fashion.