def investigation
result = "------------------------------\n".dup
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(&:timestamp).max
result << "latest-prerequisite time: #{latest_prereq}\n"
result << "................................\n\n"
return result
end