Extract getting the current list into its own object that is injected

refactoring_external_service/youtube_video_list.rb

@@ -1,4 +1,16 @@
+ class VideoRepo
+    def videos
+      video_list_json = File.read('videos.json')
+      JSON.parse(video_list_json)
+    end
+ end
+
  class VideoService
+    attr_reader :video_repo
+  def initialize(video_repo:)
+    @video_repo = video_repo
+  end
+
   def video_list
     @video_list = get_current_video_list
     ids = @video_list.map{|v| v['youtubeID']}
@@ -16,8 +28,7 @@ def video_list
   private
 
   def get_current_video_list
-    video_list_json = File.read('videos.json')
-    JSON.parse(video_list_json)
+    video_repo.videos
   end
 
   def get_youtube_stats_on_videos(youtube_ids)

refactoring_external_service/youtube_video_list_spec.rb

@@ -4,9 +4,15 @@
 require 'date'
 
 class VideoServiceTest < MiniTest::Test
+
+    class VideoRepoMock
+        def videos
+            [{'youtubeID' => 'blahblahblah', 'views' => 3, 'monthlyViews' => 3}]
+        end
+    end
 
     def test_video_list_returns_video_list
-        video_service = VideoService.new
+        video_service = VideoService.new(video_repo: VideoRepoMock.new)
         video_array = [{'youtubeID' => 'blahblahblah', 'views' => 3, 'monthlyViews' => 3}]
         youtube_response = {'items' => 
                [
@@ -18,15 +24,12 @@ def test_video_list_returns_video_list
                 ]
             }
         video_json = JSON.generate(video_array)
-        video_service.stub(:get_current_video_list, video_array) do
-            video_service.stub(:get_youtube_stats_on_videos, youtube_response) do
-                result = JSON.parse(video_service.video_list)
-                actual = JSON.parse(video_json)
-                assert_equal(result[0]['youtubeID'], result[0]['youtubeID'])
-                assert_equal(result[0]['views'], result[0]['views'])
-                assert_in_delta(result[0]['monthlyViews'], result[0]['monthlyViews'], 0.1)
-            end      
+        video_service.stub(:get_youtube_stats_on_videos, youtube_response) do
+            result = JSON.parse(video_service.video_list)
+            actual = JSON.parse(video_json)
+            assert_equal(result[0]['youtubeID'], result[0]['youtubeID'])
+            assert_equal(result[0]['views'], result[0]['views'])
+            assert_in_delta(result[0]['monthlyViews'], result[0]['monthlyViews'], 0.1)
         end
     end
-
 end