diff --git a/spec/requests/ai_helper/assistant_controller_spec.rb b/spec/requests/ai_helper/assistant_controller_spec.rb
index 0615f9ee..333252bb 100644
--- a/spec/requests/ai_helper/assistant_controller_spec.rb
+++ b/spec/requests/ai_helper/assistant_controller_spec.rb
@@ -1,12 +1,11 @@
 # frozen_string_literal: true
 
 RSpec.describe DiscourseAi::AiHelper::AssistantController do
-  fab!(:fake_model)
   fab!(:newuser)
   fab!(:user) { Fabricate(:user, refresh_auto_groups: true) }
 
   before do
-    SiteSetting.ai_default_llm_model = "custom:#{fake_model.id}"
+    assign_fake_provider_to(:ai_default_llm_model)
   end
 
   describe "#stream_suggestion" do