Allow to toggle notifications for issues due soon

app/models/notification_setting.rb

@@ -32,6 +32,7 @@ class NotificationSetting < ActiveRecord::Base
     :reopen_issue,
     :close_issue,
     :reassign_issue,
+    :issue_due,
     :new_merge_request,
     :push_to_merge_request,
     :reopen_merge_request,

changelogs/unreleased/issue_47709.yml

+---
+title: 'Allow to toggle notifications for issues due soon'
+merge_request:
+author:
+type: fixed

spec/features/projects/show/user_manages_notifications_spec.rb

@@ -16,4 +16,36 @@ describe 'Projects > Show > User manages notifications', :js do
       expect(page).to have_content 'On mention'
     end
   end
+
+  context 'custom notification settings' do
+    let(:email_events) do
+      [
+        :new_note,
+        :new_issue,
+        :reopen_issue,
+        :close_issue,
+        :reassign_issue,
+        :issue_due,
+        :new_merge_request,
+        :push_to_merge_request,
+        :reopen_merge_request,
+        :close_merge_request,
+        :reassign_merge_request,
+        :merge_merge_request,
+        :failed_pipeline,
+        :success_pipeline
+      ]
+    end
+
+    it 'shows notification settings checkbox' do
+      first('.notifications-btn').click
+      page.find('a[data-notification-level="custom"]').click
+
+      page.within('.custom-notifications-form') do
+        email_events.each do |event_name|
+          expect(page).to have_selector("input[name='notification_setting[#{event_name}]']")
+        end
+      end
+    end
+  end
 end

spec/models/notification_setting_spec.rb

@@ -93,4 +93,10 @@ RSpec.describe NotificationSetting do
       end
     end
   end
+
+  context 'email events' do
+    it 'includes EXCLUDED_WATCHER_EVENTS in EMAIL_EVENTS' do
+      expect(described_class::EMAIL_EVENTS).to include(*described_class::EXCLUDED_WATCHER_EVENTS)
+    end
+  end
 end