Add new system note used when issue has been moved

app/services/issues/move_service.rb

@@ -36,6 +36,7 @@ module Issues
     end
     def add_note_moved_to
+      SystemNoteService.issue_moved_to_another_project(@issue_old, @project, @project_new, @current_user)
     end
   end
 end

app/services/system_note_service.rb

@@ -387,4 +387,21 @@ class SystemNoteService
     body = "Marked the task **#{new_task.source}** as #{status_label}"
     create_note(noteable: noteable, project: project, author: author, note: body)
   end
+
+  # Called when issue has been moved to another project
+  #
+  # issue          - Issue that has been moved to another project
+  # project_from   - Source project of the issue
+  # project_to     - Destination project for the issue
+  # author         - User performing the move
+  #
+  # Example Note text:
+  #
+  #   "This issue has been moved to SomeNamespace / SomeProject"
+  #
+  # Returns the created Note object
+  def self.issue_moved_to_another_project(issue, project_from, project_to, author)
+    body = "This issue has been moved to #{project_to.to_reference} by #{author.to_reference}"
+    create_note(noteable: issue, project: project_from, author: author, note: body)
+  end
 end

spec/services/issues/move_service_spec.rb

@@ -18,5 +18,9 @@ describe Issues::MoveService, services: true do
     it 'should create a new issue in a new project' do
       expect(new_issue.project).to eq new_project
     end
+
+    it 'should add system note to old issue' do
+      expect(issue.notes.last.note).to match /This issue has been moved to/
+    end
   end
 end

spec/services/system_note_service_spec.rb

@@ -441,6 +441,26 @@ describe SystemNoteService, services: true do
     end
   end
+  describe '.issue_moved_to_another_project' do
+    subject do
+      described_class.issue_moved_to_another_project(noteable, project, new_project, author)
+    end
+
+    let(:new_project) { create(:project) }
+
+    it 'should notify about issue being moved' do
+      expect(subject.note).to match /This issue has been moved to/
+    end
+
+    it 'should mention destination project' do
+      expect(subject.note).to include new_project.to_reference
+    end
+
+    it 'should mention author of that change' do
+      expect(subject.note).to include author.to_reference
+    end
+  end
+
   include JiraServiceHelper
   describe 'JIRA integration' do