module ActiveSupport::Testing::Isolation::Forking

def run_in_isolation(&blk)
  IO.pipe do |read, write|
    read.binmode
    write.binmode
    pid = fork do
      read.close
      yield
      begin
        if error?
          failures.map! { |e|
            begin
              Marshal.dump e
              e
            rescue TypeError
              ex = Exception.new e.message
              ex.set_backtrace e.backtrace
              Minitest::UnexpectedError.new ex
            end
          }
        end
        test_result = defined?(Minitest::Result) ? Minitest::Result.from(self) : dup
        result = Marshal.dump(test_result)
      end
      write.puts [result].pack("m")
      exit!
    end
    write.close
    result = read.read
    Process.wait2(pid)
    result.unpack1("m")
  end
end