filter

# File lib/minitest/unit.rb, line 47
    def filter bt
      return ["No backtrace"] unless bt

      new_bt = []

      unless $DEBUG then
        bt.each do |line|
          break if line =~ /lib\/minitest/
          new_bt << line
        end

        new_bt = bt.reject { |line| line =~ /lib\/minitest/ } if new_bt.empty?
        new_bt = bt.dup if new_bt.empty?
      else
        new_bt = bt.dup
      end

      new_bt
    end