Document stages and jobs.

docs/gitlab/drupal/index.md

@@ -365,12 +365,65 @@ Rules, when the job should run:
 
 #### Test PHPUnit
 
+This job uses [PHP Unit](../../dev_tools/test.md#unitkernelfunctional-testing) and stores the artefacts in `phpunit`.
+
+Rules, when the job should run:
+
+- the code style tests are enabled by `$DISABLE_CI_TEST_PHPUNIT` != "1"
+
 
 #### Test Backstop
 
+This job uses [Backstop](../../dev_tools/test.md#unitkernelfunctional-testing) and stores the artefacts in `backstop`.
+
+The following jobs must run before successfully. Some are optional, which means, if they exist, this job waits for them
+to complete:
+
+- [Build Site](#build-site)
+- [Build Theme](#build-theme)
+    - uses its artefacts
+    - optional
+- [Import DB](#import-db)
+    - optional 
+- [Import DB NG](#import-db-ng)
+    - optional
+- [Import Local DB](#import-local-db)
+    - optional
+- [Update DB](#update-db)
+    - optional
+
+Rules, when the job should run:
+
+- the backstop tests are enabled by `$DISABLE_CI_TEST_BACKSTOP` != "1"
+
 
 #### Test Cypress E2E
 
+This job uses [Cypress](../../dev_tools/test.md#cypress) and stores the artefacts in `cypresse2e`. The tests
+are executed in headless mode.
+
+The following jobs must run before successfully. Some are optional, which means, if they exist, this job waits for them
+to complete:
+
+- [Build Site](#build-site)
+- [Build Theme](#build-theme)
+    - uses its artefacts
+    - optional
+- [Import DB](#import-db)
+    - optional
+- [Import DB NG](#import-db-ng)
+    - optional
+- [Import Local DB](#import-local-db)
+    - optional
+- [Update DB](#update-db)
+    - optional
+- [Test Backstop](#test-backstop)
+    - optional
+
+Rules, when the job should run:
+
+- the cypress tests are enabled by `$DISABLE_CI_TEST_CYPRESSE2E` != "1"
+
 #### Internal Test Stages
 
 Every test stage needs internal reoccurring definitions.