Add host option to with_request_url test helper

[pbstriker38]

• This allows testing components that use path helpers that are constrained by a subdomain in routes.rb.

What are you trying to accomplish?

We have routes that are constrained by a subdomain in our routes file. If the requests host does not match the constraint then a ActionController::RoutingError: No route matches "..." is raised.

config/routes.rb

Rails.application.routes.draw do
  constraints subdomain: 'app' do
    resources: :products
  end
end

[joelhawksley]

👏🏻 thanks for the clean PR!