test added: tag

app/models/tag.rb

@@ -2,9 +2,8 @@ class Tag < ActiveRecord::Base
   has_many :taggings
   has_many :users, through: :taggings, source: :user
 
-  scope :fetch_list_by_tag_name, -> (tag_name){
+  scope :fetch_list_by_tag_name, -> (tag_name) {
     tag_arel = Tag.arel_table
     where(tag_arel[:tag_name].matches("%#{tag_name}%"))
   }
-
-end
+end

spec/rails_helper.rb

@@ -30,6 +30,17 @@
 
  config.include ShowMeTheCookies, :type => :feature
 
+ config.before(:suite) do
+    DatabaseCleaner.strategy = :transaction
+    DatabaseCleaner.clean_with(:truncation)
+  end
+
+  config.around(:each) do |example|
+    DatabaseCleaner.cleaning do
+      example.run
+    end
+  end
+
   # If you're not using ActiveRecord, or you'd prefer not to run each of your
   # examples within a transaction, remove the following line or assign false
   # instead of true.

spec/unit/models/tag_spec.rb

@@ -0,0 +1,14 @@
+require "rails_helper"
+
+RSpec.describe Tag, :type => :model do
+  describe "#fetch_list_by_tag_name" do
+    it "should fetch tag list where like name" do
+      tag1 = Tag.create!(tag_name: "Hello")
+      tag2 = Tag.create!(tag_name: "World")
+      tag3 = Tag.create!(tag_name: "Yellow")
+
+      expect(Tag.fetch_list_by_tag_name("Worl")).to contain_exactly(tag2)
+      expect(Tag.fetch_list_by_tag_name("llo")).to contain_exactly(tag1, tag3)
+    end
+  end
+end