Merge pull request #4882 from Matt-Yorkley/3-0-api-with-nil-id

[Spree 2.1] Fix spec setup in api/orders_controller_spec

spec/controllers/api/orders_controller_spec.rb

@@ -165,7 +165,7 @@ module Api
         before { allow(controller).to receive(:spree_current_user) { admin_user } }
 
         it "when no order number is given" do
-          get :show, id: nil
+          get :show, id: ""
           expect(response).to have_http_status(:not_found)
         end