class ParallelTests::Test::RuntimeLogger

def unique_log
  lock do
    separator = "\n"
    groups = File.read(logfile).split(separator).map { |line| line.split(":") }.group_by(&:first)
    lines = groups.map { |file, times| "#{file}:#{times.map(&:last).map(&:to_f).inject(:+)}" }
    File.write(logfile, lines.join(separator) + separator)
  end
end