Is this evil?

possibly_evil.rb

describe Something do
  before do
    @mock_view = mock("rails view")
    proc_thing = @mock_view.stub(:content_tag).with(:span).and_return("<span></span>")
    @mock_view.stub(:content_tag).with(:div).and_yield.and_return("<div>#{proc_thing.call}</div>")
  end

  it "should return a span inside a div" do
    Something.new(@mock_view).render_custom_block.should match /\<div\>\<span\>\<\\span\>\<\\div\>/
  end
end

class Something
  def initialize(view)
    @view = view
  end
  def render_custom_block
    @view.content_tag :div do
      @view.content_tag :span
    end
  end
end