Add service to list issues for a board list

app/services/boards/issues/list_service.rb

+module Boards
+  module Issues
+    class ListService
+      def initialize(project, user, params = {})
+        @project = project
+        @user = user
+        @params = params.dup
+      end
+
+      def execute
+        issues = IssuesFinder.new(user, filter_params).execute
+        issues = without_board_labels(issues) if list.backlog?
+        issues
+      end
+
+      private
+
+      attr_reader :project, :user, :params
+
+      delegate :board, to: :project
+
+      def list
+        @list ||= board.lists.find(params[:list_id])
+      end
+
+      def filter_params
+        set_default_scope
+        set_default_sort
+        set_list_label
+        set_project
+        set_state
+
+        params
+      end
+
+      def set_default_scope
+        params[:scope] = 'all'
+      end
+
+      def set_default_sort
+        params[:sort] = 'priority'
+      end
+
+      def set_list_label
+        return unless list.label?
+
+        params[:label_name] ||= []
+        params[:label_name] << list.label_name
+      end
+
+      def set_project
+        params[:project_id] = project.id
+      end
+
+      def set_state
+        params[:state] = list.done? ? 'closed' : 'opened'
+      end
+
+      def board_label_ids
+        @board_label_ids ||= board.lists.label.pluck(:label_id)
+      end
+
+      def without_board_labels(issues)
+        return issues unless board_label_ids.any?
+
+        issues.where.not(
+          LabelLink.where("label_links.target_type = 'Issue' AND label_links.target_id = issues.id")
+                   .where(label_id: board_label_ids).limit(1).arel.exists
+        )
+      end
+    end
+  end
+end

spec/services/boards/issues/list_service_spec.rb

+require 'spec_helper'
+
+describe Boards::Issues::ListService, services: true do
+  describe '#execute' do
+    let(:user)    { create(:user) }
+    let(:project) { create(:project_with_board) }
+    let(:board)   { project.board }
+
+    let(:bug) { create(:label, project: project, name: 'Bug') }
+    let(:development) { create(:label, project: project, name: 'Development') }
+    let(:testing)  { create(:label, project: project, name: 'Testing') }
+    let(:p1) { create(:label, title: 'P1', project: project, priority: 1) }
+    let(:p2) { create(:label, title: 'P2', project: project, priority: 2) }
+    let(:p3) { create(:label, title: 'P3', project: project, priority: 3) }
+
+    let!(:backlog) { create(:backlog_list, board: board) }
+    let!(:list1)   { create(:list, board: board, label: development) }
+    let!(:list2)   { create(:list, board: board, label: testing) }
+    let!(:done)    { create(:done_list, board: board) }
+
+    let!(:opened_issue1) { create(:labeled_issue, project: project, labels: [bug]) }
+    let!(:opened_issue2) { create(:labeled_issue, project: project, labels: [p2]) }
+    let!(:reopened_issue1) { create(:issue, :reopened, project: project) }
+
+    let!(:list1_issue1) { create(:labeled_issue, project: project, labels: [p2, development]) }
+    let!(:list1_issue2) { create(:labeled_issue, project: project, labels: [development]) }
+    let!(:list1_issue3) { create(:labeled_issue, project: project, labels: [development, p1]) }
+    let!(:list2_issue1) { create(:labeled_issue, project: project, labels: [testing]) }
+
+    let!(:closed_issue1) { create(:labeled_issue, :closed, project: project, labels: [bug]) }
+    let!(:closed_issue2) { create(:labeled_issue, :closed, project: project, labels: [p3]) }
+    let!(:closed_issue3) { create(:issue, :closed, project: project) }
+    let!(:closed_issue4) { create(:labeled_issue, :closed, project: project, labels: [p1]) }
+
+    before do
+      project.team << [user, :developer]
+    end
+
+    it 'delegates search to IssuesFinder' do
+      params = { list_id: list1.id }
+
+      expect_any_instance_of(IssuesFinder).to receive(:execute).once
+
+      described_class.new(project, user, params).execute
+    end
+
+    context 'sets default order to priority' do
+      it 'returns opened issues when listing issues from Backlog' do
+        params = { list_id: backlog.id }
+
+        issues = described_class.new(project, user, params).execute
+
+        expect(issues).to eq [opened_issue2, reopened_issue1, opened_issue1]
+      end
+
+      it 'returns closed issues when listing issues from Done' do
+        params = { list_id: done.id }
+
+        issues = described_class.new(project, user, params).execute
+
+        expect(issues).to eq [closed_issue4, closed_issue2, closed_issue3, closed_issue1]
+      end
+
+      it 'returns opened issues that have label list applied when listing issues from a label list' do
+        params = { list_id: list1.id }
+
+        issues = described_class.new(project, user, params).execute
+
+        expect(issues).to eq [list1_issue3, list1_issue1, list1_issue2]
+      end
+    end
+  end
+end