Calls render method directly in Rails

action_view_render_method_from_anywhere.md

http://blog.nishimu.land/entry/2013/09/18/234044

• Rails v5.0.5

helper = ActionView::Base.new
helper.lookup_context.view_paths << Rails.root.join("app/views")
  
# e.g.) app/views/shared/post_elements/heading/_heading.html.haml
helper.render(
  partial: "shared/post_elements/heading/heading",
  locals: {
    post: post,
    post_element: post_element,
  }
)
#=> <String>