add posts scope filter

spec/requests/posts_spec.rb

@@ -1,17 +1,5 @@
 require 'rails_helper'
 
-# This spec was generated by rspec-rails when you ran the scaffold generator.
-# It demonstrates how one might use RSpec to test the controller code that
-# was generated by Rails when you ran the scaffold generator.
-#
-# It assumes that the implementation code is generated by the rails scaffold
-# generator. If you are using any extension libraries to generate different
-# controller code, this generated spec may or may not pass.
-#
-# It only uses APIs available in rails and/or rspec-rails. There are a number
-# of tools you can use to make these specs even more expressive, but we're
-# sticking to rails and rspec-rails APIs to keep things simple and stable.
-
 RSpec.describe "/posts", type: :request do
   let(:user) { create(:user) }
 
@@ -27,10 +15,6 @@ RSpec.describe "/posts", type: :request do
     }
   }
 
-  # This should return the minimal set of values that should be in the headers
-  # in order to pass any filters (e.g. authentication) defined in
-  # PostsController, or in your router and rack
-  # middleware. Be sure to keep this updated too.
   let(:valid_headers) {
     {
       Cookie: "user_id=#{user.id}"

spec/services/posts_query_resolver_serivce_spec.rb

@@ -0,0 +1,37 @@
+require 'rails_helper'
+
+RSpec.describe PostsQueryResolverService, type: :service do
+  context '#call' do
+    let(:current_user) { create(:user) }
+
+    context 'when without filter' do
+      it 'returns all posts' do
+        followed_user = create(:user)
+        create(:user_follow, follower_id: current_user.id, followed_id: followed_user.id)
+
+        post1 = create(:post, user_id: followed_user.id)
+        post2 = create(:post, user_id: followed_user.id)
+        post3 = create(:post)
+
+        expect(
+          described_class.call({}, current_user)
+        ).to eq([post1, post2, post3])
+      end
+    end
+
+    context 'when scoping by user follows' do
+      it 'returns only posts from user follows' do
+        followed_user = create(:user)
+        create(:user_follow, follower_id: current_user.id, followed_id: followed_user.id)
+
+        post1 = create(:post, user_id: followed_user.id)
+        post2 = create(:post, user_id: followed_user.id)
+        post3 = create(:post)
+
+        expect(
+          described_class.call({ scope: 'follows' }, current_user)
+        ).to eq([post1, post2])
+      end
+    end
+  end
+end