UX: Improve category filtering and include subcategories

* category_filtering
  1. report_top_referred_topics
  2. report_top_traffic_sources
  3. report_post_edit
* category_filtering with subcategory topics
  1. report_top_referred_topics
  2. report_top_traffic_sources
  3. report_post_edit
  4. report_posts
  5. report_topics
  6. report_topics_with_no_response
* category_filtering tests (without subcategory topics)
  1. report_posts
  2. report_topics_with_no_response
* subcategory topics tests `in_category_and_subcategories` in `topic_spec.rb`
  1. `in_category_and_subcategories` in `topic_spec.rb`
  2. topics, posts, flags and topics_with_no_response in `report_spec.rb`

spec/models/report_spec.rb

@@ -15,6 +15,20 @@ describe Report do
     end
   end
 
+  shared_examples 'category filtering on subcategories' do
+    before(:all) do
+      c3 = Fabricate(:category, id: 3)
+      c2 = Fabricate(:category, id: 2, parent_category_id: 3)
+      Topic.find(c2.topic_id).delete
+      Topic.find(c3.topic_id).delete
+    end
+    after(:all) do
+      Category.where(id: 2).or(Category.where(id: 3)).destroy_all
+      User.where("id > 0").destroy_all
+    end
+    include_examples 'category filtering'
+  end
+
   shared_examples 'with data x/y' do
     it "returns today's data" do
       expect(report.data.select { |v| v[:x].today? }).to be_present
@@ -717,6 +731,12 @@ describe Report do
         let(:report) { Report.find('flags', category_id: 2) }
 
         include_examples 'category filtering'
+
+        context "on subcategories" do
+          let(:report) { Report.find('flags', category_id: 3) }
+
+          include_examples 'category filtering on subcategories'
+        end
       end
     end
   end
@@ -740,6 +760,12 @@ describe Report do
         let(:report) { Report.find('topics', category_id: 2) }
 
         include_examples 'category filtering'
+
+        context "on subcategories" do
+          let(:report) { Report.find('topics', category_id: 3) }
+
+          include_examples 'category filtering on subcategories'
+        end
       end
     end
   end
@@ -777,4 +803,66 @@ describe Report do
       expect(report.error).to eq(:timeout)
     end
   end
+
+  describe 'posts' do
+    let(:report) { Report.find('posts') }
+
+    include_examples 'no data'
+
+    context 'with data' do
+      include_examples 'with data x/y'
+
+      before(:each) do
+        topic = Fabricate(:topic)
+        topic_with_category_id = Fabricate(:topic, category_id: 2)
+        Fabricate(:post, topic: topic)
+        Fabricate(:post, topic: topic_with_category_id)
+        Fabricate(:post, topic: topic)
+        Fabricate(:post, created_at: 45.days.ago, topic: topic)
+      end
+
+      context "with category filtering" do
+        let(:report) { Report.find('posts', category_id: 2) }
+
+        include_examples 'category filtering'
+
+        context "on subcategories" do
+          let(:report) { Report.find('posts', category_id: 3) }
+
+          include_examples 'category filtering on subcategories'
+        end
+      end
+    end
+  end
+
+  # TODO: time_to_first_response
+
+  describe 'topics_with_no_response' do
+    let(:report) { Report.find('topics_with_no_response') }
+
+    include_examples 'no data'
+
+    context 'with data' do
+      include_examples 'with data x/y'
+
+      before(:each) do
+        Fabricate(:topic, category_id: 2)
+        Fabricate(:post, topic: Fabricate(:topic))
+        Fabricate(:topic)
+        Fabricate(:topic, created_at: 45.days.ago)
+      end
+
+      context "with category filtering" do
+        let(:report) { Report.find('topics_with_no_response', category_id: 2) }
+
+        include_examples 'category filtering'
+
+        context "on subcategories" do
+          let(:report) { Report.find('topics_with_no_response', category_id: 3) }
+
+          include_examples 'category filtering on subcategories'
+        end
+      end
+    end
+  end
 end