End-to-end Testing

What is end-to-end testing?

End-to-end (e2e) testing is a strategy used to check whether your application works as expected across the entire software stack and architecture, including integration of all micro-services and components that are supposed to work together.

How do we test GitLab?

We use Omnibus GitLab to build GitLab packages and then we test these packages using the GitLab QA orchestrator tool to run the end-to-end tests located in the qa directory.

Additionally, we use the GitLab Development Kit (GDK) as a test environment that can be deployed quickly for faster test feedback.

Testing nightly builds

We run scheduled pipelines each night to test nightly builds created by Omnibus. You can find these pipelines at https://gitlab.com/gitlab-org/gitlab/-/pipeline_schedules (requires the Developer role). Results are reported in the #e2e-run-master Slack channel.

Testing staging

We run scheduled pipelines each night to test staging. You can find these pipelines at https://gitlab.com/gitlab-org/quality/staging/pipelines (requires the Developer role). Results are reported in the #e2e-run-staging Slack channel.

Testing code in merge requests

Using the test-on-omnibus job

It is possible to run end-to-end tests for a merge request by triggering the e2e:test-on-omnibus manual action in the qa stage (not available for forks).

This runs end-to-end tests against a custom EE (with an Ultimate license) Docker image built from your merge request’s changes.

Manual action that starts end-to-end tests is also available in gitlab-org/omnibus-gitlab merge requests.

How does it work?

Currently, we are using multi-project pipeline-like approach to run end-to-end pipelines against Omnibus GitLab.

graph TB A1 -.->|once done, can be triggered| A2 A2 -.->|1. Triggers an `omnibus-gitlab-mirror` pipeline<br>and wait for it to be done| B1 B2[`Trigger-qa` stage<br>`Trigger:qa-test` job] -.->|2. Triggers a `gitlab-qa-mirror` pipeline<br>and wait for it to be done| C1 subgraph " `gitlab-org/gitlab` pipeline" A1[`build-images` stage<br>`build-qa-image` and `build-assets-image` jobs] A2[`qa` stage<br>`e2e:test-on-omnibus` job] end subgraph " `gitlab-org/build/omnibus-gitlab-mirror` pipeline" B1[`Trigger-docker` stage<br>`Trigger:gitlab-docker` job] -->|once done| B2 end subgraph " `gitlab-org/gitlab-qa-mirror` pipeline" C1[End-to-end jobs run] end
  1. In the gitlab-org/gitlab pipeline:
    1. Developer triggers the e2e:test-on-omnibus manual action (available once the build-qa-image and build-assets-image jobs are done), that can be found in GitLab merge requests. This starts a e2e test child pipeline.
    2. E2E child pipeline triggers a downstream pipeline in gitlab-org/build/omnibus-gitlab-mirror and polls for the resulting status. We call this a status attribution.
  2. In the gitlab-org/build/omnibus-gitlab-mirror pipeline:
    1. Docker image is being built and pushed to its container registry.
    2. Once Docker images are built and pushed jobs in test stage are started
  3. In the Test stage:
    1. Container for the Docker image stored in the gitlab-org/build/omnibus-gitlab-mirror registry is spun-up.
    2. End-to-end tests are run with the gitlab-qa executable, which spin up a container for the end-to-end image from the gitlab-org/gitlab registry.
note
You may have noticed that we use gitlab-org/build/omnibus-gitlab-mirror instead of gitlab-org/omnibus-gitlab. This is due to technical limitations in the GitLab permission model: the ability to run a pipeline against a protected branch is controlled by the ability to push/merge to this branch. This means that for developers to be able to trigger a pipeline for the default branch in gitlab-org/omnibus-gitlab, they would need to have the Maintainer role for this project. For security reasons and implications, we couldn’t open up the default branch to all the Developers. Hence we created this mirror where Developers and Maintainers are allowed to push/merge to the default branch. This problem was discovered in https://gitlab.com/gitlab-org/gitlab-qa/-/issues/63#note_107175160 and the “mirror” work-around was suggested in https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/4717. A feature proposal to segregate access control regarding running pipelines from ability to push/merge was also created at https://gitlab.com/gitlab-org/gitlab/-/issues/24585.

For more technical details on CI/CD setup and documentation on adding new test jobs to e2e:test-on-omnibus pipeline, see e2e:test-on-omnibus setup documentation.

Using the test-on-gdk job

The e2e:test-on-gdk job is run automatically in most merge requests, which triggers a child-pipeline that builds and installs a GDK instance from your merge request’s changes, and then executes end-to-end tests against that GDK instance.

How does it work?

In the gitlab-org/gitlab pipeline:

  1. The build-gdk-image job uses the code from the merge request to build a Docker image for a GDK instance.
  2. The e2e:test-on-gdk trigger job creates a child pipeline that executes the end-to-end tests against GDK instances launched from the image built in the previous job.

For more details, see the documentation for the e2e:test-on-gdk pipeline.

With merged results pipelines

In a merged results pipeline, the pipeline runs on a new ref that contains the merge result of the source and target branch.

The end-to-end tests on a merged results pipeline would use the new ref instead of the head of the merge request source branch.

graph LR A["x1y1z1 - master HEAD"] B["d1e1f1 - merged results (CI_COMMIT_SHA)"] A --> B B --> C["Merged results pipeline"] C --> D["E2E tests"]
Running custom tests

The existing scenarios that run in the downstream gitlab-qa-mirror pipeline include many tests, but there are times when you might want to run a test or a group of tests that are different than the groups in any of the existing scenarios.

