add failing test for AMS upgrade

spec/serializers/topic_list_item_serializer_spec.rb

@@ -0,0 +1,19 @@
+require 'spec_helper'
+require_dependency 'post_action'
+
+describe TopicListItemSerializer do
+
+  it "correctly serializes topic" do
+    date = Time.zone.now
+
+    topic = Topic.new
+    topic.title = "test"
+    topic.created_at = date - 2.minutes
+    topic.bumped_at = date
+    topic.posters = []
+    serialized = TopicListItemSerializer.new(topic, scope: Guardian.new, root: false).as_json
+
+    serialized[:title].should == "test"
+    serialized[:bumped].should == true
+  end
+end