layer at (0,0) size 800x600
  RenderView at (0,0) size 800x600
layer at (0,0) size 800x50
  RenderBlock {test} at (0,0) size 800x50
    RenderBlock {p} at (0,16) size 800x18
      RenderText {#text} at (0,0) size 503x18
        text run at (0,0) width 503: "Try selecting some text in this document. It should be have a green background."