Testing a batch with Rails test helpers and :test adapter

[maxim]

I'm using :test adapter, Minitest, and Rails test helpers (good_job 4.8.2, rails 8.0.1). It's been working very well. Now I introduced a batch for the first time, like this:

class JobStarter
  def self.start_jobs
    GoodJob::Batch.enqueue(on_finish: FinishJob, some_arg: some_arg) do
      Model.find_each { |model| NestedJob.perform_later(model) }
    end
  end
end

The tests for jobs being enqueued work well:

require 'test_helper'

class JobStarterTest < ActionDispatch::IntegrationTest
  test 'enqueues correct jobs' do
    freeze_time

    JobStarter.start_jobs
    models = Model.all.to_a

    assert_enqueued_with job: NestedJob, args: [models[0]]
    assert_enqueued_with job: NestedJob, args: [models[1]]
    # ...
  end
end

However, I noticed that the FinishJob is enqueued alongside the NestedJobs. Is that intentional?

The main question: How can I test that the FinishJob will be called at the end of NestedJobs, with the correct arguments, with this setup?

[bensheldon]

To test batches, you'll need to use a GoodJob adapter (the GoodJob Inline adapter is intended to be usable in tests), not the Active Job :test adapter.

Aside: You're seeing the FinishJob immediately run because the Batch logic only detects when jobs are enqueued to a GoodJob Adapter, so by its math, there aren't any enqueued jobs, so it triggers the on_finish job.

I'm not very familiar with minitest patterns, but this is what I have in my RSpec projects; the intent being to use test setup to configure which adapter to use:

# spec/support/active_job.rb

RSpec.configure do |config|
  config.include ActiveJob::TestHelper

  config.around do |example|
    original_queue_adapter = ActiveJob::Base.queue_adapter
    if example.metadata[:active_job]
      ActiveJob::Base.queue_adapter = :test
      example.run
      clear_enqueued_jobs
      clear_performed_jobs
    elsif example.metadata[:good_job]
      ActiveJob::Base.queue_adapter = :good_job # Inline mode is default in Rails.env.test?
      example.run
    else
      ActiveJob::Base.queue_adapter = :inline
      example.run
    end
  ensure
    ActiveJob::Base.queue_adapter = original_queue_adapter
  end

  config.after do
    GoodJob.capsule.shutdown
  end
end

[maxim]

Makes sense. I was trying to avoid this kind of switching because in Minitest I'm leaning on multi-process parallelism. That said, in multi-process, the switching might actually be acceptable, since each process would still have its own globals/configs (I think).

[maxim]

Unfortunately, it's very awkward in my case to make it inline.

The top level jobs (NestedJob) enqueue further jobs in their perform. Those further jobs are irrelevant to this test, because only top level jobs need to finish for batch to be considered finished. However, because these further jobs create transactions incompatible with transactional tests, and they're also executed inline, they break my test. Normally, when I test them in isolation, I pass a parameter into them to disable the incompatible transaction.

So I have to either create a global config for disabling transactions in those "further" jobs, or stub out those jobs somehow entirely. Not ideal.

I know batch functionality is always tricky, and people run into all kinds of weird and quirky issues when being clever with them, but I think ideally we would allow them to support jobs enqueued via test adapter, to support a workflow similar to this:

GoodJob::Batch.enqueue(on_finish: FinishJob) do
  NestedJob.perform_later(1)
  NestedJob.perform_later(2)
end

assert_enqueued_with job: NestedJob, args: [1]
assert_enqueued_with job: NestedJob, args: [2]

ActiveJob::Base.queue_adapter.enqueued_jobs.reject! { _1['job_class'] == 'UnwantedJob' }

perform_enqueued_jobs

assert_enqueued_with job: FinishJob

Not sure how difficult this might be. For now I will try to stub out those unwanted jobs.

P.S. By the way, I tried to instantiate ActiveJob jobs myself, and use batch.add(jobs) to make sure it definitely registers them, but batch still got enqueued immediately.

[maxim]

What's interesting is that even just trying to match this enqueued FinishJob, it keeps failing:

assert_enqueued_with job: FinishJob, args: [GoodJob::BatchRecord.last.to_batch, {event: :finish}]

This refuses to match it, even though the batch object is identical, and the event seems correct. 🤔