prawn-grouping failing spec

gistfile1.rb

it 'should push question #4 to the second column' do
  pdf = Prawn::Document.new do
    font_size 10
    column_box [0, cursor], columns: 2, width: bounds.width do
      4.times do |i|
        group do
          text "<b>This is question ##{i+1}</b>", inline_format: true
          move_down 10
          5.times do |j|
            text "#{j+1}. Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore"
            move_down 8
          end
          move_down 7
        end
      end
    end
  end
  pdf.render_file 'two_columns.pdf'
end