Adding a `within_cell` Capybara helper. We use this within our Turnip specs to find a particular cell within a particular column within a table.

table_steps.rb

def within_cell(row, column)
  within_row(row) do
    within_column(column) { yield }
  end
end

def within_column(column)
  # Find the table column offset for the column header, then grab the columns' cells at that offset.
  # Adapted from http://stackoverflow.com/questions/14745478
  within(:xpath, "//table/tbody/tr/td[count(//table/thead/tr/th[normalize-space()='#{column}']/preceding-sibling::th)+1]") do
    yield
  end
end

def within_row(name)
  within(:xpath, "//tr[td='#{name}']") { yield }
end