Cover #distributed_properties \w a controller spec

This exercises the controller and the serializer ensuring the
integration works allowing to confidently refactor things further.

spec/controllers/shops_controller_spec.rb

@@ -15,4 +15,25 @@ describe ShopsController, type: :controller do
     get :index
     expect(response.body).to have_content(invisible_distributor.name)
   end
+
+  it 'renders distributed properties' do
+    duplicate_property = create(:property, presentation: 'dairy')
+    producer = create(:supplier_enterprise, properties: [duplicate_property])
+    property = create(:property, presentation: 'dairy')
+    product = create(:product, properties: [property])
+    producer.supplied_products << product
+
+    create(
+      :simple_order_cycle,
+      coordinator: distributor,
+      suppliers: [producer],
+      distributors: [distributor],
+      variants: [product.variants]
+    )
+
+    get :index
+
+    expect(response.body)
+      .to match(/"distributed_properties":\[{"id":\d+,"name":"dairy","presentation":"dairy"}\]/)
+  end
 end