Add API for App Index

- Add tests for unauthorised response for APIs which require authentication

spec/controllers/apps_controller_spec.rb

@@ -0,0 +1,26 @@
+require 'rails_helper'
+
+RSpec.describe AppsController, type: :controller do
+  context "With Authentication" do
+    let(:device){create(:device)}
+    before(:each) do
+      request.env['HTTP_AUTHORIZATION'] = ActionController::HttpAuthentication::Token.encode_credentials(device.access_token)
+    end
+    it "#index" do
+      expect(App).to receive(:all)
+      
+      get :index,  format: :json
+      
+      expect(response).to have_http_status(:ok)
+    end
+  end
+  context "Without Authentication" do
+    it "#index" do
+      get :index,  format: :json
+      
+      expect(response).to have_http_status(:unauthorized)
+    end
+  end
+end
+
+