Add system note support for publishing issues

Adds helper methods for generating system notes
which correspond to publishing an issue to an
associated status page application. These
notes are meant to be used in another MR.

ee/app/helpers/ee/system_note_helper.rb

@@ -25,7 +25,8 @@ module EE
       'designs_discussion_added' => 'doc-image',
       'vulnerability_confirmed' => 'shield',
       'vulnerability_dismissed' => 'cancel',
-      'vulnerability_resolved' => 'status_closed'
+      'vulnerability_resolved' => 'status_closed',
+      'published' => 'bullhorn'
     }.freeze
 
     override :system_note_icon_name

ee/app/models/ee/system_note_metadata.rb

@@ -5,7 +5,7 @@ module EE
     extend ::Gitlab::Utils::Override
 
     EE_ICON_TYPES = %w[
-      weight approved unapproved relate unrelate
+      weight approved unapproved relate unrelate published
       epic_issue_added issue_added_to_epic epic_issue_removed issue_removed_from_epic
       epic_issue_moved issue_changed_epic epic_date_changed relate_epic unrelate_epic
       designs_added designs_modified designs_removed designs_discussion_added

ee/app/services/ee/system_note_service.rb

@@ -180,5 +180,9 @@ module EE
     def change_vulnerability_state(noteable, author)
       EE::SystemNotes::VulnerabilitiesService.new(noteable: noteable, project: noteable.project, author: author).change_vulnerability_state
     end
+
+    def publish_issue_to_status_page(noteable, project, author)
+      ::SystemNotes::IssuablesService.new(noteable: noteable, project: project, author: author).publish_issue_to_status_page
+    end
   end
 end

ee/app/services/ee/system_notes/issuables_service.rb

@@ -60,6 +60,20 @@ module EE
 
         create_note(NoteSummary.new(noteable, project, author, body, action: 'health_status'))
       end
+
+      # Called when the an issue is published to a project's
+      # status page application
+      #
+      # Example Note text:
+      #
+      #   "published this issue to the status page"
+      #
+      # Returns the created Note object
+      def publish_issue_to_status_page
+        body = 'published this issue to the status page'
+
+        create_note(NoteSummary.new(noteable, project, author, body, action: 'published'))
+      end
     end
   end
 end

ee/spec/services/ee/system_notes/issuables_service_spec.rb

@@ -104,4 +104,18 @@ describe ::SystemNotes::IssuablesService do
       end
     end
   end
+
+  describe '#publish_issue_to_status_page' do
+    let_it_be(:noteable) { create(:issue, project: project) }
+
+    subject { service.publish_issue_to_status_page }
+
+    it_behaves_like 'a system note' do
+      let(:action) { 'published' }
+    end
+
+    it 'sets the note text' do
+      expect(subject.note).to eq 'published this issue to the status page'
+    end
+  end
 end

ee/spec/services/system_note_service_spec.rb

@@ -240,4 +240,14 @@ describe SystemNoteService do
       described_class.change_vulnerability_state(noteable, author)
     end
   end
+
+  describe '.publish_issue_to_status_page' do
+    it 'calls IssuablesService' do
+      expect_next_instance_of(::SystemNotes::IssuablesService) do |service|
+        expect(service).to receive(:publish_issue_to_status_page)
+      end
+
+      described_class.publish_issue_to_status_page(noteable, project, author)
+    end
+  end
 end