DEV: Block accidental serialization of entire AR models (#27668)

spec/requests/api/notifications_spec.rb

@@ -108,6 +108,11 @@ RSpec.describe "notifications" do
       response "200", "notifications marked read" do
         schema type: :object, properties: { success: { type: :string } }
 
+        let(:notification) do
+          notification = Fabricate(:notification)
+          NotificationSerializer.new(notification).as_json
+        end
+
         run_test!
       end
     end

spec/requests/api/posts_spec.rb

@@ -221,7 +221,10 @@ RSpec.describe "posts" do
         expected_response_schema = load_spec_schema("topic_create_response")
         schema expected_response_schema
 
-        let(:params) { Fabricate(:post) }
+        let(:params) do
+          post = Fabricate(:post)
+          post.serializable_hash(only: %i[topic_id raw created_at]).as_json
+        end
 
         it_behaves_like "a JSON endpoint", 200 do
           let(:expected_response_schema) { expected_response_schema }