Able to save all elements of maildeliveryfailure

app/mailers/application_mailer.rb

@@ -15,16 +15,16 @@ class ApplicationMailer < Mail::Notify::Mailer
     #
     # @see https://github.com/rails/rails/issues/39018
     if respond_to?(:headers)
-      recipient_email = headers["To"].value
-      MailDeliveryFailure.create!(recipient_email:)
+      email_address = headers["To"].value
+      mailer_action_method = action_name
+      mailer_class = mailer_name
+      MailDeliveryFailure.create!(email_address:, mailer_action_method:, mailer_class:)
     end
 
     raise
   end
 
   def notify_email(headers)
-    headers =
-      headers.merge(rails_mailer: mailer_name, rails_mail_template: action_name)
     view_mail(GOVUK_NOTIFY_TEMPLATE_ID, headers)
   end
 end

spec/mailers/application_mailer_spec.rb

@@ -27,7 +27,11 @@ def test_notify_error
         Notifications::Client::NotFoundError,
       )
 
-      expect(Email.last.delivery_status).to eql("notify_error")
+      failure = MailDeliveryFailure.last
+      expect(failure).not_to be_nil
+      expect(failure.email_address).to eq("[email protected]")
+      expect(failure.mailer_action_method).to eq("test_notify_error")
+      expect(failure.mailer_class).to eq("anonymous")
     end
   end
 end