Add email notification for milestone changes

app/views/notify/removed_milestone_merge_request_email.text.erb

+<%= render 'removed_milestone_merge_request_email', issuable: @merge_request %>

changelogs/unreleased/ccr-51520_change_milestone_email.yml

+---
+title: Add email for milestone change
+merge_request: 22279
+author:
+type: added

spec/services/issues/update_service_spec.rb

@@ -343,7 +343,40 @@ describe Issues::UpdateService, :mailer do
         end
       end
-      context 'when the milestone change' do
+      context 'when the milestone is removed' do
+        let!(:non_subscriber) { create(:user) }
+
+        let!(:subscriber) do
+          create(:user).tap do |u|
+            issue.toggle_subscription(u, project)
+            project.add_developer(u)
+          end
+        end
+
+        it_behaves_like 'system notes for milestones'
+
+        it 'sends notifications for subscribers of changed milestone' do
+          issue.milestone = create(:milestone)
+          issue.save
+          perform_enqueued_jobs do
+            update_issue(milestone_id: "")
+          end
+
+          should_email(subscriber)
+          should_not_email(non_subscriber)
+        end
+      end
+
+      context 'when the milestone is changed' do
+        let!(:non_subscriber) { create(:user) }
+
+        let!(:subscriber) do
+          create(:user).tap do |u|
+            issue.toggle_subscription(u, project)
+            project.add_developer(u)
+          end
+        end
+
         it 'marks todos as done' do
           update_issue(milestone: create(:milestone))
@@ -351,6 +384,15 @@ describe Issues::UpdateService, :mailer do
         end
         it_behaves_like 'system notes for milestones'
+
+        it 'sends notifications for subscribers of changed milestone' do
+          perform_enqueued_jobs do
+            update_issue(milestone: create(:milestone))
+          end
+
+          should_email(subscriber)
+          should_not_email(non_subscriber)
+        end
       end
       context 'when the labels change' do

spec/services/merge_requests/update_service_spec.rb

@@ -315,7 +315,40 @@ describe MergeRequests::UpdateService, :mailer do
         end
       end
-      context 'when the milestone change' do
+      context 'when the milestone is removed' do
+        let!(:non_subscriber) { create(:user) }
+
+        let!(:subscriber) do
+          create(:user).tap do |u|
+            merge_request.toggle_subscription(u, project)
+            project.add_developer(u)
+          end
+        end
+
+        it_behaves_like 'system notes for milestones'
+
+        it 'sends notifications for subscribers of changed milestone' do
+          merge_request.milestone = create(:milestone)
+          merge_request.save
+          perform_enqueued_jobs do
+            update_merge_request(milestone_id: "")
+          end
+
+          should_email(subscriber)
+          should_not_email(non_subscriber)
+        end
+      end
+
+      context 'when the milestone is changed' do
+        let!(:non_subscriber) { create(:user) }
+
+        let!(:subscriber) do
+          create(:user).tap do |u|
+            merge_request.toggle_subscription(u, project)
+            project.add_developer(u)
+          end
+        end
+
         it 'marks pending todos as done' do
           update_merge_request({ milestone: create(:milestone) })
@@ -323,6 +356,15 @@ describe MergeRequests::UpdateService, :mailer do
         end
         it_behaves_like 'system notes for milestones'
+
+        it 'sends notifications for subscribers of changed milestone' do
+          perform_enqueued_jobs do
+            update_merge_request(milestone: create(:milestone))
+          end
+
+          should_email(subscriber)
+          should_not_email(non_subscriber)
+        end
       end
       context 'when the labels change' do

