From: Josh Cheek <josh.cheek@...>
Date: 2010-11-05T02:31:18+09:00
Subject: Re: true! or false!

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On Thu, Nov 4, 2010 at 5:55 AM, Intransition <transfire@gmail.com> wrote:

> Making good use of polymorphism I had this idea for assertion methods:
>
>  class TrueClass
>    # Assert true.
>    #
>    #   (x == y).true!
>    #
>    def true!
>      true
>    end
>    # Assert false.
>    #
>    #   (x == y).false!
>    #
>    def false!
>      raise "not false!"
>    end
>  end
>
>  class FalseClass
>    # Assert true.
>    #
>    #   (x == y).true!
>    #
>    def true!
>      raise "not true!"
>    end
>    # Assert false.
>    #
>    #   (x == y).false!
>    #
>    def false!
>      true
>    end
>  end
>
> If only the error message could say something about WHAT was not true
> or false, this could be pretty nifty.
>
>
You would need to override at a higher level, I think, because I frequently
use object/nil instead of true/false.

require 'test/unit'

class Object
  def true!   ;  self || raise("not true!")   ;  end
  def false!  ;  self && raise("not false!")  ;  end
end

class TrueBangFalseBang < Test::Unit::TestCase
  def test_object       ;  [1,2,3][2].true!   ;  end
  def test_non_object   ;  [1,2,3][3].false!  ;  end
  def test_true         ;  (1==1).true!       ;  end
  def test_false        ;  (1==2).false!      ;  end
end


I like it, except that it doesn't count these as assertions. Even if you mix
the assertions module into object and use the assert methods, like this:

class Object
  include Test::Unit::Assertions
  def true!   ;  assert self   ;  end
  def false!  ;  assert !self  ;  end
end

You would get results like "4 tests, 0 assertions, 2 failures", maybe if you
look even further under the hood you could figure out how to get them to
count. Or just choose to not care, but for me, that is a number I like to
see :)

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