class ParallelTests::RuntimeLogger

def self.log(test, start_time, end_time)
  return if test.is_a? Test::Unit::TestSuite  # don't log for suites-of-suites
  if !@@has_started # make empty log file 
    File.open(ParallelTests.runtime_log, 'w') do end
    @@has_started = true
  end
  File.open(ParallelTests.runtime_log, 'a') do |output|
    begin
      output.flock File::LOCK_EX
      output.puts(self.message(test, start_time, end_time))
    ensure
      output.flock File::LOCK_UN
    end
  end
end