Debugging Failing Tests and Test Pipelines

1. You are here:
2. Handbook
3. Engineering
4. Quality Department
5. Guidelines
6. Debugging Failing Tests and Test Pipelines

Maintained by:

On this page

• Overview
  • Scheduled QA test pipelines
• Triage overview
• Steps for debugging a QA test pipeline failure
  • 1. Initial analysis
  • 2. Create an issue
  • 3. Investigate the failure further
    • Checking Docker images
  • 4. Classify and triage the test failure
    • Stale test due to application change
    • Bug in the test
    • Bug in the application
    • Flaky Test
    • Failure due to test environment
• Following up on test failures
  • Fixing the test
  • Quarantining Tests
  • Quarantined test types
    • Examples
  • Dequarantining Tests
  • Re-evaluating tests
• Training Videos

Overview

These guidelines are intended to help you to investigate end-to-end test pipeline failures so that they can be properly addressed. This will involve analyzing each failure and creating an issue to report it. It might also involve fixing tests, putting them in quarantine, or reporting bugs in the application.

Scheduled QA test pipelines

The test pipelines run on a scheduled basis, and their results are posted to Slack. The following are the QA test pipelines that are monitored every day.

^Test pipelines also run against an Omnibus-GitLab Docker image that reflects the current release on staging.com. These are referred to in notifications as dev.gitlab.org:5005/gitlab/omnibus-gitlab/gitlab-ee:xxx

For each pipeline there is a notification of success or failure (except for master pipelines, which only report failures). If there's a failure, we use emoji to indicate the state of its investigation:

• The :eyes: emoji, to show you're investigating a failing pipeline.
• The :boom: emoji, when there's a new failure.
• The :fire_engine: emoji, when a failure is already reported.
• The :retry: emoji, when there's a system failure (e.g., Docker or runner failure).

Triage overview

• The DRI should decide in the first 20 minutes of analysis if the failure can be fixed or if a test has to be quarantined.
• In any case, the counterpart SET is kept informed about the issue.
• If the DRI finds that the issue can be fixed, they should spend not more than 2 hours in fixing the failure. Any test failure whose fix would take more than 2 hours should be quarantined.
• Please refer to the Quality Department pipeline triage rotation page to know who the current DRI is.

Steps for debugging a QA test pipeline failure

1. Initial analysis

Start with a brief analysis of the failure. The aim of this step is to make a quick decision about how much time you can spend investigating in each failure.

In the relevant Slack channel:

1. Apply the :eyes: emoji to indicate that you're investigating the failure(s).
2. Search for existing issues that have already been created with the failure::* label. By order of likelihood:
   1. failure::investigating
   2. failure::test-environment
   3. failure::broken-test
   4. failure::flaky-test
   5. failure::stale-test
3. If the issue has already been reported please use the existing issue to track the latest status.
4. If there is no existing issue for the failure, please create an issue using one of classification labels via the steps below.
5. If there's a system failure (e.g., Docker or runner failure), retry the job and apply the :retry: emoji. Read below for examples of system failures.
6. Adding a :fire_engine: emoji. It can be helpful to reply to the failure notification with a link to the issue(s), but this isn't always necessary, especially if the failures are the same as in the previous pipeline and there are links there.

Your priority is to make sure we have an issue for each failure. Each new failure should have an issue tracking its resolution.

If there are multiple failures we recommend that you identify whether each one is old (i.e., there is an issue open for it), or new. For each new failure, open an issue that includes only the required information. Once you have opened an issue for each new failure you can investigate each more thoroughly and act on them appropriately, as described in later sections.

The reason for reporting all new failures first is to allow faster discovery by engineers who may find the test failing in their own merge request test pipeline. If there is no open issue about that failure, the engineer will have to spend time trying to figure out if their changes caused it.

2. Create an issue

Please use this step if there are no issues created to capture the failure. If there is already an issue please skip this step.

