Evergreen Test Automation

The Evergreen test automation reduces the overhead of running the test cases required to test Evergreen-specific functionality. These tests must be run both internally and by partners, and making them simple and fast is good for all.


The Evergreen test automation framework is made up of a few distinct sets of files.

Core Scripts

These are files that are responsible for finding all of the tests, executing all of the tests, and outputting the results.

  • run_all_tests.sh
  • setup.sh
  • pprint.sh

Shared Scripts

These files contain code that is either non-trivial or repeated throughout the tests, and is shared across all platforms.

  • shared/app_key.sh
  • shared/cycle_cobalt.sh
  • shared/drain_file.sh
  • shared/init_logging.sh
  • shared/installation_slot.sh
  • shared/wait_and_watch.sh

Platform-Specific Scripts

These files contain code that is either non-trivial or repeated throughout the tests, and is platform specific.

  • <PLATFORM>/clean_up.sh
  • <PLATFORM>/clear_storage.sh
  • <PLATFORM>/create_file.sh
  • <PLATFORM>/delete_file.sh
  • <PLATFORM>/deploy_cobalt.sh
  • <PLATFORM>/run_command.sh
  • <PLATFORM>/setup.sh
  • <PLATFORM>/start_cobalt.sh
  • <PLATFORM>/stop_cobalt.sh


These files are responsible for changing the channels when tests are running.

  • tests/empty.html
  • tests/test.html
  • tests/tseries.html

Test Cases

These files are responsible for the test logic, and each file corresponds to a single Evergreen test case.

  • tests/abort_update_if_already_updating_test.sh
  • tests/alternative_content_test.sh
  • tests/continuous_updates_test.sh
  • tests/crashing_binary_test.sh
  • tests/crashpad_runs_test.sh
  • tests/evergreen_lite_test.sh
  • tests/load_slot_being_updated_test.sh
  • tests/mismatched_architecture_test.sh
  • tests/noop_binary_test.sh
  • tests/out_of_storage_test.sh
  • tests/quick_roll_forward_test.sh
  • tests/racing_updaters_test.sh
  • tests/update_fails_verification_test.sh
  • tests/update_works_for_only_one_app_test.sh
  • tests/valid_slot_overwritten_test.sh
  • tests/verify_qa_channel_update_test.sh

How To Run

Before beginning, please check if your target platform has a README.md and defer to the steps to run specified there. Otherwise, there are two primary methods of running the Evergreen tests.

Python Helper Script

The Python helper script at cobalt/tools/buildbot/run_evergreen_tests.py simplifies the process of running the automated tests, and relies on the existing abstract launcher infrastructure.

For this example we will use the following:

  • linux-x64x11 and qa for the target platform and configuration.
  • evergreen-x64 and qa for the Evergreen platform and configuration.

Then the following command can be used to run the tests.

python cobalt/tools/buildbot/run_evergreen_tests.py \
    -p evergreen-x64 -c qa -P linux-x64x11 -C qa


First, a directory tree containing the required binaries and content needs to be created. This directory tree must be in the following format:

Directly running the scripts requires more setup than the helper script above. We will be using the same platforms and configurations as the steps above.

First, a directory structure needs to be created where the Evergreen binary and its content is located under the content of the loader binary's content:

   +-- deploy
        +-- loader_app
             +-- loader_app <-- loader binary
             +-- content    <-- loader content
                  +-- app
                       +-- cobalt
                            +-- content           <-- cobalt content
                            +-- lib
                                 +-- libcobalt.so <-- cobalt binary

Note: This directory structure is the same as what would be generated by starboard/evergreen/shared/launcher.py.

Next, set the environment variable OUT equal to the root of the directory tree created above.

Then the following command can be used to run the tests.

  ./run_all_test.sh linux


The tests will take between 15 and 30 minutes to complete and generate a significant amount of logs. The tests can be run in the background with the logs redirected using ./run_all_tests.sh linux &> results &.

When redirecting all of the logs from the test script being output to results, you can easily check the status by running grep -E "RUN|PASSED|FAILED".


Evergreen uses “drain” files to ensure only one application downloads an update at a time. To fake update contention, some tests create this file manually:

  • tests/abort_update_if_already_updating_test.sh
  • tests/load_slot_being_updated_test.sh
  • tests/racing_updaters_test.sh

Evergreen uses “app key” files to keep track of per-application state of an update. To fake changes to the per-application state of an update, some tests create, delete, or modify these files manually:

  • tests/update_works_for_only_one_app_test.sh
  • tests/valid_slot_overwritten_test.sh

To validate Evergreen behavior when there is not enough storage for an update, a temporary filesystem is used, only 10MiB in size. One test creates a symbolic link from the storage path to this filesystem, faking an “out of storage” situation:

  • tests/out_of_storage_test.sh