class Test::Unit::Diff::SequenceMatcher

def grouped_operations(context_size=nil)
  context_size ||= 3
  _operations = operations.dup
  _operations = [[:equal, 0, 0, 0, 0]] if _operations.empty?
  expand_edge_equal_operations!(_operations, context_size)
  group_window = context_size * 2
  groups = []
  group = []
  _operations.each do |tag, from_start, from_end, to_start, to_end|
    if tag == :equal and from_end - from_start > group_window
      group << [tag,
                from_start,
                [from_end, from_start + context_size].min,
                to_start,
                [to_end, to_start + context_size].min]
      groups << group
      group = []
      from_start = [from_start, from_end - context_size].max
      to_start = [to_start, to_end - context_size].max
    end
    group << [tag, from_start, from_end, to_start, to_end]
  end
  groups << group unless group.empty?
  groups
end