For example, when we dequarantine a flaky test we first want to make sure that it’s no longer flaky. We can do that by running _ee:quarantine manual job. When selecting the name (not the play icon) of manual job, you are prompted to enter variables. You can use any of the variables that can be used with gitlab-qa as well as these:

Variable Description
QA_SCENARIO The scenario to run (default Test::Instance::Image)
QA_TESTS The tests to run (no default, which means run all the tests in the scenario). Use file paths as you would when running tests via RSpec, for example, qa/specs/features/ee/browser_ui would include all the EE UI tests.
QA_RSPEC_TAGS The RSpec tags to add (default --tag quarantine)

For now, manual jobs with custom variables don’t use the same variable when retried, so if you want to run the same tests multiple times, specify the same variables in each custom-parallel job (up to as many of the 10 available jobs that you want to run).

Selective test execution

In order to limit amount of tests executed in a merge request, dynamic selection of which tests to execute is present. Algorithm of which tests to run is based on changed files and merge request labels. Following criteria determine which tests will run:

  1. Changes in qa framework code would execute the full suite
  2. Changes in particular _spec.rb file in qa folder would execute only that particular test. In this case knapsack will not be used to run jobs in parallel.
  3. Merge request with backend changes and label devops::manage would execute all e2e tests related to manage stage. Jobs will be run in parallel in this case using knapsack.

Overriding selective test execution

To override selective test execution and trigger the full suite, label pipeline:run-all-e2e should be added to particular merge request.

Skipping end-to-end tests

In some cases, it may not be necessary to run the end-to-end test suite.

Examples could include:

  • ~"Stuff that should Just Work"
  • Small refactors
  • A small requested change during review, that doesn’t warrant running the entire suite a second time

Skip running end-to-end tests by applying the pipeline:skip-e2e label to the merge request.

caution
There is a risk in skipping end-to-end tests. Use caution and discretion when applying this label. The end-to-end test suite is the last line of defense before changes are merged into the default branch. Skipping these tests increases the risk of introducing regressions into the codebase.

Run tests in parallel

To run tests in parallel on CI, the Knapsack gem is used. Knapsack reports are generated automatically and stored in the GCS bucket knapsack-reports in the gitlab-qa-resources project. The KnapsackReport helper handles automated report generation and upload.

Test metrics

For additional test health visibility, use a custom setup to export test execution results to your InfluxDb instance, and visualize results as Grafana dashboards.

Provisioning

Provisioning of all components is performed by the engineering-productivity-infrastructure project.

Exporting metrics in CI

Use these environment variables to configure metrics export:

Variable Required Information
QA_INFLUXDB_URL true Should be set to https://influxdb.quality.gitlab.net. No default value.
QA_INFLUXDB_TOKEN true InfluxDB write token that can be found under Influxdb auth tokens document in Gitlab-QA 1Password vault. No default value.
QA_RUN_TYPE false Arbitrary name for test execution, like e2e:test-on-omnibus. Automatically inferred from the project name for live environment test executions. No default value.
QA_EXPORT_TEST_METRICS false Flag to enable or disable metrics export to InfluxDB. Defaults to false.
QA_SAVE_TEST_METRICS false Flag to enable or disable saving metrics as JSON file. Defaults to false.

Test reports

Allure report

For additional test results visibility, tests that run on pipelines generate and host Allure test reports.

The QA framework is using the Allure RSpec gem to generate source files for the Allure test report. An additional job in the pipeline:

  • Fetches these source files from all test jobs.
  • Generates and uploads the report to the S3 bucket gitlab-qa-allure-report located in AWS group project eng-quality-ops-ci-cd-shared-infra.

A common CI template for report uploading is stored in allure-report.yml.

Merge requests

When these tests are executed in the scope of merge requests, the Allure report is uploaded to the GCS bucket and comment is added linking to their respective reports.

Scheduled pipelines

Scheduled pipelines for these tests contain a generate-allure-report job under the Report stage. They also output a link to the current test report.

Each type of scheduled pipeline generates a static link for the latest test report according to its stage:

How do you run the tests?

If you are not testing code in a merge request, there are two main options for running the tests. If you want to run the existing tests against a live GitLab instance or against a pre-built Docker image, use the GitLab QA orchestrator. See also examples of the test scenarios you can run via the orchestrator.

On the other hand, if you would like to run against a local development GitLab environment, you can use the GitLab Development Kit (GDK). Refer to the instructions in the QA README and the section below.

Running tests that require special setup

Learn how to perform tests that require special setup or consideration to run on your local environment.

How do you write tests?

Before you write new tests, review the GitLab QA architecture.

After you’ve decided where to put test environment orchestration scenarios and instance-level scenarios, take a look at the GitLab QA README, the GitLab QA orchestrator README, and the already existing instance-level scenarios.

Consider not writing an end-to-end test

We should follow these best practices for end-to-end tests:

  • Do not write an end-to-end test if a lower-level feature test exists. End-to-end tests require more work and resources.
  • Troubleshooting for end-to-end tests can be more complex as connections to the application under test are not known.

Continued reading:

Where can you ask for help?

You can ask question in the #test-platform channel on Slack (GitLab internal) or you can find an issue you would like to work on in the gitlab issue tracker, or the gitlab-qa issue tracker.