### Description [Heroku CI](https://devcenter.heroku.com/articles/heroku-ci) augments standard buildpacks with a couple CI-specific steps (bin/test-compile and bin/test). They have about 6 languages supported currently and I'm sure it will take a while for third-party buildpacks to support these new steps, but if it takes off, it could be an easy way to get people started with CI without having to configure anything themselves. We already leverage buildpacks for auto deploy, how about leveraging it for zero-configuration CI? Note, Heroku CI also augments `app.json` with `scripts.test-setup` and `scripts.test`, and adds an `environments:test` way to declare addons needed during tests. We don't currently listen to `app.json` at all, but we could, if we wanted to have compatibility with Heroku CI for people who have gone beyond vanilla buildpack usage. `app.json` has a lot of the same goals as our `.gitlab-ci.yml`. ### Proposal * [x] Update `herokuish` with latest buildpacks * [x] Add test commands to `herokuish` (Note there already is a `test` command, with a different purpose.) * [ ] Make sure handling of "no tests" is reasonable (probably should no-op succeed rather than error) * [x] Add test commands to our auto deploy image * [ ] ~~Add test commands to Auto Deploy template~~ * [x] Add test commands to Auto DevOps template ### Links / references * Herokuish issue: https://github.com/gliderlabs/herokuish/issues/257 * Herokuish PR: https://github.com/gliderlabs/herokuish/pull/286 ### Test projects So far successfully tested on next projects: 1. Clojure, no db -> https://gitlab.com/dzaporozhets/clj-hello-world 1. Rails, Postgres -> https://gitlab.com/dzaporozhets/rails-hello-world 1. Nodejs, Express -> https://gitlab.com/dzaporozhets/express-hello-world 1. Java, Spring -> https://gitlab.com/dzaporozhets/spring-hello-world 1. Scale, Play -> https://gitlab.com/dzaporozhets/play-hello-world Build fails 1. Python, django -> https://gitlab.com/dzaporozhets/django-hello-world. Buildpack does not support `test` command 2. Ruby, no tests -> https://gitlab.com/dzaporozhets/sample-ruby-app/-/jobs/30607321