Added gitlab-export upgrade test plan

Added standard test plan to be used when bumping the gitlab-exporter
version.

Author: Andrew Patterson

test-plans/index.md

@@ -3,6 +3,7 @@
 ## Updating components
 
 <!-- Keep this list sorted alphabetically. -->
+- [gitlab-exporter](upgrade-gitlab-exporter-testplan.md)
 - [golang](upgrade-golang-testplan.md)
 - [go-crond](upgrade-go-crond-testplan.md)
 - [Mattermost](upgrade-mattermost-testplan.md)

test-plans/upgrade-gitlab-exporter-testplan.md

@@ -0,0 +1,33 @@
+# `gitlab-exporter` component upgrade test plan
+
+<!-- Copy and paste the following into your MR description. -->
+## Test plan
+
+- [ ] Check `gitlab-exporter` project repository for potential breaking changes at https://gitlab.com/gitlab-org/ruby/gems/gitlab-exporter.
+
+- [ ] Green pipeline with `Trigger:ee-package` and `build-package-on-all-os`.
+
+- [ ] `gitlab-exporter` starts. Run `sudo gitlab-ctl status gitlab-exporter` and check output
+  to ensure `gitlab-exporter` started successfully.
+
+  ```shell
+  sudo gitlab-ctl status gitlab-exporter
+  ```
+
+- [ ] Check exporter version. Run `/opt/gitlab/embedded/bin/gem list gitlab-exporter`
+
+  ```shell
+  /opt/gitlab/embedded/bin/gem list gitlab-exporter
+  ```
+
+- [ ] Check that `gitlab-exporter` endpoint can be queried.
+
+  ```shell
+  curl --silent http://localhost:9168/metrics | head -n5
+  ```
+
+- [ ]  Check that prometheus scrapes `gitlab_exporter_database`, `gitlab_exporter_ruby` and `gitlab_exporter_sidekiq` by poking metrics endpoint.
+
+  ```shell
+  curl --silent http://localhost:9090/metrics | grep gitlab_exporter
+  ```