Add service to create a new issue in a board list

app/controllers/projects/boards/issues_controller.rb

@@ -10,23 +10,21 @@ module Projects
         issues = issues.page(params[:page])
 
         render json: {
-          issues: issues.as_json(
-            only: [:iid, :title, :confidential],
-            include: {
-              assignee: { only: [:id, :name, :username], methods: [:avatar_url] },
-              labels:   { only: [:id, :title, :description, :color, :priority], methods: [:text_color] }
-            }),
+          issues: serialize_as_json(issues),
           size: issues.total_count
         }
       end
 
       def create
         list = project.board.lists.find(params[:list_id])
+        service = ::Boards::Issues::CreateService.new(project, current_user, issue_params)
+        issue = service.execute(list)
 
-        issue = Issues::CreateService.new(project, current_user, issue_params.merge(request: request)).execute
-        issue.labels << list.label if list.label
-
-        render json: issue.to_json
+        if issue.valid?
+          render json: serialize_as_json(issue)
+        else
+          render json: issue.errors, status: :unprocessable_entity
+        end
       end
 
       def update
@@ -70,7 +68,16 @@ module Projects
       end
 
       def issue_params
-        params.require(:issue).permit(:title)
+        params.require(:issue).permit(:title).merge(request: request)
+      end
+
+      def serialize_as_json(resource)
+        resource.as_json(
+          only: [:iid, :title, :confidential],
+          include: {
+            assignee: { only: [:id, :name, :username], methods: [:avatar_url] },
+            labels:   { only: [:id, :title, :description, :color, :priority], methods: [:text_color] }
+          })
       end
     end
   end

app/services/boards/issues/create_service.rb

+module Boards
+  module Issues
+    class CreateService < Boards::BaseService
+      def execute(list)
+        params.merge!(label_ids: [list.label_id])
+        create_issue
+      end
+
+      private
+
+      def create_issue
+        ::Issues::CreateService.new(project, current_user, params).execute
+      end
+    end
+  end
+end

spec/services/boards/issues/create_service_spec.rb

+require 'spec_helper'
+
+describe Boards::Issues::CreateService, services: true do
+  describe '#execute' do
+    let(:project) { create(:project_with_board) }
+    let(:board)   { project.board }
+    let(:user)    { create(:user) }
+    let(:label)   { create(:label, project: project, name: 'in-progress') }
+    let!(:list)   { create(:list, board: board, label: label, position: 0) }
+
+    subject(:service) { described_class.new(project, user, title: 'New issue') }
+
+    before do
+      project.team << [user, :developer]
+    end
+
+    it 'delegates the create proceedings to Issues::CreateService' do
+      expect_any_instance_of(Issues::CreateService).to receive(:execute).once
+
+      service.execute(list)
+    end
+
+    it 'creates a new issue' do
+      expect { service.execute(list) }.to change(project.issues, :count).by(1)
+    end
+
+    it 'adds the label of the list to the issue' do
+      issue = service.execute(list)
+
+      expect(issue.labels).to eq [label]
+    end
+  end
+end