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_preferences_controller_test.rb
    path of file: ./repos/openstreetmap-website/test/controllers/api
    
    the code of the file until where you have to start completion: require "test_helper"

module Api
  class UserPreferencesControllerTest < ActionDispatch::IntegrationTest
    ##
    # test all routes which lead to this controller
    def test_routes
      assert_routing(
        { :path => "/api/0.6/user/
    
    def test_update_all
      user = create(:user)
      create(:user_preference, :user => user, :k => "key", :v => "value")
      create(:user_preference, :user => user, :k => "some_key", :v => "some_value")

      # try a put without auth
      assert_no_difference "UserPreference.count" do
        put user_preferences_path, :params => "<osm><preferences><preference k='key' v='new_value'/><preference k='new_key' v='value'/></preferences></osm>"
      end
      assert_response :unauthorized, "should be authenticated"
      assert_equal "value", UserPreference.find([user.id, "key"]).v
      assert_equal "some_value", UserPreference.find([user.id, "some_key"]).v
      assert_raises ActiveRecord::RecordNotFound do
        UserPreference.find([user.id, "new_key"])
      end

      # authenticate as a user with preferences
      auth_header = basic_authorization_header user.email, "test"

      # try the put again
      assert_no_difference "UserPreference.count" do
        put user_preferences_path, :params => "<osm><preferences><preference k='key' v='new_value'/><preference k='new_key' v='value'/></preferences></osm>", :headers => auth_header
      end
      assert_response :success
      assert_equal "text/plain", @response.media_type
      assert_equal "", @response.body
      assert_equal "new_value", UserPreference.find([user.id, "key"]).v
      assert_equal "value", UserPreference.find([user.id, "new_key"]).v
      assert_raises ActiveRecord::RecordNotFound do
        UserPreference.find([user.id, "some_key"])
      end

      # try a put with duplicate keys
      assert_no_difference "UserPreference.count" do
        put user_preferences_path, :params => "<osm><preferences><preference k='key' v='value'/><preference k='key' v='newer_value'/></preferences></osm>", :headers => auth_header
      end
      assert_response :bad_request
      assert_equal "text/plain", @response.media_type
      assert_equal "Duplicate preferences with key key", @response.body
      assert_equal "new_value", UserPreference.find([user.id, "key"]).v

      # try a put with invalid content
      assert_no_difference "UserPreference.count" do
        put user_preferences_path, :params => "nonsense", :headers => auth_header
      end
      assert_response :bad_request
    end