Index: test_helper.rb
===================================================================
--- test_helper.rb	(revision 19489)
+++ test_helper.rb	(working copy)
@@ -368,6 +368,12 @@
   end
 
   class IntegrationTest < ActionDispatch::IntegrationTest
+    def setup
+      # https://github.com/rails/rails/issues/37270
+      ActionMailer::MailDeliveryJob.disable_test_adapter
+      super
+    end
+
     def log_user(login, password)
       User.anonymous
       get "/login"