Extend documentation on end-to-end integration tests

doc/development/testing_guide/end_to_end_tests.md

@@ -20,23 +20,56 @@ You can find these nightly pipelines at [GitLab QA pipelines page][gitlab-qa-pip
 
 ### Testing code in merge requests
 
-It is also possible to trigger packages build and [GitLab QA pipeline][gitlab-qa-pipelines]
-using a manual action that should be present in the merge request widget on
-your merge request. Look for `package-qa` manual action.
+It is also possible to trigger build of GitLab packages and then pass these
+package to GitLab QA to run tests in a [pipeline][gitlab-qa-pipelines].
+
+Developers can trigger a `package-qa` manual action, that should be present in
+the merge request widget in your merge request.
+
+It is possible to trigger Gitlab QA pipeline from merge requests in GitLab CE
+and GitLab EE, but QA triggering manual action is also available in the Omnibus
+GitLab project as well.
 
 Below you can read more about how to use it and how does it work.
 
-## How does it work?
+#### How does it work?
+
+Currently, we are _multi-project pipeline_-like approach to run QA pipelines.
+
+1. Developer triggers manual action in the CE or EE merge request, that starts
+a chain of pipelines.
+1. Triggering this action enqueues a new CI job that is going to be picked by a
+runner.
+1. The script, that is being executed, triggers a pipeline in GitLab Omnibus
+projects, and waits for the resulting status. We call it _status attribution_.
+1. GitLab packages are being built in the pipeline started in Omnibus. Packages
+are going to be sent to Container Registry.
+1. When packages are ready, and available in the registry, a final step in the
+pipeline that is now running in Omnibus triggers a new pipeline in the GitLab
+QA project. It also waits for the resulting status.
+1. GitLab QA pulls images from the registry, spins-up containers and runs tests
+against test environment that has been just orchestrated.
+1. The result of GitLab QA pipeline is being propagated upstream, through
+Omnibus, to CE / EE merge request.
 
-We are using _multi-project pipelines_ to run end-to-end tests.
+#### How do I write tests?
 
-## How do I test my code?
+In order to write new tests, you first need to learn more about GitLab QA
+architecture. There is some documentation about it in GitLab QA project
+[here][gitlab-qa-architecture].
 
-## How do I contribute?
+Once you decided we to put test environment orchestration scenarios and
+instance specs, take a looks at [relevant documentation][instance-qa-readme]
 
 ## Where can I ask for help?
 
+You can ask question in `#qa` channel on Slack (GitLab internal) or you can
+find an issue you would like to work on in [the issue tracker][gitlab-qa-issues]
+and start a new discussion there.
 
 [omnibus-gitlab]: https://gitlab.com/gitlab-org/omnibus-gitlab
 [gitlab-qa]: https://gitlab.com/gitlab-org/gitlab-qa
 [gitlab-qa-pipelines]: https://gitlab.com/gitlab-org/gitlab-qa/pipelines
+[instance-qa-readme]: https://gitlab.com/gitlab-org/gitlab-ce/tree/master/qa/README.md
+[gitlab-qa-architecture]: https://gitlab.com/gitlab-org/gitlab-qa/blob/master/docs/architecture.md
+[gitlab-qa-issues]: https://gitlab.com/gitlab-org/gitlab-qa/issues

doc/development/testing_guide/index.md

@@ -67,8 +67,8 @@ Everything you should know about how to test Rake tasks.
 
 ## [End-to-end tests](end_to_end_tests.md)
 
-Everything you should know about how to run end-to-end tests, also known as
-[GitLab QA][gitlab-qa] tests.
+Everything you should know about how to run end-to-end tests using
+[GitLab QA][gitlab-qa] testing framework.
 
 ---