module RSpec::Rails::ViewSpecMethods

def add_to(klass)
  return if klass.method_defined?(:extra_params) && klass.method_defined?(:extra_params=)
  klass.module_exec do
    # Set any extra parameters that rendering a URL for this view
    # would require.
    #
    # @example
    #
    #     # In "spec/views/widgets/show.html.erb_spec.rb":
    #     before do
    #       widget = Widget.create!(:name => "slicer")
    #       controller.extra_params = { :id => widget.id }
    #     end
    def extra_params=(hash)
      @extra_params = hash
      request.path =
        ViewPathBuilder.new(::Rails.application.routes).path_for(
          extra_params.merge(request.path_parameters)
        )
    end
    # Use to read extra parameters that are set in the view spec.
    #
    # @example
    #
    #     # After the before in the above example:
    #     controller.extra_params
    #     # => { :id => 4 }
    def extra_params
      @extra_params ||= {}
      @extra_params.dup.freeze
    end
  end
end