Getting Code Reviews for Tast Tests (go/tast-reviews)


To submit a Tast test change, please follow the following steps.

Firstly, do a self-review by going through the self-review checklist below. This will save your time by avoiding typical code review comments in the later step.

Once the self-review is done, send your change to the following two sets of reviewers:

  1. Test owners. If your change modifies an existing test, send it to one of the owners of the test (those listed in the Contacts field of the test declaration, excluding yourself). If your change introduces a new test, send it to your team member(s) who will co-own the test. Getting reviews from the test owners makes sure the change is good from the perspective of feature experts (details).

  2. Tast reviewers. Send your change to In a few minutes, the code review is assigned to one or more Tast reviewers using the gwsq bot. Getting reviews from the Tast reviewers makes sure the change is good from the perspective of Tast test experts (details).

After getting LGTM from both reviewers, submit the change via the Commit Queue.

Self-review checklist

Stabilize existing tests before adding new tests

As announced on the tast-users list, we have a policy that teams cannot add additional mainline tests until their existing informational tests have been stabilized and promoted to critical tests. Any new mainline test being added must have a clear plan for being promoted to a critical test.

New test authors should start out by stabilizing an existing informational test. Doing so will expose them to Tast coding conventions, making it easier to write new code in the future.

Associate changes to bug tracker issues

All Tast test changes should be associated with bug tracker issues (typically on the Buganizer). When adding a new test, it is recommended to file an issue to track promoting the test and using it to track flakiness issues that need to be resolved.

Do not make large changes

(See also go/small-cls)

If you are working on a large test, don't send the entire test out as a single, gigantic change. Split your changes into smaller changes that can be submitted separately.

Changes that consist of small, focused changes are always easier and faster to review than large, complicated changes. The length of a code review increases much faster than linearly with the size of the change.

If your change is only large because of test data (e.g. baseline information about expected processes or files), it's fine to keep it all together.

Run repo upload hooks

Tast repositories are configured to run many linters (gofmt, goimports, go vet, golint and tast-lint) as repo upload hooks to find obvious mistakes and style guide violations before time-consuming manual code reviews.

Except for WIP changes, always make sure to run repo upload hooks. Changes failing to pass lint checks may not be reviewed.

Run unit tests

Unit tests are not run automatically in repo upload hooks for technical reasons. You need to run them manually by the following command in the ChromeOS chroot:

~/trunk/src/platform/tast/ -T

CLs breaking unit tests are rejected by the Commit Queue.

Start a CQ dry run

In the Gerrit UI, set the Commit-Queue+1 label to start a CQ dry run for your change. You do not have to wait for the dry run to finish before sending code reviews to reviewers.

Check common code review comments

Check the following documents for the most common comments made during code reviews.

Verify Need for Lacros Variant

If a test utilizing the ‘chrome’ software dependency is modified or added the author needs to specify if a Lacros variant of the test is required. If a Lacros variant is needed, the author should add the Lacros variant of the test as part of the same review including the new/modified Ash-chrome test. The Ash-chrome test should then set the ‘LacrosStatus’ field to ‘LacrosVariantExists’.

If it is not possible to add a Lacros variant at review time, the ‘LacrosStatus’ field should be set to ‘LacrosVariantNeeded’.

If no Lacros variant is required, ‘LacrosStatus’ field should be set to ‘LacrosVariantUnneeded’.

New tests should never be set to ‘LacrosVariantUnknown’. Either the Lacros variant of the test should be added, or value set to ‘LacrosVariantUnneeded’.


Why are test owner reviews required?

Test owner reviews make sure your change is good from the perspective of feature experts.

Test owners know the tested feature a lot better than Tast reviewers, obviously.

Why are Tast reviewer reviews required?

Tast reviewer reviews make sure your change is good from the perspective of Tast test experts.

Tast reviewers are engineers from various teams in ChromeOS who have experience with writing and reviewing Tast tests. Their review insures that tests are written using learned best practices for test execution speed, stability and maintainability.

Why are all Tast tests owned by Tast team, not by my team?

Tast tests are in fact owned by the team listed in the Contacts field, not by the Tast team.

It is simply due to technical reasons that the tast-tests repository‘s OWNERS file lists Tast reviewers only. Changes to a test should be reviewed by both the owning person/team listed in the test’s Contacts field and Tast reviewers.

Tests are failing in the Commit Queue. Can I skip Tast reviewer reviews for demoting/disabling them?

Yes. In the case of emergency, please feel free to add Exempt-From-Owner-Approval: <reason> line to the change description to bypass Tast reviewer reviews.

In any case, please remember to file a tracking bug for demotion/disablement and CC the change/bug to the test contacts listed in the Contacts field. If you need to chump a change, please get an approval from the sheriffs and leave a comment in Gerrit for reference.

Can I send changes to a specific Tast reviewer?

Yes in some cases.

You can send changes to a specific Tast reviewer if you contact the reviewer in advance and they say okay.

Also, when you are sending a stack of related changes to reviews, you may send only the first change to tast-owners@ and rest to the same reviewer.

I am a Tast reviewer. Do I need approvals from other Tast reviewers for my own changes?

No, you do not need approvals from other Tast reviewers. But please make sure to get LGTM from a test owner (or someone who knows the context if you are also a test owner).

How can I become a Tast reviewer?

Please write and review Tast changes to get used to Go, Tast and integration test best practices in general. Typically one writes more than 5 non-trivial changes before feeling familiar with Tast.

Once you feel ready to go, please send a mail to to join shadow reviews. See go/tast-shadow-review for details of the process. Upon graduating from shadow reviews, you will be added to Tast reviewers.