1. Create an issue for the test or system failure (if retrying the job does not resolve the latter) in https://gitlab.com/gitlab-org/gitlab/issues using the QA failure template.
   • For system failures, it may make sense to open an issue in a different project such as Omnibus GitLab, GitLab QA, or GitLab Runner.
   • For staging environment-related failures, you can post a question in #infrastructure-lounge, or open an issue in the infrastructure project
   • Ask for help in #quality if you're unsure where to file the issue.
2. In the relevant Slack channel, add the :boom: emoji and reply to the failure notification with a link to the issue.

3. Investigate the failure further

The aim of this step is to understand the failure. The results of the investigation will also let you know what to do about the failure.

The following points can help with your investigation:

• Understand the intent of the test. Manually performing the test steps can help.
• Stack trace: The stack trace shown in the job's log is the starting point for investigating the test failure.
• Screenshots and HTML captures: These are available for download in the job's artifact for up to 1 week after the job run.
• QA Logs: These are also included in the job's artifact and are valuable for determining the steps taken by the tests before failing.
• Sentry logs for Staging: If staging tests fail due to a server error, there should be a record in Sentry. You can search for all unresolved staging errors linked to the gitlab-qa user with the query is:unresolved user:"username:gitlab-qa". However, note that some actions aren't linked to the gitlab-qa user, so they might only appear in the full unresolved list.
• Kibana logs for Staging: Various application logs are sent to Kibana, including Rails, Postgres, Sidekiq, and Gitaly logs.
• Reproducing the failure locally:
  • You can try running the test against your local GitLab instance to see if the failure is reproducible. E.g.:

  CHROME_HEADLESS=false bundle exec bin/qa Test::Instance::All http://localhost:3000 qa/specs/features/browser_ui/1_manage/project/create_project_spec.rb

  • Orchestrated tests are excluded by default. To run them, use -- --tag orchestrated before your file name. E.g.:

  bundle exec bin/qa Test::Instance::All http://localhost:3000 -- --tag orchestrated qa/specs/features/browser_ui/1_manage/project/create_project_spec.rb

  • Use the environment variable QA_DEBUG=true to enable logging output including page actions and Git commands.
  • You can also use the same docker image (same sha256 hash) as the one used in the failing job to run GitLab in a container on your local. In the logs of the failing job, search for Downloaded newer image for gitlab/gitlab-ce:nightly or Downloaded newer image for gitlab/gitlab-ee:nightly and use the sha256 hash just above that line. To run GitLab in a container on your local, the docker command similar to the one shown in the logs can be used. E.g.:

  docker run --publish 80:80 --name gitlab --net test --hostname localhost gitlab/gitlab-ce:nightly@sha256:<hash>

  • You can now run the test against this docker instance. E.g.:

  CHROME_HEADLESS=false bundle exec bin/qa Test::Instance::All http://localhost qa/specs/features/browser_ui/1_manage/project/create_project_spec.rb

  • Additional information about running tests locally can be found in the QA readme.
• Determine if the test is flaky: check the logs or run the test a few times. If it passes at least once but fails otherwise, it's flaky.

Checking Docker images

Sometimes tests may fail due to an outdated Docker image. To check if that's the case, follow the instructions below to see if specific merged code is available in a Docker image.

Checking test code (QA image)

If you suspect that certain test is failing due to the gitlab/gitlab-{ce|ee}-qa image being outdated, follow these steps:

1. Locally, run docker run -it --entrypoint /bin/sh gitlab/gitlab-ce-qa:latest to check for GitLab QA CE code, or docker run -it --entrypoint /bin/sh gitlab/gitlab-ee-qa:latest to check for GitLab QA EE code
2. Then, navigate to the qa directory (cd /home/qa/qa)
3. Finally, use cat to see if the code you're looking for is available in certain file (e.g., cat page/project/issue/show.rb)

Note if you need to check in another tag (e.g., nightly), change it in one of the scripts of step 1 above.

Checking application code

1. Locally, run docker run -it --entrypoint /bin/sh gitlab/gitlab-ce:latest to check for GitLab CE code, or docker run -it --entrypoint /bin/sh gitlab/gitlab-ee:latest to check for GitLab EE code
2. Then, navigate to the gitlab-rails directory (cd /opt/gitlab/embedded/service/gitlab-rails/)
3. Finally, use cat to see if the code you're looking for is available or not in a certain file (e.g., cat public/assets/issues_analytics/components/issues_analytics-9c3887211ed5aa599c9eea63836486d04605f5dfdd76c49f9b05cc24b103f78a.vue.)

