Allow to make test cases confidential

Enable /confidential quick action for test cases

Changelog: added
EE: true

app/models/concerns/issue_available_features.rb

@@ -11,8 +11,8 @@ module IssueAvailableFeatures
     def available_features_for_issue_types
       {
         assignee: %w(issue incident),
-        confidentiality: %(issue incident),
-        time_tracking: %(issue incident)
+        confidentiality: %w(issue incident),
+        time_tracking: %w(issue incident)
       }.with_indifferent_access
     end
   end

ee/app/models/concerns/ee/issue_available_features.rb

@@ -11,7 +11,11 @@ module EE
       override :available_features_for_issue_types
       def available_features_for_issue_types
         strong_memoize(:available_features_for_issue_types) do
-          super.merge(epics: %w(issue), sla: %w(incident))
+          super.tap do |available_features|
+            available_features[:epics] = %w(issue)
+            available_features[:sla] = %w(incident)
+            available_features[:confidentiality] += %w(test_case)
+          end
         end
       end
     end

ee/spec/services/quick_actions/interpret_service_spec.rb

@@ -1106,12 +1106,12 @@ RSpec.describe QuickActions::InterpretService do
 
     context 'confidential command' do
       context 'for test cases' do
-        it 'does not mark to update confidential attribute' do
+        it 'does mark to update confidential attribute' do
           issuable = create(:quality_test_case, project: project)
 
           _, updates, _ = service.execute('/confidential', issuable)
 
-          expect(updates[:confidential]).to eq(nil)
+          expect(updates[:confidential]).to eq(true)
         end
       end
     end