Add start merge and merge request job

app/controllers/merge_requests_controller.rb

@@ -61,6 +61,15 @@ class MergeRequestsController < ApplicationController
     @new_merging_org_ids = []
   end
 
+  def start_merge
+    if @merge_request.status == "ready_to_merge"
+      @merge_request.update!(status: :processing)
+      ProcessMergeRequestJob.perform_later(merge_request: @merge_request)
+    end
+
+    redirect_to merge_request_path(@merge_request)
+  end
+
 private
 
   def page

app/jobs/process_merge_request_job.rb

@@ -0,0 +1,11 @@
+class ProcessMergeRequestJob < ApplicationJob
+  queue_as :default
+
+  def perform(merge_request:)
+    absorbing_organisation_id = merge_request.absorbing_organisation_id
+    merging_organisation_ids = merge_request.merging_organisations.pluck(:id)
+    merge_date = merge_request.merge_date
+
+    Merge::MergeOrganisationsService.new(absorbing_organisation_id:, merging_organisation_ids:, merge_date:).call
+  end
+end

app/models/merge_request_organisation.rb

@@ -8,12 +8,19 @@ class MergeRequestOrganisation < ApplicationRecord
   scope :merged, -> { joins(:merge_request).where(merge_requests: { status: "request_merged" }) }
   scope :with_merging_organisation, ->(merging_organisation) { where(merging_organisation:) }
 
+  after_save :update_merge_request_status
+
   has_paper_trail
 
   def merging_organisation_name
     merging_organisation.name || ""
   end
 
+  def update_merge_request_status
+    merge_request.update_status!
+    merge_request.save!
+  end
+
 private
 
   def validate_merging_organisations

app/views/merge_requests/show.html.erb

@@ -27,7 +27,9 @@
 </h1>
 <% unless @merge_request.status == "request_merged" %>
 <div class="govuk-button-group">
-  <%= govuk_button_link_to "Begin merge", "#", disabled: @merge_request.status != "ready_to_merge" %>
+   <%= form_with model: @merge_request, url: start_merge_merge_request_path(@merge_request) do |f| %>
+    <%= f.govuk_submit "Begin merge", disabled: @merge_request.status != "ready_to_merge" %>
+  <% end %>
   <%= govuk_button_link_to "Delete merge request", delete_confirmation_merge_request_path(@merge_request), warning: true %>
 </div>
 <% end %>

config/routes.rb

@@ -203,6 +203,7 @@ Rails.application.routes.draw do
       get "helpdesk-ticket"
       get "delete-confirmation", to: "merge_requests#delete_confirmation"
       delete "delete", to: "merge_requests#delete"
+      patch "start-merge", to: "merge_requests#start_merge"
     end
   end
 

spec/jobs/process_merge_request_job_spec.rb

@@ -0,0 +1,29 @@
+require "rails_helper"
+
+describe ProcessMergeRequestJob do
+  let(:job) { described_class.new }
+  let(:merge_organisations_service) { instance_double(Merge::MergeOrganisationsService) }
+
+  before do
+    allow(Merge::MergeOrganisationsService).to receive(:new).and_return(merge_organisations_service)
+    allow(merge_organisations_service).to receive(:call).and_return(nil)
+  end
+
+  context "when processing a merge request" do
+    let(:organisation) { create(:organisation) }
+    let(:merging_organisation) { create(:organisation) }
+    let(:other_merging_organisation) { create(:organisation) }
+    let(:merge_request) { MergeRequest.create!(requesting_organisation: organisation, absorbing_organisation: organisation, merge_date: Time.zone.local(2022, 3, 3)) }
+
+    before do
+      create(:merge_request_organisation, merge_request:, merging_organisation:)
+      create(:merge_request_organisation, merge_request:, merging_organisation: other_merging_organisation)
+    end
+
+    it "calls the merge organisations service with correct arguments" do
+      expect(Merge::MergeOrganisationsService).to receive(:new).with(absorbing_organisation_id: organisation.id, merging_organisation_ids: [merging_organisation.id, other_merging_organisation.id], merge_date: Time.zone.local(2022, 3, 3))
+
+      job.perform(merge_request:)
+    end
+  end
+end

spec/requests/merge_requests_controller_spec.rb

@@ -364,6 +364,38 @@ RSpec.describe MergeRequestsController, type: :request do
         end
       end
     end
+
+    describe "#start_merge" do
+      let(:merge_request) { MergeRequest.create!(requesting_organisation: organisation, absorbing_organisation: organisation, merge_date: Time.zone.local(2022, 3, 3)) }
+      let(:merging_organisation) { create(:organisation, name: "Merging Test Org") }
+
+      before do
+        allow(ProcessMergeRequestJob).to receive(:perform_later).and_return(nil)
+      end
+
+      context "when merge request is ready to merge" do
+        before do
+          create(:merge_request_organisation, merge_request:, merging_organisation: other_organisation)
+          create(:merge_request_organisation, merge_request:, merging_organisation:)
+        end
+
+        it "runs the job with correct merge request" do
+          expect(merge_request.reload.status).to eq("ready_to_merge")
+          expect(ProcessMergeRequestJob).to receive(:perform_later).with(merge_request:).once
+          patch "/merge-request/#{merge_request.id}/start-merge"
+          expect(merge_request.reload.status).to eq("processing")
+        end
+      end
+
+      context "when merge request is not ready to merge" do
+        it "does not run the job" do
+          expect(merge_request.status).to eq("incomplete")
+          expect(ProcessMergeRequestJob).not_to receive(:perform_later).with(merge_request:)
+          patch "/merge-request/#{merge_request.id}/start-merge"
+          expect(merge_request.reload.status).to eq("incomplete")
+        end
+      end
+    end
   end
 
   context "when user is signed in with a data coordinator user" do