Fix preview of commit tagging

app/services/quick_actions/target_service.rb

@@ -24,8 +24,6 @@ module QuickActions
     end
 
     def commit(type_id)
-      return nil unless type_id
-
       project.commit(type_id)
     end
   end

spec/features/commits/user_uses_slash_commands_spec.rb

@@ -32,5 +32,15 @@ describe 'Commit > User uses quick actions', :js do
       expect(page).to have_content tag_message
       expect(page).to have_content truncated_commit_sha
     end
+
+    describe 'preview', :js do
+      it 'removes quick action from note and explains it' do
+        preview_note("/tag #{tag_name} #{tag_message}")
+
+        expect(page).not_to have_content '/tag'
+        expect(page).to have_content %{Tags this commit to #{tag_name} with "#{tag_message}"}
+        expect(page).to have_content tag_name
+      end
+    end
   end
 end

spec/services/quick_actions/target_service_spec.rb

@@ -57,13 +57,19 @@ describe QuickActions::TargetService do
 
     context 'for commit' do
       let(:project) { create(:project, :repository) }
-      let(:target) { project.commit }
+      let(:target) { project.commit.parent }
       let(:target_id) { target.sha }
       let(:type) { 'Commit' }
 
       it_behaves_like 'find target'
       it_behaves_like 'no target', type_id: 'invalid_sha'
-      it_behaves_like 'no target', type_id: nil
+
+      context 'with nil target_id' do
+        let(:target) { project.commit }
+        let(:target_id) { nil }
+
+        it_behaves_like 'find target'
+      end
     end
 
     context 'for unknown type' do

spec/support/helpers/features/notes_helpers.rb

@@ -20,6 +20,13 @@ module Spec
               end
             end
           end
+
+          def preview_note(text)
+            page.within('.js-main-target-form') do
+              fill_in('note[note]', with: text)
+              click_on('Preview')
+            end
+          end
         end
       end
     end