correct random suggested topic selection

spec/components/suggested_topics_builder_spec.rb

@@ -95,21 +95,6 @@ describe SuggestedTopicsBuilder do
       end
     end
 
-    context "adding topics that are more than n days old" do
-      let!(:new_topic) { Fabricate(:topic, created_at: 2.days.ago) }
-      let!(:old_topic) { Fabricate(:topic, created_at: 3.years.ago) }
-
-      it "adds topics based on suggested_topics_max_days_old setting" do
-        SiteSetting.suggested_topics_max_days_old = 365
-
-        builder.add_results(Topic)
-        expect(builder.size).to eq(1)
-        expect(builder).not_to be_full
-        expect(builder.excluded_topic_ids.include?(old_topic.id)).to eq(false)
-        expect(builder.excluded_topic_ids.include?(new_topic.id)).to eq(true)
-      end
-    end
-
     context "category definition topics" do
       let!(:category) { Fabricate(:category) }