[rails] RSpec matchers for render(:nothing => true)

This is matchers for render(:nothing => true).

Add some code into spec/spec_helper.rb is as follows:

# Matchers for render(:nothing => true)
class RenderNothing
  def initialize
  end

  def matches?(controller)
    @actual = controller.rendered_file
    @actual == nil
  end

  def failure_message
    return "render_nothing expected (render :nothing => true), got #{@actual.inspect}"
  end

  def negative_failure_message
    return "render_nothing expected (render :nothing => true) not to equal #{@actual.inspect}"
  end
end

def render_nothing
  RenderNothing.new
end

Use render_nothing.

it "should not render anything" do
  post :destroy, :id => 1
  response.should render_nothing
end