Note if you want to check another tag (e.g., nightly) change it in one of the scripts of step 1 above.

4. Classify and triage the test failure

The aim of this step is to categorize the failure as either a stale test, a bug in the test, a bug in the application code, or a flaky test.

We use the following labels to capture the cause of the failure.

• ~"failure::investigating": Default label to apply at the start of investigation.
• ~"failure::stale-test": Stale test due to application change
• ~"failure::broken-test": Bug in the test
• ~"failure::flaky-test": Flaky test
• ~"failure::test-environment": Failure due to test environment
• ~bug: Bug in the application

Note: It might take a while for a fix to propagate to all environments. Be aware that a new failure could be related to a recently-merged fix that hasn't made it to the relevant environment yet. Similarly, if a known failure occurs but the test should pass because a fix has been merged, verify that the fix has been deployed to the relevant environment before attempting to troubleshoot further.

Stale test due to application change

The failure was caused by a change in the application code and the test needs to be updated.

• Include your findings in a note in the issue about the failure.
• Apply the ~"failure::stale-test" label.
• If possible, mention the merge request which caused the test to break, to keep the corresponding engineer informed.

See Quarantining Tests

Bug in the test

The failure was caused by a bug in the test code itself, not in the application code.

• Include your findings in a note in the issue about the failure.
• Apply the ~"failure::broken-test" label.

See Quarantining Tests

Bug in the application

The failure was caused by a bug in the application code.

• Include your findings in a note in the issue about the failure.
• Add the steps to reproduce the bug and expected/actual behavior.
• Apply the ~"bug" label, and cc-ing the corresponding Engineering Managers (EM), QEM, and SET.
• If there is an issue open already for the bug, mark the new issue as a duplicate of the original bug.
• Communicate the issue in the corresponding Slack channels.
• Do not quarantine the test immediately unless the bug won't be fixed quickly (e.g. if it is a minor/superficial bug). Instead, leave a comment in the issue for the bug asking if the bug can be fixed in the current release. If it can't, quarantine the test.
• When the reason for quarantining a test is because of a low severity bug in the code which will not be fixed in the upcoming couple of releases, add type: :bug in the quarantine tag.

To find the appropriate team member to cc, please refer to the Organizational Chart. The Quality Engineering team list and DevOps stage group list might also be helpful.

See Quarantining Tests

Flaky Test

The failure is due to flakiness in the test itself.

• Include your findings in a note in the issue about the failure.
• Apply the ~"failure::flaky-test" label.

Flakiness can be caused by a myriad of problems. Examples of underlying problems that have caused us flakiness include:

• Not waiting appropriately for pages to load or transitions from one state to another to complete.
• Animations preventing tests from interacting with elements.
• Non-independent tests (i.e. test A passes when run first, but fails otherwise).
• Actions not completing successfully (e.g. logging out).

For more details, see the list with example issues in our Testing standards and style guidelines section on Flaky tests.

See Quarantining Tests

Failure due to test environment

The failure is due external factors outside the scope of the test. This could be due to environments, deployment hang-ups, or upstream dependencies.

• Include your findings in a note in the issue about the failure.
• Apply the ~"failure::test-environment" label.

A job may fail due to infrastructure or orchestration issues that are not related to any specific test. In some cases these issues will fail a job before tests are ever executed. Some examples of non-test related failures include:

• Failed to download Docker image
• Failed to complete orchestration of a Geo cluster
• CI runner timeouts
• 500 error while uploading job artifacts

Following up on test failures

Fixing the test

If you've found that the test is the cause of the failure (either because the application code was changed or there's a bug in the test itself), it will need to be fixed. This might be done by another SET or by yourself. However, it should be fixed as soon as possible. In any case, the steps to follow are as follows:

• Create a merge request (MR) with the fix for the test failure.
• Apply the ~"Pick into auto-deploy" and ~P1 labels.

If the test was flaky:

• Confirm that the test is stable by ensuring it passes 3 to 5 times while in quarantine.

