You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: user_mailer_test.rb
    path of file: ./repos/openstreetmap-website/test/mailers
    
    the code of the file until where you have to start completion: require "test_helper"

class UserMailerTest < ActionMailer::TestCase
  def test_html_layout_is_used
    email = UserMailer.message_notification(create(:message))

    assert_match(/<html lan
    
  def test_gpx_success_trace_link
    trace = create(:trace)
    email = UserMailer.gpx_success(trace, 100)
    body = Rails::Dom::Testing.html_document_fragment.parse(email.html_part.body)

    url = Rails.application.routes.url_helpers.show_trace_url(trace.user, trace, :host => Settings.server_url, :protocol => Settings.server_protocol)
    assert_select body, "a[href='#{url}']", :text => trace.name
  end