deliver_later for controller actions.

test/controllers/admin/user_controller_test.rb

@@ -3,6 +3,8 @@ require 'test_helper'
 
 module Admin
   class UserControllerTest < ActionDispatch::IntegrationTest
+    include ActiveJob::TestHelper
+
     def setup
       post admin_auth_url, params: { auth:
           { email: 'alan.admin@mailinator.com', password: 'password' } }
@@ -29,7 +31,7 @@ module Admin
     end
 
     test "should post create" do
-      assert_difference("ActionMailer::Base.deliveries.size", 1) do
+      assert_enqueued_jobs 1 do
         assert_difference("User.count", 1) do
           post admin_create_user_url, params: { user:
               { email: 'new.user@mailinator.com', name: 'New User', role: 'reviewer' } }