[SOLVED] Set locale via default_url_options for Rails tests (Rails 6 and newer)

Set locale via default_url_options for Rails tests (Rails 6 and newer)

Is there a reliable way to set the locale via default_url_options for Rails tests (controller and system tests) globally, without having to pass the locale manually to url helpers?

Prior to Rails 6.0.1, this used to work:

# Set locale via default_url_options
class ActionDispatch::Routing::RouteSet
  def default_url_options(options = {})
    { locale: I18n.locale }.merge options
  end
end

Solution

It's still tricky to get this right in Rails 7, but fortunately much more straightforward compared to Rails 6.

It can be done by adding this line in config/environments/test.rb:

Rails.application.routes.default_url_options[:locale] = I18n.default_locale

Or by adding this in test_helper.rb:

class ActiveSupport::TestCase
  setup do
    Rails.application.routes.default_url_options[:locale] = I18n.default_locale
  end

However, neither of the above solutions solve the issue for system tests. To address that, add this into application_system_test_case.rb:

class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
  ...

  setup do
    default_url_options[:locale] = I18n.default_locale
  end