FEATURE: implements user based sidebar mode (#23078)

plugins/chat/spec/serializer/user_serializer_spec.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+RSpec.describe UserSerializer do
+  fab!(:current_user) { Fabricate(:user) }
+
+  let(:serializer) do
+    described_class.new(current_user, scope: Guardian.new(current_user), root: false)
+  end
+
+  describe "#chat_separate_sidebar_mode" do
+    it "is present" do
+      expect(serializer.as_json[:user_option][:chat_separate_sidebar_mode]).to eq("default")
+    end
+  end
+end