spec/services/notification_service_spec.rb

@@ -952,6 +952,134 @@ describe NotificationService, :mailer do
       end
     end
+    describe '#removed_milestone_issue' do
+      let(:milestone) { create(:milestone, project: project, issues: [issue]) }
+
+      let!(:subscriber_to_milestone) { create(:user) { |u| issue.toggle_subscription(u, project) } }
+
+      it "doesn't send email to anyone but subscribers of the given milestone" do
+        notification.removed_milestone_issue(issue, issue.author)
+
+        should_email(subscriber_to_milestone)
+        issue.assignees.each do |a|
+          should_email(a)
+        end
+        should_email(@u_watcher)
+        should_email(@u_guest_watcher)
+        should_email(@u_participant_mentioned)
+        should_email(@subscriber)
+        should_email(@subscribed_participant)
+        should_email(@watcher_and_subscriber)
+        should_not_email(@u_guest_custom)
+        should_not_email(@u_committer)
+        should_not_email(@unsubscriber)
+        should_not_email(@u_participating)
+        should_not_email(@u_lazy_participant)
+        should_not_email(issue.author)
+        should_not_email(@u_disabled)
+        should_not_email(@u_custom_global)
+        should_not_email(@u_mentioned)
+      end
+
+      context 'confidential issues' do
+        let(:author) { create(:user) }
+        let(:assignee) { create(:user) }
+        let(:non_member) { create(:user) }
+        let(:member) { create(:user) }
+        let(:guest) { create(:user) }
+        let(:admin) { create(:admin) }
+        let(:confidential_issue) { create(:issue, :confidential, project: project, title: 'Confidential issue', author: author, assignees: [assignee]) }
+        let(:milestone) { create(:milestone, project: project, issues: [confidential_issue]) }
+
+        it "emails subscribers of the issue's milestone that can read the issue" do
+          project.add_developer(member)
+          project.add_guest(guest)
+
+          confidential_issue.subscribe(non_member, project)
+          confidential_issue.subscribe(author, project)
+          confidential_issue.subscribe(assignee, project)
+          confidential_issue.subscribe(member, project)
+          confidential_issue.subscribe(guest, project)
+          confidential_issue.subscribe(admin, project)
+
+          reset_delivered_emails!
+
+          notification.removed_milestone_issue(confidential_issue, @u_disabled)
+
+          should_not_email(non_member)
+          should_not_email(guest)
+          should_email(author)
+          should_email(assignee)
+          should_email(member)
+          should_email(admin)
+        end
+      end
+    end
+
+    describe '#changed_milestone_issue' do
+      let(:new_milestone) { create(:milestone, project: project, issues: [issue]) }
+
+      let!(:subscriber_to_new_milestone) { create(:user) { |u| issue.toggle_subscription(u, project) } }
+
+      it "doesn't send email to anyone but subscribers of the given milestone" do
+        notification.changed_milestone_issue(issue, new_milestone, issue.author)
+
+        should_email(subscriber_to_new_milestone)
+        issue.assignees.each do |a|
+          should_email(a)
+        end
+        should_email(@u_watcher)
+        should_email(@u_guest_watcher)
+        should_email(@u_participant_mentioned)
+        should_email(@subscriber)
+        should_email(@subscribed_participant)
+        should_email(@watcher_and_subscriber)
+        should_not_email(@u_guest_custom)
+        should_not_email(@u_committer)
+        should_not_email(@unsubscriber)
+        should_not_email(@u_participating)
+        should_not_email(@u_lazy_participant)
+        should_not_email(issue.author)
+        should_not_email(@u_disabled)
+        should_not_email(@u_custom_global)
+        should_not_email(@u_mentioned)
+      end
+
+      context 'confidential issues' do
+        let(:author) { create(:user) }
+        let(:assignee) { create(:user) }
+        let(:non_member) { create(:user) }
+        let(:member) { create(:user) }
+        let(:guest) { create(:user) }
+        let(:admin) { create(:admin) }
+        let(:confidential_issue) { create(:issue, :confidential, project: project, title: 'Confidential issue', author: author, assignees: [assignee]) }
+        let(:new_milestone) { create(:milestone, project: project, issues: [confidential_issue]) }
+
+        it "emails subscribers of the issue's milestone that can read the issue" do
+          project.add_developer(member)
+          project.add_guest(guest)
+
+          confidential_issue.subscribe(non_member, project)
+          confidential_issue.subscribe(author, project)
+          confidential_issue.subscribe(assignee, project)
+          confidential_issue.subscribe(member, project)
+          confidential_issue.subscribe(guest, project)
+          confidential_issue.subscribe(admin, project)
+
+          reset_delivered_emails!
+
+          notification.changed_milestone_issue(confidential_issue, new_milestone, @u_disabled)
+
+          should_not_email(non_member)
+          should_not_email(guest)
+          should_email(author)
+          should_email(assignee)
+          should_email(member)
+          should_email(admin)
+        end
+      end
+    end
+
     describe '#close_issue' do
       before do
         update_custom_notification(:close_issue, @u_guest_custom, resource: project)
@@ -1304,6 +1432,64 @@ describe NotificationService, :mailer do
       end
     end
+    describe '#removed_milestone_merge_request' do
+      let(:milestone) { create(:milestone, project: project, merge_requests: [merge_request]) }
+
+      let!(:subscriber_to_milestone) { create(:user) { |u| merge_request.toggle_subscription(u, project) } }
+
+      it "doesn't send email to anyone but subscribers of the given milestone" do
+        notification.removed_milestone_merge_request(merge_request, merge_request.author)
+
+        should_email(subscriber_to_milestone)
+        merge_request.assignees.each do |a|
+          should_email(a)
+        end
+        should_email(@u_watcher)
+        should_email(@u_guest_watcher)
+        should_email(@u_participant_mentioned)
+        should_email(@subscriber)
+        should_email(@subscribed_participant)
+        should_email(@watcher_and_subscriber)
+        should_not_email(@u_guest_custom)
+        should_not_email(@u_committer)
+        should_not_email(@unsubscriber)
+        should_not_email(@u_participating)
+        should_not_email(@u_lazy_participant)
+        should_not_email(merge_request.author)
+        should_not_email(@u_disabled)
+        should_not_email(@u_custom_global)
+        should_not_email(@u_mentioned)
+      end
+    end
+
+    describe '#changed_milestone_merge_request' do
+      let(:new_milestone) { create(:milestone, project: project, merge_requests: [merge_request]) }
+
+      let!(:subscriber_to_new_milestone) { create(:user) { |u| merge_request.toggle_subscription(u, project) } }
+
+      it "doesn't send email to anyone but subscribers of the given milestone" do
+        notification.changed_milestone_merge_request(merge_request, new_milestone, merge_request.author)
+
+        should_email(subscriber_to_new_milestone)
+        should_email(merge_request.assignee)
+        should_email(@u_watcher)
+        should_email(@u_guest_watcher)
+        should_email(@u_participant_mentioned)
+        should_email(@subscriber)
+        should_email(@subscribed_participant)
+        should_email(@watcher_and_subscriber)
+        should_not_email(@u_guest_custom)
+        should_not_email(@u_committer)
+        should_not_email(@unsubscriber)
+        should_not_email(@u_participating)
+        should_not_email(@u_lazy_participant)
+        should_not_email(merge_request.author)
+        should_not_email(@u_disabled)
+        should_not_email(@u_custom_global)
+        should_not_email(@u_mentioned)
+      end
+    end
+
     describe '#merge_request_unmergeable' do
       it "sends email to merge request author" do
         notification.merge_request_unmergeable(merge_request)