# File lib/rake.rb, line 231
231:     def investigation
232:       result = "------------------------------\n"
233:       result << "Investigating #{name}\n" 
234:       result << "class: #{self.class}\n"
235:       result <<  "task needed: #{needed?}\n"
236:       result <<  "timestamp: #{timestamp}\n"
237:       result << "pre-requisites: \n"
238:       prereqs = @prerequisites.collect {|name| Rake::Task[name]}
239:       prereqs.sort! {|a,b| a.timestamp <=> b.timestamp}
240:       prereqs.each do |p|
241:         result << "--#{p.name} (#{p.timestamp})\n"
242:       end
243:       latest_prereq = @prerequisites.collect{|n| Rake::Task[n].timestamp}.max
244:       result <<  "latest-prerequisite time: #{latest_prereq}\n"
245:       result << "................................\n\n"
246:       return result
247:     end