investigation

# File lib/rake/task.rb, line 314
    def investigation
      result = "------------------------------\n"
      result << "Investigating #{name}\n"
      result << "class: #{self.class}\n"
      result <<  "task needed: #{needed?}\n"
      result <<  "timestamp: #{timestamp}\n"
      result << "pre-requisites: \n"
      prereqs = prerequisite_tasks
      prereqs.sort! { |a, b| a.timestamp <=> b.timestamp }
      prereqs.each do |p|
        result << "--#{p.name} (#{p.timestamp})\n"
      end
      latest_prereq = prerequisite_tasks.map { |pre| pre.timestamp }.max
      result <<  "latest-prerequisite time: #{latest_prereq}\n"
      result << "................................\n\n"
      return result
    end