From: Ryan Davis <ryand-ruby@...>
Date: 2012-09-08T06:19:04+09:00
Subject: Re: assert All lines


On Sep 7, 2012, at 05:43 , Mario Ruiz <lists@ruby-forum.com> wrote:

> Hi,
> I'm trying to create a method to assert all lines and if any of them
> fail then the whole block will fail
> require 'test/unit'
> 
>    def assert_all(message="assert_block failed.") # :yields:
>        _wrap_assertion do
>          if (!yield)
>            puts "ERROR"
>            raise Test::Unit::AssertionFailedError.new(message.to_s)
>          else
>            puts "PERFECT"
>          end
>        end
>      end
> 
> class MyTest < Test::Unit::TestCase
>  def test01
>    assert_all {
>      1==1
>      2==3
>      3==3
>    }
>  end
> end

Switch {} to () and add commas:

def assert_all(message, *exprs)
  exprs.each_with_index do |expr, i|
    assert expr, "Failed on #{i+1}: #{message}"
  end
end

I know you're trying to make this as succinct and clean as possible, but there is no way to individually evaluate each expression w/o some seriously heinous "magic". This alternative tries to balance out the magic vs the syntax.

I also removed the optional message argument for a mandatory one so you don't have to try to distinguish between a message and the first assertion. The alternative to that is to pass in a hash with expr => message, but that starts to get gross too.