Separate populating the queue from working off the queue about ci-queue

[casperisfine]

It's already split off, here's how we initialize the queue right now:

  Minitest.queue = CI::Queue::Redis.new(
    TestGlobs.all_tests(seed: ENV['BUILDKITE_COMMIT']),
    build_id: build_id,
    worker_id: ENV.fetch('BUILDKITE_PARALLEL_JOB'),
    redis: CIRedis.connection,
    **queue_config,
  )

All queue implementations just stupidly take a list of strings (test identifiers). If we want to filter out parts of the tests, it can and should be done beforehand.

The only downside is that for resiliency purposes, all workers can potentially be elected master, which mean they all compute the list of tests, but only one actually get to populate the shared queue with it.

So if we were to have a costly way to reduce the list it would be a bit wasteful.

what do you think?

IMO if we want to filter out the tests, it should be the responsibility of a dedicated service which can hold state, record all tests runs results and refine it's heuristics based on that data.

e.g. curl https://example.com/commits/abcdef092332432/tests.txt.