From: Robert Klemme <shortcutter@...>
Date: 2006-10-31T05:10:17+09:00
Subject: Re: __FILE__ for requiring file

Jim Freeze wrote:
> Hello
> 
> I keep wondering if there is a way to have __FILE__ be delayed
> in its evaluation. For example, in my tests cases, I usually do the
> following so that my test cases are imune to where they are run from:
> 
> class TestMyClass < Test::Unit::TestCase
> 
>  TEST_DIR = File.dirname(__FILE__)
>  DATA_DIR = File.join(TEST_DIR, "data")
> 
>  def data_file(file)
>    File.join(DATA_DIR, file)
>  end
> 
>  def test_xyz
>    open(data_file("fred"))
>    assert ...
>  end
> end
> 
> The problem is I have to add this to every test case since I can't put
> data_file inside a module and include it without also having o define
> TEST_DIR as a constant of Object inside every testcase.
> 
> In other words, I don't want to do:
> 
> TEST_DIR = File.dirname(__FILE__)
> class TestMyClass < Test::Unit::TestCase
>  require 'test_helper'
>  include TestHelper
>  TestHelper.init __FILE__
> end
> 
> This just seems a bit verbose.
> 
> I guess what I need is something like:  __REQUIRING_FILE__
> so my TestHelper module could be written as:
> 
> module TestHelper
>  TEST_DIR = File.dirname(__REQUIRING_FILE__)
>  DATA_DIR = ...as above
> end
> 
> Has anyone ever needed such a thing? Is there a better way of solving
> this problem?
> 
> Thanks

Untested - just sketching ideas:

mytest.rb:

require 'test/unit'

class TC < Test::Unit::TestCase
   def open_data(f,&b)
     File.open(File.join(get_dir, f), &b)
   end

   def get_dir
     x = caller(2).shift
     if /^(.*):\d+:in / =~ x
       File.dirname $1
     else
       raise "Whatever"
     end
   end
end


your_test.rb:

class TestFoo < TC
   def test_x
     open_data("foo") do |io|
       io.each_line ...
     end
   end
end

	robert