Replace too long list of arguments with keywords

Rubocop was complaining about too many arguments. But
`ApplicationJob#perform` needs all arguments handled in one call. While
we could allow the `perform` method generally to have more arguments,
there could be other methods called `perform` which should still be
scrutinised. Instead, it seems acceptable to me to have more arguments
as long as they are clearly named as keyword arguments. Rails uses this
a lot to document all options including their default values, for
example in Active Storage. It's better then bundling several arguments
in an undocumented hash just to reduce the number of given arguments.

And once we upgraded to Ruby 3.1, we can clean the method calls up as
well. `call(user: user)` becomes `call(user:)` without repetition.

.rubocop_styleguide.yml

@@ -44,6 +44,9 @@ Metrics/BlockLength:
     "xdescribe",
   ]
 
+Metrics/ParameterLists:
+  CountKeywordArgs: false
+
 Rails/ApplicationRecord:
   Exclude:
     # Migrations should not contain application code:

app/controllers/admin/reports_controller.rb

@@ -65,7 +65,8 @@ module Admin
       blob = ReportBlob.create_for_upload_later!(report_filename)
 
       ReportJob.perform_later(
-        report_class, spree_current_user, params, format, blob, ScopedChannel.for_id(params[:uuid])
+        report_class: report_class, user: spree_current_user, params: params,
+        format: format, blob: blob, channel: ScopedChannel.for_id(params[:uuid]),
       )
 
       render cable_ready: cable_car.

app/jobs/report_job.rb

@@ -9,7 +9,7 @@ class ReportJob < ApplicationJob
 
   NOTIFICATION_TIME = 5.seconds
 
-  def perform(report_class, user, params, format, blob, channel = nil)
+  def perform(report_class:, user:, params:, format:, blob:, channel: nil)
     start_time = Time.zone.now
 
     report = report_class.new(user, params, render: true)

spec/jobs/report_job_spec.rb

@@ -3,7 +3,10 @@
 require 'spec_helper'
 
 describe ReportJob do
-  let(:report_args) { [report_class, user, params, format, blob] }
+  let(:report_args) {
+    { report_class: report_class, user: user, params: params, format: format,
+      blob: blob }
+  }
   let(:report_class) { Reporting::Reports::UsersAndEnterprises::Base }
   let(:user) { enterprise.owner }
   let(:enterprise) { create(:enterprise) }
@@ -13,13 +16,13 @@ describe ReportJob do
 
   it "generates a report" do
     job = perform_enqueued_jobs(only: ReportJob) do
-      ReportJob.perform_later(*report_args)
+      ReportJob.perform_later(**report_args)
     end
     expect_csv_report
   end
 
   it "enqueues a job for async processing" do
-    job = ReportJob.perform_later(*report_args)
+    job = ReportJob.perform_later(**report_args)
     expect(blob.content_stored?).to eq false
 
     perform_enqueued_jobs(only: ReportJob)
@@ -29,12 +32,16 @@ describe ReportJob do
   end
 
   it "triggers an email when the report is done" do
+    # Setup test data which also triggers emails:
+    report_args
+
     # Send emails for quick jobs as well:
     stub_const("ReportJob::NOTIFICATION_TIME", 0)
 
-    ReportJob.perform_later(*report_args)
-
     expect {
+      # We need to create this job within the block because of a bug in
+      # rspec-rails: https://github.com/rspec/rspec-rails/issues/2668
+      ReportJob.perform_later(**report_args)
       perform_enqueued_jobs(only: ReportJob)
     }.to enqueue_mail(ReportMailer, :report_ready).with(
       params: {
@@ -46,9 +53,13 @@ describe ReportJob do
   end
 
   it "triggers no email when the report is done quickly" do
-    ReportJob.perform_later(*report_args)
+    # Setup test data which also triggers emails:
+    report_args
 
     expect {
+      # We need to create this job within the block because of a bug in
+      # rspec-rails: https://github.com/rspec/rspec-rails/issues/2668
+      ReportJob.perform_later(**report_args)
       perform_enqueued_jobs(only: ReportJob)
     }.to_not enqueue_mail
   end