Challenge 3: Testing the Job — Solution

# spec/jobs/resize_image_job_spec.rb
RSpec.describe ResizeImageJob, type: :job do
  it "enqueues the job with the correct image_id" do
    image = create(:image)
    expect { ResizeImageJob.perform_later(image.id) }
      .to have_enqueued_job.with(image.id)
  end

  it "calls resize! on the image when performed" do
    image = create(:image)
    expect(image).to receive(:resize!)
    allow(Image).to receive(:find).with(image.id).and_return(image)

    ResizeImageJob.perform_now(image.id)
  end
end

=begin
Notes:
- The first example checks only that enqueuing happened with the right
  argument -- have_enqueued_job.with(image.id) -- without running perform at
  all, matching the chapter's "was it enqueued" vs "does it work when it
  runs" split.
- The second example stubs Image.find to return the exact in-memory image
  instance (so the expectation on that specific object can be set), then
  sets expect(image).to receive(:resize!) before calling perform_now --
  RSpec's message expectation confirms resize! was actually called during
  the job's execution, not just that no error was raised.
- perform_now runs the job's perform method synchronously and immediately,
  which is what lets this example assert on resize! being called within the
  same test, rather than needing an async worker process to actually
  execute it.
=end