checkout_spec.rb

  # find a cell based on the _exact_ text in the column, and a row that
  # _contains_ the row text.
  def within_cell column, row
    col_eq = "text()='#{column}'"
    col_index = "count(//table//td[#{col_eq}]/preceding-sibling::*) + 1"
    row_matches = "..//td/text()[contains(., '#{row}')]"
    within(:xpath, "//table//td[#{col_index}][#{row_matches}]") { yield }
  end

look up a cell in table with xpath