Wait for fanned-out search jobs in testing API

Commit 55bb078 wired `?wait=true` to
`EnqueueVaccinationsSearchInNHSJob.perform_now`,
but that job uses `perform_bulk` to fan out
per-patient `SearchVaccinationRecordsInNHSJob`s onto the
`immunisations_api_search` Sidekiq queue.
Those run async on workers, so the controller
returned 200 before any patient was actually searched —
defeating the point of the wait flag for end-to-end tests.

Poll the queue after `perform_now` returns and only
respond once it has drained (or after a 5-minute timeout).

Author: benilovj

app/controllers/api/testing/vaccinations_search_in_nhs_controller.rb

@@ -1,13 +1,32 @@
 # frozen_string_literal: true
 
 class API::Testing::VaccinationsSearchInNHSController < API::Testing::BaseController
+  POLL_INTERVAL = 0.25
+  POLL_TIMEOUT = 300
+
   def create
     if params[:wait].present?
       EnqueueVaccinationsSearchInNHSJob.perform_now
+      wait_for_search_jobs_to_complete
       render status: :ok
     else
       EnqueueVaccinationsSearchInNHSJob.perform_later
       render status: :accepted
     end
   end
+
+  private
+
+  # EnqueueVaccinationsSearchInNHSJob fans out to per-patient
+  # SearchVaccinationRecordsInNHSJob jobs via perform_bulk. Poll
+  # until Sidekiq workers have drained the queue so callers see
+  # updated patient statuses when the response arrives.
+  def wait_for_search_jobs_to_complete
+    queue = Sidekiq::Queue.new("immunisations_api_search")
+    deadline = Time.current + POLL_TIMEOUT
+
+    # rubocop:disable Style/ZeroLengthPredicate -- Sidekiq::Queue has no #empty?
+    sleep POLL_INTERVAL until queue.size.zero? || Time.current > deadline
+    # rubocop:enable Style/ZeroLengthPredicate
+  end
 end

spec/requests/api/testing/vaccinations_search_in_nhs_spec.rb

@@ -17,6 +17,9 @@
     context "with wait=true" do
       before do
         allow(EnqueueVaccinationsSearchInNHSJob).to receive(:perform_now)
+        allow(Sidekiq::Queue).to receive(:new).with(
+          "immunisations_api_search"
+        ).and_return(instance_double(Sidekiq::Queue, size: 0))
       end
 
       it "runs the job synchronously and responds with ok" do