diff --git a/spec/models/integrations/gitlab_slack_application_spec.rb b/spec/models/integrations/gitlab_slack_application_spec.rb
index fb3247a1f72467f3c500bdebc33fd9864840cb8f..8f2aff0191d45539f28a3922ec584a6361884354 100644
--- a/spec/models/integrations/gitlab_slack_application_spec.rb
+++ b/spec/models/integrations/gitlab_slack_application_spec.rb
@@ -373,5 +373,29 @@ def stub_slack_request(channel:, success:)
         expect(new_integration).not_to be_active
       end
     end
+
+    context 'when duplicating an instance-level integration without project parent' do
+      let(:slack_integration) { create(:slack_integration) }
+      let(:initial_integration) do
+        create(:gitlab_slack_application_integration, :instance, slack_integration: slack_integration)
+      end
+
+      let(:new_integration) { build(:gitlab_slack_application_integration, :instance) }
+
+      it 'duplicates slack_integration with INSTANCE_ALIAS' do
+        initial_integration.after_build_from_integration(new_integration)
+
+        new_slack_integration = new_integration.slack_integration
+        expect(new_slack_integration.slack_api_scopes.ids).to match_array(slack_integration.slack_api_scopes.ids)
+        expect(new_slack_integration).to have_attributes(
+          alias: SlackIntegration::INSTANCE_ALIAS,
+          team_id: slack_integration.team_id,
+          team_name: slack_integration.team_name,
+          user_id: slack_integration.user_id,
+          bot_user_id: slack_integration.bot_user_id,
+          bot_access_token: slack_integration.bot_access_token
+        )
+      end
+    end
   end
 end