Note The number of passes needed to be sure a test is stable is just a suggestion. You can use your judgement to pick a different threshold.

If the test was in quarantine, remove it from quarantine.

Quarantining Tests

Note We should be very strict about quarantining tests. Quarantining a test is very costly and poses a higher risk because it allows tests to fail without blocking the pipeline, which could mean we miss new failures. The aim of quarantining the tests is not to get back a green pipeline, but rather to reduce the noise (due to constantly failing tests, flaky tests, etc.) so that new failures are not missed.

Following are the steps to quarantine a test:

• Add the :quarantine metadata to the test with a link to the issue (see quarantined test types)

Note If the example has a before hook, the quarantine metadata should be assigned to the outer context to avoid running the before hook

• The merge request shall have the labels: ~"Quality", ~"QA", ~"bug", ~"Pick into auto-deploy".
• The merge request may have stage or group labels. E.g. ~"devops::create" ~"group::source code".
• The merge request shall have the current milestone.

To be sure that the test is quarantined quickly, ask in the #quality Slack channel for someone to review and merge the merge request, rather than assigning it directly.

Here is an example quarantine merge request.

Quarantined test types

If a test is placed under quarantine, it is important to specify why. By specifying a quarantine type we can see quickly the reason for the quarantine.

The report accepts custom quarantine types, but we follow the below guidelines for the most commonly recurring reasons.

Note Be sure to attach an issue to the quarantine metadata if there is a related issue or merge request for maximum visibility

Examples

it 'is flaky', quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/12345'
it 'is flaky', quarantine: { issue: 'https://gitlab.com/gitlab-org/gitlab/issues/12345', type: :flaky }
it 'is due to a bug', quarantine: {
                        issue: 'https://gitlab.com/gitlab-org/gitlab/issues/12345',
                        type: :bug
                      }
it 'is being worked on', quarantine: { type: :investigating }
context 'when these tests rely on another MR', quarantine: {
                                                 type: :waiting_on,
                                                 issue: 'https://gitlab.com/gitlab-org/gitlab/merge_requests/12345'
                                               }

Dequarantining Tests

Failing to dequarantine tests periodically reduces the effectiveness of the test suite. Hence, the tests should be dequarantined on or before the due-date mentioned in the corresponding issue.

Before dequarantining a test:

• If the test failure was originally discovered in nightly, MR or master pipeline, please make sure that the test passes on your local against GDK with latest code and that it has passed a few times in the nightly pipeline's quarantine job for that test.
• If the test failure was originally discovered in staging, canary or production pipeline, please make sure that the test passes in the CI pipeline against that environment. You can trigger a CI pipeline against a live environment by clicking "Run Pipeline" button on the staging, canary or production pipelines page and setting the RELEASE variable to the release that has your changes. See Running Gitlab-QA pipeline against a specific GitLab release for instruction on finding your release version created and tagged by the Omnibus pipeline.

To dequarantine a test:

• Create a merge request that removes the :quarantine tag.
• Close the issue created as part of the quarantining process.

As with quarantining a test, you can ask in the #quality Slack channel for someone to review and merge the merge request, rather than assigning it.

Re-evaluating tests

If the due date of a failing test issue is reached, you should re-evaluate if the failing test should really be covered at the end-to-end test level, or if it should be covered in a lower level of the testing levels pyramid.

If you decide to delete the test, open a merge request to delete it and close the test failure issue. In the MR description or comment, mention the stable counterpart SET for the test's stage for their awareness. Then open a new issue to cover the test scenario in a different test level.

If you decide the test is still valuable but don't want to leave it quarantined, you could replace :quarantine with :skip, which will skip the test entirely (i.e., it won't run even in jobs for quarantined tests). That can be useful when you know the test will continue to fail for some time (e.g., at least the next milestone or two).

Training Videos

Two videos walking through the triage process were recorded and uploaded to the GitLab Unfilitered YouTube channel.

• Quality Team: Failure Triage Training - Part 1
  • Covers the basics of investigating pipeline failures locally.
• Quality Team: Failure Triage Training - Part 2
  • Continued discussion with a focus on using Docker containers that were used in the pipeline that failed.