From: sl4m <skim.la@...>
Date: 2010-04-01T02:27:54+09:00
Subject: Re: Ruby Koans: will this method ever return :empty?

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Yes it's true, you're suppose to fix the code and/or test, but only if it
has a '__' or a comment indicating to fix something.  In this case, however,
it's asking what the method will return if the method was called with and
without arguments.  Here's the test:

class MessageCatcher
  def add_a_payload(*args)
    return :empty unless args
    args
  end
end

def test_sending_a_message_with_arguments
  mc = MessageCatcher.new

  assert_equal __, mc.add_a_payload
  assert_equal __, mc.send(:add_a_payload)

  assert_equal __, mc.add_a_payload(3, 4, nil, 6)
  assert_equal __, mc.send(:add_a_payload, 3, 4, nil, 6)
end

The return statement will never return :empty in the asserts.  This is what
confused me.  I wanted to know when the method will ever return :empty.  The
test doesn't test that...because it will never return it ;-)


skim

On Wed, Mar 31, 2010 at 09:07, Gennady Bystritsky <
Gennady.Bystritsky@quest.com> wrote:

>
> On Mar 31, 2010, at 8:57 AM, Gennady Bystritsky wrote:
>
> >
> > On Mar 31, 2010, at 8:36 AM, sl4m wrote:
> >
> >> Thanks guys!  It looks like there's a mistake in the koans then.  I'll
> >> report it to the author.  I ran this piece of code over and over on irb,
> but
> >> could not figure it out.
> >
> > Wasn't that the idea behind "koans"? I haven't heard about them until
> your post, however according to
> http://brandon.dimcheff.com/2009/02/05/how-to-learn-ruby.html:
>
> Darn, looks like ":" becomes the part of URL when you click the above link.
> Try just this:
> http://brandon.dimcheff.com/2009/02/05/how-to-learn-ruby.html
>
> >
> > "... The Koans are essentially a series of failing test cases that you
> need to figure out how to fix in order to move on to the next step."
> >
> > From that, my understanding is that a user is supposed to find problems
> in "koans" and fix them. You found one, good going ;-)
> >
> > Regards,
> > Gennady.
> >
> >>
> >>
> >> Cheers,
> >> skim
> >>
> >> On Wed, Mar 31, 2010 at 05:23, Aldric Giacomoni <aldric@trevoke.net>
> wrote:
> >>
> >>> Aldric Giacomoni wrote:
> >>>> Steve Kim wrote:
> >>>
> >>>>> Is it possible to have this method return :empty?
> >>>
> >>>>
> >>>> class MessageCatcher
> >>>> def add_a_payload *args
> >>>>   args.empty? :empty : args
> >>>> end
> >>>> end
> >>>>
> >>>> args.empty? [:empty] : args
> >>>>
> >>>
> >>> I'd appreciate it if no one mentioned that I forgot the '?' twice! I am
> >>> so ashamed.
> >>>
> >>> args.empty? ? :empty : args
> >>> args.empty? ? [:empty] : args
> >>> --
> >>> Posted via http://www.ruby-forum.com/.
> >>>
> >>>
> >
> >
>
>
>

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