REFACTOR: New spec tests and code improvement

spec/models/tag_spec.rb

@@ -10,14 +10,15 @@ describe Tag do
     end
   end
 
+  let(:tag) { Fabricate(:tag) }
+  let(:topic) { Fabricate(:topic, tags: [tag]) }
+
   before do
     SiteSetting.tagging_enabled = true
     SiteSetting.min_trust_level_to_tag_topics = 0
   end
 
   it "can delete tags on deleted topics" do
-    tag = Fabricate(:tag)
-    topic = Fabricate(:topic, tags: [tag])
     topic.trash!
     expect { tag.destroy }.to change { Tag.count }.by(-1)
   end
@@ -94,4 +95,14 @@ describe Tag do
       end
     end
   end
+
+  context "topic counts" do
+    it "should exclude private message topics" do
+      topic
+      Fabricate(:private_message_topic, tags: [tag])
+      described_class.ensure_consistency!
+      tag.reload
+      expect(tag.topic_count).to eq(1)
+    end
+  end
 end

spec/models/topic_tag_spec.rb

@@ -0,0 +1,47 @@
+require 'rails_helper'
+
+describe TopicTag do
+
+  let(:topic) { Fabricate(:topic) }
+  let(:tag) { Fabricate(:tag) }
+  let(:topic_tag) { Fabricate(:topic_tag, topic: topic, tag: tag) }
+
+  context '#after_create' do
+
+    it "tag topic_count should be increased" do
+      expect {
+        topic_tag
+      }.to change(tag, :topic_count).by(1)
+    end
+
+    it "tag topic_count should not be increased" do
+      topic.archetype = Archetype.private_message
+
+      expect {
+        topic_tag
+      }.to change(tag, :topic_count).by(0)
+    end
+
+  end
+
+  context '#after_destroy' do
+
+    it "tag topic_count should be decreased" do
+      topic_tag
+      expect {
+        topic_tag.destroy
+      }.to change(tag, :topic_count).by(-1)
+    end
+
+    it "tag topic_count should not be decreased" do
+      topic.archetype = Archetype.private_message
+      topic_tag
+
+      expect {
+        topic_tag.destroy
+      }.to change(tag, :topic_count).by(0)
+    end
+
+  end
+
+end