add deprecation message to rspec command

[doodzik]

This PR adds a message when the rspec test runner is invoked that it is deprecated.

reference https://github.com/Shopify/test-infra/issues/350

[wvanbergen]

I prefer adding this to the README.

This is going to be obnoxious for projects that use it. They will see it on every run. And if you have a large spec suite, you're not going to use that warning as a reasonto rewrite all of it to minitest.

Made changes based on the review.

[ianks]

Can this deprecation be re-considered? We are heavily reliant on ci-queue and RSpec and there is really no way for us to migrate to mini-test. Is it a problem with having maintainers? If so, I would be happy to help manage the load for RSpec. @jessicaxiejw @doodzik

[wvanbergen]

Hello @ianks. We are standardizing on minitest at Shopify, and hence won't be supporting the RSpec implementation anymore. We have no plans to remove the RSpec implementation any time soon though.

Short-term, we are happy to review and merge any bug fixes that you may contribute. Long-term, I think it is better for the minitest and rspec implementations to not share the same repository. We haven't really put a lot of thought into this "split" yet, but maybe you have ideas?

[agis]

Heads up: We are working on an alternative implementation (pretty similar to ci-queue) that focuses solely on RSpec and solves some additional issues we encountered while evaluating ci-queue. We've been gradually rolling it the past few weeks and it's been working great until now. It might be of interest to you, @ianks: rspecq.

[ArturT]

@ianks I work on a similar problem of running tests in parallel on CI. Recently for RSpec, I built an integration to auto split slow RSpec test files by test examples to run CI build faster.
https://knapsackpro.com/faq/question/how-to-split-slow-rspec-test-files-by-test-examples-by-individual-it

There are 2 ways to split tests static or dynamic with queue and it works for all ruby test runners and some JS test runners like Jest or Cypress. Here is more technical examples:
https://docs.knapsackpro.com/2020/how-to-speed-up-ruby-and-javascript-tests-with-ci-parallelisation
Maybe you find it useful.

[jamie]

We are standardizing on minitest at Shopify, and hence won't be supporting the RSpec implementation anymore.

Every so slightly offcopic, but is there any public discussion around what led Shopify to this decision? I'm rather curious as it does run contrary to larger community adoption.

[casperisfine]

No public discussion no, but in short it's simply that only a small minority of our repos was using rspec, so maintaining all our various tools (not just ci-queue) to work with both Minitest and RSpec wasn't really worth the amount of work it required.

No specific beef against RSpec, and I encourage anyone willing to fork ci-queue to make and maintain a RSpec version of it.