Fix tests

spec/factories/widgets.rb

@@ -8,6 +8,7 @@ FactoryGirl.define do
     order 1
     type 'formula'
     title 'The Title'
+    source_id 'a0'
     options do
       {
         type: "formula",

spec/requests/carto/api/widgets_controller_spec.rb

@@ -69,7 +69,7 @@ shared_context 'layer hierarchy' do
     title: 'the title',
     options: { 'a field' => 'first', 'another field' => 'second' },
     order: nil,
-    source: nil,
+    source: { id: 'a0' },
     style: { 'widget_style': { 'fill': 'wadus' } })
 
     payload = {
@@ -230,6 +230,12 @@ describe Carto::Api::WidgetsController do
       other_map.destroy
     end
 
+    it 'returns 422 if missing source' do
+      post_json widgets_url(user_domain: @user1.username, map_id: @map.id, map_layer_id: @widget.layer_id, api_key: @user1.api_key), widget_payload(source: nil), http_json_headers do |response|
+        response.status.should == 422
+      end
+    end
+
     it 'returns 403 if visualization is private and current user is not the owner' do
       post_json widgets_url(user_domain: @user2.username, map_id: @map.id, map_layer_id: @widget.layer_id, api_key: @user2.api_key), widget_payload, http_json_headers do |response|
         response.status.should == 403