Use cached_tag_list_array for tags (#2857)

app/views/api/v0/articles/show.json.jbuilder

@@ -7,7 +7,7 @@ json.published_at       @article.published_at
 json.readable_publish_date @article.readable_publish_date
 json.social_image       article_social_image_url(@article)
 json.tag_list           @article.cached_tag_list
-json.tags               @article.cached_tag_list.split(", ")
+json.tags               @article.cached_tag_list_array
 json.slug               @article.slug
 json.path               @article.path
 json.url                @article.url

spec/requests/api/v0/articles_spec.rb

@@ -77,14 +77,15 @@ RSpec.describe "Api::V0::Articles", type: :request do
   end
 
   describe "GET /api/articles/:id" do
+    let(:article) { create(:article) }
+
     it "gets article based on ID" do
-      article = create(:article)
       get "/api/articles/#{article.id}"
-      expect(JSON.parse(response.body)["title"]).to eq(article.title)
+      expect(json_response["title"]).to eq(article.title)
     end
 
     it "fails with an unpublished article" do
-      article = create(:article, published: false)
+      article.update_columns(published: false)
       get "/api/articles/#{article.id}"
       expect(response).to have_http_status(:not_found)
     end
@@ -93,6 +94,11 @@ RSpec.describe "Api::V0::Articles", type: :request do
       get "/api/articles/99999"
       expect(response).to have_http_status(:not_found)
     end
+
+    it "contains tags as an array" do
+      get "/api/articles/#{article.id}"
+      expect(json_response["tags"]).to eq(article.decorate.cached_tag_list_array)
+    end
   end
 
   describe "POST /api/articles" do