assert_throws

# File lib/minitest/unit.rb, line 434
    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