module Minitest::Assertions

def assert_throws sym, msg = nil
  default = "Expected #{mu_pp(sym)} to have been thrown"
  caught = true
  catch(sym) do
    begin
      yield
    rescue ThreadError => e       # wtf?!? 1.8 + threads == suck
      default += ", not \:#{e.message[/uncaught throw \`(\w+?)\'/, 1]}"
    rescue ArgumentError => e     # 1.9 exception
      default += ", not #{e.message.split(/ /).last}"
    rescue NameError => e         # 1.8 exception
      default += ", not #{e.name.inspect}"
    end
    caught = false
  end
  assert caught, message(msg) { default }
end